Managing Stormwater

8B 28

OPERATORManaging INSIGHTS O timum management strategy. pollutants, and determiningtheop- ing stormwaterflows,identifying have workedfirst-handon calculat- nator, andnowasaconsultant, I and stateorganicsrecycling coordi- former compostingfacility operator Asa meet regulatoryrequirements. what typesoftreatmentworkto have, howisitbeingregulatedand what typesofcontaminantsitmight produced atacompostingfacility, cle istoexaminehowstormwater regulate itasstormwater. ing padsasawastewater,andsome storm waterrunofffromcompost- dress thisissue;someregulate state regulatoryapproachestoad- nately, thereisawidevarietyof sive treatmentsystems.Unfortu- permitting andpotentiallyexpen- problems thatrequireregulatory believed tocreatewaterquality while beingmanufactured,isnow Yet, thissamebeneficialmaterial, ability ofcomposttoretainwater. pacity ofthesoil.Thisisdueto ity toincreasethewaterholdingca- tr Water Storm IO The purposeofthistwo-partarti- Craig Coker BioCycle’s newOperatorInsightsfeature. PartI These questions,andmore, are answered in the bestmethodtocalculateflowsatsite? Is itstormwater?wastewater?Whatis C YCLE as asoilamendmentisitsabil- benefits ofcompostwhenused NE OFtheclearlyrecognized with automatedsamplingequipment(above). composite andtime-compositesamples,oftencollected Sampling methodstooffsetthisdifficultyincludeflow- daily operations. topics thatsite managersfaceintheir issue, OperatorInsightswill examine Insights.” Appearinginevery other editorial featurein2008, “Operator these articles. Those lessonslearnedarereflected in Part IalsokicksoffanewBioCycle not trulyrepresentative. concentrations thatare result inpollutant the wrongtimemay sample ofrunoff(left)at Taking amanualgrab manure, biosolids andfoodscraps).Yet start with(relativeto contamination to amount ofchemicalandpathogenic ture ofthefeedstocks,i.e., least nation duetotherelatively cleanna- have theleastpotentialfor contami- facilities havelongbeenthought to posted. Yardtrimmingscomposting receiving streamsunmanaged,the amounts ofpollutants.Ifdischargedto windrows canpickupsubstantial rain fallingonexposedcomposting in the1990s—itisnowapparentthat System (NPDES)programestablished al PollutantDischargeElimination — imposedunderthePhase1Nation- requirements oncompostingfacilities annual stormwaterrunoffmonitoring virtue ofsomethedatacollectedin WHAT’S THEPROBLEM? In anutshell,contamination.By ADVANCING COMPOSTING,ORGANICSRECYCLING 1 tt vne mas PA18049-3097 419 StateAvenue,Emmaus, Reprinted WithPermissionFrom: 610-967-4135 •www.biocycle.net feedstocks beingcom- some extent,onthe ter runoffdepend,to posting padstormwa- constituents incom- elements (Cole,1994). these compoundsand compost containing land applicationof than anystandardsfor at muchlowerlevels cides, metals)areset constituents (i.e.pesti- standards forsome because waterquality in thecompostitself of thesamecompounds than asimilaramount higher levelofconcern off-site lossespresenta those streams.These quality problemsin tential tocausewater pollutants havethepo- & RENEWABLEENERGY Not surprisingly,the February, 2008 F EBRUARY 2008 runoff from these facilities has been water bound inside plant and animal cell Quantities Of Storm Water shown to be highly variable, containing walls, the presence or absence of forced There are several tools of hydrology potentially significant levels of nutri- aeration that tends to evaporate more and hydraulics available to calculate ents, soluble salts, Biological and Chem- moisture and whether the composting runoff quantities from various storm ical Oxygen Demand (BOD/ COD), tan- process uses supplemental irrigation events. Storm water management reg- nins and phenols from decomposing during active composting. A more ulations and programs have historical- leaves, herbicides, pesticides, fungicides coarsly textured mix, like yard trim- ly been focused on managing quantities and fecal coliform (probably from animal mings, will have less water holding ca- of storm water. These rules are often feces mixed in the yard trimmings). An- pacity than a more finely textured mix, based on what is called the “recurrence imal manure, biosolids and food scraps such as dairy manure bulked with saw- interval” of a storm; terms such as “25- composting facility runoff will likely dust. Leachate draining through a com- year, 24-hour” and “10-year, 1-hour” have higher levels of nutrients, organic posting pile will pick up soluble materi- storms are often used. acids produced during decomposition als (tannins, nutrients, salts) as well as The recurrence interval of a storm is and fecal coliform bacteria (Oregon small particulate matter created by the a statistical abstract, and mathemati- DEQ, 2004). Little data is available on decomposition process. It is a combina- cally is the inverse of its probability of other pathogenic microorganisms in tion of the tannic acids and the particu- occurrence in any given year. For ex- composting facility runoff. late matter that give leachate its char- ample, a “25-year” storm has a statisti- Potential impacts of these con- acteristic dark brown color. cal probability of occurring once every stituents on stream and river water Process storm water is precipitation 25 years (the inverse is 1/25, which quality are the same as, and in some cas- that falls on the site and contacts the equals 0.04, or 4 percent). Thus the 25- es more severe than, untreated dis- composting material without flowing year storm has a 4 percent chance of oc- charges of sanitary wastewater. BOD through the pile. This includes runoff curring in any given year. Similarly, a and COD exert an oxygen demand on the from the sides of the pile as well as storm 10-year storm has a 10 percent chance dissolved oxygen in water, which if de- water that comes in contact with waste of occurrence and a 100-year storm has pleted will cause significant aquatic eco- material and compost that has strayed a 1 percent chance of occurrence. It is logical mortalities. Widespread fish kills from the pile. Nonprocess storm water is worthwhile to note that these statisti- are the most obvious of these problems. precipitation that falls on the compost cal abstractions can be misleading. Nutrients contribute to the geomorpho- site, but that doesn’t come into contact Many people think that if a storm has logic process known as eutrophication, with wastes or compost. Wash water is only a 4 percent chance of occurring where nutrients support the growth of generated by washing vehicles and (i.e. once every 25 years), it is unlikely algae, which also deplete oxygen upon equipment and contains materials dis- to occur more frequently. It is entirely their deaths, as well as stimulate the lodged from vehicle wheels and bodies, possible that two 25-year storms can growth of vegetation (this is an accelera- but the concentrations tend to be lower occur in the same year, or even in the tion of the natural process by which shal- due to the high volumes of dilutive water same week or month. low watercourses become swamps, and used in washing. On the other hand, A “24-hour” storm is the total in turn, eventually become dry land). wash waters can contain surfactants amount of precipitation that falls in Tannins and lignins are natural dis- and other chemicals from any washing 24 hours, which, for example, is 6.5 solved organic acids that give water the detergents used. Run-on is rainfall inches here in western Virginia. Simi- characteristic color of compost tea. Phe- runoff from uphill of the composting site larly, a one-hour storm is the amount nols are a group of related acidic com- that flows through the site and comes in of rain falling in one hour (about 2.2 pounds that are hydroxyl derivatives of contact with wastes or compost. En- inches here). However, storm water aromatic hydrocarbons. These include closed composting facilities also have management systems are based on such substances as cresol, catechol, condensate — water that evaporates both volumes of storm water as well as quinol, xylenol, guaiacol and resorcinol. from the compost and condenses on cool- flow rates of water to be managed, so There are two effects apparent in phe- er surfaces such as building walls. a storm of one hour duration with a nol-contaminated waters: toxicity to rainfall intensity of 1.5 inches per aquatic life and the generation of an un- HOW MUCH RUNOFF? hour will produce the same volume of pleasant taste in fish and shellfish. Figuring out how much storm water rain (1.5 inches) as a storm of six hour There are different sources of water runoff will have to be managed at a com- duration but only one-quarter contributing to runoff from a composting posting facility is not an exact science. inch/hour rainfall intensity. That 1.5 facility and each is subject to different lev- Rainfall varies in intensity both in space inches of rain will produce a volume of els of potential contamination. Ordered and in time, as evidenced by the intensi- 54,450 cubic feet of rainfall (about from most to least potential for contami- ty of a thunderstorm on one side of a 407,000 gallons) on a 10-acre concrete nation, they are: leachate, process storm road, but not on the other. Similarly, or asphalt composting pad. Not all of water, nonprocess storm water, wash wa- runoff quantities vary as a function of that rain becomes runoff. ter and run-on. “Runoff” is generally a how much rain has fallen recently, pos- Flow rates are measured in volumes mix of leachate, process storm water, sibly saturating the ground, as well as per unit of time (for example, cubic wash water and nonprocess storm water. constructed conditions like composting feet per second, or cfs). Flow rates of Each has different characteristics, as de- pad construction materials; presence, runoff from a storm vary over the du- fined below, and should be managed to orientation, spacing and age of ration of the storm and are character- prevent potential environmental harm. windrows; and moisture content in those ized by hydrographs, which plot the In most composting piles, water moves windrows. A 2004 Canadian study con- change in runoff flow rate over time to the bottom under the influence of cluded that about 68 percent of the in- for a given storm. Figure 1 is a runoff gravity and creates leachate if the mois- coming rainfall became runoff at hydrograph for a 10-year, 1-hour ture content of the compost exceeds its windrow composting facilities, and that storm of 2.2 inches/hour falling on water holding capacity (Krogmann, there was a significant delay between 13.25 acres of gravel compost pad 2000). Moisture content in a pile is af- rainfall and runoff as the compost de- draining to a pond. This storm will fected by feedstock types, mixing proce- tained the rainfall and released it slowly produce a peak discharge of 14.13 cfs dures, incoming rainfall, decomposition over a period of one to two days (Wilson, and a runoff volume of 18,274 cubic rates of organic matter that release the 2004). feet (136,690 gallons).

