111-C5 b

COLD REGIONS SCIENCE AND ENGINEERING Monograph 111 - C 5 b

" and disposal IN COLD REGIONS^

.3" Amos J. Alter

i Octp*be-r 1969,/

2. CORPS OF ENGINEERS, U.S. ARMY OLD REGIONS RESEARCH/NDJNGINEERiNG LABORATORY HANOVER, NEW HAMPSHIRE 3

THIS DOCUMENT HAS BEEN APPROVED FOR PUBLIC RELEASE AND SALE; ITS DISTRIBUTION IS UNLIMITED. ■■5V

m i t 1 0 7 0 -n of Recia«ia**efl D e n v e r , Cofora«

The findings in this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.

Destroy this report when no longer needed. Do not return it to the originator. BUREAU OF RECLAMATION DENVER LIBRARY 92098615

92098615

SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS Amos J. Alter

October 1969

DA PROJECT 1T062112A130 CORPS OF ENGINEERS, U.S. ARMY COLD REGIONS RESEARCH AND ENGINEERING LABORATORY HANOVER, NEW HAMPSHIRE

THIS DOCUMENT HAS BEEN APPROVED FOR PUBLIC RELEASE AND SALE; ITS DISTRIBUTION IS UNLIMITED. 11

PREFACE

This monograph was prepared by Mr. Amos J. Alter under contract with the U.S. Army Cold Regions Research and Engineering Laboratory. The author was for many years the Chief Engineer of the Department of Health and Welfare, Division of Public Health, of the State of Alaska and is eminently qualified to summarize existing knowledge with an extensive bibliography in the subject of Sewerage and Sewage Dis­ posal in Cold Regions. The work supplements information available in standard works of reference in the subject. This monograph was published under DA Project 1T062112A130, Cold Regions Research. Permission has been obtained for the use of copyrighted material. Ill

CONTENTS Page Preface...... • ...... ii Editor’s foreword., ...... • •... vii Introduction...... 1 Practice and problems ...... 2 Sewerage and sewage disposal in cold regions...... 2 Magnitude of temperature effects...... 4 General requirements...... 5 Sewage characteristics...... 5 Health and welfare implications ...... 7 Waste salvage and ultimate disposal ...... 13 Present practice...... 15 Summary...... 21 Collection and transport ...... 22 Wet collection and transport system s...... 22 Dry collection and transport systems ...... 28 Collection and disposal at point of generation ...... 31 Physical treatment and processing...... 32 Conditioning processes...... 32 Treatment processes...... 33 Disposal methods...... 37 Chemical application...... 41 Conditioning processes...... 41 Treatment processes...... 42 Disposal methods...... 44 Biological processes ...... 45 Dispersal to the environment...... 45 Aerobic processes ...... • • 45 Anaerobic processes...... - ...... 54 Utilization of super-species...... 58 Thermology ...... 59 Heat losses create system s tre s s ...... • • • • • ••••••• 59 Concepts for protection of sewage works facilities...... 60 Low temperature as a resource ...... 61 Thermal analysis of collection and transport works...... 61 Thermal analysis of basic treatment w orks...... 66 Salvage and utilization of waste h eat...... 70 Reuse and regenerative processes...... 71 Unit processes utilized...... 71 Partial reclamation ...... 71 Construction and operation...... 75 Collection and transport...... 75 Processing units ...... 75 Weather protection and enclosure ...... 75 Paints and protective coatings ...... 75 Safety requirements...... 76 Summary...... 77 Selected bibliography...... 78 Appendix A: North Dakota standards for the design of small waste stabilization ...... 39 IV

CONTENTS (cont’d) Page Appendix B: Criteria for evaluation of cold region sewage works equipment and devices...... 93 Appendix C: Characteristics of sewer pipe...... 95 Appendix D: Ventilation and air conditioning in sanitary engineering in cold environments...... 97 Appendix E: Management of solid wastes...... 101 Appendix F: Classification of wastes and incinerators ...... 105

ILLUSTRATIONS Figure 1. Indiscriminate disposal of wastes near an arctic community ...... 3 2. Dogs may be a link in spread of disease as a result of improper waste disposal...... 3 3. Experimental plant, USA CRREL, Alaska Field Station, Fairbanks, Alaska ...... 4 4. Diurnal fluctuations in dissolved at different latitudes during summer...... 6 5. Dissolved in distilled water exposed to 20.9% oxygen gas at various temperatures and pressures ...... 6 6. Saturation values of dissolved oxygen at given temperature and pressure 7 7. Normally anticipated variations in rate of flow of domestic sewage from a small residential area during a typical 24-hour cycle...... 8 8. Approximate mean annual ain temperatures in Alaska ...... 12 9. Approximate minimum recorded temperatures in Alaska...... 12 10. Approximate mean annual ground temperatures in A laska...... 13 11. The c y c le ...... 13 12. Influence of temperature upon the nitrogen content of s o ils ...... 14 13. Abundance of in at different seasons of the year ...... 14 14. Salt water collection and transport system ...... 22 15. Adjustable vertical alignment support for sewer in permafrost that be­ comes unstable upon thawing ...... 23 16. Air gap installation, Fairbanks, Alaska...... 24 17. Diagram of typical single household recirculating system...... 24 18. Single line siphon ...... 25 19. Conventional pumping station design...... 26 20. Two story pumping station ...... 27 21. Pumping station with enclosed storage tank in a single chamber ...... 27 22. Pumping station with enclosed storage tank in a single chamber ...... 28 23. Recirculating synthetic-flushing-fluid system/fluid lighter than water. . . 29 24. Recirculating synthetic-flushing-fluid system, fluid heavier than water .. 29 25. Various arrangements for reuse of synthetic flushing fludd ...... 29 26. Diagram of recirculating water-flush system with treatment ...... t ...... 30 27. Continuous sewage treatment system flow diagram ...... 33 28. Section through continuous unit ...... 33 29. Circular-plain sedimentation tank T...... 34 30. Rectangular-plain sedimentation tank...... 34 31. Theoretical relation of hydraulic subsiding values to temperature ...... 34 CONTENTS (coat’d)

ILLUSTRATIONS (coat’d) Figure Page 32. The foaming process ...... 35 33. incinerator ...... 38 34. Wet combustion ...... 39 35. Solubility of chlorine in water ...... 43 36. Flushing type chemical ...... 44 37. Typical waste stabilization ...... 47 38. Waste stabilization pond at Ft. Yukon, Alaska ...... 47 39. A standard type biological filter ...... 48 40. process ...... 48 41. Modifications of the biological filter ...... 49 42. Diagram of controlled filtration process ...... 50 43. Activated system ...... 50 44. Activated aeration...... 52 45. Extended aeration system ...... 53 46. sewage disposal system ...... 54 47. ...... 55 48. Diagram of anaerobic contact p ro c e ss...... 56 49. Relation of digestion tank capacities to mean sludge temperature ... 57 50. Circblation diagram of gas and oil burning heat exchanger system .. 57 51. Temperature difference between any two points under consideration . 63 52. Temperature drop of flowing water in a pipeline ...... 64 53. Example of a closed ecological system ...... •...... 71 54. Moving bed treatment process ...... 72

TABLES Table L 1966 average residential usage of electrical energy...... 8 II. Approximate volume of domestic sewage generated at selected cold re­ gion installations ...... ------•. 9 III. Approximate flow and strength of domestic sewage for various places 9 IV. standards for waters within the state of Alaska, 1967 .. 10 V. Approximate monthly mean ground and air temperatures at certain points in the arctic permafrost area ...... 16 VI. Approximate monthly average temperature of naw sewage at the treatment plant. , ...... 17 VII. Examples of sewage treatment facilities in use in northern regions ... 17 VHI. Characteristics of selected stabilization in North Dakota serving communities of one hundred or more population ...... 18 IX. Characteristics of selected stabilization ponds in South Dakota serving communities of one hundred or more population ...... 19 X. Adequacy of waste collection methods ...... 31 XI. Percentage of year that is daylight and twilight at different latitudes . 46 XII. Relation of air characteristics and temperatures ...... 51 XIII. Approximate number of days annually that the maximum temperature is 32F or less for various Alaska communities...... 66 vi

CONTENTS (cont’d)

TABLES (cont’d) Table Page XIV- Sphericity factors for commonly used sanitary engineering structures .. 66 XV- Typical overall heat transfer coefficients for various structures in sanitary engineering...... 67 XVI. Typical overall heat transfer coefficients for common hot water coils immersed in fluid ...... 67 XVII. Coefficients of thermal conductivity for various soils ...... 68 XVIII. Coefficients of thermal conductivity of various fluids and solids ..... 68 vii

EDITOR’S FOREWORD

Cold Regions Science and Engineering consists of a series of monographs written by specialists to summarize existing knowledge and provide selected references on the cold regions, defined here as those areas of the earth where operational difficulties due to freezing tempera­ tures may occur. Sections of the work are being published as they become ready, not necessarily in numeri­ cal order but fitting into this plan, which may be amended as the work proceeds:

I. Environment A. General - Characteristics of the cold regions 1. Selected aspects of geology and physiography of the cold regions 2. Permafrost (Perennially frozen ground) 3. Climatology a. Climatology of the cold regions. Introduction, and Northern Hemisphere I. b. Climatology of the cold re gions. Northern Hemisphere, II. c. Climatology of the cold regions. Southern Hemisphere. d. Radioactive fallout in northern regions. 4. Vegetation a. Patterns of vegetation in cold regions b. Regional descriptions of vegetation in cold regions c. Utilization of vegetation in cold regions B. Regional 1. The Antarctic ice sheet 2. The Greenland ice sheet n. Physical Science A. Geophysics 1. Heat exchange at the ground surface 2. Exploration geophysics in cold regions a. Seismic exploration in cold regions b. Electrical, magnetic and gravimetric exploration in cold regions B. Physics and mechanics of snow as a material C. Physics and mechanics of ice 1. Snow and ice on the earth’s surface 2. Ice as a material a. Physics of ice as a material b. Mechanics of ice as a material 3. The mechanical properties of sea ice 4. Mechanics of a floating ice sheet viii EDITOR’S FOREWORD (Cont’d)

D. Physics and mechanics of frozen ground 1. The freezing process and mechanics of frozen ground 2. The physics of water and ice in

ID. Engineering A. Snow engineering 1. Properties of snow 2. Construction a. Methods of building on permanent snowfields b. Investigation and exploitation of snowfield sites c. Foundations and subsurface structures in snow d. Utilities on permanent snowfields e. Snow roads and runways 3. Technology a. Explosions and snow b. Snow removal and ice control c. Blowing snow d. Avalanches 4. Oversnow transport B. Ice engineering 1. -ice engineering a. Winter regime of and b. Ice pressure on structures 2. Drilling and excavation in ice 3. Roads and runways bn ice C. Frozen ground engineering 1. Site exploration and excavation in frozen ground 2. Buildings on frozen ground 3. Roads, railroads and airfields in cold regions 4. Foundations of structures in cold regions 5. Sanitary engineering a. Water supply in cold regions b. Sewerage, and sewage disposal in cold regions c. Management of solid wastes in cold regions 6. Artificial ground-freezing for construction D. General 1. Cold-weather construction 2. Materials at low temperatures 3. Icings SEWERAGE AND SEWAGE DISPOSAL IN GOLD REGIONS

by Amos J. Alter

INTRODUCTION

This manual is an updated revision of Arctic Sanitary Engineering - Sewage Disposal5 by the same Author. Almost twenty years have elapsed since its initial preparation and the subject matter has been expanded extensively. The First International Permafrost Conference205 held at Purdue University in 1963 under auspices of the Building Research Advisory Board of the National Academy of Sciences - National Research Council and the 1963 Geneva conference, Medicine and Public Health in the Arctic and Antarctic,60 sponsored by the World Health Organization added interdisciplinary depth to the infor­ mation pool. Other efforts of the NAS—NRC have focused attention on and evaluated cold effects on sanitary engineering processes. U.S. Army, Navy, and Air Force studies have added much to the knowledge. Arctic Engineering, Low Temperature Sanitation,** and Sanitary Waste Disposal for Navy Camps in Polar Regions,54 all Navy publications, have traced change in concern and concept in the field. These and work of the Cold Regions Research and Engineering Laboratory, the U.S. Public Health Service, and several universities and private investigators have extended to topics and concerns unmentioned in the text of two decades ago. Correlation of data and experience with sanitary engineering processes, as they are known in tropical, temperate, and frigid zones of the world, has better defined applications in each zone. It has been demonstrated that greater economy and efficiency in some temperate zone practice can re­ sult through application of knowledge gained in frigid zone studies. Direct association and partici­ pation2 3 4 6 in much of the above has led the author to this current assessment of cold region waste disposal practice. This manual of the current state of the art,in sewerage and sewage disposal in cold regions is intended to supplement information available in standard engineering reference works. 2

PRACTICE AND PROBLEMS

Inadequate attention has been given to meeting sewerage and sewage disposal needs in cold regions.(Fig*. 1, 2).* Often an attitiide of despair has prevailed on the part of designers and builders, and many excellent and modern jet-age facilities, devoid ot anything more than 19th cen­ tury waste disposal systems, have been built in the cold regions. The following quotation from the official Bulletin, Alaska State Department of Education, Vol. 1, No. 3, December 1960, aptly emphasizes the prevalent time gap in sanitary facilities: “The other day one of our supervisors came back from a visit to outlying schools with fire in his eye. Before his righteous indignation had time to cool, he had hurled himself and his entire department into a campaign which, if it succeeds, may one day be hailed as a highly significant victory in Alaskan education. We have thrown dull caution out the window, burned our bridges behind us, and combined forces for a finish fight! Would you care to join us? “Briefly stated, our objective is this: Final and complete abolition of the outdoor toilet. “ We propose to begin now an active and vigorous campaign to get rid of this hor­ rid remnant of the middle ages. Our efforts will not cease until that happy day when every school and teacher’s quarters in Alaska is equipped with modem, streamlined plumbing in good working order. We contend that no expenditure of effort, time, and money is too great if it will result in a decent standard of living. We invite any and all interested persons to join this non-partisan, humanitarian movement.” The publication Science, Vol. 159, No. 3813, 26 Jan 1968, p. 407-412, gives the following news and comment (copyright 1968 by the American Association for the Advancement of Science): “ Science in Antarctica: Problems and Opportunities ‘On Ice,’

“The environment is a hazardous one; but, with increasingly sophisticated tech­ nological aids, the danger and inconvenience originally associated with Antarctica have greatly diminished.

“ Serving high-quality food is regarded as essential in maintaining ‘good morale/ as is the provision of flush at the more isolated stations such as Byrd and Pole. (Most of those stationed at McMurdo, the largest U.S. post, are still con­ signed to using less-sophisticated latrines.) One researcher complained that the continued use of such facilities at McMurdo was ‘inexcusable’;he said that it would be difficult to get prestigious scientists to work in Antarctica if such primi­ tive conditions were allowed to remain. The New Zealanders pride themselves on having Antarctica’s only bathtub, and the American stations are equipped with showers though people are told not to shower more than once a week because of the constant scarcity of water.”

Sewerage and sewage disposal in cold regions Some designers have defied custom and problems and conceived and built modern systems in the cold regions.36 125 203 Government, industrial and military effort to occupy and use polar areas has produced many functioning and modem facilities. Although much more research is needed, a sizable of information has become available through experience. Figure 3 shows an

* Ref. 11. 44. 45. 48, 56, 115. 138, 148, 193, 202. PRACTICE AND PROBLEMS 3

Figure 1. Indiscriminate disposal oi wastes near an arctic community. (Photo by L.S. Parker.)

Figure 2. Dogs may be a link in spread of disease as a result ct improper waste disposal. (Photo by L.S. Parker.) 4 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

MgillStif

Figure 3. Experimental sewage treatment plant, U.S. Army Cold Regions Research and Engineering Laboratory, Alaska Field Station, Fairbanks, Alaska.

experimental sewage treatment plant for a small community. It has operated successfully at an ambient temperature of zero F and/or liquid temperature of 34F (1C).* Sufficient information is available to build and operate modem sewage works in cold re­ gions. To build cold region facilities and communities for human habitation and not provide mod­ ern and safe sewage works is inexcusable. Design and operation concepts for successful facili­ ties demand informed consideration and approach. They also demand initial and continued cooperative interaction among the various forces and participants that develop cold region facilities. Freezing of wastes and waste collection facilities, frost-related structural effects on facili­ ties, and the retarding effect of low temperature on reductive and stabilizing processes all present problems to the designer149 and operator of cold region sewage works.t

Magnitude of temperature effects Temperature affects the equilibrium constants and saturation values of chemicals, solids, and gases which may be dissolved in sewage. Also, reaction rates for biological, chemical, bio­ chemical, and physical reactions are influenced by temperature.63 68 Temperature effects are significant in each of the following aspects of sewerage and sew­ age works:

* Personal communication by the project engineer, Sherwood C. Reed, CRREL. t Ref. 3, 14, 33, 46. 52, 138, 176. PRACTICE AND PROBLEMS 5

Aeration Disease transmission BOD Dissolved oxygen* Lagoons Biochemistry Elutriation Odor control Biology Explosions Operation Byproduct recovery Filtration Ozonation COD Flocculation Paints and painting Chemistry Flotation Pumps and pumping Chlorination Garbage Safety Clarification Gas Screening Comminution Grease Sedimentation Concentration Grit removal Sewage characteristics Construction Hydraulics Sludge conditioning Corrosion Stabilization (aerobic) Costs Incineration Stabilization (anaerobic) Dewatering Infiltration Ventilation Digestion Insect control Weatherproofing Dilution Ion exchange There are significant social, aesthetic, economic, hygienic, structural, biological, chemical and physical aspects to cold region waste disposal which must not be ignored. Cold region en­ vironment paradoxically enhances normal values accruing from adequate and healthful housing and the amenities of . At the same time inadequacies are magnified.

General requirements Facilities for collection, transport, treatment and disposal of cold region sewage wastes should: 1. Serve as an effective barrier against disease transmission. 2. Be aesthetically acceptable. 3. Not degrade the quality of the natural environment. 4. Provide the maximum of comfort and safety necessary in man's adjustment to cold region living. 5. Be capable of relatively dependable “ fail safe" function at all times. 6. Be compatible with the pattern and sequence of community development. 7. Be economically feasible. 8. Be simple to build and operate. 9. Be compatible with efficient use of energy in the community {Table I, p. 8).

Sewage characteristics Design for proper management of waste water requires consideration of many characteristics of the wastes: their strength, temperature, volume, flow characteristics, point of origin and ultimate point of disposal. Wastes in cold regions as in other regions may include human excreta, food wastes, bath and laundry water, storm drainage, and industrial wastes. They may be hot or cold, radioactive, silt­ laden, half snow or ice, heavy in dissolved chemicals and organic matter, or diluted by infiltration of ground water. In each instance, the exact nature of the wastes must be determined. This

* See Figures 4, 5 and 6. SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Figure 4. Diurnal fluctuations in dissolved oxygen at different latitudes during summer.

Water Temperature

Figure 5. Dissolved oxygen saturation in distilled water exposed to 20.9% oxygen gas at various temperatures and pressures. (Tabulated values from data given by Whipple and Whipple (1911) and Division of Military Aeronautics (1919).) PRACTICE AND PROBLEMS 7

Saturation Values of Dissolved Oxygen, ppm

(At $iv«n Temperature and Pressure) 6 7 8 9 10 II 12 13 14 15 I I I » I 1 1 I I I I » I I 1 I -L I . . I .1 I . I 1 1 I I t 1 I I I I I I I I I I I I . 1 I 1 I I I I I I I I I I I . 1 I I I I I I I I I I » I I . I . I I I 1 I I Q ©!

Figure 6. Saturation values of dissolved oxygen at given temperature and pressure. discussion is essentially confined to domestic waste waters containing human excreta, wash water, food wastes and diluting water used for flushing as as infiltration into the sewerage system. Because of thermal problems storm drainage must be kept out of cold region sanitary sewers. Domestic waste waters in cold regions (Tables II and III) tend to be less in quantity and of greater strength than similar wastes generated in a temperate climate, but hourly, daily, and sea­ sonal variations in flow and strength are similar to those' found in temperate climates (Fig. 7). The degree of required treatment of cold region wastes discharged to receiving waters is comparable to temperate climate requirements.222 The 1967 Alaska water quality standards are shown in Table IV. It may be argued that such standards are inapplicable in cold regions. But it is apparent that standards are necessary where concentrations of people or industry occur or where insult to the natural environment is probable. This basis for standard setting makes no ex­ ception for cold regions, if communities are built there or industry locates there. There is ample evidence that an insult to cold region environment is longer lasting than a similar insult in tem­ perate regions. are present in the cold region environment (Fig. 8, 9 and 10) as are vectors for transmission of disease (see Cold Regions Science and Engineering Monograph III-C5a). Disease-producing organisms tend to persist in a viable state for a longer period of time in the cold region environment. Evidence of waste pollution persists much longer in cold region receiving waters.139 152

Health and welfare implications Disease transmission109 204 in sewage wastes is much commoner at low temperatures than might be expected.10 74 Organisms may remain viable for extended periods of time1143 while the rate at which pathogens become diluted in the environment is retarded.93 96 The village dwellers of northern Canada, Alaska and Scandinavia have a long history of enteric infection.64 65 73 1471195 8 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

mid 4 8 noon 4 8 mid night night

Figure 7. Normally anticipated variations in rate of flow of domestic sewage from a small residential area during a typical 24-hour cycle.

Table I. 1966 average residential usage of electrical energy (based on a 12-hour day).

No. of Total Community customers population Usage (kw-hr)

Fairbanks, Alaska (city) 4,000 20,000 0.9 Fairbanks, Alaska (suburban) 4,000 20,000 1.6 Barrow, Alaska 300 1,500 1.2 Nome, Alaska 500 2,500 1.4 Juneau, Alaska 2,000 9,000 1.0 United States average 54,000,000 1.5 Fossil-fueled plants used in the generation and supply of electric energy as well as nuclear powered facilities may be expected to reject large amounts of waste heat. Efficiencies, with current technology, are very low, when based on comparisons of energy used by the customer with potential energy available. Conventional fossil-fueled plants reject approximately $0OQ> Btu for each kw-hr of electrical energy produced. Reject heat for nuclear plants i» approximately 8500 Btu for each kw-hr of electrical energy produced. This reject heat could constitute a significant contribution toward satisfaction of the large heat losses from water supply and waste water systems used in ad­ jacent cold region sites. PRACTICE AND PROBLEMS 9

Table II. Approximate volume of domestic sewage generated at selected cold region installations.

Thule ÂB, Greenland 80 gal per capita per day Camp Century, Greenland 50 Fort Churchill, Canada (Air Force Base) 60 Barrow, Alaska (DEWLine station) 30 Barter Island, Alaska (DEWLine station) 25 College, Alaska 70 Fairbanks, Alaska 80 Island Homes, Fairbanks, Alaska 35

Average 55

Table in. Approximate flow and strength of domestic sewage for various places. Flows are given in gallons per capita per day and strength is shown as parts per million (ppm) biochemical oxygen de­ mand (BOD - 5 day, 20C).

Average Average flow strength

United States so 180 Fairbanks, Alaska 80 260 College, Alaska 70 280 Ketchikan, Alaska* 650 30 Juneau, Alaska* 410 40 Anchorage, Alaska 270 165 * Water distribution system is kept from freezing by wast­ ing water, thus sewage flows are high and strengths aretlow.

Sea mammals, bears, dogs and birds have been implicated in disease transmission and rodents and possibly some insects are suspect.

The biological and chemical reduction of organic material proceed very slowly under low tem­ peratures (Pig. 11). Putrefaction and occur in cold regions under certain conditions, but. the usual processes of decomposition do not eeem to occur within the permafrost. Organic mate« rials exposed on the surface of the ground, or placed within the shallow top layers of seasonally thawed ground, decompose slowly. An abundance of psychrophilic organisms apparently accomplish the process along with frost and chemical action. Slow decomposition of organic matter tends to maintain a greater supply of food for many forms of life, and it is presumed that this may account for the reported abundance of life (Fig. 12 and 13). In deeper and colder permafrost decomposition is almost at a standstill; preservation occurs. Table IV. State of Alaska water quality standards for waters within the state of Alaska, 1967. Notes: 1. The analytical procedures used as methods of analysis to determine the chemical, bacteriological, biological and radiological quality of waters sampled shall be in accordance with the latest edition of Standard Methods for the Examination of Water and Waste Water or other approved standards. H* 2. These standards apply to man-made alterations to waters of the State. O S. Policy Statement of the State of Alaska, Alaska Statutes, Title 46, Chapter 46, Chapter 05, Section 46.05.010: "It is the public policy of the state to maintain reasonable standards of purity of the waters of the state consistent with public health and public enjoyment, fhe propagation and protection of fish and wildlife, 4b* eluding birds, mammals and-Othbr terrestrial and aquatic life, add the industrial development of the state, and to require the use of all known available and reason­ able methods to prevent and control the pollution of the waters of the state.” 4. The Department of Health and Welfare will administer these standards in accordance with all other state laws. 5. Enforcement will be based on samples essentially representative of the receiving water and not upon samples taken immediately adjacent to an outfall.

