Sewage Pollution in British Columbia in Perspective
Total Page：16
File Type：pdf, Size：1020Kb
SEWAGE POLLUTION IN BRITISH COLUMBIA IN PERSPECTIVE by Michael Waldichuk West Vancouver Laboratory Fisheries and Oceans Canada 4160 Marine Drive West Vancouver, B.C. LIBRARY V7V 1 N6 SCIENCES B.C. Presented at the Workshop on Municipal Marine Discharge, Sheraton Plaza 500 Hotel B.C. 14 - 15.February 1984 TD 763 W3 1. I I () :i. l C 1984 Canadian Industry Report of Fisheries and Aquatic Sciences These reports contain the results of research and development that are useful to industry for either immediate or future application. Industry Reports are directed pri marily towards individuals in the primary and secondary sectors of the fishing and marine industries. No restriction is placed on subject matter and the series reflects the board interests and policies of the Department of Fisheries and Oceans, namely, fish eries management, technology and development, ocean sciences, and aquatic envi ronments relevent to Canada. Industry Reports may be cited as full publications. The correct citation appears above the abstract of each report. Each report will be abstracted in A qua tic Sciences and Fisheries Abstracts and will be indexed annually in the Department's index to scientific and technical publications. Numbers 1-91 in this series were issued as Project Reports of the Industrial De velopment Branch, Technical Reports of the Industrial Development Branch, and Technical Reports of the Fisherman's Service Branch. Numbers 92-110 were issued as Department of Fisheries and the Environment, Fisheries and Marine Service Industry Reports. The current series name was changed with report number 111. Details on the availability oflndustry Reports in hard copy may be obtained from the issuing establishment on the front cover. Rapport canadier :. _ __. • sciences · TD763 W3 1984 Ces rapports contiennent les Waldichuk, M. utiles l'industrie pour des sewage pollution in !'intention Columbia in perspective de l'industrie des et de la me 145396 0 4 0 15643 c. l reflete la vaste gamme des int : _ Library / MPO - Bibliothequ e 1111111 11111 1111\ 111111111\ 11111111111111111111111 Oceans, notamment gestion des p · ques et environnements Les Rapports tions completes. Le titre e publie dans la revue Aqu, C,::, !'index annuel des publica Library Les numeros de I Institute of Ocean Sciences travaux de la Direction d Fisheries and Oceans Canada Direction du developpeme Box 6000 (9860 W. Saanich Rd .) services aux pecheurs. Les dustrie du Service des Sidney, B.C . V8L 4B2 Le nom de la a C La page couverture po Jes rapports sous couvertu SEWAGE POLLUTION IN BRITISH COLUMBIA IN PERSPECTIVE 0009 LIBRARY INSTITUTE OF OCEAN SCIENCES BOX 6000 TD763 W3 1984 B.C. Waldichuk, M. by Sewage pollution in British Columbia in perspective 145396 04015643 c.1 Michael Waldichuk West Vancouver Laboratory Fisheries and Oceans Canada 4160 Marine Drive West Vancouver, B.C. V7V 1N6 Presented at the Workshop on Municipal Marine Discharge, Sheraton Plaza 500 Hotel, Vancouver, B.C. 14-15 February 1984 - ii - TABLE OF CONTENTS Page ABSTRACT i i i 1. INTRODUCTION 1 2. HISTORICAL PERSPECTIVE 2 3. CHARACTERISTICS OF SEWAGE THAT AFFECT THE AQUATIC ENVIRONMENT AND ECOSYSTEM 7 3.1 Solids 8 3.2 Microorganisms 9 3.3 Dissolved Organic Constituents 10 3.4 Nutrients 11 3.5 Metals 12 4. TREATMENT 13 4.1 Primary 13 4.2 Secondary 14 4.3 Tertiary 15 5. CASE STUDIES 16 5.1 Greater Vancouver 16 5.2 Greater Victoria 18 5.3 Comox - Courtenay 19 5.4 Nanaimo 21 5.5 Other Coastal Areas 24 6. SEWAGE MANAGEMENT OPTIONS AND TRENDS IN THE 80 1 s 25 7. PROBLEMS THAT REQUIRE SOLUTIONS 28 7.1 Specificity of Microbiological Tests 29 7.2 Sludge Disposal 30 7.3 Sewage Treatment Lagoons 30 7.4 Urban and Agricultural Runoff 31 7.5 Viability of Pathogenic Microorganisms from Fecal Matter in Seawater 31 7.6 Epidemiological Studies on the Effects of Bathing in Sewage-contaminated Seawater 32 7.7 Tracing Sewage Chemically 32 7.8 Dechlorination 33 8. CONCLUSIONS 33 REFERENCES 37 FIGURES 1 - 6 45 - iii - ABSTRACT The historical development of sewage disposal, in the context of its effect on the environment, is reviewed briefly, starting with unconfined land disposal, then the outdoor privy, through the septic tank and tile field disposal system, and finally, the various forms of municipal sewage collection, treatment and disposal into fresh and marine waters. The characteristics of sewage, i.e., solids, microorganisms, dissolved organic constituents, nutrients and metals, that affect the aquatic environment and ecosystem are discussed. A brief review is given of the three levels of treatment: primary, secondary and tertiary. Then four case studies of sewage treatment and ocean disposal in coastal areas of British Columbia (Greater Vancouver, Greater Victoria, Comox-Courtenay, and Nanaimo) are reviewed in some detail. Other areas are discussed with respect to specific problems. The