BIOCYCLE FEBRUARY 2008 29 Figure 1. Royal Oaks site peak runoff have higher amounts of impervious sur- to the time of concentration of the Runoff hydrograph for a 10-year, 1-hour storm of 2.2 face have higher runoff coefficients, re- watershed inches/hour falling on 13.25 acres of gravel compost pad flecting that more of the incoming rain- A = the drainage area, in acres draining to a pond fall is being converted to outgoing The term “time of concentration” 15 15 runoff and less is lost to interception refers to the time it takes for runoff to Cubic feet per second and infiltration. move from the most hydrologically dis- 12 12 Hydrologic soil groups are assigned tant point in the drainage area to the by the U.S. Department of Agriculture point of interest, such as the inlet to a 9 9 and reflect the “runoff potential” of a storm pond, a flow monitoring station particular soil. For example sandy on a stream or the design location for a 6 6 soils tend to be in Groups A and B (see new impoundment. For paved com- Table 1 categories), while clayey soils posting pad runoff calculations, time of 3 3 tend to be in Groups C and D, which concentration is measured in minutes, have higher runoff potential. provided upgradient runoff is properly 0 0 01020304050607080 Calculating a runoff curve number or diverted around the pad. For natural coefficient for a composting pad re- watersheds, time of concentration is Time (minutes) quires use of a weighted average ap- measured in hours. proach (weighted by the percentage of There are a number of limitations Calculating A Runoff Curve the pad occupied by windrows and the with the Rational Method in determin- Or Coefficient percentage not covered with windrows). ing runoff volumes and flow rates: it as- Figuring out how much of the rain The total square footage of the pad oc- sumes the duration of the design storm falling becomes runoff to be managed in cupied by windrows has a lower value is equal to the time of concentration in a storm water system requires an esti- than the total square footage of the pad the drainage area; it fails to account for mation of the absorptive capacity of the between windrows. Not all composting the fact that compost windrows can shed surface onto which that rain falls. In a windrows have the same runoff coeffi- rainfall, absorb rainfall or act as a reser- forested watershed, rainfall is intercept- cient. Drier compost, subject to summer voir and detain rainfall; and it assumes ed by leaves and infiltrates into the temperatures and lighter rain intensi- that the fraction of rainfall that becomes ground, so only a portion becomes runoff ty, would likely result in a lower mea- runoff is independent of rainfall intensi- that reaches streams. In an asphalt sured runoff coefficient. For an asphalt ty or volume (with windrows of compost, parking lot (or composting pad), little is composting pad, assume a coefficient of runoff varies with rainfall intensity), intercepted or infiltrated, so most of it be- 0.85 for the aisle spaces between along with others (Kalaba, 2007). comes runoff (but not all, as even asphalt windrows. For the windrows them- Using the Rational Method on the or concrete will intercept small amounts selves, assume a coefficient between same composting facility illustrated in of rain in surface irregularities). 0.50 and 0.70 (Kalaba, et al., 2007). Figure 1 (i.e. drainage area = 13.25 Dimensionless numerical coefficients The most widely used nonhydro- acres, rainfall intensity = 2.2 in/hr) and have been developed to represent dif- graph method for calculating runoff is assuming a weighted runoff coefficient ferent surface conditions affecting the Rational Method. It was developed of 0.75, the calculated peak discharge runoff. The exact number used depends in 1889 as a method for calculating rate is 21.86 cfs, a 54 percent overesti- on the method of hydrological analysis peak flows for sizing storm drains: mate compared to the more rigorous — whether it is hydrograph-based or Q = C x I x A and accurate hydrograph method nonhydrograph-based. Table 1 presents where Q = maximum rate of runoff, in shown in Figure 1. This might have re- runoff coefficients for different land cubic feet per second sulted in expensive overdesign of a uses (or “cover types”) for both nonhy- C = a dimensionless runoff coef- storm water management system. drograph methods and for hydrograph- ficient (see Table 1) Developing an accurate natural hy- based methods (Virginia DCR, 1999). I = the design rainfall intensity, drograph of a storm event requires ex- Generally speaking, land uses that in inches per hour, for a duration equal tensive real-time flow monitoring. Given the cost and difficulty of real-time moni- toring of small watersheds, synthetic Table 1. Runoff coefficients unit hydrographs were developed by Snyder in 1938 to establish a method of simulating a natural hydrograph by us- Nonhydrograph Method Hydrograph Method ing watershed parameters (area, shape, Rational Method Runoff Coefficients Runoff Curve Numbers for Urban Areas slope and ground cover) and storm char- Hydrologic Soil Group acteristics. The synthetic unit hydro- Land Use “C” Value Cover Type ABCD graph method is the cornerstone of the hydrologic work done by the USDA’s Soil Business, industrial and commercial 0.90 Paved parking lots 98 98 98 98 Conservation Service (now the Natural Apartments 0.75 Paved streets 8389 92 93 Schools 0.60 Gravel streets 76 85 89 91 Resources Conservation Service), em- Residential – lots of 10,000 sq. ft. 0.50 Residential – 1/8 acre 77 85 90 92 bodied in the National Engineering - lots of 12,000 sq. ft 0.45 Residential – 1/4 acre 61 75 83 87 Handbook, Section 4, Hydrology (1985) - lots of 17,000 sq. ft 0.45 Residential – 1/2 acre 54 70 80 85 and in widely-available computer mod- - lots of 1/2 acre or more 0.40 Residential – 1 acre 51 68 79 84 els like TR-20, “Project Formulation, Hy- Parks and unimproved areas 0.34 Newly graded areas 77 86 91 94 drology” (1982) and TR-55, “Urban Hy- Paved and roof areas 0.90 Pasture or grassland 39 61 74 80 drology for Small Watersheds” (1986). Cultivated areas 0.60 Meadow 30 58 71 78 TR-55 presents two general methods Pasture 0.45 Farmsteads 59 74 82 86 for estimating peak discharges from ur- Forest 0.30 Woods- grass combo 32 58 72 79 Steep grass slopes (2:1) 0.70 Woods 30 55 70 77 ban watersheds: the graphical method Shoulder and ditch areas 0.50 Open Space (parks, lawns) 39 61 74 80 and the tabular method. The graphical Lawns 0.20 method is limited to watersheds where runoff characteristics are fairly uniform