A. B. c. D. E. F. G. \ Water uses Water supply, drinking, Water supply, drinking, Bathing, swimming, rec­ Growth and propagation Shellfish growth and prop­ Agricultural water supply, Industrial water supply culinary and fetid proc­ culinary and food procr reation. of fish and other aquatic agation (natural and com­ including irrigation, (other than food process­ essing. Without treat­ essing. With adequate life, including waterfowl, mercial growing areas). stock watering, and truck ing) . REGIONS COLD IN DISPOSAL SEWAGE AND SEWERAGE ment other than simple treatment equal to co­ fur-bearers, and other farming. disinfection and removal agulation, sedimentation, aquatic and semi-aquatic of naturally present im­ filtration, disinfection, life. Water \ . purities. and any additional treat­ quality \ . ment necessary to remove parameters naturally present impuri­ ties. i. Organisms of the Coliform Average less than 50 Average less than 2,000 Average less than 1,000 Same as C-1 to protect Not to exceed limits Average less than 1,000 The requirements of C-1 Group by MPN or equiva­ per 100 ml in any month. per 100 ml over any con­ per 100 ml with 20% of associated recreational specified in Manual of per 100 ml with 20% of should be met whenever lent MF, using a repre­ secutive 30 days. Not samples not to exceed values. Recommended Practices samples not to exceed worker contact is re­ sentative number of more than 20% of samples this number. No sample for Sanitary Control 6t 2,400 per 100 ml for quired. samples (where associ­ examined during this shall exceed 2,400 per the Shellfish Industry, livestock watering, for ated with fecal sources). period should exceed 100 ml. USPHS. irrigation of crops for 2,000 per 100 ml. human consumption, and for general farm use.

dissolved oxygen mg/1 Greater than 75% satur­ Greater than 60% satur­ Greater than 5 mg/1. Greater than 6 mg/1 in Greats iLthxa<6 ing/Lsat- Greater than 3 mg/1. Greater than 5 mg/1 for or % saturation. ation. ation. salt water. Minimum of Ufalten in the larval . Not 7 mg/1 in fresh water. stage. Greater than 5 limiting except as it af­ mg/1 in the adult stage. fects other parameters. 3. PH Between 0.5 and 8y5. Between 6.5 and 8.5 Between 6.5 and 8.5 7.8 and 8v5 salt. 6.5 Between 7.8 and 8.5. Between 6.5 and 8.5 Between 7.0 and 8.0 Natural pH conditions and 8.5 fresh. 0.5 pH outside this range shall change per hour max. be maintained without change. Induced varia­ tion less than 0.5 pH unit. 4. - Jackson tur­ Less than 5. (See nar­ Less than 5 above nat­ Below 25 except when Less than 25 when at­ None of mineral origin in Numerical values are No imposed values that bidity Units - JTU* rative for discussion of ural conditions. natural conditions lie tributable to solids re­ excess of 25 JTU. not applicable. will interfere with es­ natural conditions above this figure then sulting from other than tablished levels of above 5.). effluents shall not in­ natural origin. treatment. crease the turbidity. T Temperature °F Below 60F waste flows Below 80F waste flows Numerical value is not May not exceed natural Less than 68F. Between 60 and 70F for Less than 70F. above 60F adjusted to above 60F adjusted to applicable. temperature by more optimum growth to pre­ ambient receiving water ambient receiving water than 5% for salt, 10% vent physiological temperature. temper ature. for fresh. No change shock to plants. permitted for tempera­ ture over 60F. Maxi­ mum rate of change 0.5F/hr. 6 . Dissolved inorganic Numerical value is not Numerical value is not Within ranges to avoid Within ranges to avoid Conductivity less than No amounts above nat­ substances. under 500 mg/1. None applicable. applicable. chronic toxicity at sig­ chronic or acute toxicity 1,500 micromhos at 77F. ural conditions which in addition to natural nificant ecological or significaatjeeological SAR less than 2.5, sodi­ will cause undue corro­ background if this val­ change. .change. um percentage less than sion, scaling, or proc­ ue exceeds 500 mg/1. 60%, residual carbon­ ess problems. • ate less than 1.25 mg/1 and boron less than 0.3 mg/1. Table IV (cont’d).

A. B. c. D. E. F. G. N. Water uses Water supply, drinking, Water supply, drinking, Bathing, swimming, rec­ Growth and propagation Shellfish growth and prop­ Agricultural water supply, Industrial water supply culinary and food proc­ culinary and food proc­ reation. of fish and other aquatic agation (natural and com­ including irrigation, (other than food process­ essing. Without treat­ essing. With adequate life, including waterfowl, mercial growing areas). stock watering, and truck ing). ment other than simple treatment equal to co­ fur-bearers, and other farming. disinfection and removal agulation, sedimentation, aquatic and semi-aquatic of naturally present im­ filtration, disinfection, life. purities. and any additional treat­ Water \ ment necessary to remove quality \ . naturally present impuri­ parameters \ ties. 7- Residues: oils and flo a t­ Below normally detect­ Below normally detect- , No visible concentra­ None alone or in combin­ No visible evidence of None in sufficient quan­ No visible eviience ing solids, sludge de­ able amounts. able amounts. tions of wood fiber, oil ation with other sub­ wastes. Less than ; ■ tities to cause soil plug­ from wastes. posits. sludge, sewage, scum, stances or wastes as to acute or chronic prob* ging and reduced yield foam, or other wastes make receiving water un­ lem levels as revealed of crops. that may adversely af­ fit or unsafe for the use by bioassay or other fect the use indicated. indicated, except that no appropriate methods. PROBLEMS AND PRACTICE waste oils, tars, greases or animal fats are per­ mitted. 8. Sediment*t Below normally meas­ No imposed loads that Numerical values not No appreciable deposi­ No appreciable deposi­ For sprinkler irrigation, No imposed loads that urable amounts in the will interfere with es­ applicable.. No visible tion which adversely af­ tion which adversely af­ water free of particles will interfere with es­ water diverted. tablished levels of concentrations of silt. fects fish spawning and fects fish spawning and of 0.074 mm or coarser. tablished levels of treatment. habitat. habitat. For irrigation or water treatment. spreading, not to exceed 200 mg/1 for an extended period of time.

9. Toxic or other deleteri­ Chemical constituents Chemical constituents None or below concen­ Shall be absent or below Less than acute or Less than that shown to Chemical constituents ous substances, pesti­ should conform to cur­ should conform to cur­ trations found to be of concentration affecting chronic problem levels be deleterious to live­ should be below con­ cides and related organ­ rent USPHS Drinking rent USPHS Drinking public health signifi­ public health or the eco­ as revealed by bioassay stock or plants or their centrations found to be ic and inorganic mate­ Water Standards, CCE Water Standards. cance. logical balance. or other appropriate subsequent consumption of public health signi­ rials.* (carbon chloroform ex­ methods. Less than by humans. ficance. tract) 0.1 mg/1. amount that causes tainting of flesh of ed­ ible species. Pesti­ cides 0.001 of the LCj0 for the most sensitive organism on 90-hour ex­ posure. 10. Color True color le ss’than 15 True color less than 15 True color less than 15 True color less than 50 True color less than 50 Not applicable. True color less than 50 color units. color units. color units. color units. cola units. color units. 11. Radioactivity Conform with current Conform with current Conform with current Current USPHS Drinking Concentrations shall be Conform with current Conform with current USPHS Drinking Water USPHS Drinking Water USPHS Drinking Water Water Standards except less than those result­ USPHS Drinking Water USPHS Drinking Water Standards. Standards. Standards. where concentration fac­ ing in radionuclide con­ Standards. Standards. tors of aquatic flora and centrations in shellfish fauna exceed reduc­ meats which exceed the tion factors; then MPC recommendations of the of radioisotopes shall be National Shellfish Sani­ reduced below acute or tation Program, Manual chronic problem levels. of Operation, USPHS. 12. Aesthetic considerations Shall not be unreasonably impaired by the presence of materials or their effects (excluding those of natural origin) which axe offensive to the senses of sight, smell, taste or touch.

* Short term activities which may be specifically authorized by the Department of Health and Welfare may temporarily exceed these amounts, t Silt from gravel washing and. placer mining is excluded as pollution by Alaska statutes. 12 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Figure 8, Approximate mean annual ait temperatures (°F) in Alaska, (Based on ESSA-Weather Bureau data.)

Figure 9. Approximate, minimum recarded.temperatures (°F) in Alaska. (Based on ESSA-Weather Bureau data.) PRACTICE AND PROBLEMS 13

Figure 10. Approximate mean annual ground temperatures (°F ) in Alaska. (Based on ESSA-Weather Bureau data.)

ANIMAL PLANT TISSUES TISSUES Figure 11. The nitrogen cycle.

Waste salvage and ultimate disposal In temperate climates, natural processes reduce and destroy great quantities of organic and infectious material through the normal action of the soil. The soil is a living thing presenting many of the vital phenomena that characterize life: digestion, metabolism, assimilation, growth, respira­ tion, motion, and reproduction. The soil breathes - it absorbs oxygen and exhales carbon di­ oxide - through complex metabolic processes; it digests vast amounts of organic material; it ex­ cretes wastes; and if the: wastes are retained it becomes choked with the accumulation of its own poisons. The rise and fall of ground water is analogous to the movements of the human diaphragm and assists the respiratory functions of the soil which teems with life - bacteria, actinomycètes, fungi and (microflora) and the , worms and arthropods (fauna). Figure 13. Abundance of bacteria in soils at different seasons of the of seasons different at soils in bacteria of Abundance 13. Figure BACTERIA (10®/cm SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS COLD IN DISPOSAL SEWAGE AND SEWERAGE Figure 12. influence of influence 12. Figure nitrogen content of noils. (After Jenny.) (After noils. of content nitrogen year. (After Russell.190) (After year. temperature upon the

PRACTICE AND PROBLEMS 15

Permafrost and the extended period of seasonal frost in cold regions (Fig. 8, 9 and 10) in­ terfere with normal breathing and metabolic processes of the soil and retard the assimilation of or­ ganic material. Permafrost (Table V) frequently does not permit proper drainage of the soil, and it becomes waterlogged when it is not in a frozen state. The vigorous frost action, however, opens up the interstices or pores in the upper layers of the soil to a greater degree in permafrost areas than in ground where permafrost does not exist. Very little investigation has been made concerning the specific role cold region soil may play in carrying on the metabolic processes necessary to render harmless the organic waste which must be assimilated in proper sewage and garbage disposal. It appears that the sluggish biological state and the difficult physical state of many cold region soils almost preclude normal use of them for biological and drainage practices now used in temperate climates for sewage disposal. Table VI shows approximate waste temperature and Table VII lists selected treatment facili­ ties in use in cold regions. Stabilization ponds are the most common treatment facilities in com­ munity use in North and South Dakota (Tables VIII and IX). In general, aerobic treatment processes appear to be the choice where low temperature is a concern. The stabilization pond offers the simplest form of the aerobic process, and where, even for short periods, light, temperature, and evaporation permit it to operate, generally satisfactory results have been reported.

Present practice Various types of sewerage systems have been tried in the northern countries, although pre­ dominantly dry collection systems have been used. Flush systems are in use in the larger com­ munities of the North. Mechanical processes are the most positive in their action but suffer from problems of lubri­ cation, repair and maintenance. Mechanical treatment of wastes has not been tried to any great degree in Alaska. Chemical processes are retarded by low temperatures. Chemicals for sewage treatment are not readily available in the North and must be imported, which limits their use for sewage treat­ ment. Biological processes appear to offer the most promise for use under low temperature condi­ tions, although biological reactions are influenced by temperature. Certain psychrophilic organ­ isms are effective in waste stabilization processes. In general, aerobic processes offer more promise than anaerobic processes since heat appears to affect the latter much more than the former. The Alaskan Air Command is investing heavily in aerated lagoons at remote sites and the Public Health Service is installing lagoons routinely in native villages. High transportation costs, infrequent service and lack of transportation facilities in many parts of the North increase the cost of supplies and services. Logistics assume considerable sig­ nificance. Construction, operation and maintenance also cost much more than in temperate climates. The shortage of trained and experienced operating personnel and the complex features of operation emphasize the importance of simplicity in sewage work facilities. The senparid climate of the cold regions makes humidification and dehumidification important. Extreme cold, wind, ice cover and similar features of the environment strongly affect receiving waters and open treatment devices. Several possibilities exist for the designer of cold region sewerage and sewage disposal systems.75 79 98 He must evaluate each alternative and the resulting effects on the facility.*

* Ref. 175, 176, 181, 185, 201, 202. 16 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Table V. Approximate monthly mean ground and air temperatures (°F) at certain points in the arctic permafrost area. (Based on data from ESSA-Weather Bureau and Tsytovich and Sumgin, 1937.)

Depth Jan Feb Afar Apr May June July Aug Sept O ct N ov Dec Ann. Va1. (tt)

Barrow, Alaska

- 1 9 . 1 -12.8 -14.9 1.8 10.9 29.8 40.1 36.7 31.6 16.2 4.6 -6.6 9.9 Air 0.0 -7.0 -4.9 -3.9 4.2 18.6 38.1 53.6 43.3 34.5 20.0 9.5 0.5 17.2" lAcuve1 A A t i ff A -4.3 -2.6 - .6 4.6 18.4 33.1 45.7 41.6 34.0 21.5 11.0 2.5 17.1 0.5 flayer 1.0 -2.8 -1.7 .2 4.8 17.6 29.8 38.9 37.2 33.5 23.0 11.5 4.0 16.3W 2.0 3.0 1.9 2.6 5.5 12.7 22.3 26.2 29.9 30.0 25.5 17.5 9.0 15.S' 4.0 6.8 5.0 5.0 7.1 13.3 17.6 23.2 26.9 27.0 26.5 20.0 14.0 14.5 7.0 7.8 9.1 7.7 8.2 9.8 14.0 18.7 22.3 23.0 24.5 21.5 17.5 15.3 ^Perma- 11.0 15.8 13.0 11.1 10.7 10.7 12.2 15.8 18.6 20.0 2 U0 20.5 19.0 15.7 fros t 16.0 14.3 15.2 16.3 12.2 11.4 12.2 13.9 ■ 13.1 11.5 17.5 18.5 13.0 14.1 22.0 16.8 16.8 15.8 15.1 14.1 14.3 14.1 15.0 15.0 16.0 16.5 17.0 15.5,

Bomnak, Siberia 4.9 30.6 27.3 25.2 26.8 29.7 30.;V 31.5 33.4 34.9 33.3 32.2 32.0 30.6'\ Active 6.6 31.8 29.8 27.7 27.5 29.5 30.4 30.9 31.6 32.5 32.4 32.2 32.0 30.7,J layer 9.2 31.6 31.9 29.8 29.1 29.5 30.2 30.7 30.9 31.3 31.5 31.6 3 K6 30.7 Permafrost Kotzebue, Alaska -6.4 -6.4 -6.8 15.7 31.3 43.8 53.9 49.2 36.8 22.2 5.7 2.8 20.1 Air 1.0 26.0 23.0 18.8 21.5 27.0 35.0 40.5 40.0 31.5 30.5 30.5 29.'5 29.5'^Active 2.0 27.5 25.5 21.0 22.5 24.5 31.5 33.0 34.5 32.5 30.3 30.5 30.0 28.6,j layer 4.0 31.0 28.5 24.0 24.5 27.0 30.5 30.5 31.0 31.5 30.5 30.8 31.0 29. é 7.0 31.5 31.0 26.8 26.0 26.5 29.5 29.0 29.0 29.5 30.0 30.8 30.5 29.2 11. GL 30.5 31.0 29.0 27 8 28.0 30.0 29.0 29.0 29.5 29.8 30.5 30.5 29.5 Perma- 16.0 29.5 30.0 24.8 28.8 28.8 29.5 28.3 27.5 29.5 29:3 29.5 29.5 29.8 frost 22.0 29.0 30.0 29.8 29.5 29.3 29.5 28.5 27.5 29.5 29.3 29.5 29.0 29.2J McGrath, Alaska -4.1 -2.2 6.2 24.7 43.7 57.4 57.2 51.8 40.3 23.1 2.6 -5.2 24.6 Air 0.5 30.7 30.5 30.6 31.3 40.7 56.1 58.9 56.1 44.3 32.0 30.6 40.2> 1.0 31.0 30.7 30.5 31.0 !39.8 54.7 58.7 56.4 45.1 32.2 31.4 40.2 2.0 31.1 30.5 30.7 30.7 1 38.8 52.5 57.5 55.5 45.7 32.3 31.0 39.7 4.0 32.9 32.3 32.1 32.0 34.9 44.9 51.3 52.0 46.5 35.4 33.7 38.9 ^Active 7.0 34.9 34.1 33.8 33.5 ' 33.8 38.7 42.1 45.3 44.9 38.2 36.1 37.8 layer 11.0 36.5 35.3 35.0 34.7 34.4 36.1 37.8 39.1 41.3 39.1 37.4 37.0 16.0 37.5 36.6 36.4 36.1 35.5 36.0 36.1 36.8 39.0 39.2 38.4 37.0 22.0 37.3 36.6 36.6 36.3 35.8 36.1 36.0 35-9 36.8 38.1 37.9 36.7 J Nome, Alaska 1.9 7.3 2.9 23.4 35.5 48.4 48.9 38.2 25.8 17.6 25.0 Air 0.0 17.4 25.2 23.6 29.1 46.3 59.3 61.7 43.5 31.1 22.4 36.0" 0.6 31.3 31.7 30.5 31.0 33.0 35.2 39.4 35.8 32.5 31.7 33.2 l Active 2.8 31.2 32.0 31.2 31.6 32.0 31.3 34.7 32.2 32.1 31.2 32.0^j layer 5.7 31.4 29.2 31.5 31.8 32.1 31.4 30.8 31.6 31.7 31.6 31.3"\ 10.7 30.5 31.0 30.7 31.1 31.4 30.7 30.3 30.9 31.2 30.7 30.9 l Perma- 19.6 31.2 3i:2 31.3 J frost 31.9 32.0 31.3 27.8 31.6 31.3 31.4 3 1 - 1 . Skovorodino, Siberia 1.3 8.8 8.6 15.6 26.1 32.5 43.2 51.3 53.2 45.3 34.7 28.0 16.5 30.4"\ 2.6 17.1 14.7 18.3 25.7 30.4 34.9 43.5 47.3 43.5 34.9 32.0 25.9 30.6 (Active 5.2 30.4 25.7 24.3 26.8 29.5 30.4 31.3 29.7 36.3 33.8 32.2 32.0 30.6 [ layer 6.6 31.3 28.6 26.2 27.3 29.3 30.2 30.7 32.0 33.8 SSJ 32.2 32.0 30.6. 8.2 31.6 31.6 30.2 28.9 29.7 30.2 30.6 30.7 31.3 31.6 31.6 31.6 30,f9 Permafrost PRACTICE AND PROBLEMS 17

Table VI. Approximate monthly average temperature (°F) of raw sewage at the treatment plant .

Place Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec

Aurora, 111. 48 47 46; 49 57 59 63 68 63 49 49 50 Canton, Ohio 42 40 42 44 52 58 62 64 61 56 50 47 F lint, Mich. 50 48 45 52 55 62 69 71 67 63 58 53 Schenectady, N.Y. 48 43 36 43 52 57 63 64 65 64 60 56 Traverse City, Mich. 48 46 44 48 54 59 65 65 62 60 55 52 Fairbanks, Alaska* 52 51 51 50 51 52 53 53 53 53 52 52 Fairbanks, Alaska! 32 32 32 32 32 32 34 35 37 35 33 32 Eielson AFB, Alaska** 70 69 68 68 67 68 70 74 73 72 72 70 College, Alaska!! 63 68 59 66 66 63 68 68 69 68 66 62 Juneau, Alaska 38 36 37 42 40 46 45 48 48 46 46 44

* Recirculating water system in use and 33F well water is heated to nearly constant temperature of almost 60F. After circulation through system, water returns to plant with a drop of approximately 6F in summer and 10-12F in winter. Water lines and sewers pass through permafrost. Sewers are of wood-stave pipe and in­ sulated plugs are placed in manhole entrances. ! These data are from sewers in a suburban area of Fairbanks served by individual producing water at a temperature of approximately 33F. The observed sewer is constructed of wood-stave pipe and manholes are closed with insulated plugs. ** All sewers are enclosed in warm utilidors which also carry heat lines. !! Most of the sewers are enclosed in heated utilidors.

Table VII. Examples of sewage treatment facilities in use in northern regions. (Regions where the average annual temperature is 40F or less.)

Design Place Type of plant pop. Remarks

Alaskan Village (tr. court) Clarification, digestion 420 Anchorage (scenic park) Extended aeration 100 Bethel (school) Extended aeration 250 Enclosed in heated structure Churchill (HMCS “ Churchill” ) Septic tanks 80 Enclosed and heated Churchill (AFB) Extended aeration, chlori­ 80 Unit enclosed nation College (“College utilities”) Oxidation ditch 2,000 Unenclosed Eielson (AFB) Clarification (experimental 7,000 aerated lagoons) Fairbanks (Adler School) Extended aeration 120 Fairbanks (airport) Extended aeration 500 Enclosed plant Fairbanks (tr. court) Extended aeration 100 Fairbanks (city) Pre-aeration, clarification, 14,000 Plant enclosed - raw sludge chlorination, sludge in­ burned cineration Fairbanks (ESRO) Extended aeration 20 Fairbanks (Gilmore Creek) Extended aeration 20 Fairbanks (Joy School) Extended aeration 150 Fairbanks (North Pole School) Extended aeration 100 Fort Greely Imhoff tank 1,000 Fort Smith Raw sewage lagoon 1,000 Effluent to Slave River Fort Wainwright Clarification, digestion 9,000 Fort Yukon Raw sewage lagoon 200 Glennallen (hospital) Extended aeration, lagoon 50 Inuvik Raw sewage lagoon 2,200 Juneau (airport) Extended aeration 700 Unenclosed 18 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Table VII (coat'd). Examples of sewage treatment facilities in use in northern regions. (Regions where the average annual temperature^s 40F or less.)

Design Place Type of plant pop. Remarks

Juneau (Memndenhaven) Extended aeration 250 Unenclosed Kenai (city) Imhoff tank 200 Nome (city) Clarification, digestion 2,400 Enclosed Nome (station) Pklmer Raw sewage lagoon 600 Rae Extended aeration, clarifi­ 100 Receives hospital and hauled cation and chlorination waste Resolute Bay Septic tank 250 Sutton (Alpine Inn) Lagoon 40 Talkeetna (airport) Extended aeration 300 Thule AB Comminution and dilution 6,000 Thule (Camp Tuto) Primary and secondary clari­ All units except incinerator fication trickling filter, enclosed in heated buildings coil-type vacuum filtration of sludge and sludge incin­ eration Yellowknife Natural lagoon 2,700 Effluent to Great Slave Lake

Table Vm. Characteristics of selected stabilization ponds in North Dakota “* serving communities of one hundred or more population.

Design No. Size in Kind of Location population cells acres sewage

Cavalier 1,450 3 9.0, 8.0 Raw Center 300 1 4J5 Raw Devils Lake 11,650 1 107 Raw Dunn Center 200 1 3.0 Raw Flasher 300 1 6.0 Raw Fort Berthold: South School 100 1 1 Raw Jamestown 12,550 1 135 Raw Max 400 1 1.5 Raw Medina 500 1 4.0 Raw Neeche 700 1 16 Raw New Salem 890 1 10.5 Raw New Town 1,300 1 8 Raw Park River 1,600 2 32.6 Raw Portland 800 1 8.0, 6.0 Raw Wishek 1,490 1 7.8 Raw PRACTICE AND PROBLEMS 19

Table IX. Characteristics of selected stabilization ponds in South Dakota188 serving communities of one hundred or more population,

D esign N o. o f S ize in K ind of L ocation population c e lls acres sew a g e

Bell Fourche 5,200 22 2 2.9, 29.1 Raw Canton 3,000 2 15.0, 15.0 Raw Clear Lake 1,200 1 12.0 Raw Edgemont 2,000 1 20.4 Raw Elk Point 1,600 1 16.0 Raw Faulk ton 900 1 9.0 Raw Hayti 500 2 2.6, 2.3 Raw H ecla 600 1 7.4 Raw Kimball 1,000 2 5 .0, 5.0 Raw Milbank 3,400 2 14.4, 14.1 Raw M ission 400 2 2 .3, 1.8 Raw Morristown 300 1 3.0 Raw Parks ton 1.550 1 15.5 Raw Plankinton 796 1 7.4 Raw P ollock 500 2 2,3, 2.3 Raw Sturgis 6,000 2 3 6.5, 24.2 Raw Summit 400 2 3 .6, 2.1 Raw Watertown 10,600 2 3 0.0, 23.8 Secondary Wessington Springs 2,000 1 20.0 Raw White River 500 1 5.0 Raw Oahe Administration 100 2 0 .5 , 0.4 Raw Rosebud Boarding School 200 4 0 .2 , Each Primary

It must first be determined whether the facility is to be part of a total energy and total ser­ vice system or an independent system. The designer must determine if the system is to be 1) en­ capsulated and isolated from the environment, -2) insulated and heated to protect it from the environ­ ment, or 3) non-frost-susceptible. Sites must be evaluated* 12 345*to determine whether “ active" or “passive" construction and operation techniques are indicated (refer to Monograph I-A2, Permafrost, by S.R. Stearns). The proposed solution must be analyzed for compatibility with the logistics, personnel, materials, economy, energy, housing, and health and welfare implications imposed at the site.53 In making such analyses, most observers agree on the importance of: 1. Design simplicity - elimination of as much gadgetry as possible. 2. Utilization of energy in nature, and materials available at the site. 3. Flexibility and proven reliability. 4. Minimizing need for specially trained or experienced personnel. 5. Safety, minimum operating manpower, and aesthetic and psychological acceptability by users. Clark and Groff34 enumerate the following military criteria for evaluating the adequacy of cold region sewage collection methods: Compatibility with mission Performance life of facility Population served 20 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Ready procurement Easily shipped Easily installed Handles all normal wastes Protection of health and safety Effective barrier to disease spread Wastes inaccessible to vermin Free from fire or safety hazard Aesthetic features No odors Acceptable appearance Comfortable to use Operating characteristics Simple to operate Suitable for repeated use Easily maintained Easily cleaned Few repair or replacement parts Economy Conserves water Conserves manpower Uses minimum power Criteria listed in publication 586 of the National Academy of Sciences - National Research Council222 include the following special criteria for evaluating units for use in areas of low tempera­ ture :

'' Weatherproofing In areas of low temperature special consideration shall be given to the need for weatherproofing piping, tanks, air supply and air intake lines, and sewers. “Additional criteria In addition to the previously outlined criteria for evaluation and testing of individual aerobic household sewage treatment systems there are certain special criteria for design, installation, influent characteristics, operation, maintenance, and effluent discharge that must be applied in ¿determining the suitability of the units for use in areas of low temperature. These criteria are applicable when units must be used where they may be subjected to freezing temperatures or in an environ­ ment where the average annual air temperature may be less than 40°F. These addi­ tional criteria are as follows: 1. Design must provide necessary location, insulation, weatherproofing, facilities for heating, and elimination of odors in living areas - unit must not be allowed to freeze under normal operating care. 2. Design should provide for treatment of wastes at temperatures compar­ able with temperate climate use. Otherwise, it may be necessary to modify load­ ings. 3. The installation should be easily operated and maintained under outdoor temperatures of less than 0°F. 4. Particularly in remote installations, the design should include component parts that are interchangeable wherever possible and are permanently lubricated and sealed. Parts which must be changed or for which maintenance must be provided PRACTICE AND PROBLEMS 21

must be sufficiently simple that the work may be performed by an untrained per­ son. Spare parts should be provided for items known to need replacement. 5. Wastes entering the treatment unit should be kept at temperatures com­ patible with proper operation of the unit. 6. In disposal of the effluent from the unit it must not be allowed to con­ duct heat to structural members of the enclosing structure or to surrounding per­ mafrost in such a fashion that resulting thawing will affect the stability of the structure. 7. Air intakes and venting should be designed so that they may be kept operable under severe low temperature conditions. The iair intakes should be located so that temperatures necessary for proper functioning of the unit may be maintained.’’ (See Appendix D for special considerations applied at the Winnipeg plant in Canada.)