perceived problems are largely associated with the impact of sewage bacteria and viruses on shellfish and the potential hazard to consumers. Closure of shellfish beds to harvesting, because of sewage pollution, has had a major economic impact. An unanticipated effect of effluent disposal from the Iona Island Sewage Treatment Plant has been depressed oxygen in waters overlying Sturgeon Bank and debilitation of fish exposed to these waters, particularly during the warm months of summer. The current trend in sewage disposal is toward deep (50-100 m) coastal outfalls, at considerable distance (1-5 km) from shore, with a diffuser designed for rapid initial dilution (1:100-150), and trapping of the sewage/seawater mixture at considerable depth (20-40 m) below the surface. Treatment is often of the primary type, involving only solids removal, although there is argument for disposal of raw comminuted sewage with retention of only the floatables. Disposal of sewage sludge continues to be a problem in some areas. If disposal is far enough from bathing areas and shellfish beds on shore, there is sometimes no compelling reason for disinfection, particularly in view of the toxicity of chlorine to fish-life. 1. INTRODUCTION I am going to talk about some of my percep,ti ons, as an oceanographer and one who has spent most of his professional career on marine pollution problems as they pertain to effects on fisheries, concerning pollution in this province by domestic or so-called sanitary sewage. _Certain questions emerged during the course of my involvement with sewage pollution from time to time in the last 30 years, and I plan to pose them here. They tell me that rather than 11 11 11 sewage , the more genteel term is "municipal wastewaters • Whatever one wishes to call it, the material we are dealing with originates almost entirely from human wastes, and as our populations increase the world over, so does the amount of sewage. The effects of these wastes are also bound to increase, if we continue to dispose of them untreated into the aquatic environment; and so it is encumbent on us to cope in some way with this increased volume of sewage, if we are not to witness serious ecological and human health damage. Scientists, looking at industrial wastes and sewage in the marine environment on a worldwide basis (GESAMP 1982), have often noted that the effects of sewage are local, and hence, globally inconsequential. The impact, however, is largely in the coastal zone where 90% of our fisheries resources are located and virtually all the water-related marine recreation takes place. While the volume of sewage discharged is generally increasing with time, the composition of raw sewage and the environmental and ecological effects of discharging a unit volume of it into surface waters, be they freshwater or marine, are not substantially changing. What is changing, however, is the way in which we perceive the effects of sewage on the aquatic ecosystem, human health and aesthetics., The environmental movement of the 1970 1 s has had a great impact on perceptions of pollution by sewage as well as by many other • materials. Some of these perceptions may have been ill-founded, but they have necessitated, nevertheless, a very close look by environmental scientists and engineers at all the environmental and ecological effects of sewage, and have led to designs of systems for treatment and disposal that would minimize these effects as much as possible. In this review, I plan to take a brief historical excursion through the - 2 - .. past to examine the ways that sewage has been handled from ancient times; then I shall review the general effects of sewage in the aquatic environment as I perceive them; and finally, I shall touch on a number of sewage disposal problems in British Columbia to show how they were resolved at the time, and then take one particular case study, in the Nanaimo area, and follow it through from my earliest involvement in it some 30 years ago to the present day. I hope that this example will illustrate not only the changing technology and approaches in sewage treatment and disposal during the last 3 decades, but will also show the changing attitudes of people toward this subject. 2. HISTORICAL PERSPECTIVE It is useful to take a historical glance at the way sewage has been. disposed of since the earliest times. Primitive societies, and some of these still exist today, did not worry much about the way sewage was disposed of; and excreta were deposited almost anywhere, especially in a rural setting. Some more advanced societies even considered excrement as a good source of fertilizer for their crops, and methodically collected so-called ''night soil" for this purpose. This has been particularly true even into modern times in the heavily-populated areas of the Orient. In a less methodical fashion, such "fertilization'' continues in subsistence agriculture of Central and South American countries.