30 BIOCYCLE FEBRUARY 2008 and soils, land use and ground cover can gloves; grab samples with the storm wa- be represented by a single Runoff Curve ter entering directly into bottles provid- Number (see Table 1 for examples). The ed by the laboratory (don’t transfer Table 3. Analysis of runoff from open graphical method provides a peak dis- them from other containers that may be windrow composting facilities (30 samples) charge only and is not applicable for sit- contaminated with phosphorus-based uations where a hydrograph is required. detergent residue); sample where the Parameter Range(mg/l) The tabular method is a more complete water has a moderate flow and some approach and can be used to develop a turbulence, if possible, so that the sam- Arsenic (As) 0.001 – 0.044 hydrograph at any point in a watershed. ple is well-mixed; do not overfill the bot- Lead (Pb) <0.001 – 0.500 There are a number of other comput- tle so as not to wash out any sample Cadmium (Cd) <0.001 – 0.172 er-based storm water hydrologic and Zinc (Zn) 0.011 – 2.4 preservative provided by the laboratory + water quality models available, such as (normally used for ammonia and phos- Ammonium (NH4 -N) 2.0 – 46.0 Nitrate (NO -N) <0.1 – 96.4 the U. S. Environmental Protection phorus); and cap and label the bottle as 3 Nitrite (NO2-N) <0.1 – 0.80 Agency’s Storm Water Management soon as the sample is taken (Washing- Chlorides 106 – 445 Model (SWMM), which is a comprehen- ton DOE, 2005). BOD5 <2.0 – 513 sive computer model for analysis of If samples are to be analyzed for bio- COD5 56 – 1768 quantity and quality problems associat- logicals (fecal coliform, other BOD5/COD5 ratio 0.02 – 0.37 ed with urban runoff. Both single event pathogens), the same sample preserva- and continuous simulation can be per- tion and shipping issues that affect formed on catchments having storm compost samples will affect these wa- tio of the runoff from the large-scale open sewers, or combined sewers and natural ter samples. Refrigerate the sample windrow facility in Krogmann’s study drainage, for prediction of flows, stages immediately after collection and ship it ranged between 0.02 (minimum) and and pollutant concentrations. These to the laboratory using an overnight 0.37 (maximum) with a geometric mean models tend to be watershed-scale mod- service, packing the sample in iced gel- of 0.05, suggesting it is a wastestream els, rather than site-scale models. packs, or the equivalent. that may be difficult to biodegrade.