Summary In summary, low temperatures influence almost all sewage, sewerage and sewage works in the cold regions. It is a challenge to the engineer, designer and operator to make these influences beneficial to the greatest degree possible. Those influences that cannot be utilized beneficially must be isolated or modified. The characteristics of sewage wastes including the volume produced, biochemical oxygen demand (BOD), (COD), dissolved oxygen, biology and other characteris­ tics of fluid wastes reflect the influence of low temperature. The volume of sewage may be less for a given population than might be expected in temperate climates, although the strength of the wastes may be expected to be higher. The long-term BOD reflects the effect of low temperature. Dissolved oxygen may be present in considerably greater quantities in cold water than in warm water. The number of species of organisms in sewage waste and receiving waters may be less than in temperate climates although the population of each species may be considerably greater. The permanently frozen state of the soil in cold areas has a pronounced effect upon the infiltration and dissipation of fluid wastes. Drainage is severely affected and is mostly horizontal rather than vertical. 22

COLLECTION AND TRANSPORT

Collection and transport of sewage in cold regions in the past has been almost one and the same operation. In many places, little effort has been exerted in collecting and transporting wastes to points for proper treatment and safe disposal.32 Such systems, with the exception of some recent modifications, may be classed as dry collection and transport systems. Wet collection and trans­ port systems are relatively recent but experience has proved them to be entirely feasible and justi­ fied in most instances. A third grouping is disposal at point of generation by incineration or chemi­ cal treatment.

Wet collection and transport systems In wet collection and transport systems, fresh water, saline water and synthetic fluids have been used for a flushing and transpat vehicle (Fig. 14). In some systems, the transpat fluid has been partially reused by recirculation while in others it has been reused by repeated recirculation. Improved results have been obtained by use of minimum-flow fixtures and arrangements. Wet col­ lection and transpat systems must incapaate special features for protection from freezing. The namal cyclic nature of fluid flow in sewers (Fig. 7) and the large variation in quantity of wastes present special problems. Heat losses from sewers are almost as great during periods of practically no flow as they are during larger flow periods. A dribble of sewage with insufficient heat in it to satisfy the heat losses of the line may result in a frozen sewer.24 Manholes, venting systems, pumping stations, and outfalls open to cold outside air often cause excessive heat loss from the sewerage system. Hydraulically, the beginning and ending periods in the useful life of a sewer are both critical. Thermally, the initial low flow period is of extreme significance in design. Several innovations have been instituted in design, construction and operation of sewage col­ lection systems to minimize effects of low temperature.163 Collection facilities not located in

Figure 14. Salt water collection and transport system. (N ehi sen.137) COLLECTION AND TRANSPORT 23 utilidors or specially heated are predominantly constructed of materials which minimize heat trans­ fer. In some systems, house sewers, laterals, trunks and manholes have all been constructed of wood. Manholes have not been ventilated and in some instances the manholes have been covered with double wooden covers with insulation between the covers. Collection of ground water with its available heat has been encouraged in some places to help satisfy heat losses from the sewerage system. Storm water, which may at times ohoke the sewer with 32F water and ice spicules, has been excluded. Storm water inlets and catch basins have been discouraged in efforts to eliminate heat loss. Heat conservation is an additional justifi­ cation for use of separate sewage collection systems in cold regions. The use of sewer pipe in maximum lengths facilitates sewer maintenance. Vertical alignment suffers less under the deteriorating effects of unstable frost-susceptible soils and perma­ frost. Supporting posts and cross members have been placed under sewer pipe in an effort to main­ tain alignment in particularly unsatisfactory soils (Fig. 15). The depth of embedment of the posts in permafrost should be three times the thickness H of the seasonal frost zone. Assuming all other factors are equal, it is advantageous to select sewer pipe of a material which suffers minimum dam­ age when subjected to freezing (see Appendix C for summary of pipe characteristics). Wood, as­ bestos-cement, steel, cast iron, copper, cement, aluminum, and plastics are used. Insulated pipe is available in prefabricated units at competitive prices. Steam tracers, steam condensate and heated utilidors* have been used to heat sewers. Ex­ perience has well established the dangers of placing a sewer with a potable water main in the same utilidor. Fracture of the sewer submerges the potable water line in sewage with resultant danger to health.

Figure 15. Adjustable vertical alignment support for sewer in permafrost that becomes unstable upon thawing.

* Refer to CRSE Monograph III-C5a. 24 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS Aeration Settling Puri f ication Tank T ank From Supply

Sewer

Figure 16. Air gap installation, Figure 17. Diagram of typical single household Fairbanks, Alaska. recirculating system.

A review of characteristic ground temperatures (Table V) shows the lowest temperature and greatest temperature fluctuation near the ground surface. Ground temperature increases with depth below the ground surface. In optimizing depth of burial for pipes, at Fairbanks, Alaska, a depth of approximately 6 ft is used, but each installation must be evaluated on its own merits to deter­ mine the optimum depth. To bury a pipe deeply costs more for excavation, and heat must be sup­ plied over a longer period of time, but the maximum slope of the temperature gradient will be much less than at shallow depth during the coldest periods. Operating, as well as construction, costs must be evaluated for each system and site. Heat balance for water pipes and sewers is similar; essential differences are discussed in the thermology chapter. Sewers are laid on the maximum feasible slope; a sewer of theoretically minimum slope may be inadequate to prevent pocketing of sewage and blockage of the system with possible undesirable anaerobic decomposition. Frosting and icing may occur in the crown of a sewer supplied with mar­ ginal amounts of heat. Sewers 8 in. or'more in diameter appear to be large enough to permit melt­ ing and sloughing of the ice and self-opening of the sewer without blockage when slightly greater than marginal amounts of heat are applied to the system. Experience has shown that dead ends should be avoided as much as possible. Where ground water is available nearby, special flushing wells have been constructed on dead end sewers to make up lost heat through additional flow of water. The wells are pumped at a predetermined rate that will provide enough water (and heat with­ in the water) to prevent freezing. Electric heating by cable or impedance heating has also been used to heat aboveground, buried, or utilidor-encased sewers. Insulation of both buried and aboveground lines has been practiced.* In some instances arrangements have been made to discharge water from a community water system into the dead end of a sewer to provide heat needed to prevent freezing. This is a danger­ ous practice and may jeopardize the health of an entire community unless the potable water system

* Refer to ORSE Monograph III-C5a. COLLECTION AND TRANSPORT 25

is completely severed from the sewerage system by an appropriate air break in the water supply line. Such an air break has been designed at Fairbanks to function in the heated area of the near­ est home served by water and sewer (Fig. 16). Flushing from a special well is far preferable. Water-carriage systems are most common among fluid collection and transport systems used in cold regions. Where insufficient heat exists in the sewage to satisfy losses from the system, heat is either added directly to the sewage or the enclosing piping system. Insulation or other special construction features have often been incorporated to reduce the rate of loss from the sys­ tem. Polyurethane is a popular insulating material; though costly, it has low heat conductivity and is easy to apply. Recirculating-type collection and transport systems have been under study for several years and have been used for small groups (Fig. 17). This system utilizes water-flushing toilets|, and transports the solids with water as a carrier to a treatment unit. Fluids are salvaged from the treatment unit and reused for flushing. Water cannot be reused for drinking and food preparation without a higher degree of treatment. Color in the flushing fluid has been found objectionable by some users. Further perfection of the process should greatly improve its acceptability. Partial recirculating systems have been used in DEWLine stations. Water from the laundry, lavatories and showers is collected separately from food wastes, kitchen drainage and toilet and urinal wastes and is reused for flushing. Partial or recirculating systems with water-conserving fixtures greatly reduce water use; they are most advantageous in water-short areas. Conventional fluid carriage systems, using water as the transport vehicle, must be designed and constructed within certain constraints on hydraulic design, materials used, appurtenances, and layout. Experience at Fort Yukon, Alaska, has demonstrated the advantages of intermittent dis­ charge of wastes through sewers which periodically might be expected to have very small flow. Sewage is collected in a sump in the building and discharged by periodic pumping, producing a 26 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Figure 19. Conventional pumping station design. (After Rogers.165)

“ slug-type” flow. Somewhat smaller-than-normal lines may be used for discharge under pressure. Automatic dosing siphons (Fig. 18) have also been used to provide the “ slugttype” flow desirable in sewers with otherwise inadequate flows to keep them from freezing. However, most siphons are not dependable without careful maintenance. There are advantages to the use of sewers with a low coefficient of thermal conductivity where the sewers are placed directly in frozen material; there are also advantages to the use of materials or devices which may be readily thawed. Facilities for thawing and continuing use of a frozen sewer should be incorporated into the design and construction if the sewer is to be buried and not readily accessible. A sewer must also be designed and constructed so that proper align­ ment may be retained if it is placed in materials which become unstable when thawed. Sewers placed in utilidors are accessible for maintenance and can be raised or lowered to maintain proper grade. They may be heated by warming the sewage or the environment of the sewer. However, utilidors have disadvantages: higher cost and maintenance problems. Minimum-flow fluid-carriage systems are advantageous where collection and transport serve» one or a few heavily populated areas. They are used in conjunction with other facilities which partially reclaim and reuse the flushing fluid. The unused portion is transported with a heavy concentration of solids under pressure to a point of final treatment and discharge. Such systems COLLECTION AND TRANSPORT 27

Figure 21. Pumping station with en­ Figure 20. Two story pumping station. (After Rogers.165) closed storage tank in a single chamber. (After Rogers. 16S) act intermittently and even seasonally, depending upon the volume of holding facilities and upon operating characteristics of the salvage and reuse facilities. Domestic plumbing systems for normal wet transport and collection systems should be located on the interior walls of structures. The house vents should be constructed of material with a low coefficient of conductivity, and should increase in size from a point well below the roof of the structure toward the exterior. House connections and the upper ends of laterals are the most vulnerable parts of conven­ tional collection systems. Proper grades are essential in all parts of the sewerage system but they are of extreme significance in the house connection and upper lateral. The slug-type flow produced by steep grades in house connections is the simplest known device for minimizing the freezing prob­ lem. Protection beyond that provided by slug-type flow involves special design and construction features. Pumping stations and other appurtenances used to collect and transport sewage should also be specially designed to protect the system,166 since conventional pumping station design (Fig. 19) often incorporates practice inappropriate to cold region use. Sewage lift stations with separate wet and dry wells constructed side by side, regardless of whether the motor is located above or below grade, have disadvantages for cold regions use. Rela­ tively large storage with considerable exposed wall space on the double enclosure results in un­ desirable heat loss from the system. The open area where sewage discharges creates an undesir­ able release point for volatile materials. Ventilation of the facility may be a problem. The size of the structure may also create^structural problems on sites which are unstable upon thawing. The single-chamber, two-story type lift-station (Fig. 20) also presents problems of a similar nature for cold region use. Although the excavation for this type of station may be smaller in area, it is deeper. Pumping stations with an enclosed storage tank in a single chamber (Fig. 21, 22) have the fewest disadvantages for cold region use. The sewage is stored for a shorter period of time, the 28 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS problem of release of volatile materials is minimized, and the unit may be more readily insulated. Such stations are also more easily constructed at the site and several prefabricated units are on the market. Miscellaneous appurtenances such as manholes and cleanouts should be constructed to minimize heat losses from the system.MS Except! under specially protective environ­ ments, inverted siphons may be particularly susceptible to freezing. Non-frost-susceptible fluid-carriage systems using oil or a synthetic flushing fluid such as an antifreeze have been used with some success. Where the flushing and transport vehicle may be used for another purpose the fluid is used only once for col­ lection and transport of wastes. Systems using fuel oil as a collection and transport vehicle exemplify the single-use fluid sys­ Figure 22. Pumping station with enclosed stor­ tems concept. Antifreeze fluids are treated age tank in a single chamber. (After Rogers.165) to remove wastes and are then clarified and reused. A small experimental system at Barrow which used fuel oil as a collection and transpat vehicle has been described by Logan111 and others. In this system, toilets were flushed with fuel oil and the resulting slurry of fuel oil and waste was prepared for use in firing the boilers that provided heat and power f a the installation. No smoking signs were much in evidence. In the synthetic-recirculating fluid system (Fig. 28,24*25) the fluid may bo a simple anti« freeze mixture a a specially famulated agent with characteristics that improve ite use as a collection and transpat vehicle. The ideal synthetic flushing vehicle would be non-toxic, readily separated from wastes, non-frost-susceptible, relatively cheap, odorless, colorless and would not break down in re-use. Although further research is indicated in developing such agents, some are now available that satisfy several of the ideal requirements. Clark and Groff, in a repat to the Navy on cold region waste disposal,^recommended as one of their alternatives a non-frost-susceptible fluid carriage system combining collection and disposal on site.which would incinerate the waste and recover the flushing agent. Although no systems of this type are in use, they are under study.

Dry collection and transport systems Dry collection and transpat systems range from the most primitive to extremely sophisticated devices. Mechanical and pneumatic systems as well as hand labor, and sleds and wheeled a tracked vehicles have been employed in dry collection and transpat. Most of these systems are either aesthetically offensive a involve the use of complicated equipment. The euphemistic chamber pot and box-and-can are still the most common types of waste dis­ posal system in use in the cold regions. In some places the chamber-pots are emptied indisaimi- nately on the surface of the ground near the homes. This dangerous practice should be abandoned. Pathogenic aganisms, which may exist in excrement, may remain viable fa great lengths of time. The excrement freezes almost immediately during the winter; however, it thaws and becomes a stinking and disgusting, as well as a potentially disease-producing, accumulation during warm weather. COLLECTION AND TRANSPORT 29 Hone Pump

Figure 23. Recirculating synthetic-flushing-fluid Figure 24. Recirculating synthetic-flush­ system. (Clark, Alter, and Blake.**) Separation ing-fluid system. (Clark, Alter, and is accomplished by using a flushing fluid that is Blake. 33J Separation is accomplished by lighter than water and thus the wastes freeze in the using a heavier than water flushing fluid lower part of the disposable tank. that floats wastes in the unfrozen state.

Condenser

, Lower Sewage Discharge (alternate)

Hand Pump

Cleanout

Figure 25. Various arrangements for reuse of synthetic flushing fluid. (Clark, Alter, and Blake.**) Collected wastes may be periodically discharged to point of ultimate disposal. The arrangement on the right provides for vaporization and condensation of flushing fluid. 30 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Excrement from chamber pots is some­ times dumped into receptacles such as empty barrels. The filled barrels are then hauled away and dumped on the tundra or at some other convenient point. In coastal areas, dur­ ing the winter, filled containers may be placed on the ice and allowed to drift out to sea when the thaw comes and the ice moves out from shore. Filled metal oil barrels drifting out from a village have been reported to have accumulated at shallow points in such an Figure 26. Diagram of recirculating water-flush amount that they created a hazard to navigation. system with extended aeration treatment (Clark, In many communities, private or municipal Alter, and Blake.33) scavenger services are operated. Some scaven­ gers collect the filled can and leave an epipty one while others empty the filled containers into a tank truck and return the can unwashed. Washing of cans at the truck is unsatisfactory at o extreme low temperatures. Heated quarters must be provided for emptying and cleaning cans. Al­ though the scavenger usually dumps the collected excrement in a relatively isolated spot, it may be a source of infection unless it is buried or otherwise properly disposed of. Burial is very dif­ ficult in permafrost and usually possible only in summer. In some places, the standard chemical toilet is used with or without chemicals. The boxes should be designed for proper ventilation, or the device will cause an unpleasant odor to permeate the room and sometimes the entire building. Usually the boxes are vented outside the living quarters, although there are many installations which are not vented. Hoarfrost forms in vents to the outer air in such quantities that the vent is almost inoperative. Frequently the box is con­ structed of wood ahd almost any type of can which does not leak is used* All cans should have tight-fitting lids for use when the can is carried for emptying. Although much effort has gone into development of reliable mechanical systems they are rarely used. Conveyors of the chain and screw type have some application in connection with other handling methods, but simple practical units are not yet available for general use in commun­ ity systems. A pneumatic collection and transport system that transports wastes by vacuum has been re­ ported in Sweden and Mexico. There are apparently none in use in Alaska or Canada. Freezing processes are under study as an aid in collection and transport of wastes. Using the natural low temperature to keep wastes frozen is an ingenious use of available resources. How­ ever, much work is necessary to perfect methods of preparing wastes for transport and to keep them frozen and transportable by pneumatic system as long as temperatures are low enough. The slightest occurrence of moisture in the system is potential cause for bulking of the waste material and subsequent plugging of the system. The method offers promise under extremely low temperature use. At installations on ice, wastes have been discharged into pits. The wastes have included body wastes in small and large quantities and cooling water from power generation. Freezing wastes in snow or ice crypts at point of origin is a simple form of dry collection; transport problems are avoided. The method has little general application. However, as a method of ultimate disposal, freezing of wkstes in crypts will be discussed in more detail in the next section. COLLECTION AND TRANSPORT 31

Table X. Adequacy of waste collection methods. (Clark, Alter, and Blake.33)

COLLECTION METHODS

DRY COLLECTION FLUSHING : SYSTEMS

* 0 - v G o * ' £ « T & oVr

4? < A p ? Basis for Evaluation w Military Criteria Suitable for six months Q Q Q s S s S s Q s Suitable for ten years U U U s s s s Q U s Suitable for 25 men Q Q Q s s s s S Q s Suitable for 100 men U U U Q s s s Q U s Suitable for 500 men U U U U s s s U U s Readily manufactured & procured S S Q Q s s s Q Q Q Easily shipped S S S S Q s Q S S S Easily installed S S S S S s U S S S Combines with kitchen& wash wastes U U U U S s S U U U Health & Safety Criteria Effective barrier to disease spread U U U S S s S S Q S Wastes inaccessible to vermin U U U S S s S S S s Free from fire or safety hazard S S S Q s s S S S u Aesthetic Criteria Non-odorous u U U Q s s s S Q u Not unsightly u U U S s s s S Q Q Comfortable to use u Q Q S s s s S S S Operating Criteria Simple to operate s S S Q s s s S S S Suitable for repeated use s S S U s s s S S S Easily maintained s S S Q s s $ S S Q Easily cleaned u U Q Q s s s S Q Q Few repair or replacement parts s S S Q s s s s S S Economic Criteria Uses minimum water volume s S S S u Q s s S S Uses minimum manpower s U U S s s s s S S Uses minimum power s S S Q s s s s S S Satisfactory (S) 11 10 9 11 21 22 21 18 12 16 Questionable (Q) 2 3 5 9 1 1 1 3 7 4 Unsatisfactory (U) 10 10 9 3 1 0 1 2 4 3

Collection and disposal at point of generation Collection and disposal at point of generation is accomplished by the incinerator toilet and by chemical digestion tanks. Although these systems have extremely limited application, there are several of them in use. The principal disadvantage is that they only accommodate part of the wastes and leave a collection and transport problem unsolved for bath, laundry and similar wastes. Incin­ eration and chemical treatment will be discussed in more detail in the next section. Various analyses of the cold region waste collection and disposal problem have been made.51 137 Table X is perhaps the best summary available. 32

PHYSICAL TREATMENT AND PROCESSING

In sewage-works design and operation physical treatment and processing devices and pro­ cedures are significantly affected by low temperature. Although much more investigation will be necessary before precise assessment can be made, experience has resulted in sufficient informa­ tion for good design and operation. The almost continuous low temperature in the cold regions adds greater importance to pro­ cesses benefitbetlby cold which have little or no value in sewage-works practice in warmer regions. Freezing processes for solids separation, removal of grease and oils, storage of wastes, and de­ hydration are examples. Spraying and atomization of wastes in the air at low temperature has been found effective in separation and removal of dissolved chemicals as well as organic matter from water.

Conditioning processes Conditioning processes, treatment methods, and disposal methods all utilize physical proc­ esses to some extent. Numerous physical concepts have been applied in waste handling. Although physical processes are affected by low temperature they are not as susceptible to temperature ef­ fects as are biological or chemical processes. The most common conditioning processes are skim­ ming, screening, filtering, and freezing. Skimming tanks for the removal of grease and oil operate much more efficiently at low tem­ perature than in temperate climates. Skimming chambers should be kept as cold as possible with­ out permitting freezing. Low temperatures have little or no effect upon the screening of sewage to remove coarse suspended and floating matter unless icing of the screen is not prevented. Frazil ice may form in the channel following the screen if the temperature of the sewage is too low. Screen chambers can be heated electrically or with steam and should be enclosed in heated structures. If sewage com­ ing into a bar screen is at or very near the freezing point ice will form on the screen. Screens constructed to minimize the rate at which heat is conducted away from the screen tend to minimize the icing problem. Microscreens22 207 used for sewage clarification (Fig. 27, 28) may present operational diffi­ culties with very low temperature sewage. The fine screen occupies less space in a heated area but presents more mechanical problems in operation than conventional clarification units do. In frozen soil and soils near the freezing point it is doubtful if filtering wastes into the soil accomplishes much more than mechanical filtration. This is particularly descriptive of the so- called cesspool. A deep leaching pit (cesspool) allows liquids to drain away and retains the solids. Most installations of this kind are so deep in the ground, to minimize the effects of season­ al freezing, that they are below the zone of biological activity in the soil. In reality, the cesspool in a low temperature area appears to be a filter. Under certain conditions, cesspools may be kept operative during most of the year. At points where drainage from the cesspool finds its way to an aquifer, which discharges to a large drainage course, sufficient heat may be added to keep the system operating. Such an occurrence is rare and, in general, cesspools cannot be depended upon for operation during the winter.

Figure 27. Continuous sewage treatment system flow diagram. PHYSICAL TREATMENT AND PROCESSING 33

Dump and Cleanout Valve Figure 28. Section through continuous filtration unit.

Frost mounds in many places attest to the pressures exerted on entrapped water and contra­ indicate the use of any waste disposal system which must rely upon the discharge of effluent into the soil or raw liquid wastes into the soil. If a cesspool is operable, it is quite probable that ground water or food stored in pits underground will be contaminated and that such a method will be dangerous. Freezing has been used very effectively for temporary, semipermanent and permanent storage of wastes. Freezing makes the temporary storage in dry collection systems less offensive. Many sewage stabilization ponds have been designed for planned use of freezing for storage of wastes until warmer weather.

Treatment processes Treatment of sewage by physical means may involve one or more of several processes: sedi­ mentation, flotation, foaming, heating, centrifuging, filtering, grinding, evaporation, irradiation, desiccation, freezing, electrical treatment, adsorption, ultrasonic vibration and combustion. As in conventional practice, sedimentation, filtering, grinding and combustion are the most commonly applied processes in cold region practice. The additional processes of heating, irradiation and freezing assume greater significance in cold regions. In plain sedimentation in cold regions (Fig. 29, 30) certain physical factors must be con­ sidered162 that may well spell the success or failure of this stage of sewage treatment. Theorem ically, temperature has a marked effect upon the subsidence of particles (Fig. 31). Settling velocities decrease with falling temperatures. Viscosity of sewage increases at low temperatures and more resistance is offered to the settling of some particles. Depending upon size and nature of the particle it takes almost a third longer for some particles to settle at 32 to 35F than it does at 50F and twice as long for them to settle at 32F as at 74F. Settling tanks designed for cold re­ gions should have minimum settling rates. Surface area loading is probably the best basis for design. Tray-type settling basins lend themselves more readily to cold region construction. 34 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

E fflu en t

Figure 29. Circular-plain sedimentation tank.

Scum

Figure 30. Rectangular-plain sedimentation tank.

HYDRAULIC SUBSIDING VALUES, mm/sec. Figure 31. Theoretical relation of hydraulic sub­ siding values to temperature. According to Stokes’ Law as applied by Hazen for particles with speci­ fic gravity of 1.2 and a diameter of 0.5 mm. PHYSICAL TREATMENT AND PROCESSING 35

Settling chambers should be protected from freezing. Too much heat and uneven heating of the enclosure in which the tanks are located may seriously affect the op­ eration. Proper ventilation and vapor barriers in the en­ closing structure will prevent undue condensation on the walls (App. D). As a result of the increased viscosity of water and decreased rate of subsidence of certain part­ icles, plain settling tanks should be increased to one and one-half times the design size necessary in a tem­ perate climate, or provision should be made for maintain­ ing a sewage* temperature favorable for treatment. Settling tanks for flocculent material at low tempera­ Figure 32. The foaming process. tures may be more desirable if they are designed for up­ (Clark, Alter and Blake. **) ward flow and if the tanks are deeper than necessary for settling of plain granular material; however, tray type units may be best protected from freezing. Design should be preceded by field and laboratory tests for optimization. Pilot plant tests should be made where treatment is planned for an existing facility. Field temperatures and conditions should be faithfully duplicated in the laboratory. A detention period as long as that required for effective sedimenta­ tion in a glass tube as deep as the effective depth of the proposed tank may be used as a guide in design of a pilot plant. The design of grit chambers that will function properly at low temperatures is difficult. Due to change of viscosity it takes almost one and one-half times as long for finely divided mineral solids to settle at 32 to 35F as it does for them to settle at 50F. Removal of settled and floating materials from sedimentation chambers presents a special problem in cold regions. Complicated mechanical devices should be avoided in isolated polar facilities, yet hand movement and scraping under low temperature conditions is also objectionable. Every effort should be made to simplify cold region facilities and to minimize safety hazards. Flotation of suspended particles lighter than water or raising solids heavier than water by the injection of air bubbles, thus decreasing their density, is not a common cold region practice.94 However, aeration tends to mix the water mass and maintain an even heat distribution. A more favorable heat distribution may be maintained if the injected air is heated. If the air is not heated freezing may be expedited. Flotation, as a cold region treatment process, is very effective in re­ moving grease and oils. Low temperature also increases the effectiveness of foaming (Fig. 32) as a treatment pro­ cess.57 Dissolved material as well as suspended matter are removed, although the process is not in common cold region use. Heating sewage is common practice in cold regions. Several methods are utilized but, where possible, the most desirable method is to raise the water supply temperature and thus indirectly raise sewage temperature. In the city of Fairbanks, Alaska, a small part of the otherwise waste heat from power generation is now used to warm the community water supply. As a result of this practice, water treatment has been simplified, water pipe freezing problems reduced, and average temperatures of community sewage raised 20 to 25F. Nuclear-powered generating facilities pro­ duce even larger quantities of waste heat. Sewage may be heated by immersion heaters, heat exchangers, and by mixture with warm water or steam. In a digestion chamber the sludge is heated by circulating hot water through pipe coils in the tank wall. All these methods present operation and maintenance problems. Organic material builds up on the warm surfaces exposed to the sewage and gradually reduces the efficiency of the heating devices. They must be cleaned periodically. Sewer lines placed in utilidors with heat lines often become so warm that the sewage becomes septic (see Table VI). 36 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Sewage may be heated to prevent it from freezing, to improve treatability, to pasteurize it, and to stabilize it. In practice it is usually heated to prevent freezing and to improve treatability, rather than as a direct method of treatment. Sludge digestion units are heated to optimum tempera­ ture for operation. Based on the present state of the art both in temperate climates and in cold regions, psychrophilic and mesophilic digestion appear to be much less efficient than thermophilic digestion. Clark and Groff34 recommend a temperature of 160F for 6 minutes for disinfection of mas- cerated sewage, when heat is used. Such a temperature is readily attainable from waste heat from nuclear power plant coolants. The process is not in current use in cold regions. Concentration of sewage solids by centrifuging is not practiced in cold regions but does offer promise.92 The equipment is simple to operate, requires little space, and may be readily housed. The temperature of tte waste, if it is unfrozen, does not present a problem.