WHAT’S IN THE RUNOFF? Pollutant Concentrations Craig Coker is a Contributing Editor to Sampling Methods and Tools Pollutant concentrations in runoff BioCycle and a Principal in the firm of Sampling of storm water for laborato- from composting facilities vary widely. A Coker Composting & Consulting in ry analysis and characterization is con- 1997 study by the Clean Washington Roanoke, Virginia. He can be reached at siderably more difficult than sampling Center characterized runoff from four (540) 904-2698 or by email at craigcok- process wastewaters coming out of the composting facilities in the Pacific [email protected]. Part 2 of this article, to be pub- end of a pipe, because of the lack of con- Northwest, which is shown in Table 2 lished in April 2008, will discuss struc- trol over sampling times and conditions. (CWC, 1997). Another study (Krog- tural and operational management options Rainfall events often occur at night, on mann, 2000) monitored storm water for managing storm water quality and the weekends and holidays, and sometimes quality for three years at a European storm water permitting programs and is- with little advance notice. It is also diffi- composting facility handling residential sues affecting the composting industry. cult to obtain a truly “representative” source-separated organics. The results sample. For example, the storm water of that monitoring are shown in Table 3. discharge permit issued by the Missouri The BOD5/COD5 ratio is a measure of REFERENCES – PART 1 Department of Natural Resources to a the biodegradability of a wastewater. A Clean Washington Center, “Evaluation of private composter requires sampling BOD5/COD5 ratio of 0.5 is the same or- Compost Facility Runoff for Beneficial “during a storm water event of 0.1 inch der of magnitude as municipal wastew- Reuse,” prepared by E & A Environmen- or greater and during the first 30 min- ater and is considered easily degradable. tal Consultants, May 1997, p. 11. utes of the discharge.” This is meant to A wastewater with a BOD5/COD5 ratio Cole, M.A., “Assessing the Impact of Com- capture the “first flush” of pollutants less than 0.1 is considered biologically posting Yard Trimmings,” BioCycle, Vol. 35, No. 4, April 1994, p. 92. swept up by runoff, which is obviously difficult to degrade. The BOD5/COD5 ra- meant to capture a “worst-case” situa- Kalaba, L., et al., “A Storm Water Runoff tion. Taking a one-time sample of runoff Model for Open Windrow Composting (known as a “grab” sample) at the wrong Sites,” Compost Science & Utilization, time may result in pollutant concentra- Table 2. Runoff ranges from four facilities Vol. 15, No. 3, p. 142-150. Krogmann, U., “Selected Characteristics of tions that are not truly representative. Parameter Range(mg/l) Leachate, Condensate, and Runoff Re- Sampling methods to offset this diffi- leased During Composting of Biogenic culty include flow-composited and time- Wastes,” Waste Management and Re- composited samples, often collected BOD5 20 - 3,200 search, Vol. 18, 2000, p. 235-248. with automated sampling equipment. A Total solids 1,100 - 19,600 Oregon Department of Environmental Volatile solids 430 - 9,220 flow-proportional composite sample Quality, “Commercial Composting Wa- Color (color units) 1,000 - 70,000 consists of discrete samples collected at ter Quality Permit Development,” pre- a rate proportional to flow. Taking flow- Fecal (MPN/100ml) 200 - 24,000,000 Copper (ppb) 33 - 821 pared by CH2MHill, May 2004. composited samples requires knowing Zinc (ppb) 107 - 1,490 Virginia Department of Conservation and the flow rate of the watercourse, which Nutrients: Recreation, “Virginia Storm water is normally done by inserting a tempo- Ammonia N 32 - 1600 Handbook,” 1999, Sec. 4, Hydrologic rary calibrated V-notch weir in the Total Kjeldahl N 14 - 3,000 Methods. channel. A time composite sample con- Nitrate+nitrite N 0 - 8 Washington Department of Ecology, “How sists of discrete samples collected at Total phosphorus 4 - 170 to do Storm water Sampling – A Guide constant time intervals. Ortho phosphate 0 - 90 for Industrial Facilities,” Publication 02- Actual procedures used to obtain good pH (standard units) 6.7 - 9.5 10-071, Dec. 2002, revised Jan. 2005. quality representative samples are im- Conductivity 887 - 16,500 Wilson, B.G., et al., “Stormwater Runoff Chloride 52 - 2,100 From Open Windrow Composting Facil- portant. Recommended procedures in- Potassium 167 - 4,640 clude: wear disposable, powder-free ities,” Journal of Environmental Engi- neering Science, Vol. 3, 2004, p. 537-540.

BIOCYCLE FEBRUARY 2008 31 B IO tr Water Storm C

YCLE OPERATOR INSIGHTS W Other pollutants ofimportancein ents andbacterial contamination. substances, suspendedsolids, nutri- tants includeoxygen-demanding mestic wastewater.These pollu- exceed levelsfoundinstandard do- tional waterpollutantsthat can with leachatehavelevels of tradi- leachate andrunoffcontaminated data suggeststhatcompostpile rather limited;however,available zation dataforstormwaterrunoffis chemical andbiologicalcharacteri- The amountanddataqualityof quality considerationsofthisrunoff. 2008) lookedatthequantityand and finishedcompostproducts. waste materials,compostingpiles rainfall comesintocontactwith turned windrowsystems,where stream technologyofopen-air jority ofattentionisonthemain- cilities arebeingexamined,thema- and configurationsofcompostingfa- posting facilities.Whilealltypes from rainfall-inducedrunoffatcom- scrutiny ofwaterpollutionpotential tants. Thishasledtoincreased nonpoint sourcesofwaterpollu- to includerunoff-generatedarea Part 1ofthisseries(February Treatment Craig Coker treatment costs.PartII contaminated runoff goesalongwaytoreducing facilities tominimizegenerationofhighly Segregating stormwaterflowsatcomposting ual end-of-pipepointsources have expandedfromindivid- ATER qualityregulations if theyremain suspended.Inaddition, and aquaticvegetation photosynthesis also interferewithlighttransmission as sedimentssettle.These solids can smother bottom-dwellingaquatic life washed intostreamscanblanket and fects onaquaticlife.Suspended solids waterways hassignificantadverse ef- Consuming thedissolvedoxygenin (like lignininwoodfibers)arepresent. biologically resistantorganicmatter greater whensignificantamountsof than BODvaluesandmaybemuch ter. CODvaluesareusuallyhigher ganic mattertocarbondioxideandwa- needed tocompletelyoxidizeallor- fined asthetotalquantityofoxygen under aerobicconditions.CODisde- decomposable organicmatterinwater required bybacteriawhilestabilizing mally definedastheamountofoxygen Oxygen Demand(COD).BODisnor- Oxygen Demand(BOD)andChemical using twosurrogates—Biological wastewater arenormallymeasured impacts onaquaticlife. treated, havepotentiallysignificant hydrocarbons which,ifdischargedun- ing, andarederivativesofaromatic the woodymaterialsusedincompost- Tannins andphenolsarederivedfrom and grease,tanninsphenols. compost runoffareheavymetals,oil Oxygen-demanding substancesin veloped acustomized stormwaterper- cilities. Forexample, Oregonhasde- storm waterrunoffatcomposting fa- trolling potentialwaterpollution from trol strategiesinusebystates forcon- There isavaryingassortment ofcon- are considerablymoreunpredictable. and relativelyconsistent. tions wherewaterflowispredictable end-of-pipe dischargesfrominstalla- approach workswellwithtraditional lowable quantitiesofwaterflow.This measure forcompliance)basedonal- in thedischarge(whichareeasierto tities areconvertedtoconcentrations be discharged.Theseallowablequan- the quantitiesofpollutantsallowedto state environmentalagenciesregulate water pollution.Permitsissuedby ulate pointandnonpointsourcesof vironmental ProtectionAgencytoreg- delegated authorityfromtheU.S.En- ulated. MoststatesintheU.S.have from compostingfacilitiesisbeingreg- 2008) willlookathowstormwater REGULATORY APPROACHES trol strategiesforcompostingfacilities. tion indevelopingwaterpollutioncon- lutants oflargelysecondaryconsidera- compost facilityrunoff,thesearepol- cates nomigrationofheavymetalsin year samplingatsomefacilitiesindi- with limitedheavymetals,andmulti- posting facilitiesprocessfeedstocks feedstocks. Asthemajorityofcom- cilities handlingindustrialorbiosolids ing facilityrunoff,particularlyfromfa- eas, andcanbeaconcernincompost- storm waterrunofffromurbanizedar- copper, leadandzincareaconcernin less complexforms. dissolved oxygenastheydegradeto toxic intheirownway,butconsume and similarsubstancesarenotonly swimmable” status.Tannins,phenols waters havelosttheir“fishable, one oftheprincipalreasonswhysome nation ofwaterswithfecalcoliformis life insufficientquantities.Contami- die, andammoniaistoxictoaquatic oxygen demandsonwaterswhenthey gae inwater,whichcreatetheirown These canstimulatethegrowthofal- and nitrites)aswellphosphorus. forms ofnitrogen(ammonia,nitrates pollution controlarethewater-soluble solved oxygenlevelsfall. which causeodorproblemsasdis- manding substancesintothewater, they oftencarryadsorbedoxygen-de- Water flowsinstormwater runoff Part 3ofthisseries(toruninMay Heavy metalssuchaschromium, Nutrients ofimportanceinwater A PRIL 0829 2008 mitting program for composting facili- schedule for implementing additional or back to gallons), another formula for cal- ties. North Carolina, on the other hand, enhanced BMPs; a list of operational and culating the maximum volume of water has decided not to issue any storm water structural BMPs; and development of that can be added to compost piles is permits for composting facilities, in- operation and maintenance procedures (The Composting Association, 2007): stead making facilities get wastewater (Washington DOE, 2004). discharge permits. Several states use VL = VM x dM x (MCmax – MCM) x 1000 the Multi-Sector General Permit ap- Reuse 100 x dL proach used for industrial facilities, The most feasible method of reusing where: choosing to regulate composters under collected storm water is to reintroduce it VL = volume of water to be added the SIC Code for Fertilizer Mixing (SIC to the compost piles to keep moisture (litres) 2875). Others have no regulations at all. contents at the optimum 50 to 55 per- VM = total volume of composting ma- It is becoming increasingly clear, how- cent level. Windrows can be “irrigated” terial (cubic metres) ever, that composting facilities must with hoses, sprinklers or water trucks. dM = bulk density of composting mate- plan for control and management of As compost piles have considerable wa- rial (tonnes/cu. meter) storm water through a combination of ter-absorptive capacities, a substantial MCmax= target moisture content, per- both structural and nonstructural man- amount of water can be reused this way. cent (usually 55%) agement techniques. Table 1 shows a sample calculation of MCM= starting moisture content of how much water can be reused for one pile, percent REDUCE, REUSE, RECYCLE irrigation event. Assumptions used in dL= density of water (tonnes/cu. this example include: Facility captures meter) Reduce and holds the 25-year, 24-hour storm Because there is some risk that the Reducing the quantities of storm wa- (6.62 inches for coastal mid-Atlantic collected storm water will have fecal co- ter to be managed is the first step. Un- state); all up-gradient runoff is diverted liform contamination, irrigation with der the conditional no exposure exclu- around composting facility; capture and storm water should not be done after a sion, operators of industrial facilities in contain runoff from 8-acre compost pad; compost pile reaches the Process to Fur- any of the categories of “storm water all windrows are covered with fabric and ther Reduce Pathogens (PFRP) time- discharges associated with industrial are impermeable; site soils are in Hy- temperature standard unless that wa- activity,” may have the opportunity to drologic Soil Group A or B. ter has been disinfected. Otherwise, certify to a condition of “no exposure” if In this example, the windrows are cov- there is a risk of reinoculating a finished their industrial materials and opera- ered with fabric blankets. Open compost pile with viable pathogens. tions are not exposed to storm water. windrows will produce much less runoff This is true even if only yard trimmings At least one in-vessel composting oper- to be managed due to absorption of rain- or vegetative debris are being compost- ation in North Carolina is pursuing water into the windrow (see Part 1 of ed, as monitoring data has shown ele- this to avoid permitting. Several water this series). While the above method is vated levels of fecal coliform in runoff quality regulators interviewed for this based on computing the weight of water from yard trimmings compost facilities. series of articles expressed a desire to to be added (and then converting that This fecal contamination is presumably see new composting facilities enclosed in buildings, and existing facilities retrofitted with roofed structures to keep rainfall from compost piles. Table 1. Example storm water reuse calculation Another method of reducing the quan- tity of “contaminated” storm water is Calculate runoff curve number for site through segregation of runoff flows to Area occupied by windrows = 35 windrows, each 14’ wide x 400’ long 196,000 SF minimize the quantities of waters with Area open 152,480 SF the highest degree of contamination (i.e. Total windrow area 348,480 SF leachates). Strategies include site grad- Assumed curve numbers (CN)1 Windrows (impervious) 98 ing to divert up-gradient runoff around a Open areas (packed earth) 85 composting facility, using design and Weighted average CN = 92.3 construction techniques to segregate Amount of runoff leachate from storm water (see “Enzyme Per USDA NRCS rainfall-runoff tables: Producer Grows Greener With Compost- 6.62” of rain falling on a CN= 92.3 produces 5.76 inches ing,” BioCycle December 2006) and iso- lating vehicle and equipment washing Volume of runoff to be controlled stations with their own runoff contain- Runoff amount 5.76 inches ment. By segregating water flows, costs Runoff linear volume (inches x area) 167,270 cubic feet for treating highly-contaminated Runoff liquid volume (1 CF = 7.48 gallons) 1,251,183 gallons wastewaters can be reduced and less ex- pensive Best Management Practices Quantity to be used in windrow irrigation (BMPs) and pollution prevention mech- Assume 50% of windrows are below PFRP and can be irrigated anisms can be used for managing lightly Assume initial moisture content of windrows is 45% and end moisture level is 55% contaminated storm waters. Material on pad: 17 windrows x 871 CY/windrow = 14,807 CY Storm Water Pollution Prevention Convert to weight @ 1200 lbs/CY = 8,884 tons Plans (SWPPP) are another widely used Amount of water @ 45% = 3,998 tons mechanism to reduce pollutants in Amount of water @ 55% = 4,886 tons Amount of water to be added = 888 tons storm water. While more specifics are Volume of water to be added (at 8.4 lbs/gal) = 211,529 gallons provided in Part 3 of this series, a SW- Amount of water available - 1,251,183 gallons2 PPP includes: a facility assessment; Excess irrigation water available = 1,039,654 gallons identification of areas of potential or past pollution discharge; a monitoring (sam- 1Dimensionless numbers that reflect the relative amounts of infiltration versus runoff pling and visual inspection) plan; a 2Would have to be captured in a pond or tank for reuse