Filters of the spring coil type are functioning satisfactorily at the sewage treatment plant at Camp Tuto, Greenland. Fairbanks, Alaska, also processes sludge by means of a filter. This process is accomplished in a heated structure and no special cold weather design and operation criteria have been indicated. Mechanical filters present problems in maintaining mechanical sim­ plicity in cdd region treatment. However, reliable operation should be expected with adequate design and construction and experience in operation. Grinding and disintegration is widely practiced as a treatment process. It facilitates waste reduction by dilution and biological action, and improves fluid transport. The size of transport lines may be reduced. According to present water quality standards, the process is unacceptable in itself as a treatment method and cannot be considered to be an effective public health protec­ tion measure. Solids separation is more difficult after grinding. A minimum of heat is lost if the process is enclosed, and it is useful in preparing kitchen wastes for transport in fluid carriage systems. The process may also be used in preparing material for transport in the frozen state.

Evaporation is a more valuable process for cold region use than might be expected. Much of the cold regions is semi-arid and the air is relatively dry. Evaporation is useful in connection with freezing in drying sludge. The air is so dry during the period of thaw that snow and ice evaporate rather than melt, although proper use of evaporation in conditioning sludge requires adequate means for drainage from the sludge drying bed. Drying beds are most effective when they are designed to permit circulation of air both above and below thin layers of drying sludge. Shallow sludge dry­ ing trays with bottoms constructed of wire mesh appear to be most effective. Ionizing irradiation112 of wastes, is under study as a process for both disinfection and stabil­ ization.55 By special design nuclear reactor coolant may be used as a radiation source. Unintere cepted neutron flux must be changed to beta and gamma radiation and deposited material will be­ come radioactive. Decay occurs with storage but this requires special facilities. The process needs much further refinement to make it generally applicable for cold region use. Desiccation (air drying) as a treatment method for use in freezing temperatures has not been reported. It appears that the process would take place very slowly. A large storage and exposure area would have to be maintained if the processes were to treat any large amount of wastes. Where ample waste heat is available (as from a nuclear power facility) it might be feasible to carry on the process at above-free zing temperatures. However, this amount of waste heat could be used to greater advantage in some other form of treatment. Freezing offers considerable promise as a method for treating cold region wastes.50 174 With proper management it can be effectively used to separate solids from waste water.70 The effective­ ness is enhanced by use of a synthetic fluid in which the wastes may be partially separated by dif­ ferences in density of the fluid as well as by freezing. The Arctic Environmental Engineering Lab­ oratory of the University of Alaska has had success with the freezing process for separation of PHYSICAL TREATMENT AND PROCESSING 37 suspended and dissolved material from water prepared for drinking. By spraying water at a tem­ perature slightly above freezing into -30F air the water is quickly frozen and the foreign materials remain unfrozen and leach away from the accumulated ice pile of frozen clean water. Regulation of the spraying environment as well as the rate and size of spray is necessary for proper results but the equipment is simple to operate. When spraying sewage wastes, it is necessary to control the spread of possible infective droplets in the environment. Where electricity is economical, electrical treatment offers promise. Electrodialysis, use of electric current for disinfection,209 and electrochemical treatment are the principal methods. None of them are particularly changed by the cold region environment. The availability of elec­ tricity is the vital key but it should be available at little or no direct cost to the treatment process. In electrodialysis direct current forces ionic migration through specially prepared membranes which collect the concentrated material. The low ionic strength of waste waters makes them more adaptable to treatment by electrodialysis than material such as sea water. The process is, as yet, not used for cold region waste treatment but is being studied. It would appear that wastes should be well filtered before treatment by electrodialysis. Present efficiencies of electrolytic cells would preclude their use for cold region waste treatment. The process, however, is intriguing in that new water can theoretically be created from sewage wastes. By breaking the waste into elemental oxygen and hydrogen and then recombining the elements, solids and objectionable materials could be separated. Use of electric current for disinfection27 has not appeared to offer any advantage over other disinfecting processes. Energy requirements are about the same as for heat treatment. Electro­ chemical treatment offers much more in that the wastes undergo the equivalent of coagulation, flocculation, and settling as well as disinfection. In the electrochemical process,127 sea water is mixed with screened sewage, and the mix­ ture is passed through an electrolytic cell. It is then flocculated and settled, becoming disin­ fected in the process. The effluent is clear and the sludge may be dried without further process­ ing. The process is quick and simple but requires electricity and sea water or . Magnesium hydroxide from sea water serves as. the flocculent and the chlorine is a disinfectant. Proper operation is essential and the costs depend on the availability and price of power. The process is rapid, and housing and weatherproofing would be simplified since a minimum of space would be required. The process has not been reported in use in ther cold regions. Adsorption has not been reported as applicable to cold region waste treatment. Adsorption is a surface phenomenon, and after use the media used to pick up waste materials must be dis­ carded or recharged. The somewhat increased viscosity of waste water near the freezing point would appear to make the process less effective at low temperatures than at higher temperatures. Although the speed of adsorption might be retarded by low temperature, the retentive capacity of the medium might improve. Adsorbents have long been used in water treatment to remove trace impurities. The heavy load of impurities in waste water would spend the adsorptive media rapidly and regenerative facilities or medium resupply would be a major item. The effectiveness of ultrasonic vibration113 as a disinfection process85 is considerably re­ duced at low temperatures. Turbidity also limits its effectiveness. Operating costs and the com­ plications of the process may also limit its use in cold regions.

Disposal methods Combustion, including incineration, wet combustion, and high temperature oxidation, has been used extensively in sewage treatment. Incineration is most common in cold regions as a means of ultimate disposal. Combustion appears to have few limitations as a direct result of low temperature. However, the availability and cost of fuels in isolated areas, ice fog problems 38 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Figure 33. Human waste incinerator. resulting from release of moisture and particles to the atmosphere, and equipment complications have impaired the effectiveness and efficiency of the process. Incineration of dry wastes has been more effective than attempts to incinerate fluid-carried wet wastes. Incinerating-type toilets,140 utilizing electricity, gas, or other fuel directly in the commode unit, have been developed. Operating temperatures during the incinerating process must be held continuously high, otherwise foul odors result.171 Maintenance of the unit requires some experience and must be done regularly. Venting of the unit is most important. The incinerating commode does not permit the disposal of other wastes such as kitchen and bath wastes. It does provide a means for ultimate disposal without use of water, which may be in critical supply, and with proper operation appears to be aesthetically more acceptable than other dry collection and disposal systems. Central incineration of dry wastes has been tried with limited success. Figure 33 shows an experimental unit for incineration of human wastes. The unit and its operation have not been adequately perfected for general use. Problems are high fuel consumption (about 1 gal per 20 lb of waste), odors and foaming. Ultimate disposal of sludge has been accomplished by the incineration process.142 Fair­ banks, Alaska, incinerates raw sludge from the primary treatment plant and the multiple-hearth type incinerating furnace performs satisfactorily. The sludge is dewatered by a mechanical filter prior to firing. Undigested sludge, except for chemically precipitated sludge, contains sufficient fuel for incineration. Chemically precipitated sludge does not burn as readily as plain undigested sludge, unless a firing agent has been added. In some rather advanced industrial processes, mag­ nesium is utilized in settling the wastes and in firing them. With sufficiently effective recovery of chemicals, the processes are economical and useful. Although the use of such a process may be effective for a large industrial installation, it has^ not been perfected for use in small installations and is somewhat complicated to operate. Under cold region conditions available gas from digestion of sewage sludge will probably not meet the added needs for heat to protect the process and also satisfy fuel needs for incinerating the digested sludge. PHYSICAL TREATMENT AND PROCESSING 39

Holding Heat Tank Exchanger

Figure 34. Wet combustion (Zimmerman Process200),

The major limitations on the incinerating process are as follows: 1. As nearly as possible, continuous operation of the incinerating process is necessary for fuel and other operational efficiencies. 2. If intermittent operation is necessary, such operation should provide adequate holding facilities so that batch treatment is as efficient as possible. 3. The incinerating unit should provide at least primary and secondary combustion chambers. The primary chamber should have sufficient heat for evaporation, burning of dried organic matter, and raising vapor temperatures to 1000F. The secondary chamber should subject vapors to 1600F with sufficient oxygen, turbulence and time to prevent odors and com­ plete the process. 4. Consideration should be given to minimizing ice fog and fly ash, or arrangements made to eliminate them. 5. Facilities for holding wastes to be incinerated should be located and maintained so that they do not create a nuisance. Where possible, low temperature may be used to advan­ tage in providing satisfactory holding facilities. The incineration process has the advantage of complete destruction and disposal without nuisance or health hazard. The proper operation of incinerating facilities requires training of per­ sonnel, and experience in operation. Present equipment has not been specifically designed for cold regions and has not reached the efficiencies for small installations that are achievable for large plants. At Barrow, Alaska, an experimental unit used fuel oil to collect and transport wastes. The wastes and fuel oil then fired boilers for heat and power at the site. The unit was effective but there were dangers in the use of fuel oil for transport. Difficulties arose in keeping the firing nozzles trouble-free, and operation required experienced and trained personnel. In the wet combustion process200 208 (Fig. 34) aqueous sludge and air are pumped into a pres­ sure reactor maintained at a temperature of 500-600F and a pressure of 1200 psi. Oxidation of the organic matter is thus accelerated and accomplished even though the sludge is wet. With suffici­ ent volatile matter in the sludge the process can be self sustaining and thus not require added fuel. Additional power can be produced in volatile-rich-sludge combustion. Primary sludge maybe 40 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS expected to produce about one-third as much heat in the process as is produced by fuel oil. Flame­ less combustion occurs, gases are released to the atmosphere, and residue remains in the water. The process is highly sophisticated and not yet adapted to small installation use. It has promise for development as a suitable cold region process but is not now in use in the cold regions. Odors and air pollution other than moisture, which may form ice fog, are eliminated by the process. High temperature oxidation of organic materials69 is also a flameless process but is con­ ducted under normal pressure at temperatures of about 750F. Ground wastes are injected by atom­ ization into a reactor tower. The finely divided (20 to 25 microns) particles settle slowly in the tower and are dried as they settle. After drying, the particles are« mixed with air to completely oxidize them. Water can be removed by condensation and the solids are removed as fly ash in a cyclone separator. Gases such as nitrogen and excess oxygen are exhausted to the atmosphere. The process is fast - about 10 seconds. Initial costs are low, the equipment is simple, little or no power is required for sludge disposal, and it appears to have its principal application in places where water is to be reused. Although maintenance and operation are simple, some training and experience are required for operating personnel. The process offers considerable promise for cold region use in places where it is necessary to recover water for reuse. Undoubtedly some problems may be expected in developing small automatic type units that are dependable and prevent air pollution with moisture which may result in ice fog. However, this system, even though it is a patented process, appears to offer the most promise as an efficient incinerating device for handling wastes in areas where water is scarce and expensive. In addition to physical treatment and processing for disposal by incineration, wastes may be physically disposed of by freezing, atomization and irrigation, and by deep well injection193 or dispersion into the environment. Deep well injection is costly even for large installations and it is doubtful if it is feasible for small cold region communities. Injection presents serious public health problems unless wastes are discharged deep enough to be almost into the crystalline struc­ ture of the deep rock. The cost of drilling a disposal well to this depth plus the lack of experience in discharging into permanently frozen ground would almost preclude this as a practicable method. With proper study of conditions and observation of past actions, the method might have some appli­ cation for storage of wastes from nuclear power generators. The temperature of such wastes would probably satisfy the heat losses. However, the decay of radioactive materials might be very slow (depending upon the radionucleides being discharged) and the disposal area might present a long-time hazard to health. The state of soils in cold regions almost precludes effective and safe irrigation of wastes on the surface of the ground. Freezing air temperatures are helpful in recovery of the water and in treatment to separate solids if the wastes are atomized into the air. This process for treatment is described under Freezing processes. Ultimate disposal by dispersion in the environment, whether it be on land, in the air, or in re­ ceiving waters | may dissipate the wastes but the process is so slow and unpredictable at low tem­ peratures that it is not considered safe and reliable. Ultimate disposal by freezing in a storage crypt has served as an effective storage device in Greenland.12 144 155 156 However, this process does not solve the problem of waste dispbsal as much as it postpones the decision of what to do with wastes. The wastes are stored in a controlled area and do not create an immediate problem, but reoccupation or reuse of the site for other purposes demands great care. 41

CHEMICAL APPLICATION

Chemical application may be for conditioning, treating, or ultimate disposal. In general, chemicals are not readily available in cold regions, and logistical problems and cost place a seri­ ous handicap on their use. Therefore chemicals other than disinfectants and deodorants are not normally used. These handicaps should not discourage the engineer from carefully evaluating the applicability of chemical processes in solving some of the difficult problems of waste treatment and handling because chemical application may still be the best solution. Chemical application usually requires metering equipment in continuous processing as well as measuring facilities for batch treatment. Storage facilities are necessary where large quantities of chemicals must be used. Difficulty in resupply may necessitate the stocking of a several months’ supply of chemicals. The additional costs of storage facilities and stocks to be maintained should be considered in planning. Low temperature makes serious adjustments necessary in feed­ ing gaseous chemicals and affects the solubility and reaction times of most chemicals used in the dry state.

Conditioning processes Chemicals have been used in cold region communities for conditioning operations in waste treatment, and processing operations such as freezing processes designed for solids separation, coagulation and flocculation, and in sludge conditioning. Clark, Alter and Biiake33 cite and describe the use of certain chemicals as follows: “A synthetic flushing fluid may be used in a fluid-carriage system to achieve the convenience of a water-flush system but not use water. By the selection of a fluid with proper characteristics, various functions can be performed. Possible de­ sirable characteristics would include that the fluid be: 1. Lighter or denser than water. 2. Immiscible in water. 3. Readily available at low cost. 4. Noncorrosive, non-toxic, nonflammable, inert and nonvolatile at normal temperatures and preferably to -80F. 5. Not objectionable in odor or color. 6. Non-freezing to a low temperature, preferably -80F. “If such a fluid were available it could be recirculated as a flushing fluid from a holding tank to the toilet and thus have little or no effluent to discharge. “Several such fluids are available which are heavier than water, but it is un­ known whether toilet solids will settle out, gather at the liquid-liquid interface or disperse in the flushing fluid. An example would be Freon MF (CC13F), boiling point 75F, freezing point -168F, specific gravity 1.5, and solubility in water 0.009% by weight. “A contrasting fluid would be lighter than water, thus assuring rapid clarifica­ tion of solids and also allowing, at temperatures below freezing, the wastes to freeze at the bottom of the holding tank and thus be preserved. A possible difficulty in the use of a lighter than water fluid might be its inability to carry solids in transmission lines if there is a great difference in specific gravities. One possibility of this type would be white, or mineral, oil. Although the normal mineral oils are quite viscous, they can be produced more cheaply with much less (Viscosity. One presently available, 42 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

with a viscosity of 70 Saybolt Universal at 100F, has a specific gravity of 0.87, flash point of 320F, pour point of -50F, is odorless and is immiscible with water. “ Some advantages may be gained by mixing different fluids in order to ob­ tain the required characteristics. “The advantages of this system are evident from the list of characteristics required. The system would be simple, compact, operation-free, and inexpensive. It would still have the volume of sanitary wastes in storage to dispose of some time in the future unless it is combined with a continuous solids disposal process/’ The chemical used for synthetic flushing could also be designed to be used as a refrigerant to prepare wastes for either storage or transport^ the frozen state. By selection of the proper chemical agent, cold in nature could be used in an almost automatic and relatively trouble-free system. Flocculation, by use of chemicals, seems to be significantly speeded up by relatively low temperatures. Increased viscosity of the sewage at low temperatures may play a part in this oc­ currence, as may a change in electrochemical phenomena under low temperature conditions. The floe may form readily but precipitation of the floe is retarded by low temperature, as mentioned under plain sedimentation. Very little change in the quantities of chemicals needed for floccula­ tion is noted at low or average sewage temperatures. In certain instances it is necessary (for good precipitation in a minimum time) to add more chemicals when the sewage is at about 32 to 35F than when it is at average sewage temperatures. Efficient operation depends on settling time and chemical concentration. Conservative design for chemical precipitation basins, under low temperature conditions, would include: 1. Moderate mixing of chemicals in sewage prior to sedimentation. 2. Use of deep tanks which are enclosed and located above the ground surface or where they will not affect the permafrost. 3. Application of a factor to tank size as determined from a pilot plant. This factor may be as high as V/2. Chemical sludge accumulation may amount to as much as 0.3% of the volume of sewage treated and some provision must be made for handling increased quantities of sludge. Chemicals used for sludge conditioning coagulate the solids dispersed in the sludge and in­ crease the rate of mechanical filtration. Ferric chloride, chlorinated copperas, ferric sulfate, and aluminum sulfate are used as coagulants. Lime is often used to facilitate the process. Low tem­ perature affects the solubility and reaction time. This is not a common practice in domestic waste treatment and is even less common in cold regions. The magnesium oxide process has been suc­ cessful in treating industrial pulp waste material. The magnesium is recovered after the combined magnesium and waste material is burnt off. The problem of resupply is thereby reduced and in addi­ tion the fuel value of the waste is partially recovered and utilized. Although chemical conditioning of sludge is not in common use it may offer a fruitful area for further investigation.

Treatment processes Chemicals are most commonly used in waste treatment processes for disinfection, although they may be used for oxidation and for total disintegration of the waste material through chemical digestion. Halogens, coal tar distillates, heavy metals, strong alkalis, ozone,130 219 and quaternary ammonium compounds are used for disinfection. Chlorine is the only disinfectant widely used. Temperature has a marked effect on the application of all these agents. Iodine appears to be pre­ ferred because it is affected by low temperature less than many other agents are. Theoretically, temperature would not seriously affect the use of some of the other agents but experience is in­ sufficient to draw general conclusions. CHEMICAL APPLICATION 43

Below 49.2 °F

TEMPERATURE Figure 35. Solubility of chlorine in water.

Use of chlorine gas or similar disinfectants may be indicated in some instances where a relatively safe effluent is required, and where sewage temperatures permit effective use of chlorine. It is generally not necessary to chlorinate for odor control although in instances where little or no treatment is provided and dilution is insufficient, unsatisfactory conditions may occur. Ice cover during a great part of the year may prevent reaeration of the receiving water. Accumulations of waste may give trouble during the warm period. Low temperature and high dissolved oxygen con­ tent of arctic waters tend to minimize the immediate effects of pollution but greatly prolong self­ purification of the receiving water. Pathogenic bacteria in dilution water under such conditions may remain viable for great lengths of time, and where there is any possibility of sewage wastes contaminating water or food sources, disinfection should be provided. The solubility of chlorine in water increases at low tem­ perature down to the point where chlorine hydrate forms (Fig. 35) but the contact time must be lengthened greatly. At temperatures near freezing, chlorine is relatively ineffective, so high concentrations or extremely long contact periods are required for disinfection. Approximately a 100% increase in con­ tact time and concentration should be allowed for disinfection of sewage at less than 40F. The pressure of chlorine gas at 70F is more than five times as great as it is at OF, and special considerations must be given to control of chlorine dosing in arctic areas. Slight variations in temperature of the enclosing structure may affect equipment and vary dosage considerably. Oxidation of the organic matter in wastes occurs when strong oxidizing agents are added. At low temperatures the reactions are usually slowed. Peroxides, sulfuric acid and similar agents have been suggested for oxidizing agents. It has been suggested that wastes might be collected in a pressure vessel until it is full and then oxidants added and the vessel subjected to heat and/or pressure and the waste matt« thus stabilized. These -processes are all in the speculative stage and none have been reported in the literature for cold region use. Wastes disintegrate when strong alkalis are added and allowed to digest or partially digest the organic material. This is a process similar to that used in the old style chemical toilet in which the toilet is charged regularly with strong alkali, and wastes are digested in a collection 44 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Figure 36. Flushing type chemical toilet. tank. The system is useful for disposal of wastes collected without flushing fluid or dry wastes. The digested material is a heavy fluid which is offensive and presents an ultimate disposal prob­ lem after digestion. The chemical disintegration process is retarded by low temperature. There is no record in the literature of application of this process in the cold regions. Modifications of the process (Fig. 36) are common; they use bacteriostatic agents and masking agents to hide the odors from the collection vessels. In this latter modification little or no disintegration of the wastes occurs.

Disposal methods Disposal methods utilizing chemicals involve complete chemical digestion and leaching to the environment, or disposal by dilution. They also involve use of magnesium or oil, or other readily combustible materials, which may be fired with the wastes. Although only a few such agents have been used they offer a fruitful and promising field for further investigation. The ap­ plication of chemicals to sewage has received little or no study under specifically cold region conditions. By consideration of waste disposal requirements in connection with other needs of such a unit it may be possible to find ways to salvage the fuel values of wastes and at the same time provide expedient and satisfactory disposal techniques. 45

BIOLOGICAL PROCESSES

Biological reduction and ultimate stabilization of organic wastes in nature seems simple and automatic. Under proper conditions, the complex multiplicity of actions, reactions and interactions occur rapidly. Although at times offensive, nature’s cleanup forces are effective except at low temperature, which normally retards and almost immobilizes these cleanup forces. Cold region bio­ logical waste treatment systems can be effective if proper conditions are maintained. Activity of the living matter such as bacteria, molds, algae, and protozoa, which are active in biological treatment, is significantly temperature-related. The rate of assimilation of organic matter by the mixed population, and conversion of the organic waste to cellular and other constituents of the metabolic process, slow rapidly as temperature is depressed below the range experienced in normal practice. Depression of temperature exerts a much greater effect on anaerobic processes than on aerobic processes. Molds appear to be slightly less sensitive to temperatures near the freezing point than do bacteria Land protozoa. It has been conjectured that there may be certain cold-resist­ ant “ super species” of organism that are effective in waste stabilization. The literature does not identify such species. It is doubtful if effective biological reduction and waste stabilization occur at temperatures below 30F, although organisms can survive at much lower temperatures.

Dispersal to the environment During certain brief periods of the year and in the unfrozen portions of an otherwise low temperature environment, some waste assimilative processes take place. Such anomalies occur in nature and under controlled conditions, but are not reliable enough to justify dispersal or other­ wise untreated wastes in the cold environment. Uncontrolled dispersal of wastes on land, in the air, or in fresh or salt water may cause disease. The predictability of proper assimilation of the wastes in the environment is uncertain. In certain cold regions there may be a favorable micro­ climate for waste assimilation in air and in the sunshine near the ground surface. This favorable microclimate exists only during a small part of the year and has not been studied or exploited. Waste stabilization lagoons13* at or just below the ground surface have performed adequately in some parts of the cold regions. Present known biological methods for separation or stabilization of sewage solids in suspen­ sion or in solution, such as stabilization ponds,' contact beds, trickling filters, and activated sludge processes will require modification for cold regions use.170 Most units must be housed or other­ wise weatherproofed and ventilated. Pilot plant studies should be made over an extended period of time before large biological treatment facilities are installed.

Aerobic processes In view of present technology aerobic processes appear to offer the greatest promise for cold region sewage treatment. Aerobic treatment ranges from the simplest devices to very complicated systems requiring highly trained operators. Air is provided in sewage treatment processes primarily to satisfy the environmental needs of the assemblage of organisms that stabilize organic matter and cause it to settle. The physical, chemical and biological reactions that take place in the process are all affected by the temperature of the injected air as well as environmental temperatures and ultimately the temperature of the en­ tire medium.

* This term is used interchangeably with “waste stabilization pond” or just “stabilization pond.“ Some­ times it is called a “sewage lagoon.“ 46 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Table XI. Percentage of year that is daylight and twilight at different latitudes. (Arctic Environmental Engineering Laboratory of the Uni­ versity of Alaska, College, Alaska.)

Twilight and Latitude Twilight* Daylight daylight

25 3.49 59.50 53.99 35 3.92 50.60 54.52 45 4.68 50.75 55.43 52.5 5.71 50.94 56.65 55 6.24 51.03 57.27 59.5 6.95 51.14 58.00 60 8.11 51.28 59.39 62.5 9.80 51.49 61.29 65 10.39 51.37' 62.26 67.5 10.56 52.24 62.80 70 10.94 51.97 62.91 72.5 10.18 51.90 62.08 75 8.93 51.89 60.82

* Civil twilight is the period when the sun is from zero to 0P below the horizon.

In aerobic treatment, the broad spectrum of are contained in tanks, ponds or teds, and surrounded by an aqueous medium. Molecular oxygen is an essential reactant and must be resupplied in the form of dissolved oxygen as the biota use it.26 30 Air may be supplied mechanically72 or naturally.128 Mechanical aeration diffuses air through the fluid sewage mass by injection through porous plates placed within the mass in a tank, by bub­ bling air into the mass from perforated headers or tubing,158 159 or by stirring the surface of the fluid mass.151 Surface stirring devices, such as horizontally turning vaned rotors and vertically rotating brush mechanisms, are used for surface aeration. Aeration is accomplished in nature by wind and surface currents as well as the growth and life processes of photosynthetic organisms. The temperature-viscosity relationships of the fluid mass have a direct bearing on the dynamics of gas absorption as molecules are transferred between gas and liquid phases in the aeration process. Ice cover, light transmission (Table XI), and temperature play important roles in photosynthe­ sis. In addition to the usual parameters, criteria which govern selection of the type, size, and con­ figuration of an aeration unit for cold region use include the energy and operating costs for site de­ velopment and weather protection. Treatment by aeration77 has been practiced for many years and in many forms in the cold regions. Plain waste stabilization ponds, modified ponds, extended aeration (package units), and conventional activated sludge plants have been used. The sewage stabilization pond,81 84 187 188 the simplest form of aerobic treatment, is nothing more than a properly designed and located open pond. In temperate climate practice the confin­ ing walls are diked earth (clay or silt) of very low permeability on the order of 10"6 cm/sec. If the soil is pervious a waterproof asphaltic or plastic membrane may be laid and suitably protected by a thin layer of soil. Numerous stabilization ponds are in use in the northern United States (Fig. 37) and in Europe, and there are a few in Alaska9 and Canada. Favorable operational results have been reported. See p. lg-19for a list of facilities and Appendix B for suggested design and opera­ tional criteria. Ninety percent reduction of biochemicaLoxygen demand and suspended solids is BIOLOGICAL PROCESSES 47 mMÊ

Figure 38. Waste stabilization pond at Ft. Yukon, Alaska. 48 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Distributor

4 Overflow

PRIMARY SETTLING Sludge Line

To 4 SLUDGE DRYING BED FINAL SETTLING Figure 40. trickling filter process. possible with this type erf aerobic treatment unit. The Fort Yukon, Alaska (66§30‘ N), stabiliza­ tion pond has operated satisfactorily for several years (Fig. 38). Temperature has a much greater effect on self-purification processes54 than on biological treatment units. Low temperatures reduce the rate of the BOD reaction. Temperatures of 35 to 40F require 200% to 300% greater time for satisfaction of BOD. For all practical purposes, the sewage stabilization pond designed for use under low temperature conditions may be assumed to lie dormant for at least 6 months of the year. During this period the pond serves principally as a sewage stor­ age area. Mechanical aeration has been suggested and tried in preventing ice formation and in con­ tinuing the aeration process. The concept of biological treatment units serving principally as col­ lection and storage areas is common in low temperature practice. At most cold region sites permafrost presents serious problems for stabilization-pond con­ struction. The alteration of thermal regime at the site of such a tends to thaw and open up leakage channels in the frozen soils. Special provision should be made for sealing most stabilization ponds in Alaska, and a thorough thermal analysis should be made to determine the effects of heat on the site. Advantages of the stabilization pond include consistent under a wide range of temperatures, minimal required supervision, resistance to shock loadings, and unusual economy in installation and maintenance. Unfortunately, a large area of impervious soil is re­ quired. In very cold regions on ice-bound sites the stabilization pond would be little more than a storage device. As of 1968, interest is being shown in aerated lagoons and in long aeration ditches BIOLOGICAL PROCESSES 49

Recirculation

b. Accelo-filter

c. Aero-filter

Figure 41. Modifications of the biological filter. in which sewage is circulated by paddles to ensure rapid and efficient mixing of fresh air with the sewage. A biological filter consists of a bed of stone 3 to 12 ft deep upon which settled sewage is sprinkled (Fig. 39, 40). Microorganisms responsible for purification are attached to the stone where, separated from the atmosphere by only a thin film of liquid, they easily obtain oxygen by dif­ fusion. As they adsorb and assimilate the dissolved and colloidal solids they grow and slough off into the filter effluent and are removed by secondary settling. Various modifications of the bio­ logical filter are obtained by recirculation of the sewage133 (Fig. 41). The biological filtration process is more seriously affected by low temperature than is die activated sludge process. Cold region filters must be enclosed. Storage of organic solids in films on biological filters during cold periods may completely clog the filter and stop aeration. Biological filters are advantageous in that operation is reliable within a certain temperature range and they do not require constant attention.20 BOD removals are equal to those of the acti­ vated sludge process. Cold region disadvantages include odors, Ibgifetfcal problems of medium supply, and the long time required to start them. Synthetic filter media have been developed and may have some application in cold regions. 50 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Recirculation

Figure 42. Diagram of controlled filtration process.

4 i i G R IT C H A M B E R Removed sand and 1 ^ grit (inorgonic)

SLUDGE DRYING BED FINAL SETTLING Figure 43. Activated sludge system.

Biological filters are not common in cold region installations; however, if used, such units probably should be enlarged as much as 25% to 60% for proper functioning. This increase in size is based on the assumption that the sewage is not heated in a utilidor or otherwise warmed, and the units are enclosed in weatherproof enclosures. A modification of the biological filter called “ controlled filtration" theoretically handles hydraulic loadings 25 to 30 times that of the conventional filter and 3 to 15 times that of a high- rate filter (Fig. 42). Organic loadings Oth BOD/1000 ft3 day) approximately 12 to 15 times that applied to conventional filters and 7 times that applied to high-rate filters appear possible. Such an installation would be easier to weatherproof than conventional facilities. Aeration treatment of sewage wastes almost reaches the pinnacle of sophistication in some forms of the activated sludge process (Fig. 43).126 Although the concept is basically simple, re­ finements16* and control make constant skilled operation necessary. Without capable operation trouble can develop. There is some uncertainty in prediction of results under all conditions and the process is sensitive to influent variations. BIOLOGICAL PROCESSES 51

Table XII. Relation of air characteristics and temperature. (Based on data from the ASHRAE Guide and Data Book.)

Relative volume Moisture and fan speed content* compared with Temp (Vapor Volume same weight of CF) density) (ft2/lb dry air) air at 70F

80 156 14.1 1.02 70 110 13.7 1.00 60 77 13.3 0.98 50 54 18.0 0.96 40 36 12.7 0.94 30 24 12.4 0.92 20 15 12.1 0.90 10 9.2 11.8 0.88 0 5.4 11.6 0.86 -10 3.2 11.3 0.84 -20 1.8 11.1 0.82 -30 1.0 10.8 0.80 -40 0.55 10.6 0.78 -50 0.29 10.4 0.76 -60 0.15 10.1 0.74 -70 0.07 9.81 0.72 -80 0.03 9.55 0.70 * In grains per pound of dry air. Moisture content is total at (dew* point) saturation for the respective air temperatures (7000 grains of water is equal to 1 pound).

Although there are several modifications of the basic process, treatment generally involves aeration of screened, presettled sewage mixed with some activated sludge collected from the sedi­ mentation chamber just before mixing with the incoming sewage. Non-settleable substances in finely divided or colloidal form as well as dissolved organic substances are converted to settleable sludge. The process provides a high degree (90% BOD reduction) of secondary treatment. Oxygen is supplied in the form of fine air bubbles with high liquid-gas interface ratios al­ lowing efficient transfer of oxygen into solution. Air may be supplied continuously or intermittently by submerged compressed air jets or by entrapment of air from the tank surface by mechanical de­ vices, such as brushes or propellers (see Table XII). An enclosed activated sludge plant has func­ tioned satisfactorily for many years at Helsinki, Finland, where the average annual temperature is 40F. Smaller plants in Canada have also operated satisfactorily under similar conditions. Design for these plants has allowed for longer-than-normal detention periods. Possibly, under low tempera­ ture conditions, detention periods should be increased from 50% to 100%. Current work indicates that this additional holding time may not be necessary with certain wastes being treated in an ex­ tended aeration version of the activated sludge process. Ludzack,114 in evaluating activated sludge performance at 5C and 30C, stated that: 1. Temperature had a significant effect on the variety and motility of the predator population. 2. Solids accumulation was substantially greater at 5C. 3. Low temperature flocculation was substantially inferior. 4. Foaming difficulties were increased by low temperature. 5. BOD and COD removals were about 10% less at 5C. 52 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Aeration tank 6 to 8 hrs detention

a. Conventional activated sludge

Aeration tank

b. Step aeration

Primary Effluent or Raw Sewage Aeration tank Final Settling 2 hrs detention

To Primary Influent Return ♦ if Sludge Primary tank used Excess Sludge 10% to Digester Excess Sludge ♦ Return and Excess Sludge or Thickener

c. Modified aeration

Thickener d. Activated aeration Figure 44. Activated aeration.

Thomas1*6 found extensive use of activated sludge in Canada and indicated that the process was better suited to cold than was the trickling filter process. Activated sludge treatment plants are readily housed. Some versions of the process occupy a small space, and housing or weatherproofing treatment units is feasible.. However, in some situations it may be necessary to heat the incoming air used for aeration. BIOLOGICAL PROCESSES 53

Although Eddy and Fales5 report that volumes of air in the ratio 3250 parts air to 1 of water are necessary to impart the same heat change in sewage, severe operating conditions may necessi­ tate the heating of air for aeration in very cold regions. In Siberia, a minimum temperature of -89F has been reported. Alaska newspapers have reported a low at Snag, Yukon Territory, of -81F; other sources have reported the low at Snag to be -84F. Such temperatures even for brief periods of time would mean at least a difference of 113F between unheated air and minimum permissible sewage temperature. The basic process produces large quantities of wet sludge and special provisions must be made for sludge drying and disposal. Modifications of the process (Fig. 44) include step aeration, bioadsorption, high rate aera­ tion, extended aeration, and the individual household aerobic system. These modifications gen­ erally reduce tank volumes but add complications to equipment and requirements for skilled operation. The individual household aerobic sewage treatment system (a miniature modification of the activated sludge process15) may prove useful at certain sites under low temperature conditions.222 Several such units have been installed in cold regions but many failures have resulted,136 apparent­ ly as a result of one or more of the following defects: overloading, improper protection from weather and low temperature, difficulty and lack of maintenance, and improper location of the unit. Similar commercially manufactured units are available in larger sizes for institutions and small groups. The extended aeration systems,*6 97 100 154 often called total oxidation, are identical in principle with the conventional activated sludge process (Fig. 45), except that there is no primary settling tank and no provision for sludge wasting.223 To eliminate the formation of excess sludge, the aeration tank detention period is 24 hours or more (compared with 6 to 8 hours in conventional activated sludge treatment). Theoretically this allows complete self-oxidation.or“ endogenous respiration,”134 whereas the conventional process allows fa little endogenous respiration. Since this process is considered to be a possible solution to fringe area (suburban) sewage treatment, considerable literature is available on the design and operation. Most of these investigators find good possibilities but are cautious of total acceptance. 54 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Among advantages listed are 1) elimination of primary settling and sludge disposal, 2) greater treatment efficiencies than septic tanks (up to 90% BOD removal claimed under optimum conditions), and 3) minimum odor problems. Critical evaluations of difficulties of present installations included 1) requirement of con­ sistent operation and maintenance, 2) scum accumulation, 3) clogging of air sludge lift, 4) inade­ quate air control (generally too much air which breaks up floe and inhibits settling), and 5) turbid effluent and greater growth of filamentous organisms under low temperature conditions, Proprietary claims of elimination of sludge wastage appear improbable. Total oxidation is neither theoretically nor practically attainable and some buildup of biological solids is inevitable unless effluent carryover of solids is sufficient for balance. A special application of extended aeration191 220 with good possibilities for cold region use is a unit where the supernatant liquor is recirculated (Fig. 26) as a flushing fluid.21 39 74 221 A recent study evaluated three installations in Alaska. Use of one 500-gallon unit for six to eight men was discontinued after two months when ammonia odors developed. Another remote unit serv­ ing three men was used successfully for two years without complaint. The third unit at a prison farm used by eight men was carefully monitored. The flushing fluid turned brown during the first week and remained that color; no odors were detected, floating solids accumulated to 17 in. of depth, and the unit never stabilized in regard to parameters monitored (COD, solids, chloride, ammonia and nitrogen).

Anaerobic processes In the anaerobic processes microorganisms capable of living in the absence of oxygen partially stabilize the wastes. Metabolic processes of living matter are utilized but the end pro­ ducts are different. Most anaerobic processes are less efficient than aerobic processes in BOD removal, and are considered primary treatment processes. They are simpler in design and equip­ ment, but in most cases they require some supervision. Sludge digesters, Imhoff tanks, septic tanks,76 106 anaerobic contact and anaerobic stabilization ponds16 are examples of the anaerobic process. Small waste disposal systems, such as septic tanks (Fig. 46) and subsurface tile fields or sand filters, as ordinarily constructed for use in temperate climates, are impractical in the con­ tinuous permafrost or on ice. During much of the year under severe site conditions, such a system remains frozen when it is located near the surface of the ground where the effluent may be assimil­ ated by the soil.2 29 Unless the tank is deep enough so that the ground temperature is only a few degrees below freezing, the sewage may freeze. Temperatures at this point in the ground are so low that biological action103 in the tank is sluggish, and it is not economically feasible to con­ struct a standard tank big enough for a single premises. Increasing the size of the tank tends to increase its heat losses, thus enhancing freezing problems. Artificial heating has not proved

Figure 46. Septic tank sewage disposal system. BIOLOGICAL PROCESSES 55 economically feasible in this situation. It is necessary to compute thermal stresses on such facilities to determine environmental limits on their use even for collection and holding. The septic tank is a sedimentation tank where the sludge is not withdrawn for lengthy periods but is allowed to deposit and liquefy through anaerobic action. Its principal advantage is the small amount of sludge produced compared to plain sedimentation: 25-40% less in weight and 75-80% less in volume. It also requires little or no maintenance and is inexpensive. '* Septic tanks are not widely used in municipal practice because of the better results ob­ tained by other processes, the occasional discharge of effluent worse than the influent, and the oc­ casional discharge of sludge caused by violent septic boiling. In polar areas, heating and weather­ proofing are required. Recently developed in Sweden after much research is an improvement in septic tank design called the Sewage Digestion Tank. BQD reductions of 70-80% are claimed. The system is encased in a steel tank with five separate compartments through which the sewage flows in se­ quence. Present units being marketed are sized for 5 , 10, 20 and 50 persons, and larger units are being designed. Little operating information is available. Septic tanks are commonly found in the cold regions serving 25 to 100 persons or more. Usually they are enclosed in heated buildings. Septic tanks must be heated, enclosed and con­ structed so that they do not degrade the permafrost. Septic tanks for cold regions should be ap­ proximately twice as large as is necessary where sewage temperatures are 55 to 60F. Imhoff tanks combine sedimentation and sludge digestion in upper and lower sections of one tank and thus are primary treatment units (Fig. 47). However, the digestion proceeds at a much slower rate than in conventional digestion tanks since the tank is normally not heated and the mixing of the fresh sludge with digesting sludge is neither immediate nor thorough. The Imhoff tank has the advantage over the septic tank in that it performs better digestion and will not deliver sludge in the effluent. It delivers a fresher effluent with less supervision than separate sedimentation and digestion units. The Imhoff tank does however require periodic sludge withdrawal. Reported BOD removal ranges from 30 to 50%. Reports of unsatisfactory per­ formance during cold weather have not been uncommon) The causes have usually been overloading, lack of attention (cleaning, skimming, etc.) and insufficient heat in the sludge storage compartment. Thus it appears that although temperate installations require no heating, cold region installations do. Heat must be added to the sewage in an Imhoff tank as ordinarily designed to make it oper­ ate properly. If enough heat is added to permit mesophilic digestion of the sludge in toe sludge

Figure 47. Imhoff tank. 56 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Figure 48. Diagram of anaerobic contact process. digestion chamber, excessive heat is lost to the effluent of the tank and the process becomes un­ economical under low temperature conditions. An enclosure must be provided to protect the tank from freezing in addition to the heating of the sludge compartment to permit mesophilic digestion. Psychrophilic digestion would require almost three times as much sludge storage space as meso­ philic digestion. Minimal heating of the raw sewage may be required to prevent freezing. Sedi­ mentation rates are only about two-thirds of those at normal temperatures, and the sedimentation ¡chamber must be increased in size accordingly. The size and proportions of such a tank make it cumbersome for use in an enclosure. Based on the same principles as the “biolytic” tank which Phelps designed and abandoned in 1910, the “anaerobic contact process” (ACP)33 62 forces incoming sewage through the anaerobic sludge blanket for maximum filtering and absorption of organic solids (Fig. 48). It differs from the Imhoff tank in that while the Imhoff process deliberately keeps the influent separate and at a mini­ mum detention time to keep it aerobic the ACP allows the influent to become anaerobic as an ef­ fluent. In the Imhoff tank, sludge solids are stabilized by liquefaction and elutriation. Efficiencies range from BOD reductions of 80-95% with loadings of 0.10 to 2 lb BOD/day ft3 at 35C, 80-90% with loadings of 0.05 to 0.10 at 25C and as low as 34% with less control. Advantages claimed are 1) economy of installation and operation, 2) no scum or foaming problem, 3) resistance to shock loadings, 4) high sludge storage capacity, and 5) high flow-through capacity. The major disadvantage is the need to dispose of a disagreeable sludge which requires treatment before spreading on open beds for drying. Anaerobic waste stabilization ponds have been used principally to reduce the land area re­ quirements of waste stabilization ponds without reducing removal efficiencies. A pond at Redmond Washington, where detention times were varied, indicated reliable BOD removals of over 65% with a detention time of two to four days, without the generation of unpleasant odors. Surface loadings of 550 lb of BOD/acre day have been more than doubled without adverse effects (compared to 20-60 lb normally specified for aerobic ponds). Advantages and disadvantages are similar to those of aerobic ponds. In general, installa­ tions are two-stage, consisting of an anaerobic pond followed by an aerobic pond. Sludge19 is digested by anaerobic action in which the solid organic matter previously de­ posited by sedimentation is liquefied and gasified. The digestion of sludge prepares it for sub­ sequent disposal, reduces its volume and recovers valuable gas. Disadvantages include cost of equipment and the careful operation required to maintain optimum environmental conditions for con­ trolled digestion. In addition, cold region conditions require weatherproofing. The accumulation of combustible gases increases the fire hazard. BIOLOGICAL PROCESSES 57 in o>

Figure 49. Relation of digestion tank capacities to mean sludge temperature. Exhaust

Conditions affecting digestion include temperature, detention time, mixing, quality and quantity of sludge solids, pH, volatile acids of digesting mixture, and manner of feeding and chemi­ cals added, if any. The importance of temperature is well-known and has been studied by many workers. Investigators of digestion in Alaska have been primarily concerned with insulation for the maintenance of optimum temperatures. Tanks for separate sludge digestion by biological processes require considerable heat,61 but they may be useful in certain instances even under cold region conditions. Heat losses for digestion in the thermophilic range may be so great that this range is probably impracticable. Di­ gestion capacity for the mesophilic range at 40F must be approximately twice that at 60F.(Fig. 49). Since, under Arctic conditions, heating is necessary throughout the entire year for optimum meso­ philic digestion, it is possible that, in certain instances, additional gas recovery might more than offset operation at this temperature. Insulation of the digester, and efficiency and economy of heating methods, would have to be highly favorable for such operation (Fig. 50). Digester capacity at the optimum mesophilic temperature of 100F need be only about Vi of that at 40F. At present, known psychrophilic digestion is impracticable, but.it has been suggested that the possibility of 58 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS more efficient use of this range should be investigated further. Properly digested sludge can be readily dried and represents only approximately V* of the volume of the undigested sludge. The resulting simplification of final de-watering and incineration or burial represents an appreciable saving in effort and money in ultimate disposal.

Utilization of super-species Utilization of “ super-species” has been suggested for biological treatment of cold region sewage wastes. Under freezing conditions there are certain organisms that attack wastes and very slowly reduce and stabilize them. It has been suggested that these organisms be isolated and cultured to produce populations adequate for decomposition. Certain molds in particular seem to develop at low temperatures and be capable of attacking even unlikely materials, such as leather. However, there is insufficient information in the literature for use in designing treatment units.*4 59

THERMOLOGY

Heal losses create system stress The word stress assumes new proportions in cold region waste-water-system design and operation. Heat flow can relieve or enhance system stress.7 8 Excessive heat loss places stress on the system7 and can even cause failure. The transfer of thermal energy from one region of a facility to another is not as immediately dramatic as load­ ing a beam to the breaking point. However, failure of the overstressed member is the result in either example. Favorable thermal characteristics are as important as favorable hydraulic, structural, and other physical characteristics of a successful sanitary waste system; they are all essential to an effective system for collection, transportation, and treatment of sewage wastes under low tempera­ ture conditions. Favorable thermal characteristics must be designed and built into a system; they are often ineffective if they are merely added as an afterthought. Experience has also proved that favorable thermal characteristics must be simple, fail-Safe, and readily acceptable to users of the system. Temperature has always been significant in most sanitary engineering processes but not necessarily a controlling consideration in design and operation. Polar experience, in both the Arctic and Antarctic, establishes heat transfer as a dominant consideration in design and operation of low temperature area sewage works. American experience in sewage works design and operation is based largely on modified temperate and tropical climate conditions. System concepts, mechanical and electrical equipment, and operating procedures are generally not suited to cold areas. Design and operating personnel are generally unfamiliar with low temperature problems. However, the limited low temperature area experience available has focused attention upon what now appear to be obvious fundamentals. When these fundamental considerations are applied, stress due to heat transfer can be kept within the limits necessary for an efficient and operable system. Cold region stresses due to heat loss or low temperature may be manifested in physical response, process response, or operational difficulties. Physical stresses may result in site problems, rupture of facilities and interruption of service. The effects are often cumulative. The site may be in permanently frozen earth, a mixture of permanently frozen earth and ice, snow, ice, in air or in space. On the ground waste heat from the system may or may not destroy the structural stability of the site. In some Alaskan installation^ mechanical refrigeration units keep the site frozen and prevent damage to the structure. Structures placed below the surface of the Greenland Ice Cap have been ventilated with cold air from the surface to keep the site frozen. Thermal protection of waste systems must be adequate to protect them from damage by natural temperatures and temperatures created by man. Existence of permafrost, ice, moisture content of the soil, temperature of the soil, and thermal characteristics of the soil must be studied carefully in the selection of a facility suited to the site. An appropriate system concept may be selected by considering site conditions, avail­ ability of water, type of group to be served, and climate. Operational difficulties will follow if adequate consideration is not given to the effects of heat transfer. Although operational difficulties are usually physical, chemical or biological, high cost is also £ potential difficulty. Four questions should be considered in thermal design of sewage works: 60 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

1. Can weatherproofing be eliminated or at least minimized? 2. Can a location be chosen that will accomplish weatherproofing without use of special heating or insulating devices and materials? 3. Are heat transfer methods utilized which take maximum advantage of waste energy,88 which are most economical and efficient, and which are compatible with the mission of the project and the regimen of the area? 4. Are weatherproofing methods sufficiently simple and inviting to be acceptable to the average person who must rely upon them? The mission of an installation, whether fixed or portable, temporary or permanent, the type of personnel, and the caliber of maintenance personnel all have a bearing on answers to the above questions. A single type of waste may mean a single method of weatherproofing. A variety of wastes may demand a variety of weatherproofing techniques. Where water is scarce and it may be necessary to reclaim waste water, still other considerations are important in weatherproofing a system.

Concepts for protection of sewage works facilities In the cold regions where it is necessary to protect sanitary waste systems from heat trans­ fer stresses18 there are usually such attendant problems as: 1. Labor and material costs are high. 2. Construction materials must be imported unless design utilizes locally available and unusual materials. 3. Most fuels are imported and energy costs are high. 4. There are few skilled craftsmen and maintenance men. 5. Replacement parts must be stocked at the site, or the system must be operable for ex­ tended periods of time without spare parts. Every part of the sewage works system should be subjected to a thorough thermal analysis. In conventional systems, waste heat should be utilized wherever possible. Reclaimed heat is ex­ tremely valuable in low temperature areas where energy costs are high. In addition, heat transfer not only should be controlled in most parts of the system but it also should be kept from rendering any part of the system inoperable. Simple but unanticipated heat transfer such as occurs in a metal part extending from inside a heated structure to the exterior cold may result in condensation and icing of the part to the extent that it is useless. Electrical control panels have been rendered inoperative because of heat transfer with attendant condensation and icing. Three basic design concepts are employed to offset heat loss effects on cold regions waste systems. 1. Heating and insulation or addition of sufficient heat to satisfy heat losses from the sys­ tem or facility, with or without insulation. 2. Encapsulation or complete enclosure of the system in a favorable environment. 3. Utilization of non-frost-sensitive technique or modification of usual methodology to create systems and facilities unaffected by heat losses, and in some instances selection of a methodology which converts cold effects to beneficial use. During the last 30 years system concepts might be said to have progressed from the initial heating and insulation concept, through encapsulation to use of non-frost-sensitive techniques, but each site and system presents somewhat different problems, and no concept can be given gen­ eral preference. Often more than one concept may be followed in the different parts of a total sys­ tem. Based on objectives, resources available, and the particular site conditions, the designer must produce systems which are simple, reliable, flexible, and economically feasible to construct, operate and maintain. THERMOLOGY 61

Low temperature as a resource The engineer is challenged to profit from cold as a resource to be utilized. In the marginal regions of transition from temperate climate to frigid climate, it is most difficult to efficiently utilize cold effects as a resource, and it is in these transition zones that it is most difficult to construct and operate reliable facilities and services. Cold effects are almost continuous, are more reliable and predictable in the higher latitudes. In very cold areas soils at a site can be kept frozen and site development may be treated passively. Treatment processes will require an almost continuously uniform buffering. It is safely possible to depend upon the environment to semipermanently preserve wastes released to it through controlled discharge. Conventional waste disposal practice is wasteful of both heat and water, which are in short supply for most cold region communities. Good design can benefit both.

Thermal analysis of collection and transport works Thermal analysis of waste collection and transport works, treatment units, and evaluation and use of waste heat are essential. Sewers, manholes, pumping stations and other appurtenances, clarification units, filters, digestion chambers, and aerating devices should be studied. The dis­ tribution of heat within facilities is significant. Some freezing may be prevented by mixing, stir­ ring, or otherwise circulating fluids within a unit until the reservoir of heat within the unit be­ comes depleted. Open water has been observed in some stabilization ponds even under extreme low temperature largely as a result of distribution of heat within the fluid mass. Methods for application of heat to wastes should be analyzed and the most advantageous selected.107 The relative advantages and disadvantages of heating and ventilation of processes and process areas demands careful evaluation. The thermology of waste water systems is a de­ sign regimen which should result in facilities, processes, and systems capable of withstanding heat loss stress within the limits of reasonable safety factors. Computation of heat transfer for conventional sewers presents a complicated problem. Analysis must be sufficiently detailed to ensure reasonable economy and to avoid freezing prob­ lems. In current practice, precise analysis is not made; empirical methods are used for design and operation. Several variables must be considered in computing heat transfer from pipes containing fluid such as water or sewage: 1. Fluid characteristics a. Temperature b. Quantity of fluid (1) Rate of flow (2) Continuity and pattern of flow c. Capacity for heat transfer 2. Pipe characteristics a. Thermal characteristics of materials b. Pipe section (wetted perimeter) c. Insulation 3. Environment around pipe a. Air, soil, water, ice, etc. (thermal characteristics of surrounding medium) b. Temperature (1) Variation (2) Duration c. Temperature-induced changes in surrounding medium 62 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

4. Heat input into system a. Direct (1) Additional flow (2) Tracing devices b. As a result of dissipated heat loss energy c. Indirect (as a result of locations which modify normal environment) Any or all of these interrelated variables are subject to change. Conditions affecting heat transfer and beat balance in a fluid-filled conduit are constantly changing under normal operation of the system. Normal fluctuations in gravity-flow of wastes in some sanitary sewers result in heat transfer conditions even more .complicated than those in water pipes. Manhole structures, vents, sewage quantities inadequate to fill a pipe (and often a mere trickle), and frequent charging with slushy mixtures of ice and water introduce additional variables in thermal analysis of sewers. Designers must make simplifying assumptions for thermal design. Hydraulically critical conditions occur at the beginning and end of the useful life of a sewer. Thermally critical conditions occur when a sewer is new or at other periods of partial or no flow. Empirical thermal design calculations14* for a sewer may be made in the same manner as for water pipes (see CRREL Monograph ffl-C5a), provided certain assumptions are made: 1. It is assumed that the thermal characteristics of sewage are essentially the same as those of water. 2. In computing heat loss from a sewer, the sewer is assumed to be completely filled with 32 to 35F sewage flowing at minimum velocity (based on size and velocity relationships necessary to prevent deposition). 3. In determining heat available in sanitary sewage discharged into a sewer, the critical flow periods are assumed to be a 6- to 8-hr period in which the hourly flow is approxi­ mately 20 to 25% of the 24-hr average hourly flow and a 1- to 2-hr period in which the hourly flow is approximately 3 to 5% of the 24-hr average hourly flow. 4. Manholes, pumping stations, cleanouts and vents are assumed to be weatherproofed to minimize heat losses from them, and heat losses through such appurtenances are the normal heat loss per unit length of line multiplied by the ratio of the diameter of the ap­ purtenance to the diameter of the sewer. 5. Capabilities for direct heat input into the sewer during emergency periods (starting operation after a period of non-service) are sufficient to provide 200% of the computed heat input requirements for the most critical flow period. For empirical solution71 of heat transfer problems occurring in sewers, it is also assumed that heat transfer occurs principally by conduction. Heat balance and observation of the extent of variability of factors affecting the heat balance have been determined by: 1. Observation of distribution systems already in place and operating. 2. Predictions based on formulas derived from steady-state heat transfer relationships. 3. Steady-state heat transfer analysis by computer. 4. Non-steady-state heat transfer analysis by computer. Assuming that heat transmission by conduction is the principal mode of transfer of heat in and from a sewer, steady-state or non-steady-state flow is possible. Experience has shown that calculations assuming a steady state are sufficiently accurate to use in design provided accurate information on environmental temperatures, sewage temperature and flow rates, and thermal con­ ductivity of the material through which the heat is flowing are known. The coefficients of thermal conductivity and temperature factors are extremely significant and large errors may be made under most critical conditions. Soil temperatures and conductivity should be based on detailed and ex­ tensive direct observations. THERMOLOGY 63

Figure 51. Temperature difference between any two points under consideration (sewer placed directly in soil, and insulated sewer).