30 BIOCYCLE APRIL 2008 ture crops (such as hybrid poplar trees). physical improvements and treatments Irrigation methods include overland that can control, treat and protect water flow, a spray system, drip irrigation or quality. Examples include bioretention using subsurface infiltration galleries. basins, vegetated filter strips and con- Hydraulic loading is a primary design structed wetlands. Operational BMPs tool when using irrigation to recycle focus on pollution prevention activities purely storm water. Hydraulic loading, and on operation and maintenance of or how much water a field can absorb, is structural BMPs. defined by site-specific soil conditions, The Oregon Department of Environ- depths to seasonal high groundwater ta- mental Quality retained the consulting bles and regional climate considerations engineering firm, CH2MHill, to evaluate (a water balance analysis of precipita- suitable BMPs for composting facilities tion and pan evaporation). as part of the background research for Photos courtesy of Coker Comopsting & Consulting Because composting facility runoff development of the new Compost Facili- The Royal Oak Farm irrigation system contains nutrients, it is more likely to be ty Storm Water Permit program (see consists of 3-inch stanchions around the regulated as a wastewater and be subject Part 3 for more information on this per- perimeter of the four compost pads, fed to both nutrient and hydraulic loading mit). This study ranked 27 BMPs in by a network of 6-inch PVC pipes constraints. Many states now require terms of space efficiency, odor control, (above). The system serves as both a land application systems to be based on cost, level of complexity, number of water reuse function, and for fire fighting purposes (below). Nutrient Management Plans (NMPs), benchmark constituents potentially con- which are site- and field-specific assess- trolled and whether the BMP was bene- from animal feces ments of the potential for nitrogen and ficial for control of bacteria, lead and ni- mixed in with the phosphorus transport to surface waters. trates (Oregon DEQ, 2004). Table 2 lists yard debris. Whether compost facility runoff is the 27 BMPs evaluated. The study con- Disinfection of classified as a “wastewater” or a “storm cluded that these BMPs were suitable collected storm water” is a legal question and has impli- for use by composting facilities, with water is possible, cations for recycling via land application. some modifications of definitions to tai- using a dosage Many states require some degree of lor them to composting. Oregon’s new rate of 5 to 25 mg/L treatment of a “wastewater” prior to land compost storm water permitting pro- available chlorine application. For example, in Virginia, gram requires the use of one or more of (i.e. between 2 and wastewater to be land applied must be these BMPs for runoff that has not been 6.5 ounces of pretreated to a maximum BOD level of mixed with compost pile leachate. The Clorox® bleach per 60 mg/L and predisinfected to a maxi- Fiscal Impact Analysis estimated, for 100 gallons of water). The effectiveness mum fecal coliform level of 200 MPN/100 two hypothetical composting operations, of this depends on the suspended solids ml. The degree of disinfection often in- total annual BMP costs (amortized capi- content of the storm water, and it may fluences the size of the required buffer tal plus operation) of $87,900 to have adverse effects on the composting zone. In Washington, the setback re- $114,100. Estimated impact on tipping process once used as irrigation water. In quirement from property lines is 100 feet fees varied from $1.61/ton to $9.10/ton addition, some states may consider this if the wastewater meets the disinfection (Oregon DEQ, 2008). a “wastewater treatment process” for pre-application limit of 200 MPN/100 ml, permitting requirements. but climbs to 650 feet if it does not. Some composters are developing per- TREATMENT STRATEGIES manent water reuse systems to manage Table 2. BMPs evaluated by Oregon storm water. At Royal Oak Farm, a 500- Traditionally, storm water manage- Department of Environmental Quality tons/day open-air turned windrow facili- ment has been about managing the quantity of water more than the quality ty in Evington, Virginia, a subterranean Oil water separator irrigation system was built as part of an of that water. With the new focus on Grading facility areas upgrade. This system serves both water nonpoint source pollution, the emphasis Appropriate site vegetation reuse and fire fighting purposes, and is now on pollutant removal efficiencies Graveling or paving consists of a series of 3-inch stanchions, of existing storm water quantity control Sediment basins or traps measures, like detention ponds, as well Bioswale or grassy swale or standpipes, around the perimeter of Soil filter the four compost pads, fed by a network on treatment devices now on the mar- ket, like storm water filtration systems Wetland of 6-inch PVC pipes. The system is Holding pond/detention basin charged by two 30-HP electric pumps, that can be incorporated into a munici- pal storm drain network. Sediment control w/ filter berms where irrigating windrows is done with Sediment control w/ centrifugal devices one pump in service, drawing water from Best Management Practices Granular filtration tanks a lined storm water pond on site. Both Soil and plant systems pumps are used if fire fighting is needed; BMPs remain the cornerstone of Chemical treatment additional water can be drawn from a storm water management strategies, Coagulation & sedimentation Aeration & ozonation separate farm pond. Royal Oak uses a and many are very suitable for use at composting facilities. BMPs are prac- Underground injection with pretreatment Backhus windrow turner and a windup Diversion with containment barriers hose reel to connect the turner to the ir- tices, procedures or structural controls used to prevent or reduce adverse im- Liner systems rigation standpipes. Collection and reuse pacts to receiving waters. BMPs do this Minimize runoff through operating procedures Recycle by managing the quantity and quality of Roof structure One way to recycle composting facility the storm water, the leachate from com- Membrane, tarp or cover runoff is to use it as irrigation water for post piles and equipment washdown Indoor operations crops. These can include row crops, pas- wastewater generated at a composting Elimination of standing water Prompt processing of feedstocks tureland, turfgrass or biomass silvicul- facility. BMPs can be structural, opera- tional or both. Structural BMPs are Shaping of piles