The following equations based on the Fourier law, steady state, are used for computation of heat transfer with buried sewers: The basic equation for steady-state heat flow by conduction may be stated:

q = (km/x) Am (Tj - Tg)

where q Heat flow or heat loss from pipe in Btu per hour per lineal foot of pipe km Thermal conductivity, in this case the mean thermal conductivity expressed as Btu in./ft2 hr F X Thickness (in.) of the material, measured in the direction of heat flow. It may be assumed to be the distance in inches between the pipe wall (point where T1 is measured) and point where T2 is measured. For iron or steel pipe where the thermal conductivity is high and no insulation is provided, may be taken at the exterior wall of the pipe. Am Area (ft2) of the material normal to the direction of heat flow, in this case the log­ arithmic mean surface area of the two concentric cylinders, one cylinder being that formed by the exterior of a l-ft*long section of the pipeline and the other concentric cylinder being an imaginary cylinder located at a selected distance from the exterior of the pipe and this imaginary cylinder also being 1 ft in length (see Fig. 51). The logarithmic mean may be represented as follows:

If Ag/A1 does not exceed 2, the arithmetic mean area is within 4% of the logarithmic mean area. Use of the arithmetic mean is satisfactory for most computations. = temperature in °F at the exterior of the pipe - usually assumed to be the temperature of the sewage in the pipe assuming that the pipe has a high thermal conductivity, is not insulated and is buried directly in the ground. Tg = temperature in °F at a specific distance x from the exterior of the pipe. 64 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS P-Line

Figure 52. Temperature drop of flowing water in a pipeline. 216

v = speed of flow h = coefficient of surface heat transfer, pipe to ground S = length of pipe between two points at temperatures of and respectively Ts = temperature of soil far from influence of pipe rp = tadiug of pipe THERMOLOGY 65

Steady state conduction through multilayers. „ x R = resistance per unit area to heat flow = — kA x = thickness of conducting material in the direction of heat flow k = thermal conductivity A = area of the material normal to the direction of heat flow (logarithmic mean area or arithmetic mean). Heat flow through a series of layers may then be expressed as:

, - TL-JEi______^ % ------+ ------+ • • • 4 a kb 4 b in consistent units. The mathematical operations involved in thermal design of sewers may be expedited by use of computer techniques, which, however, may not be justifiable in repetitive solutions in very simple systems. Thermal analysis of simple systems may be expedited by the use of nomograms; e.g. Fig. 52.218 More complicated networks could be handled best by computer analysis. Sewers liable to freeze can be protected by introducing heat at the source or at critical points on the system. The system can be designed as a conventional gravity system, pressure system with intermittent flow, or a recirculating system. Computations and ultimate design must adequately provide for periods of non-flow, maximum flow and normal flow. After a period of operation, pipes in frozen ground create a thawed area around them and over extended operation this area more or less stabilizes. During flow in the pipe the temperature isotherms around the pipe, in a dry soil, are approximately circular in shape with a particular isotherm being roughly two to six times closer to the top of the pipe than it is to the bottom of the pipe. Changes in use and protection of the ground surface change the frost penetration pattern. The critical point for design is the distance between the top of the pipe and the isotherm selected. On large pipes, at normal depth of burial, in dry soil and with a mean annual temperature of 20 to 30F, the 32F isotherm may be expected to be approximately a distance equal to the pipe diameter above the top of the pipe. Specific soil, moisture and temperature conditions for the particular site in question are imperative for meaningful thermal design. Not only is it imperative that appropriate site data be used but it is also important to properly define and maintain system operating characteristics. Figures 9, 10 and 11 and Table XIII give data to approximate the intensity and duration of low temperatures in Alaska. Conventional combined sewers are contraindicated where wastes must be treated because of the extra load placed on treatment facilities. In addition to this contraindication in cold regions the storm water inlets on combined sewers and occasional charging with slush-ice and water mix­ tures completely disrupt the thermal balance of the sewer. Design for cold region combined sewers requires heating facilities sufficient to thaw ice and water mixtures and to heat inlets during critical periods. Current practice indicates that storm runoff should be transported on the surface rather than in combined sewers. 66 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Table Xin. Approximate number of days annually that the maximum temperature is 32F or less for various Alaska communities (based on ESSA records). Intensity and duration of cold weather in Alaska exceeds that of the contiguous states. In some areas critical design ranges have been observed to lie between -50F and -70F. Rapid temperature variations of as much as 20F per hour are frequently experienced at the edge of the polar air mass.

No. days No. days max temp max temp Community £32F Community £82 F

Adak 30 Kotzebue 205 Anchorage 125 McGrath 165 Barrow 280 Nome 185 Bethel 140 Northway 165 Cordova 60 Petersburg 30 Fairbanks 160 Seward 70 Galena 180 Sitka 20 Gambell 205 Skagway 50 Homer 90 Umiat 240 Juneau 55 Valdez 95 Kenai 120 Wasilla 110 Ketchikan 30 Wrangell 25 Kodiak 30

Table XIV. Sphericity factors for commonly used sanitary engineering structures.1*6

Sphericity Shape (actor

Sphere 1 Cube 0.806 1:2:4 right solid (settling tank) 0.674 1:1 cylinder (digestion tank) 0.873 1:3 cylinder (settling tank) 0.755 1:6 cylinder (high-rate filter) 0.595

Thermal analysis of basic treatment works Thermal analysis of basic treatment units such as sedimentation basins, filters, sludge digesters and aeration units may be made empirically by use of the steady-state heat transfer equation for transfer by conduction. Thomas“6 has suggested the use of a sphericity factor (sur­ face area of a sphere of equal volume * actual surface area of unit being considered), for calcula­ tion of heat losses from various treatment units. It is evident from the heat-flow formula q = UA(TZ - Tx) that heat loss may be reduced by reducing the surface area exposed to cold air. An approximation of the relative surface areas of tanks of different shapes (Table XIV) may be had from an evaluation of their sphericity factors. Thomas also presents typical overall heat transfer coefficients U for various structures and certain heating elements as shown in Tables XV and XVI. Kersten, in work for the Corps of Engi­ neers at the University of Minnesota, determined coefficients of thermal conductivity for various soils. Some of Kersten’s data are presented in Table XVII. Coefficients (k factors) for various other materials are shown in Table XVIII. THERMOLOGY 67

Table XV. Typical overall heat transfer coefficients for various structures in sanitary engineering. The overall transfer coefficients for fluid-filled concrete tanks vary markedly with the moisture content of the surrounding soil, wind velocity, humidity, and the temperature and rate of flow of fluid in the tank.

Structure and condition U(Btu/ft2 hr F)

Concrete tank in dry soil, top covered and flush with surface 0.10 Concrete tank in dry soil, top covered with Va of structure above ground 0.20 Concrete tank in wet soil, top covered with Va of structure above ground 0.49 - 0.75 Concrete tank in wet soil, top open with Vz of structure above ground 1 - 2.5 Housed trickling filters 0.5 - 2.0 Open trickling filters 2.0 - 6.0

Table XVI. Typical overall heat transfer coefficients for common hot water co ils immersed in fluid.

Type of fluid in which coil is immersed U(Btu/ft2 hr F)

Water, sewage, thin supernatant liquid 60 - 80 Thin sludge 30 Thick sludge 8-15

Heating coils buried in concrete walls and flooring (panel heating) have low overall trans­ fer coefficients depending on the thickness of the concrete. Tests indicate [/-values of 5 to 6 for lVi-in. steel or wrought-iron pipes spaced 15 in. apart in concrete walls 12 in. in thickness. Heating coils submerged in sewage and sludge tend to accumulate films that lessen heat transfer rates (U decreases). The heat sink characteristics of a sewage stabilization lagoon are significant in analyzing, predicting, designing, and operating successful cold region lagoons. The lagoon traps and holds heat as well as dissipating it through outflow and heat losses to the environment. Heat input into a lagoon may be from warm sewage and/or other miscellaneous sources such as warming of the total environment of the lagoon. Other heat input, e.g. biological activity, is insignificant. Site conditions and climate and the operating regime of the lagoon impose many variables which must be considered for precise assessment of the heat sink characteristics of a lagoon. Physical and technical limitations in securing accurate site data as well as a dearth of experience and ob­ servations of operating facilities necessitate a more or less empirical approach to thermal analysis of a lagoon. This approach is sufficiently accurate for assigning orders of magnitude to the factors which a designer must consider. The empirical approach thus makes it possible to assign reason­ able, if not precise, numbers to the parameters under consideration in developing a design. 68 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS Table XVII. Coefficients of thermal conductivity (k) for varions soils (Kersten). Heat transfer characteristics are variable, depending on soil density and moisture, as well as upon mean temperature. The overall coefficient of heat transfer, 17, for a compound wall of several materials (including air spaces) of thickness x^, Xg, Xg, etc. may be cal­ culated from:

1 /hi f xi/ki + x2/k 2 + ... + l/hQ in which h|= inside coefficient of transfer at the air surface = 1.6 approximately for ordi^ nary materials in still air and h^ = outside coefficient of transfer at the air surface = ap­ proximately 6.0 for ordinary materials in air with a velocity of 15 mph. The units of 17, hi andh0 are Btu/ft2 hr F, of etc.: Btu in./ft2 hr F, and of x, etc.: inches. Material k(Btu in./ft2 hr F Material k(Btu in./ft2 hr F) Fine crushed quartz 12 - 16 Crushed trap rock 5.0- 7.0 Ottawa sand 10 - 14 Ramsey sandy loam 4.5 - 16.5 Fairbanks sand 8.5 - 19 Northway fine sand 4.5 - 9.5 JLowell sand 8.5 - 17.5 Northway sand 4.5- 8.5 Chena River gravel 9.0 - 13 Healy clay 4.0 - 11.5 Crushed feldspar 6.0 - 9.5 Fairbanks silty loam 5.0- 12.0 Crushed granite 5.5 - 10 Fairbanks silt clay loam 5.0- 9.5 Dakota sandy loam 6.5 - 19 Northway silt loam 4.0- &D

Table XVm. Coefficients of thermal conductivity (k, Btu in./ft2 hr F) of various fluids and solids.38 Material k Material k Fluids Solids (cont’d) Water 4.0 Kapok between layers of paper 0.24 Sewage 4.0 - - 4.1 Sulfur (foamed - 10 lb/ft3) 0.3 Raw sludge 4.5 Polystyrene (10 lb/ft3) 0.3 Partly digested sludge 5.0 Urethane (10 lb/ft3) 0.25 Digested sludge 5.1 Roofing Ice 13 - 17 1. Asphalt composition 6 7 Air space (over 5A in.) 1.1 2. Built up: bitumen and gravel- 1.5 - 3 surface Solids 3. Plaster board, gypsum fiber con- 0.5 - 0.6 Asbestos 1.48 crete, 3-ply Asbestos board 0.85 Air spaces/over %-in.-thick wood 1.1 1. California redwood, dry 0.7 Brick masonry 5.0 16% moisture 0.8 Cement mortar 12 2. White pine 0.8 Cinder concrete 5.4 3. Yellow pine 1.0 Concrete (typical) 12 4. West Coast hemlock, dry 0.74 Concrete blocks 0.8 - 1.0 16% moisture 0.88 Tile flooring 12 5. Douglas fir, dry 0.70 Glass wool 0.27 16% moisture 0.87 Mineral wool 0.27 - 0.30 6. Red oak, dry 1.08 Sawdust and shavings 0.36 - 0.40 16% moisture 1.21 Cork board' 0.25 - 0. 30 Fiber (flexible blanket) 0.27 - 0.29 Hair felt between layers of paper 0.25 THERMOLOGY 69

Still water in a lagoon loses heat to the atmosphere. On permafrost, or in soil that is colder than the water in the lagoon, heat is also lost to the surrounding soil. Although it is not possible in actuality, heat transfer from water to the surrounding frozen soil would theoretically reach an equilibrium at some point in the soil beyond the confining surface of the lagoon. The dynamics of heat transfer through the bottom and sides of the reservoir can be evaluated and computed. How­ ever, for the purpose of this discussion, heat transfer through the botton and sides has not been con­ sidered. The zone of influence of heat losses to the surrounding soil should be estimated?12 because the melting of lagoon sides in permafrost of high moisture-content camtesult in significant damage. As the water in a lagoon cools, upper layers become denser and move to the bottom. Warmer water at the bottom is forced to the top. This circulation continues until an isothermal temperature of 39F is reached. Continued cooling reduces the density of the surface layer, which remains at the top, and it rapidly cools to the freezing point. Continued cooling of the surface after it reaches 32F (heat losses of 144 Btu per pound of fluid, the latent heat of fusion for water) causes ice forma­ tion. Although ice normally appears near the edges of the lagoon first, a continuous ice cover will form rapidly over the entire surface of a quiescent lagoon. Ice insulates against heat loss from the pond. As the ice sheet thickens, the rate of heat transfer from the lagoon is reduced. Snow greatly reduces heat loss. Heat transfer from a lagoon may be formulated as ice forms on it, and as the insulating ef­ fect of the forming ice layer reduces the rate of heat transfer. If the amount of heat flowing out in a short time interval dt is equated to the heat of formation of an ice layer of thickness dx (i.e. sensible heat is neglected), then:

(k/x) (32 - T) A dt = (V12) w(L) A dx where k = Thermal conductivity of ice = approximately 15 Btu in./ft2 hr F x = Ice thickness, in. A = Surface area of the lagoon, ft2 w = Unit weight of water =* 62.4 lb/ft3 L = Latent heat of fusion of water * 144 Btu/lb T = Air temperature, °F t = Time, hr. By assuming that T remains constant, and integrating the equation, an expression may be obtained for the length of time t to freeze an ice sheet of thickness x:

f w L x2 25x2 24(32 - T)k ~ 3 2 - T ’

Also knowing the length of time a given temperature prevails, the theoretical thickness of ice formed can be computed. If the temperature varies (as it usually does) an average value based on a daily average of V2 (maximum and minimum temperatures) for T is adequate. Knowing heat input normally available to the system, heat available during critical periods, and heat losses from the stabilization pond, adequate prediction of operation can be made. Heat requirements H (in Btu/hr) necessary to maintain a specific drop in temperature (T in­ fluent - T effluent, °F) for different treatment units may be computed empirically with sufficient accuracy for design and operation purposes, if the surface area of the unit A (ft2), the quantity of flow Q (in MGD), air temperature T (°F) and the overall heat transfer coefficient U (in Btu/ft2 hr F) is known. The equation is as follows: 70 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

H = V A^ ~ ~ - Ta^ - 347,000 Q(7$ - %) .

Buildings enclosing open water and sewage surfaces must be heated and air conditioned to prevent condensation in the enclosing structure (refer to Appendix D). Temperature gradients through the enclosing walls must be designed far and maintained to prevent dewpoint temperatures on ceilings and walls. There are various methods for applying heat to treatment units but the most desirable are those which warm the relatively clear water and return the heated water to the system. Coils, plates and tubes, and similar heating devices readily lose their efficiency as a layer of scale and organic deposits builds up on the warming surface. These effects are minimized by making the heating surface relatively large and utilizing the minimum reasonable temperature difference be­ tween the heating surface and the sewage.

Salvage and utilization of waste heat prefer to Table I, page 8) Salvage and utilization of otherwise waste heat is often the most desirable objective in heating facilities. The total energy concept in facility design and operation is highly desirable. Large quantities of heat are often available in power generation, heating plants, ground water, in­ ternal combustion engines, sewage gas from sludge digesters, and other miscellaneous sources. Frostproofing a sanitary waste system involves more than the use of insulation and/or heating. Frostproofing is a concept that must be woven into the overall planning, construction and operation of a system. It may be possible to eliminate the need for special frostproofing through use of different processes or methods to create a non-frost-sensitive installation. Completely enclosing facilities in favorable surroundings minimizes the need for other special frostproofing techniques. However, encapsulation of frost-susceptible facilities in heated areas may present problems in aesthetics which make encapsulation unacceptable. The importance of heat transfer considerations in design and operation of low-temperature- area water and sewage works cannot be overemphasized. Stresses due to heat transfer must be re­ garded as much in design and operation as structural, hydraulic, aesthetic, and other considerations. 71

REUSE AND REGENERATIVE PROCESSES

Reuse and regenerative processes for treating waste water offer more promise in cold re­ gions than in most other places. The cost and inconvenience of obtaining water place more signi­ ficance on minimizing water use. Water does not wear out; it only becomes fouler (or frozen) and unusable until cleansed (or thawed). If the energy expended reclaiming used water is less than the effort required to obtain more water, may be the best source. Potential advantages in reclaiming water198 might be listed as follows: 1. May contribute to facilitating waste disposal. 2. Low temperature may be used to advantage in at least the process of cleansing by freez­ ing, which separates out solids. 3. Adds materially in preventing pollution of the environment. 4. Makes it possible to obtain water where it might not be available otherwise. 5. Concentrates waste materials and makes them more readily processed for final disposal or utilization. These potentials add to the economic feasibility of reuse or regeneration.

Unit processes utilized Distillation, phase separation, segregation of wastes, and high temperature oxidation have been suggested as means of reclamation in addition to other treatment methods discussed under physical, chemical, and biological treatment methods. These processes may be used simply as unit processes in treatment of wastes, for partial reclamation, or total reclamation. Refinements such as flash distillation, vapor compression distillation, multiple-effect distillation, solar energy distillation, electrolysis, and high temperature oxidation have been selected where total reclama­ tion is desired. Closed ecological systems80 89 90 (Fig. 53) have been studied for use in space flight101 where the problems of water supply and waste disposal are very similar to those encountered in some of the most difficult sites in the cold regions.

Partial reclamation Waste water may be reclaimed and reused for many purposes such as flushing and transport of wastes and for cooling mechanical equipment. Such uses do not present the severe aesthetic problems met in full or total reclamation. Complete regenera­ tion is offensive and objectionable to many people unless it is effective beyond question. The salts in sea water, plus, perhaps, float­ ing and suspended material, make it much higher in objectionable materials than sewage wastes. For reuse or regeneration, waste water should be treated only to the degree required for the pur­ pose to be served. However, it is hazardous to have Figure 53. Example of a closed ecologi­ any water that might cause disease in use where it cal system.33 is accesoxuic to people. Oenain reuses may we achieved without total regeneration if the water is 72 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Water Weak Base Resin

Raw Water Water Figure 54. Moving bed ion exchange treatment process. (After Higgins.63) not hazardous to health. Proper plumbing as well as disinfection are necessary for full protection. Potable and non-potable systems must be designed to prevent cross-connection or back-siphonage. Most regenerative processes are sophisticated and present problems to untrained or inex­ perienced operators. It is difficult to meet criteria for simplicity and at the same time provide the necessary sophistication. Reuse and regenerative processes imply tertiary treatment129 180 which must be preceded by efficient primary and secondary treatment. Floating and suspended solids must be removed and the waste water stabilized by effective removal and stabilization of dissolved material. One or more of the processes described in the chapters on physical, chemical and biological treatment must be applied to prepare the wastes for tertiary treatment. Distillation is the most common tertiary treatment, and efficient distillation units are com­ mercially available. Some of these systems operate on the waste heat from internal combustion engines. Freezing, ion exchange beds, filtering media, and similar devices are available to separate both Suspended and dissolved material. Figure 54 is an example of a moving-bed ion exchange process which cuts operating costs through reuse of the regenerants. The cations (principally sodium, potassium, calcium, magnesium, and ammonium) are removed by ion exchange, using strong acid-type resin. A decarbonator removes bulk bicarbonate. Strong acids (chloride, sulfate, nitrate, and phosphate anions) are removed by weak base-type resins. Such processes are effective but do not aesthetically satisfy as well as distillation, which is necessary following these processes. The achievement of producing aesthetically acceptable regenerated water may be greatly facilitated by separation of wastes according to type (laundry, bath, kitchen, etc.). High temperature oxidation, as described under physical processes and treatment (p. 32), offers the most promise for total waste water regeneration to potable water that is aesthetically acceptable. Reuse of bath and laundry wastes for flushing and transport of kitchen and human wastes is perhaps the most common example of partial reuse. À collection and storage tank receives these wastes and they are held for flushing later. Several DEWLine stationsuêmploy this method in water-short areas. The recirculating type toilet system has also been used to recirculate treated waste water for flushing. This system is described under biological processes (p. 45). REUSE AND REGENERATIVE PROCESSES 73 Clark, Alter and Blake’3 describe flash distillation, vapor compression distillation, and multiple effect distillation, in their exhaustive study for the Navy, as foEows: “Water under low pressure will boil at a correspondingly low temperature. When applied to mineralized water, part of the water will flash to vapor which can then be condensed. “A urine still, developed by General Electric, operates on this principle. The still has also been operated with total human wastes with equal success. One addi­ tion to the basic vacuum distillation process is the use of a high temperature cataiy lytic zone. Operating conditions of the process are: 60 mm Hg vacuum, 40°C still temperature and 110CPC catalyst temperature. For the one-man unit the air bleed rate was .05 - .20 cubic feet per hour, catalyst (Platinum - 10% Rhodium) weight was lOg and the catalyst flow-through area diameter was 22 mm. “The investigators state that the process can be scaled up by increasing the catalyst weight and flow-through area in direct proportion to the contributing popula­ tion. They have already developed a unit with 25 times the capacity of the original one-man unit. This unit is being Operated for the U.S. Navy Air Crew Engineering Laboratory. “Energy requirements of evaporation and catalysis are calculated to be 9350 Btu/gal of recovered water (2.74 kff h/gal) of which approximately 1.26% is required for catalyst heating. This does not include recovery of heat in the condensation process. “Advantages of the process are recovery of potable water, simplicity of equip­ ment (batch process requires only a vacuum pump), minimum space required, and significant reduction (95%) of waste volume for disposal. “Disadvantages are principally items which can be solved by further research. Since the process works best as a batch process, feed to the still and disposal of waste from the still could be automated as a batch feed process. Vacuum pupps must be protected from vapor carryover. The process has the possible psychologi­ cal disadvantages of all water regenerative processes. “This process is an application of the heat pump. The steam produced in the one evaporator is compressed and fed right back'into the heating coil of the evap­ orator. Because of its heat of compression, which raises the temperature of steam slightly, the steam is capable of driving its latent heat back through the heating coil into the body of the evaporator to evaporate more of the feed. “A variation of the vapor compression process, the rotary still, has recently been used to process primary sewage effluents. Chemical oxygen demand was re­ duced by over 90%, chlorides by over 99%, and the product- was considered potable water. “Several boiling chambers, or ‘effects’, are used to achieve greater efficiency of heat utilization. Steam from a boiler evaporates part of the mineralized water in the first effect. The vapor from the first effect moves to the next effect where it passes on its heat, causing evaporation there. This process is repeated through several effects until the gradual reduction in total heat minimizes the amount of water evaporated. “Solar energy distillation processes are well documented in the literature. They show little promise for arctic or polar application due to the seasonal restric­ tion of a long winter night.” 74 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

Electrolysis would theoretically provide a method for regeneration of water from waste water by breaking down the wastes and recombining the elements to provide an aesthetically acceptable product. The advantages and disadvantages of this system are discussed under the chapter on physical treatment methods. Although high temperature oxidation hasi not been utilized in producing regenerated potable water, further research and possible use was recommended by Clark, Alter and Blake.33 75

CONSTRUCTION AND OPERATION

A dollar will not buy as much in cold region facilities177 as it will in the contiguous United States. Various cost studies show purchasing power of the dollar, in terms of cold region facilities, ranging from a low of 30 to a possible high of 650. A man cannot produce as much under low tem­ perature conditions as he can at 50F to 65F. His productivity may be reduced as much as 90%. Construction and operation of sewage facilities for use in cold regions must be adjusted to accom­ modate these constraints.

Collection and transport Construction and operation of facilities40 59 214 216 must be compatible with the physical con­ straints imposed by the site and amenable to the attitudes: of the people who work there. It is often easy to neglect maintenance if a door is frozen shut, if steps are icy, if there is no provision for collection of a sample for quality control, if it is too cold to take time to make a gauge reading or do repair work, if snow has drifted until a control point is inaccessible, if ventilation is so in­ adequate that an enclosed place is objectionable to enter, if excess moisture and condensation shower a person who must enter a humid enclosure, etc. Construction using exotic materials is expensive, causes delays, and almost defies proper maintenance. Construction and operation can be simplified184 if sufficient consideration is given to po­ tential problems. Collection and transport works should be of proper materials, capable of remain­ ing in alignment or of being adjusted to maintain alignment; they should fail safe, have utilidors properly drained and ventilated, pumping stations accessible, and measuring devices reliable at low temperature. Wherever possible, frost and cold should be used to advantage.

Processing units Processing units, if enclosed, should preclude exposure of operators to aerosols and should be properly ventilated. Air must be conditioned to prevent icing and severe condensation problems. Construction and maintenance of operating units may place more of a demand on their shape, loca­ tion, and accessibility than other factors. Compactness and minimum exposure of warm surfaces to the cold environment is desirable. The relationship of these objectives to costs must be weighed carefully. Operating simplicity and reliability outweigh small savings in construction cost. Units must drain readily when they are taken out of service voluntarily or involuntarily. Clark, Alter and Blake33 list criteria desirable for selecting equipment for cold regions (Appendix B).

Weather protection and enclosure Weather protection and enclosure should be adequate to reduce exposure of facilities to an absolute minimum unless they are specifically designed for use in extreme cold.210 211 212 Insulat­ ing materials such as foamed sulfur (reported by USA CRREL41 to be low in cost, easily applied in the field, and of good protective value) could be used instead of more costly materials. Frost- susceptible piping should preferably not be located on exterior walls of structures or at other points where damage from freezing might occur.