BIOCYCLE APRIL 2008 31 Onsite Treatment would have to run 153.5 Figure 1. Bioretention pond cross section On-site treatment alternatives are hours to consume the en- complicated by several factors. The de- tire BOD in the pond (ne- Capped Overflow 8" Gravel clean out pipe structure gree of treatment needed depends on the glecting microbial uptake 3-5' Grass 2-4" Mulch ultimate disposition of the contaminat- and utilization of both oxy- gen-demanding organic ed storm water. Another factor is the 9-12" Ponding 3:1 need for some form of flow equalization, materials and the dissolved oxygen in the water). Fill soil media as wastewater treatment systems oper- Mix 85-88% Sand ate most efficiently under a relatively Biological conversion is 8-12% Fines Filter fabric constant flow. As runoff varies with the fundamental process 3-5% Organic (or choking Depth Trees/shrubs=3ft stone) storm intensity and amount of compost- used in activated sludge Grass=2ft ing pad occupied by windrows, a reten- and fixed-film wastewater 4" Washed Sand tion basin of adequate size is needed up- treatment systems (i.e. aer- 8" #57 Stone stream of any treatment processes. obic lagoons), as well as the 2'+ Distance If the water is to be reused for crop ir- processes at work in biolog- In situ soil to water table Underdrain rigation via a spray field, then pretreat- ically-rich features like en- Water table ment (as noted above) is usually suffi- gineered wetlands, bio- SOURCE: NCDENR, 2007 cient. If it is to be discharged, treatment retention basins, bio- levels depend on discharge permit lev- swales, etc. Biological conversion will re- ical activity than most ecosystems els. In a nutrient-sensitive waterway duce pollutant concentrations of BOD, fe- and, as a result, are capable of trans- subject to water quality-based effluent cal coliform, some heavy metals and forming the conventional pollutants limitations, it is possible that storm wa- nutrients. Bioretention ponds (also found in storm water into harmless ter would have to be treated to ad- known as rain gardens) are becoming byproducts, or into nutrients that can vanced (or “tertiary”) levels. Tertiary ef- widespread in areas adopting Low Im- be used to encourage higher levels of fluent discharge concentrations are pact Development policies, and have biological productivity (see sidebar). typically on the order of 3 to 5 mg/L been shown to remove significant BOD, 3 to 5 mg/L TSS, 1 mg/L Total Ni- amounts of pollutants from storm water. Pump & Haul trogen and 1 mg/L Total Phosphorus. Figure 1 illustrates a conceptual cross In some cases, composting facilities The pollutants found in composting fa- section of a bioretention pond. may have to consider “pump-and-haul.” cility storm water can be treated by sev- Suspended solids are a common prob- Due to capacity restrictions at the local eral different “unit processes” or in com- lem in compost storm water systems due treatment plant, and to extremely strict bination “package plants.” Table 3 lists to compost fines washed in with the water quality standards in the water- some of the various unit processes used runoff. Keeping solids out of storm wa- shed of a potable water reservoir, this is in wastewater treatment. ter management systems provides sev- an alternative being considered for the Aeration/oxidation is the process of re- eral benefits: improves the efficiency of Durham, North Carolina Yard Waste ducing oxygen-demanding substances by other treatment processes, such as dis- Composting Facility. North Carolina raising dissolved oxygen levels. Most infection; eliminates or reduces difficult regulations require the capture and simply, this involves aerating a storm maintenance tasks in lined ponds; re- management of the runoff from the 24- water pond. Numerous types of pond aer- duces or eliminates the potential for hour, 25-year storm, which in the case of ators are on the market, but composters anaerobic conditions to form in a pond or Durham, is about 1.8 million gallons. At should seek models with the highest oxy- basin (with accompanying malodors); $0.15/gallon cost to pump, haul and dis- gen transfer rate. For example, in Table and minimizes the potential for dis- charge at a treatment plant, this could 1, a pond could contain 1.25 million gal- charge of solids in the event of a pond be a cost of $270,000 each time the pond lons after the 24-hour, 25-year storm. If overflow. Use of Filtrexx™ compost- has to be emptied. that storm water has a BOD concentra- filled filter socks is an inexpensive way tion of 100 mg/L, then the pond would to keep solids out of ponds. BOTTOM LINE contain 1,044 lbs of BOD. One pond aer- Disinfecting storm water for either Water quality management — along ator on the market has an oxygen trans- reuse in the compost pile, for recycling via with odor control and air emissions —may fer rate of 6.8 lbs/hour, so that aerator a spray field or for discharge permit com- well be another powerful impetus for new pliance is difficult. The three primary composting facilities to consider in-vessel methods are adding chlorine-containing systems or enclosure in buildings. New compounds (like sodium hypochlorite), open-air facilities likely will need to care- Table 3. Water pollutants and treatment making and introducing ozone gas into fully engineer sites to segregate storm wa- processes the water or passing the water through a ter runoff into manageable amounts to bank of ultraviolet lights for irradiation. limit the quantity of highly contaminated Water Pollutant Treatment Process All three methods are sensitive to the sus- and associated high-cost treatment re- pended solids levels in the storm water. A quirements. Existing facilities facing per- BOD/COD Aeration/oxidation new process for disinfecting storm water mit renewals in states with aggressive Biological conversion is electrocoagulation, which was original- storm water management programs like- Suspended solids Clarification ly used for precipitating heavy metals out ly will have to consider multiple manage- Filtration of wastewater. A 2004 pilot study on ur- ment measures, including pollution pre- vention operational practices, and Fecal coliform Disinfection (Chlorine, ban runoff in Los Angeles showed a 99 percent removal of total coliform, a 98 combinations of water quantity and water Ozone, UV) Biological conversion percent removal of chromium, a 96 per- quality management facilities. Nitrogen and phosphorus Biological conversion cent removal of copper and a 98 percent Precipitation removal of lead (Brzozowski, 2007). Craig Coker is a Contributing Editor to Bio- (phosphorus only) Engineered wetlands may offer one Cycle and a Principal in the firm of Coker Composting & Consulting in Roanoke, Vir- Heavy metals Precipitation of the best alternatives for manage- Adsorption ment of composting facility runoff. ginia (www.cokercompost.com). He can be Wetlands have a higher rate of biolog- reached at (540) 904-2698.