Paints and protective coatings Paints and protective coatings should be applied in accordance with the standards of the Control Federation for applications in cold and wet environments. Although it is not practicable to apply coatings at extremely low temperature, some latitude is provided in the standards. Piping subject to condensation should be insulated sufficiently to reduce this hazard to a minimum. Every effort should be made to eliminate the causes of condensation as well as to apply protective and insulating coatings. 76 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS Safety requirements Safety requirements take on new significance in cold regions sewage works. The tendency to encibse units and heat them increases the hazards of improper vehtilation, leakage of poisonous chemicals, exposure to explosive gases and environments, collection of moisture on walkways and other surfaces, and clutter with extraneous articles. Crowding is also a result of attempts to en­ close and minimize the area to be heated. Crowding makes it more difficult to keep safe distances between walkways and moving mechanical parts. It is also common to remove guards from machin­ ery to prevent collection of ice and snow on exposed mechanical parts. Chemicals are usually stored in heated areas and may occupy a significant part of the available enclosed space. The re­ sult is that extraneous operations may occur in ill-lighted, and improperly ventilated, spaces. In many installations (particularly where heated utilidors are used) sewage may be over­ heated to the point where poisonous gases form.172 214 As the sewage becomes septic, malodorous and poisonous materials may escape to the environment, and proper ventilation is essential. Every effort should be made to correct the cause in existing situations and to design to prevent such oc­ currences in new facilities. The use of chemicals calls for special planning and construction to eliminate hazards. It must be “easier to do a job tight than to do it wrong.” Fluorides as an example should be stored, handled, and used in a form and under conditions that minimize exposure of operating personnel. Separate venting may be required. Lifts, carts, and storage bins should be so arranged that a per­ son does not have to carry heavy loads on slippery walkways. Icing of walkways, ladders and floors may be minimized by proper design and construction. Orientation of facilities to preclude or minimize icing and snow accumulation should be considered. Outside steps and doors may be hazardous, and differential heaving of frozen materials213 may make it almost impossible to gain access to structures unless appropriate design and construction measures are taken. 77

SUMMARY

In summary, the designer, builder and operator of sewage works facilities in a cold region is presented with the need for modern, convenient, reliable, and economical solutions. The clientele demands aesthetically acceptable systems as well. Although there is need for much re­ search in cold region water and waste water systems, the present state of the art is sufficient to provide acceptable facilities. The greatest obstacle is in the minds of the persons responsible for providing them. As soon as it is evident to the designer, builder and operator that facilities are needed, they will be built. Who would think of erecting a building without a roof or without a foundation? It is equally absurd to think of building homes and work places for people in the cold regions without providing fully adequate water supply and waste disposal systems. A review of practice and problems encountered in cold regions shows that many adequate or near adequate facilities have been built and are in use. Costs of such facilities have been high; but they are no higher, proportionately, than any other cold regions costs. If water and waste dis­ posal services in continental experience range from 2 to 10% of the cost of a home, then why should alarm be expressed if costs for similar services range from 2 to 10% of the cost of the cold region home? It is true that 2% of $20,000 is far different from 2% of $70,000 but water supply and waste disposal services are not the place to make up the difference. If one decides it is eco­ nomically feasible to occupy the cold regions, then it is equally feasible to provide a roof and a foundation for each structure built there for human occupancy — and it is also feasible to provide fully acceptable and reliable sanitary facilities. The constraints placed on the designer and builder as well as the operator demand ingenuity. Designs may not be conventional. They may not be purely a modification of the conventional. Certainly, it would appear that they might require more than a modified Florida or Illinois approach. Systems must be compatible with the site, the environment, the need and the money and other re­ sources available to build and operate them. Systems which flush monthly, quarterly, annually or otherwise may be the result. Systems which transport frozen material rather than water may be economically feasible. Flushing fluids may be synthetic rather than common water; they may be fuel that can be salvaged, or used for heat directly. Simplicity of the system ultimately developed is an attribute and almost a necessity. A thorough consideration of the following topics is essential in each project or facility: 1. What is the experience in similar situations and how can it be improved in the next installation? 2. What are the problems associated with collection and transport of wastes and what are the resources available for their solution? 3. Are there physical processing methods that are applicable? 4. Are there chemical processing methods that are applicable? 5. What application may be made of biological processes? 6. What are the heat transfer implications of each part of each process and each system? 7. Is reuse or regeneration a feasible alternative? 8. What special concerns are indicated, or what advantages can be gained, in construction and operation? 9. After consideration of all feasible alternatives in providing fully adequate and acceptable sewerage and sewage disposal services, which offers the most reliable as well as an economical solution? 10. Is the selected system fully acceptable to the users? 78

SELECTED BIBLIOGRAPHY

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28;V Brown, R.V.E. (1968) Proceedings of the First Canadian Conference on Permafrost, Tech­ nical memorandum no. 76, National Research Council of Canada, £81 p. 24. Bryant, C. (1942) How Fairbanks prevents its sewers from freezing. Pacific Builder and Engineer, vol. 48, no. 3, p. 46-47. 25. Bulgakov, N.P. (1962) Determination on functional graphs of the time at which water reaches the freezing point and of the depth of density mixing. Problems of the North, no. 4, p. 141-148. 26. Busch, A.W. and Myrick, N. (1960) Food-population equilibria in bench-scale bio-oxidation units. Journal of the Water Pollution Control Federation, vol. 32, no. 9, p. 949. 27. Carlucci, A.F. and Pramer, D. (1960) An evaluation of factors affecting the survival of Escherichia coli in sea water. Applied Microscopy, vol. 8, no. 4, p. 243. 28. Chapman, F.S. and Holland, F.A. (1965) Keeping piping hot, Part I — By insulation. Chemical Engineering, p. 79-90, December. 2 9 . ______(1966) Keeping piping hot, Part II - By heating. Chemical Engineering, p. 133-144, January. 30. Chase, E.S. (1944) High rate activated sludge treatment of sewage. Sewage Works Journal, vol. XVI, no. 5, p. 878-885. 31. Clay, P.E. (1968) Ins and outs of heat recovery equipment. Air Conditioning, Heating and Ventilating, p. 47-52, January. 32. Clark, L.K. (1951) Collection and disposal of human wastes — nonwater carriage systems. Personal communication. 33. ______; Alter, A.J*; and Blake, L.J. (1962) Sanitary waste disposal for Navy camps in polar regions. Journal of the Water Pollution Control Federation, vol. 34, no. 12, p. 1219-1234. 34. Clark & Groff Engineers (1962) Sanitary waste disposal for Navy camps in polar regions. U.S. Naval Civil Engineering Laboratory, Port Hueneme, Calif., 115 p. 35. Cohen, J.B. (1967) Water storage temperature study in the Arctic. Environmental Engineer­ ing Section, Arctic Health Research Laboratory, Department of Health, Education and Welfare. 36. Cohn, M;>(1961) Man in space — he takes along his waste problem. Wastes Engineering, p. 456*459, September. 37« Copps, S.S. et ai. (1956) Protection of utilities against permafrost in northern Canada. Journal of the American Water Works Association, vol. 48, no. 9, p. 1155-1168. 38. Coulter, J.B.; Soneda, S.; and Ettinger, M.B. (1957) Anaerobic contact process for sewage disposal. Sewage and Industrial Wastes, vol. 29, no. 4, p. 468-477. 39. Coulter, J.B.; Kopp, J.F.; and Thiemann, D.A. (1952) Investigation of a proposed recircula­ tion system for toilet wastes. Public Health Service, Environmental Health Center, Cincinnati, Ohio. 40. Crow, R.L. (1959) Cold-weather public works. Civil Engineering, vol. 29, no. 9, p. 59. 41. Dale, J.M. and Ludwig, A.C. (1967) Preparation of low density sulfur foam. USA CRREL Technical Report 296.(AD 661315). See also USA CRREL Technical Report 227, 1969. 42. Danishevskii, G.M. (1963) Acclimatization and sanitation problems of the population of the Soviet north in relation to the latest state of development. Problems of the North, no. 6, p. 23-32. 43. Davis, T.R.A. (1955) Infectious hepatitis in an Arctic village. Arctic Aeromedical Lab­ oratory. 44. Day, E.K. (1952) Environmental sanitation problems in Alaska and their solution. Harvard Public Health Alumni Bulletin, vol. 9, February. 45. ______(1951) Sewage and waste disposal problems. Public Health Reports, vol. 66, p. 922-928. 80 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

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140. Nehlsen, W.R. (1961) Incinerating toilets. U.S. Naval Civil Engineering Laboratory, Port Hueneme, Calif., Technical Note N-406. 141. ______(1954) Laboratory shows progress in development of sewerage system for use in the Arctic. Budocks Technical Digest, No. 43, p. 7-10. 142. Nickerson, R.D. (1960) Sludge drying and incineration. Journal of the Water Pollution Control Federation, vol. 32, no. 1, p. 90. 143. Orlov, V.A. (1966) The problem of heat supply in settlements in the permafrost regions. Problems of the North, no. 10, p. 193-212. 144. Ostrom, T.R.; West, C.R.; and Shafer, J.J. (1962) Investigation of a sewage sump on the Greenland Ice Cap. Journal of the Water Pollution Control Federation, vol. 34, no. l, p. 56-62. 145. Page, W.B. (1956) Heat losses from underground pipe lines. In Proceedings of the Third Alaskan Science Conference, p. 41-46. 146. ______(1955) Arctic sewer and soil temperatures. Water and Sewage Works, vol. 102, p. 304-308. 147. Paul, F.P. (1953) Enteric diseases in Alaska. Arctic, vol. 6, no. 3,»October. 148. Perry, A.H. Water works and sewerage practices in areas of perpetually frozen ground in Canada. Personal communications to Alaska Department of Health. 149. Pewe, T.L. (1957) Permafrost and its effect on life in the North. In Proceedings of the 18th Biology Colloquium, p. 12-25. 150. Pfeffer, J.T.; Leiter, M. and Worlund, J.R. (1967) Population dynamics, in anaerobic diges­ tion. Journal of the Water Pollution Control Federation, vol. 39, no. 8, p. 1305-1322. 151. Philleo, E.S. Engineering report-sewage treatment plant. Proposal by College Builders, Inc., Personal communication. 152. Poole, B.A. (1961) A report on water quality problems ih the state of Alaska. Special Re­ port to the Public Health Service, Indianapolis, Indiana* 19 p. 153. Quirk, T.P. (1964) Economic aspects of incineration vs incineration-drying. Journal of the Water Pollution Control Federation, vol. 36, no. 11, p. 1355-1367. 154. Reed, S.C. (1966) Interim report — research on extended aeration sewage treatment plant and utility system at Alaska Field Station. USA CRREL. 155. ______(1965) Ice cap sewage disposal. USA CRREL Technical Note (unpublished). 156. ______and Tobiasson, W. (1966) The waste water disposal system for DEWLine ice cap stations, Dye 2 and Dye 3. USA CRREL Internal Report (unpublished). 157. Reed, S.C. (1968) Settlement of activated sludge at low temperatures. USA CRREL Tech­ nical Note (unpublished). 158. Reid, L.C., Jr. (1967) Design and operational criteria for aerated lagoons in Alaska. Arctic Health Research Laboratory, College, Alaska. 159. ______(I960) The aerated sewage lagoon in arctic Alaska. Arctic Health Re­ search Center, College, Alaska. 160. Reisman, A. (1968) Engineering economics, a unified approach. Heating, Piping and Air Conditioning, p. 165-172, January. 161. ______(1968) Engineering economics, a unified approach. Heating, Piping and Air Conditioning, p. 122-148, February. 162. Ridenour, G.M. (1930) Effect of temperature on rate of settling of sewage solids. Sewage Works Journal, vol. 2\ no. 2, p. 245. 163. Rimskaya-Korsakova, T.V. (1966) Planning and architecture of towns in the far north - layout of built-up areas in towns of the far north. Problems of the North, no. 10, p. 59-70. 164. Ripperton, Dr. L.A. (1967) Effect of meteorological and climatological factors on the response to air pollution. School of Public Health, University of North Carolina, Chapel Hill, North Carolina, Publication no. 101. SELECTED BIBLIOGRAPHY 85

165. Rogers, H.G. (1954) Investigation of the design of certain appurtenances for sewage sys­ tems in low temperature areas. National Research Council, Committee on Sanitary Engineering and Environment, 6 p. 1 6 6 . ______(1950) Report on investigation of the design of sewage pumping stations for low temperature areas. National Research Council, Division of Medical Sciences, Committee on Sanitary Engineering and Environment, 7 p. 167. ______(1948) Report on investigation of sanitary features of utilidor construction and substitutes therefore in arctic installations. National Research Council, Division of Medical Sciences, Committee on Sanitary Engineering and Environment, 7 p. 168. Sawyer, C.N. (1965) Milestones in the development of the activated sludge process. Journal of the Water Pollution Control Federation, vol. 37, no. 2, p. 151-162. 169. ______(1960) Activated sludge modifications. Journal of the Water Pollution Con- trol Federation, vol. 32, no. 3; p. 232. 170. ______(1940) Activated sludge oxidations VI, Results of feeding experiments to determine the effect of the variable temperature and sludge concentration. Sewage Works Journal, vol. 12, p. 244-259. 171. ______and Kahn, P.A. (1960) Temperature requirements for odor destruction in sludge incineration. Journal of the Water Pollution Control Federation, vol. 32, no. 12, p. 1274. 172. Sayers, R.R. (1934) Gas hazards in sewers and sewage-treatment plants. Public Health Reports, vol. 49, no. 5, p. 145-155. 173. Schroepfer, G.J. and Ziemke, N.R. (1959) Development of the anaerobic contact process. Part II. Sewage and Industrial Wastes, vol. 31, no* 6, p. 697. 174. Shapiro, J. (1961) Freezing-out, a safe technique for concentration of dilute solutions. Science, vol. 133, no. 3470, p. 2063-2064. 175. Smith, Capt. F.J. (1957) Environmental problems at remote radar sites. In Proceedings of the 8th Alaskan Science conference, p. 151. 176. Smith, R.JJ. (1960) Elements of engineering unique to cold weather climates: specifically, water and sewage systems. In Proceedings of the 11th Alaskan Science Conference. 177. Spofford, C.M. (1949) Low temperatures in inaccessible Arctic inflate construction costs. Civil Engineering, vol. 19, p. 12-15. 178. Stahl, J.B. and May, D.S. (1967) Microstratification in waste treatment ponds. Journal of the Water Pollution Control Federation, vol. 39, no. 1, p. 72-88. 179. Stegantsev, V.P. (1966) Water supply’, sewerage and heating — the internal freezing of water conduits. Problems of the North, no. 10, p. 185-192. 180. Stephan, D.G. (1961) Possible-va,ter renovation processes. A paper presented to the American Institute of Chemical Engineers, December. 181. Sterling, C.L (1955) Sanitary engineering in Alaska. Journal of the Boston Society of Civil Engineers, vol. 42, p. 345-363. 182. Stoltenberg, D.H. and Sobel, M.J. (1965) Effect of temperature on the deoxygenation of a polluted estuary. Journal of the Water Pollution Control Federation, vol. 37, no. 12, p. 1705-1715. 183. Suvorov, B.T. (1966) Controlling the flooding of underground structures in permafrost. Problems of the North, no. 10, p. 155-160. 184. Taylor, C.D.N. (1959) The construction and operation of mining camps in northern latitudes. Western Miner and Oil Review, July. 185. Teetor, S.D. and Rosanoff, S. (1959) Design problems for consultants; arctic water supply and sewage disposal. Consulting Engineer, vol. 12, no. 6, p. 90. 186. Thomas, H.A., Jr. (1950) Report on investigation of sewage treatment in low-temperature areas. Report to Waste Disposal Subcommittee, National Research Council, May. 187. Towne, W.W. et al. (1956) Evaluation of sewage lagoons under various climatic conditions. Municipal Utilities, vol. 94, no. 11, p. 54. 86 SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

1&8* Towne, W.W.; Bartsch, A.F.; and Davis, W.H. (1957) Raw sewage stabilization ponds in the Dakotas. Sewage and Industrial Wastes, vol. 29, no. 4, p. 377-396. 189. Tyushin, Yu.I. (1966) The main principles of planning and provision of utilities in the apartments of residential buildings in the arctic. Problems of the North, no. 10, p. 111- 117. 190. Waksman, S.A. and Starkey, R.L. (1931) Soil and the Microbe. New York: Wiley and Sons. 191. Walters, C.F. (1962) Single premise disposal system. Water and Sewage Works, p. 323, August. 192. ______and Anderegg, J.A. (1960) Water conservation through reuse of flushing liquid in an aerobic sewage treatment process. In Proceedings of the 11th Alaska Science Conference. 193. Warner, D.L. (1965) Deep-well injection of liquid waste. U.S. Department of Health, Edu­ cation and Welfare, Public Health Service, 55 p., April. 194. Whittaker, H.A. (1949) Sanitation needs in Alaska. Alaska Department of Health, 26 p. 195. Williams, R.B. (1959) Summary of Salmonella and Shigella of Alaska. Public Health Re­ ports, vol. 74, no. 1, p. 55. 196. Wilson, W.R. (1965) Design criteria for a sewage oxidation pond in arctic Alaska. Tech­ nical Documentary Report AAL-TDR-64-19. 197. Wolman, A. (1967) Environmental issues in the arctic. 1967 Symposium on Circumpolar Health Related Problems presented by Arctic Institute of North America, University of Alaska. 198. ______(1961) Impact of desalinization on the water economy. Journal of the American Water Works Association, vol. 53, noi 2, p. :1£9. 199. Zenger, N.N. (1966) Ways in which to improve the economics of water supply in the north­ ern regions. Problems of the North, no. 9, p. 213-219. 200. Zimmerman, F.J. (1961) Wet air combustion. Industrial Water and Wastes, vol. 6, no. 4, p. 102-106.

201. Repair and utilities problems in the arctic — Big Delta, Alaska. U.S. Troops, Big Delta, Headquarters, 4 p. 202. Sanitary problems in operations in snow and extreme cold. Medical Field Service School, Department Military Sanitation, 11 p. 203. Low temperature sanitation. U.S. Office of Naval Operations, Washington, D.C., 89 p, 1954. 204. Human wastes in arctic and sub-arctic. Army Environmental Health Laboratory, Final Re­ port, Project 6-61-13-004, 1954. 005. Proceedings of the Permafrost International Conference. Publication 1287, National Acad­ emy of Sciences, National Research Council, 563 p., 1965. 206. Sanitary waste handling by AST-individual household. Pulp and Paper Research Institute of Canada, Report to Central Mortgage and Housing Corporation, Progress Report No. 3, 1959. 207. A new method for continuously treating sewage. J.J. Baier and Company for Forming Machine Co. of America, 1966. 208. The Zimmermann process as applied to the disposal of sewage sludge. Report by the Sterling Drug, Inc., 1958. 209. Summary report sewage wastes from railroad passenger cars. Association of American Rail­ roads, Technical Report no. 9, 1950. 210. Arctic Engineering. Department of the Navy, Bureau of Yards and Docks, TP-PW-11. 211. Arctic Construction. Department of the Army, TM5-560. 212. Arctic and Subarctic Construction. Department of the Army, Corps of Engineers, TM5-852-1 to 8. SELECTED BIBLIOGRAPHY 87

213. Arctic and subarctic construction - utilities. Department of the Army, Corps of Engi­ neers, TM5-852-5. 214. Minimum design standards for community sewerage systems. Federal Housing Adminis­ tration Publication No. 720, 1963. 215. Safety in wastewater works. Federation of Sewage and Industrial Wastes Associations, 1959. 216. Top is bottom on Alaska lake. Engineering News-Record, July, 1965. 217. Septic tank performance at low temperatures. Division of Industrial Research, Institute of Technology, Washington State University, Report no. 27, 1962. 218. Calculation methods for determination of depths of freeze and thaw in soils. Depart­ ments of the Army and the Air Force TM5-852-6 and AFM 88-19, Chapter 6, 1966. 219. Waste purification by using ozone. Armour Research Foundation, Research Proposal No. 62-2 H2GTto Aeronautical Systems Division, U.S. Air Force, 1961. 220. Aerobic treatment of sewage for individual homes and the reuse of the treated waste water for toilet flushing. Purdue University, 1954. 221. Development of an aerobic recirculating waste treatment unit to serve remote Arctic sites. Arctic Health Research Center, 1959. 222. Individual household aerobic sewage treatment systems. National Academy of Sciences, National Research Council, Publication no. 586, 18 p, 1958. 223. Sewage treatment at military installations — summary and conclusions. Sewage Works ¡Journal, vol. 20, no. 1, p, 52, 1948. 224. Extended aeration sewage treatment. Department of Health, Education and Welfare. U.S. Public Health Service, Technical Report W60-6. 225. Schmidt, G.D. (1965) The applicability of sewage ponds, with special attention to the purification of organically soiled sewage in rural districts. Translated by D.A. Sinclair, National Research Council, Canada, NRC TT-1342, 1968.

89

APPENDIX A: NORTH DAKOTA STANDARDS FOR THE DESIGN OF SMALL WASTE STABILIZATION LAGOONS 1. Location: The site of any waste treatment facility for any of these should be selected after careful consideration of many factors. The location of any waste treatment facility must be approved by the State Department of Health. Time and expense can be saved by obtaining site approval during the planning phase. The following are some of the factors that must be con­ sidered in selecting a lagoon site: a. Any treatment facility must be located a safe distance from any water supply. b. It should be located as far as practical from any dwelling. c. The facility should, whenever possible, be located where drainage from the stabilization pond will be to a definite watercourse. d. Provisions must be made, when indicated by the topography, to divert surface water runoff and to prevent surface water from entering the lagoon. 2. Construction: a. The entire stabilization lagoon area, where construction will be required, should be stripped of vegetation and debris. No organic material should be used in the lagoon construction. b. Sufficient topsoil should be removed and stockpiled for reuse. c. The earth is then excavated, placed, compacted, and trimmed to form a uniform levee with recommended inside and outside slopes of 3:1. The slopes may be flattened to 6:1, where needed, to control . The levee should have a minimum top width of 6 feet, preferably 8 feet, to insure stability and to allow proper maintenance. d. All required inlet, drain, or overflow piping should be installed, and all trenches backfilled and compacted to prevent seepage through the levee. (1) The inlet line may be either a pressure main or a gravity line. The details of construc­ tion for the inlet line must be designed for each particular installation. (2) A drain line complete with a gate valve is required to lower the liquid level to provide adequate storage through the winter season. The drain line should be installed above the floor of the lagoon to avoid drawing sludge from the bottom. The outlet of the drain pipe should be screened to prevent small animals from entering the pipe. (3) The ground below the discharge end of the drain pipe should be protected from erosion by placing of riprap. (4) The bottom, as well as the banks surrounding the lagoon, should be tight enough to limit seepage to a maximum rate of \ to V4 inch per day. If the soil at the site is un­ satisfactory the lagoon must be sealed with clay, bentonite, or an impervious membrane lining. e. The floor of the lagoon should be constructed as level as possible. f. The stockpiled topsoil is then distributed on the outside slope, the top of the levee, and on the inside slope to the optimum liquid level elevation. g. The topsoil should be prepared for seeding. If adequate moisture is available in the topsoil, seeding can be accomplished whenever time is available. Best results will normally be realized if planting is done in the spring or fall. h. The entire stabilization lagoon site should be fenced, including an access gate to allow maintenance vehicles to enter. The most desirable location for the fence is on the outside 90 APPENDIX A

Gt the lagoon levee, allowing sufficient room for vehicle movement during maintenance operations. i. A sigh indicating the nature of the waste treatment facility and advising against trespass­ ing should be posted on the gate and on the fence at visible locations.

3. Maintenance: a. The grass should be mowed several times during the summer months. b. Unwanted weeds should be removed. c. The fence gate should be locked at all times to keep out livestock and trespassers. d. Additional grass may have to be planted to fill in areas void of grass. e. The lagoon should be drained in the late fall or at such time as the effluent can drain into the nearest watercourse without causing inconvenience to adjacent land users or property owners.

4. Design: Stabilization lagoons are generally built in a square or rectangular shape although any shape that .will not hinder solids-dispersion or circulation is acceptable. There should be a minimum of two feet of freeboard above the maximum liquid level, although three feet is recom­ mended. Waste stabilization lagoons will operate satisfactorily at liquid levels from two feet to five feet. The majority of stabilization lagoons in North Dakota have been designed with a maximum liquid level of five feet and three feet of freeboard. A properly designed lagoon should have sufficient surface area to treat the wastes and sufficient volume to retain all wastes during the reduced activity period. Ice and snow cover prevents the lagoon from main­ taining its normal reduction rate; therefore all wastes must be retained during this season. The accumulated wastes will be reduced after ice and snow cover have gone and the lagoon should not be drained until the effluent will not constitute a hazard to any water supply or cause an inconvenience to adjacent land users. Stabilization lagoons can be designed using biochemical oxygen demand loading criteria, or by using liquid volume as the basis for design. A small stabilization lagoon designed to treat do­ mestic sewage can be loaded at the rate of 0.5 pounds of BOD per 1,000 square feet per day, or 21.8 pounds of BOD per acre per day. This loading is approximately equivalent to 340 square feet per person, or 128 persons per acre. Any stabilization lagoon designed to treat agricultural or industrial wastes must be designed on an individual basis due to extreme varia­ tions in quantity and strength bf these wastes. A design based on volume must include suffi­ cient lagoon capacity to retain all wastes until the lagoon has recovered and the effluent is acceptable by State standards. Normally, the period of ice cover will vary from 120 to 150 days. Allowances should also be made for lagoon recovery time in determining the total days storage required. See next page for North Dakota guide material to be used in sizing stabilization lagoons. APPENDIX A 91

Suggested sewage volume and B.O.D. for various services.

Gallons Pounds 5-Day ______Per Day______B.O.D. Per Day

Airports Each employee 15 0.05 Each passenger 5 0.02 Bars Each employee 15 0.05 Each customer 2 0.01 Camps and Resorts Construction camp 50 0.15 Summer camp 50 0.15 Tourist camp 50 0.15 Trailer camp 50 0.15 Country Club Each employee 15 0.05 Each member present 50 0.05 Hospitals Each bed 200 0.30 Hotels Each employee 15 0.05 Each guest 50 0.15 Industrial Building (Excluding industry and restaurant) Each employee 15 0.05 Institutions other than Hospitals Each patient 100 0.20 Laundry (Self-service) Each machine 500 0.50 Motels Each room 125 0.15 Offices Each employee 15 0.05 Parks (Sanitary wastes only) 5 0.01 Residential Average home, each person 75 0.17 Better home, each person 90 0.20 Luxury home, each person 100

93

APPENDIX B: CRITERIA FOR EVALUATION OF COLD REGION SEWAGE WORKS EQUIPMENT AND DEVICES Based on studies conducted by Glark and Groff, Engineers, Salem, Oregon.

A. Manufacture and Procurement: 1. General. a. Readily manufactured and procurable from several sources on short notice. b. Few, if any, unusual dies, castings, forms, parts or materials which are difficult to make or obtain. c. Relatively inexpensive. 2. Specific. a. Containers for collection (nondisposable type) should be of indestructible material, re­ tain shape, and be so shaped or fitted that they maybe joined by welding, bolting, etc. ttop, sides and bottom, to make walls for buildings :■ fehélíers, platforms, snow fences, markers, rafts, etc. Nonleak cover or closure. b. Containers for collection (disposable type) to be readily decomposable, collapsible, or flammable.

B. Shipping: 1. General. a. Compact and relatively indestructible in handling. b. Easily packaged including spare parts; easily unpackaged. c. Package materials or containers suitable for other uses after unpackaging. d. Capable of air transport and air drop. e. Undamaged by freezing. 2. Specific. a. Collection piping to be short lengths capable of nesting with next smaller size. b. Collection containers (disposal type) capable of nesting or collapsing. c. Collection containers (nondisposable type) may be used to ship essential items such as oil and thereafter be converted to waste collection purposes. d. Treatment devices capable of dividing into sections.

C. Installation: 1. General. a. Readily installed by untrained personnel using simple directions accompanying each unit. b. Only simple hand tools required. c. Suitable for- convenient location in enclosed, heated quarters or occupied areas. 2. Specific. a. Couplings for collection piping to be simple, quick-connecting, unaffected by freezing, capable of at least 4-degrees deflection. 94 APPENDIX B

D. Operation: 1. General. a. Simple, ,by untrained personnel. b. Non-odorous. c. Not injurious to health. d. Free from hazards to safety. e. Free from fire hazards. f. Free from creating nuisance conditions. g. Minimum of liquid required, particularly fresh water. h. Minimal energy requirements (except possibly where nuclear energy is supplied) utiliz­ ing the same type of energy available elsewhere at the camp. Use of waste heat or energy if possible. i. Does not encourage or harbor growth of insects and vermin. 2. Specific. a. Collection piping should not be adversely affected by freezing or by heating methods, i.e., electric resistance cable, steam injection, etc. b. Toilet units capable of repeated use in rapid succession. c. Treatment units should exhibit consistently high efficiency in handling variations of loading. Units should convert wastes to product of value, for example, supplying nutrients for growth of algae. d. Thermostat controls must be reliable, capable of accurate setting with minimum variation.

E. Maintenance: 1. General. a. Maintenance requirements should be at a minimum in time consumed and with untrained personnel and simple tools. b. Units easiiy cleaned; cleaning required only infrequently. c. Few repair or replacement parts which are relatively inexpensive, and readily obtained or improvised. d. Repair by untrained personnel should be possible. 95

APPENDIX C: CHARACTERISTICS OF SEWER PIPE

Table CL Characteristics of thermoplastic pipe.

Thermal H eat Wax temp expansion distortion Burning Thermal Pipe rating Use (in./100 ft temp rate conductivity (° F ) for 10F) <°F) (Btu in./ft2 hr F)

Polyvinyl 150 (Type I) Process piping; 0.333 165 (Type I) Self 1.05 (Type I) chloride (PVC) 140 (Type II) Lab drains, etc. 155 (Type II) extinguishing 1.35 (Type II) Polyvinyl 200 Hot and cold water; 0.5 215 Self 0.96 dichloride (C PVC) corrosive materials extinguishing Polypropylene 135 Salt water disposal 0.46 150 Slow 1.3 lines, drainage, etc. Vinylidene 180 Handles most strong 1.0 195 Self 1.3 to 1.7 fluoride (KYNAR) oxidants and reducing extinguishing agents

At no time should plastic pipe be laid on steam pipes or other hot surfaces. All plastic piping systems have a smooth internal surface that offers little frictional resistance to flow. A “ C** factor of 145 can be used in the Hazen and Williams formula for calculating head loss. 2 general types plastic resins, thermoplastic and thermosetting. The former can be reformed by application of heat. All thermoplastics available in schedule 40 and schedule 80 designations. Wall thicknesses in these sizes corres­ pond to those of steel pipe. No correlation between schedule number and allowable working pressure. To remedy this condition the industry is attempting to standardize uniformly pressure rated pipe. PVC has been standardized and is available in schedule 40 and 80 as well as 3 standard dimension ratio (SDR) ratings — SDR 13.5 with an al­ lowable working pressure of 315 psi at 73.4F, SDR-21, 200 psi and SDR 26, 160 psi at the 73.4F temperature. Type I PVC is normal impact pipe. Type II PVC is high impact pipe. Only plastic piping which has been approved by the National Sanitation Foundation should be used for potable water.

Table CII. Dimensions and properties of various types of pipe for sewers.

Internal External Type o f Nominal Wall su rface> surface Thermal pipe siz e th ickn ess area area conductivity* Volume (in.) (in.) (ft2/I ine al ft) (ft2/lineal ft) (Btu in ./ft2 hr F) (gal/lineal ft)

Wood stave 2 1.00 0.52 1.04 0.163 (redwood or 4 1.06 1.04 *.60 0.8 to 2.2 according 0.653 similar) 6 1.12 1.58 2 .Î6 to condition of mate­ 1.47 8 1.12 2.10 2.68 rial and site condi­ 2.61 10 1.12 2.61 3 .2 i tions 4.08 12 1.19 3.14 3.80 5.88 Steel pipe 2 0.154 0.54 0.62 0.174 (standard 4 0.237 1.05 1.18 0.661 weight) 6 0.280 1.59 1.73 t 1.50 8 0.322 2.09 2.26 2.66 10 0.365 2.62 2.82 4.24 12 0.375 3.14 3.34 5.96

* Assuming pipe is buried and uninsulated, t Thermal resistance assumed to be zero 96 APPENDIX C

Table Cn (cont’d). Dimensions and properties of various types of pipe for sewers.

Internal External Type of Nominal Wall surface surface Thermal pipe size thickness area area conductivity* Volume (in.) (in.) (ft2/lineal ft) (ft2/line al ft) (Btu in ./ft2 hr F) (gal/lineal ft)

Thermoplastic 2 0.154 0.54 0.62 0.174 pipe 4 0.237 1.05 1.18 0.96 to 1.7 according 0.661 (schedule 40) 6 0.280 1.59 1.73 to specific material 1.50 8 0.322 2.09 2.26 and site conditions 2.66 10 0.365 2.62 2.82 4.24 12 0.406 3.34 5.96 Thermoplastic 2 0.218S 0.51 0.62 0.153 pipe 4 0.337 1.00 1.18 0.96 to 1.7 according 0.597 (schedule 80) 6 0.432 1.51 1.73 to specific material 1.35 8 0.500 2.00 2.26 anfl site conditions 2.37 10 0.593 2.82 12 0.687 3.34 Copper tube 2 0.083 0.513 0.556 Î (Typek) 0.157 4 0.134 1.01 1.08 0.607 6 0.192 i.So 1.60 1.35 8 0.271 1.99 2.13 2.34 10 0.338 2.47 2.65 3.65 12 0.405 2.96 3.17 5.24 * Assuming pipe is buried and uninsulated, t Thermal resistance assumed to be zero. 97

APPENDIX D: VENTILATION AND AIR CONDITIONING IN SANITARY ENGINEERING IN COLD ENVIRONMENTS

Heat and humidity control are important when water vapor and processes which must be pro­ tected from freezing are enclosed in the building. Essentially, all such structures contain water vapor. Under severe low temperature conditions, most waste water treatment units and devices re­ quire enclosure and heating. Sedimentation chambers, aeration units, flumes, screen chambers, sludge conditioning and processing units, and wet wells all contribute water vapor to the air with­ in buildings. Simple occupancy of a building contributes water vapor to the air. There is a definite limit to the amount of water vapor that maybe absorbed by the air, dependent upon its temperature. The warmer the air the greater its capacity to absorb water vapor. When air has absorbed all the water vapor possible, it is said to be saturated. If warm air is cooled, its capacity to absorb and hold water vapor is reduced in a predictable amount, directly related to the temperature of the air. Ex­ cess water vapor in the cooled air is removed, when the dewpoint* is reached, by condensation as water on exposed surfaces, and if the collecting surfaces are cold enough ice will be formed. Proper circulation of the air within a building minimizes condensation problems. Water vapor content or humidity of the air may be controlled by adjusting the temperature of the air as well as by controlling the amount of vapor available for absorption in the air. Although control of the source of water vapor is theoretically possible, it is highly improbable that this method will be effective in buildings containing water and waste-water storage, measuring and treatment units. Air can be dehumidified by cooling it to a desired dewpoint and then rewarming it to the temperature required in the building. Or it can be circulated through an absorbent cycle using beds of activated alumina or silica gel, which must then be reactivated by heat. In mechanical air con­ ditioning equipment, such processes are carried out more or less automatically. In cold regions, nature provides a.ready source of cold dry air in the external atmosphere. Cold outside air may be used to chill the inside air and to form a predetermined mixture of dry and saturated air which will be below the dewpoint. Specially designed heating coils are used to warm cold outside air prior to introducing it into the building. Heating may be accomplished by heating return or recirculated air and mixing it with the cold air or by direct heating of the outside air. In the latter method, antifreeze-filled preconditioning units are used to make first contact with the cold outside air. After warming by the preconditioning units, the outside (dry, low-humidity) air is further warmed by conventional steam, hot water or other types of warming units. The amount of water vapor in air (absolute humidity) is usually expressed as grains per pound of dry air. The ratio of the amount of water vapor in air at a given temperature to the total amount it could absorb at the same temperature, galled the relative humidity, is expressed as a percent­ age. Relative humidity may be measured by a simple sling psychrometer (giving wet and dry-bulb temperature readings) or by a hygrometer (utilizing chemical or electrical or possibly hygroscopic materials such as human hair). To prevfent condensation the relative humidity must be kept well below 100% (saturation) at the prevailing temperature of the coldest surfaces in the enclosure. Painted surfaces, equipment, corrodible metals, wood, and many other things are damaged by condensation in an enclosure. There are numerous examples of damage to walls, ceilings, and equipment by icing. At Thule Air Base, Greenland, excess humidity caused large accumulations of ice with subsequent damage to the walls . In spring and summer, the thawing ice within the walls caused water to drain from the walls to the floors of the building.

* Temperature at which the air is saturated. 98 APPENDIX D

Although vapor barriers on walls are essential, humidity control is also necessary to minimize moisture damage. At a sewage treatment plant near Fairbanks, Alaska, icing occurred on building walls, electrical entrance conduit and on the control panel in such quantities that the panel switches were unusable. An estimated 1000 to 2000 ft3 of air is used per pound of BOD to stabilize the organic mate­ rial in sewage treated by the extended aeration process. If the process is enclosed in a heated building, it may be assumed that for every pound of BOD stabilized in the treatment unit, approxi­ mately 1500 ft3 of saturated air at the approximate temperature of the sewage is released to the environment within the building. By use of psychrometric charts (humidity, temperature, water vapor charts) contained in heating and ventilating engineering handbooks, the temperature, volume and humidity necessary to prevent condensation can be calculated. If the characteristics of two atmospheres are known, a more desirable third atmosphere may be predicted graphically by use of the psychrometric chart. Characteristics of moist air at various temperatures are shown in Table XII. A crude prediction (more precise prediction may be made by use of a psychrometric chart or by computation) of quantities and characteristics of two atmospheres to be mixed and the result­ ant third atmosphere can be made by use of the “ square method” :

PAR T S OF 110 GRAIN, 70F AIR

PAR T S OF 1 GRAIN, -3 0 F A IR

It is desired to mix inside saturated air at 70F with outside saturated air at -30F in proper proportions to have a resultant mixture of saturated air at 50F. The moisture content of 70F sat­ urated air is 110 grains (Table XII). This number is inserted in circle A of the square ABED. The moisture content of saturated -30F air is 1 grain. The number 1 is inserted in circle B. Table XII shows the moisture content of saturated 50F air to be 54 grains. The desirable moisture content (54) of the mixed air is inserted in circle C. Subtracting diagonally (110 - 54 = 56 and 54 - 1 = 53), the number 53 is placed in circle D and 56 is placed in circle E. The square then shows approxi­ mately 53 parts of 110-grain air must be mixed with each 56 parts of 1-grain air to give a resultant mixture of 54-grain air. By dividing total temperature difference between the 70F air and the -30F air (100°) by 2 (100 * 2 = 50) and multiplying the result by the ratio of cold air to warm air (56 -s- 53 x 50 - approximately 50) the approximate temperature of the resulting mixture can be ob­ tained. It is obvious that the air used to aerate sewage would require little or no additional heat prior to utilization for aeration. The same mixture warmed to 70F would give low humidity air in the enclosure and would not cause condensation on surfaces warmer than approximately 50F. The problem of providing human comfort within buildings located in the cold regions is not a complicated one. In winter the objective is usually tne simultaneous control of temperature, humidity, and air motion. During summer months, little if any control of the air is considered necessary, ex­ cept in special cases. Control of dust may be required in certain localities during high winds, and in such cases the use of dust filters on ventilating fans during summer months may be advisable. Screens are advisable at all openings to control insects. APPENDIX D 99

It may be desirable during winter months to raise the relative humidity inside buildings to conform to minimum comfort standards. Control of humidity at all seasons may also be required for various reasons, particularly in connection with storage rooms for certain commodities. The raising of relative humidities within buildings during the heating season requires a cer­ tain amount of heat to evaporate the amount of water vapor that must be added to the air within the building. The amount of heat required can be calculated from the following equation, assuming that the latent heat of vapor at W\ is 1.060 Btu/lb.

Ht = 79.5 Q(Wi-Wo)

Hi = heat required to increase moisture content of air leaking into building from W0 to W\t Btu/hr. Q = volume of outside air entering building in 1000 ft3/hr. Wi = vapor density of inside air, lb/lb dry air W0 = vapor density of outside air, lb/lb dry air;

In summary, buildings in cold regions are particularly susceptible to vapor condensation and the formation of ice on the inner surfaces of outer walls and roof sections. Low outside tempera­ tures, lightweight construction materials, and uneven inside temperatures contribute to conditions favorable to condensation and accumulations of frost on inner surfaces, as do through structural members, which provide an unbroken line for freezing-temperature penetration from outside to inside. During extremely cold weather, the overall heat resistance of a wall may be insufficient to permit the maintenance of a desired relative humidity within the building without the formation of moisture on the inner surfaces. To avoid lowering the relative humidity of the room, more insula­ tion will be required in the wall section to raise the surface temperature above the dewpoint. In designing wall and roof sections, consideration should be given to the inside surface temperature in relation to the dewpoint.corresponding to the inside temperature and relative humidity. In all rooms where high relative humidities are maintained, double-glazed sash or storm windows are advisable. The use of ordinary electric fans to evenly distribute heat produced by radiant heaters has been widely adopted and has proved quite effective. Proper distribution can best be accomplished, however, and more uniform room and surface temperatures will result, if air circulation units de­ signed to meet the specific requirements of each building are installed. The methods used in the cold regions to prevent or retard water vapor penetration through building sections are no different from those elsewhere. Vapor-retarding membranes and building materials of low moisture permeability are widely used. Air conditioning and heating and ventilating design for comfort, fog control, prevention of condensation, and prevention of accumulation of frost and ice are well documented in American ex­ perience. Application of these experiences to specific cold region facilities, however, has varied from 100% to zero. Special consideration was given to heating and ventilating requirements in sewage treatment facilities for metropolitan Winnipeg in Canada*!* In this work, it is reported that main aeration and final sedimentation tanks were enclosed for weather protection. Heating and ventilation equip­ ment was designed to eliminate accumulation of hazardous gases, to permit normal aeration to be

* Special Aspects in Establishment of Secondary Treatment at the North End Sewage Treatment Plant in Metropolitan Winnipeg by G.C. Koopmans, V.H. Greer, and D.W. van Es, Engineering Journal, July 1967, p. 24-29. 100 APPENDIX D practiced, and to prevent condensation in the air and on exposed surfaces in the plant. The follow­ ing criteria were used for heating and ventilating design:

Heating and Ventilating Design Criteria Special Aspects in Establishment of Secondary Treatment at the North End Sewage Treatment Plant in Metropolitan Winnipeg by G.C. Koopmans, V.H. Greer, and D.W. vanEs, Engineering Journal, July 1967, p. 24-29.

Preaeration Aeration Final tanks tanks tanks

1. Outside winter design temperature -30F -30F -30F 2. Design sewage temperature 50F 50F 50F 3. Minimum tank air temperature to prevent con­ densation at vapor barrier 45F 45F 45F 4. Surface temperature at ceiling 40F 40F 40F 5. Minimum winter ventilation rate - blower air plus ventilation air - air changes per hour 4 4 2 6. Maximum summer ventilation rate - blower air plus ventilation air - air changes per hour 18 9 7 7. Relative humidity of exhaust air (%) 12% 75% 10% 8. Conduction heat gain from water surface to air. Btu/ft2 F 1.0 1.0 1.0 9. Radiation gain from water surface to air. Btu/ft2 (based on emissivity of 0.9). 8.7 8.7* 8.7't 10. Latent heat loss between water surface and air** 0 0 0 11. Latent heat loss from water droplets from V2 total to sprays and aeration 0 saturate air ft 0

* Radiation effect considered only for first 30 ft of tanks due to fogging conditions in tank caused by spray and aeration. t Radiation effect considered on Yz area of final tanks. ** m heat for evaporation of water is assumed to come from water. t t Assume sprays saturate air. One half of latent heat required for evaporation was assumed to come from air and one half from water droplets. 101

APPENDIX E: MANAGEMENT OF SOLID WASTES

The average American in the cold regions generates about 6 lb of solid wastes (garbage, refuse, trash, junk, etc.) every day. From 75 to 100% of the total effort in disposal of all wastes goes into the collecting and disposing of these wastes, and collection accounts for most of the cost (Table El, Eli, and EIII). The commonest practices of disposal by incineration and sanitary landfill are not easily ap­ plied in very cold regions, yet something must be done to stop the present common practices of dumping rubbish anywhere (especially in water, where it is out of sight and of mind, or on the tundra to remain a permanent eyesore and perhaps a health hazard). Incineration is handicapped by a shortage of combustibles, which have been extracted for house construction and repair or for fuel. Burial in frozen ground offers little promise. Figure El is a schematic drawing of an incinerator. Appendix F classifies wastes and in­ cinerators. The revised Incinerator and Rubbish-Handling Recommendations of the National Fire Pro­ tection Association, Publication NFPA82, 1969, is a valuable source of information on incinera­ tion, which seems to be the best means of disposal of solid wastes in very cold regions.

Figure El. Schematic drawing of an incinerator. (After University of California Institute of Engineering Research, “Municipal Incineration - A Study of the Factors Involved in Municipal Refuse Disposal by Incineration.”) 102 APPENDIX E

Table EL Estimated weight/volume relationships for constituents in solid waste.

Approximate pounds per Constituents cubic foot

Garbage (commercial - 75% wet, 25% dry) 45 Garbage (average — 65% wet, 35% dry) 35 Dry rubbish (miscellaneous from office 7 buildings, etc) Loose paper 4 Scrap wood (varies with moisture content) 12 Shavings 10 Sawdust 14 Rubbish from light industry 10 Heavy industry, pathological waste Require survey Water 62.4

Table Eli. Numbers used in estimating quantities of solid wastes.

Type of facility Estimated quantity of waste

Apartment buildings 7 pounds per bedroom per day

Cafeterias Vz - 3A pounds per meal Cities 3 to 4 pounds per capita per day (requires survey) Clubs 3 pounds per person per day plus 50% for operation­ al waste Department stores 1 pound per 25 square feet of floor area Hospitals 8 pounds per bed per day plus 2* l2A% of total waste

Hotels, First class 3 pounds per guest room plus lVz pounds per meal plus 50% for operational waste

Hotels, Medium class 2Vz pounds per guest room plus 1H pounds per meal plus 40% for operational waste Institutions 5 pounds per resident per day Markets (food) 2 pounds per 25 square feet of floor area Office buildings 1 pound per 100 square feet of floor area Restaurants 2 pounds per meal per day

Schools Vz pound per student per day plus Vz pound per meal Trailer camps 8 pounds per trailer per day Warehouses 3 pounds per 100 square feet per day APPENDIX E 103

Table EDI. Methods for solid waste disposal used or considered for use in cold regions.

Dumping Filling Dumping in water or on ice Sanitary land fill (controlled Dumping on land tipping) Trench fill method Burial Area method Reduction Feeding Incineration Dilution Burning on open dump Grinding and disposal to the Burning in incinerator sea, lakes or water courses Fermentation Grinding and disposal through Private premise composting sewers and sewage treatment Beccari system plant Indore process Miscellaneous Methods Verdier process Garchey system Frazer process Chemical disintegration Earp-Thomas process Repellents Dana process

105

AEPENDIX F: CLASSIFICATION OF WASTES AND INCINERATORS (From LLA. Incinerator Standards, Incinerator Institute of America.)

The basis for satisfactory incinerator operation is the proper analysis of the waste to be destroyed, and the selection of proper equipment to best destroy that particular waste. As a guide, mixtures of waste most commonly encountered have been classified into types of waste, together with the B.T.U. values and moisture contents of the mixtures. A concentration of one specific waste in the mixture may change the B.T.U. value and/or the moisture content of the mixture. A concentration of more than 10% by weight of catalogues, magazines, or packaged paper will change the density of the mixture and affect burning rates. Similarly, incinerators have been classified, by their capacities and by the type of wastes they are capable of incinerating.

Classification of wastes Type 0. Trash, a mixture of highly combustible waste such as paper, cardboard, cartons, wood boxes, and combustible floor sweepings, from commercial and industrial activities. The mix­ tures contain up to 10% by weight of plastic bags, coated paper, laminated paper, treated corru­ gated cardboard, oily rags and plastic or rubber scraps. This type of waste contains 10% moisture, 5% incombustible solids and has a heating value of 8500 B.T.U. per pound as fired. Type 1. Rubbish, a mixture of combustible waste such as paper, cardboard cartons, wood scrap, foliage and combustible floor sweepings, from domestic, commercial and industrial activi­ ties. The mixture contains up to 20% by weight of restaurant or cafeteria waste, but contains little or no treated papers, plastic or rubber wastes. This type of waste contains 25% moisture, 10% incombustible solids and has a heating value of 6500 B.T.U. per pound as fired. Type 2. Refuse, consisting of an approximately even mixture of rubbish and garbage by weight. This type of waste is common to apartment and residential occupancy, consisting of up to 50% moisture, 7% incombustible solids, and has a heating value of 4300 B.T.U. per pound as fired. Type 3. Garbage, consisting of animal and vegetable wastes from restaurants, cafeterias, hotels, hospitals, markets, and like installations. This type of waste contains up to 70% moisture, up to 5% incombustible solids, and has a heating value of 2500 B.T.U. per pound as fired. Type 4. Human and animal remains, consisting of carcasses, organs and solid organic wastes from hospitals, laboratories, abattoirs, animal pounds, and similar sources, consisting of up to 85% moisture, 5% incombustible solids, and having a heating value of 1000 B.T.U. per pound as fired. Type 5. By-product waste, gaseous, liquid or semi-liquid, such as tar, paints, solvents, sludge, fumes, etc. from industrial operations. B.T.U. values must be determined by the individual materials to be destroyed. Type 6. Solid by-product waste, such as rubber, plastics, wood waste, etc., from industrial operations. B.T.U. values must be determined by the individual materials to be destroyed. 106 APPENDIX F

Classification of incinerators Class /. Portable, packaged, completely assembled, direct fed incinerators, having not over 5 cu. ft. storage capacity, or 25 lbs. per hour burning rate, suitable for Type 2 Waste. Class IA. Portable, packaged or job assembled, direct fed incinerators 5 cu. ft. to 15 cu. ft. primary chamber volume; or a burning rate of 25 lbs. per hour up to, but not including, 100 lbs. per hour of Type 0, Type 1, or Type 2 Waste; or a burning rate of 25 lbs. per hour up to, but not includ­ ing, 75 lbs. per hour of Type 3 Waste. Class II. Flue-fed, single chamber incinerators with more than 2 sq. ft. burning area, suit­ able for Type 2 Waste. This type of incinerator is served by one vertical flue functioning both as a chute for charging waste and to carry the products of combustioni;to atmosphere. This type of in­ cinerator installed in apartment houses or multiple dwellings not more than five stories high. Class IIA. Chute-fed multiple chamber incinerators, with more than 2 sq. ft. burning area, suitable for Type 1 or Type 2 Waste. (Not recommended for industrial wastes). This type of in­ cinerator is served by a vertical chute for charging wastes from two or more floors above the incin­ erator and a separate flue for carrying the products of combustion to atmosphere. Class III. Direct fed incinerators with a burning rate of 100 lbs. per hour and over, suitable for Type 0, Type 1 or Type 2 Waste. Class IV. Direct fed incinerators with a burning rate of 75 lbs. per hour or over, suitable for Type 3 Waste. Class V. Municipal incinerators suitable for Type 0, Type 1, Type 2, or Type 3 Wastes, or a combination of all four wastes, and are rated in tons per hour or tons per 24 hours. Class VI. Crematory and pathological incinerators, suitable for Type 4 Waste. Class VII. Incinerators designed for specific by-product wastes, Type 5 or Type 6. Unclassified_____ Security Classification 107 DOCUMENT CONTROL DATA - R & D (Security claaeltlcation at till», body oí abatract and indexing annotation « m l 6a enterad whan ttf »W M gjjgrtJithM jg^ i. ORIGINATING a c t iv it y (Corporata author) 2M. REPORT SECURITY CLASSIFICATION U. S. Army Cold Regions Research and Engineering Unclassified Laboratory 2b. GROUP Hanover. New Hampshire 03755 3. REPORT TITLE SEWERAGE AND SEWAGE DISPOSAL IN COLD REGIONS

4. DESCRIPTIVE NOTES (Typa ot raport and Incluaira data») Monograph 5- au THOR(S) (Firat naata, midttta Initial, Imat nama) Amos Jo Alter

6* REPORT DATE 7a. TOTAL NO. OF PAGES 7b. NO. OF REFS October 1969 110 225 3a. CONTRACT OR GRANT NO. »S. ORIGINATOR** REPORT NUMBER(S)

b. p r o j e c t n o . DA Project 1T062112A130 Monograph HI~C5b

c. 9b. OTHER REPORT NO(S) (Any othar numbara that maty ba aaaigpad thia raport)

da 10. DISTRIBUTION STATEMENT This document has been approved for public release and sale; its distribution is unlimited.

11. SUPPLEMENTARY NOTES 12. SPONSORING MILITARY ACTIVITY U. S. Army Cold Regions Research and Engineering Laboratory Hanover. New Hampshire 03755 13. ABSTRACT The main items dealt with in this monograph of 106 pages are: Practice and problems Collection and transport Treatment and processes Therm ology Re-use and regenerative processes Construction and operation. There are 225 references, 54 illustrations and 18 tables. Six appendixes treat stabilization ponds, ventilation of buildings having sewage treatment plant, solid wastes, and other topics. 14. KEY WORDS Frost protection Sewage treatment Lagoons (ponds) Sewers Sewage Utilities (cold regions) Sewage disposal Waste disposal

IE ff\ «ARM m M REPLACES DO FORM 1473. 1 JAN «4. WHICH IB P P | NQV H 1 4 #W OBSOLETE POR ARMY USB. Unclassified Security Classification