32 BIOCYCLE APRIL 2008 Reprinted With Permission From: April, 2008 POLLUTANT REMOVAL VIA WETLANDS

HERE are two main types of engi- Research underway at Virginia ADVANCING COMPOSTING, ORGANICS RECYCLING neered, or constructed, wetlands Tech (Virginia Polytechnic Institute & RENEWABLE ENERGY T— the Free-Water-Surface (FWS) and State University) suggests that 419 State Avenue, Emmaus, PA 18049-3097 wetland, which has a standing pool of combining engineered wetlands with 610-967-4135 • www.biocycle.net water, and a Subsurface-Flow (SF) conventional retention ponds can in- wetland, in which water lies below the crease phosphorus removal above surface of the wetlands media (usually those levels. SF wetlands are being gravel). FWS wetlands don’t work well used to treat dairy feedlot runoff (high in northern cold regions, but SF wet- BOD and nutrients) in Vermont and lands have been shown to operate sat- are being used to treat airport deicing isfactorily at subzero temperatures in facility runoff in Buffalo, New York Wyoming and Montana. Wetlands and Hartford, Connecticut. With the have measured pollutant removal effi- Buffalo project, the runoff has a BOD ciencies of 24 to 70 percent for phos- load in excess of 10,000 lbs/day and phorus and between 31 and 84 per- an effluent discharge permit level of cent for nitrogen. 30 mg/L (Whitney, 2008).

REFERENCES – PART 2 liquor and excessive rainfall conditions”, Brzozowski, C., “Nontraditional Stormwa- Information Sheet No. 37, August 2007. ter Treatment”, Stormwater, Vol. 8, No. Washington Department of Ecology, “Guid- 6, Forester Press, September 2007. ance Manual for Preparing/Updating a North Carolina Department of Environ- Stormwater ment and Natural Resources, Stormwa- Pollution Prevention Plan for Industrial Fa- ter Best Management Practices Manual, cilities”, Publication Number 04-10-030, July 2007. April 2004. Oregon Department of Environmental Whitney, D., et.al., “ Application of Engi- Quality, “Commercial Composting Wa- neered Wetlands in Storm Water Man- ter Quality Permit Development”, pre- agement, Stormwater, Vol. 9, No. 1, pared by CH2MHill, Contract No. 044- Forester Press, January 2008. 04, May 2004. Oregon Department of Environmental Quality, “Chapter 340 Proposed Rule- making, Statement of Need and Fiscal and Economic Impact”, January 15, 2008. The Composting Association (UK), “Options for management and control of compost

STORM WATER TREATMENT SYSTEMS DIRECTORY

POND AERATORS www.scottaerator.com Filtrexx, Inc. Ste. D Aqua Control, Inc. 35481 Grafton Eastern Rd. Fallbrook, CA 92028-3292 6A Wolfer Industrial Dr. FILTRATION SYSTEMS Grafton, OH 44044 (760) 731-9960 Spring Valley, IL 61362 Clear Creek Systems (440) 926-8041 Water Tectonics www.filtrexx.com (815) 664-4900 4101 Union Ave. 802 134th St. SW www.aquacontrol.com Bakersfield, CA 93305 DISINFECTION SYSTEMS Ste. 110 Kasco Marine, Inc. (661) 324-9634 Everett, WA 98204 800 Deere Road www.clearcreeksystems.com Aquionics, Inc. (425) 742-2062 Prescott, WI 54021 CONTECH Construction 21 Kenton Lands Rd. www.watertectonics.com (715) 262-4488 Products Inc. Erlanger, KY 41018 www.kascomarine.com 9025 Centre Pointe Dr. (859) 341-0710 (Editor’s note: there are liter- www.aquionics.com LAS International, Ltd. Ste. 400 ally hundreds of companies 216 North 23rd Street West Chester, OH 45069 Ozone Water Systems providing water treatment Bismarck, ND 58501 (513) 645-7000 5401 South 39th St. technologies; this partial list (701) 222-8331 www.contech-cpi.com Ste. 1 is only provided as a courtesy www.lasinternational.com Filterra Phoenix, Arizona 85040 to BioCycle readers, and 11352 Virginia Precast Rd. (480) 421-2400 should not be interpreted to Scott Aerator Co. LLC www.ozonewatersystems.com be either complete or an en- 13261 Riley St. Ashland, VA 23005 (866) 349-3458 Salcor Engineering dorsement of any of these Holland, MI 49424 companies or their products) (616) 392-8882 www.filterra.com 447 Ammunition Rd.

BIOCYCLE APRIL 2008 33 Composting Regulation HE Clean Water Act of 1972 cre- ated the National Pollutant Dis- Review charge Elimination System (NPDES). Under NPDES, all fa- cilities that discharge pollutants from any point source into U.S. WATER QUALITY waters are required to obtain a Tpermit. The U.S. Environmental Protec- tion Agency (EPA), which enforces the Clean Water Act (CWA), developed three types of NPDES permits for discharges comprised solely of storm water: individu- STORM WATER al, general and group (or “multisector”) general permits. Most states are delegated authority from EPA to regulate storm wa- ter discharges with these types of permits. Individual storm water permits are very MANAGEMENT similar to standard NPDES permits, set- ting specific numerical effluent limita- tions on conventional, nonconventional and toxic pollutants, and on hazardous substances. General permits are largely REGULATIONS used to control storm water discharges from construction sites disturbing one or expected to monitor storm water runoff more acres of land (some industrial activi- (during a rain event) for those parameters ties fall under these baseline general per- on a periodic basis, either quarterly, semi- mits). Multi-sector general permits Regulations annually or annually. If it’s detected that (MSGP) are aimed at controlling storm benchmarks have been exceeded, the per- water discharges from similar types of in- and permits for mitted party is expected to intensify their dustrial activities, and are grouped along storm water pollution prevention activi- the lines of Standard Industrial Classifi- storm water ties. A Storm Water Pollution Prevention cation (SIC) Codes, in the belief that most Plan (usually designated as a SWP3 Plan) industrial activities within a particular at composting consists of mapping showing locations of SIC Code were fundamentally similar pollution sources, receiving streams and with regard to potential storm water facilities Best Management Practices (BMPs). runoff contamination potentials. Operational BMPs are basic, everyday The challenge for the composting indus- involve many practices and relatively small structural try is that its facilities do not fall neatly or equipment requirements that can be ef- under one of the regulated industrial cat- site-specific fective in preventing pollution, reducing egories. None of the specified SIC codes potential pollutants at the source. Opera- apply specifically to composting facilities, criteria. tional practices would include housekeep- although some composting facilities do use ing details like sweeping compost pads an SIC Code requiring coverage (SIC 2875 Part III with a rotary broom and policies to require – Fertilizers, Mixing Only). Others that periodic inspections of storm water man- have been used include SIC 4953 (Land- agement facilities (i.e. looking for trash fills) for facilities that are located at land- Craig Coker blockages of drains, etc.). Structural BMPs fills, and SIC 2499 (Wood Processing, are measures that control or manage Misc.). In addition, those composting facil- storm water runoff and drainage. Exam- ities located on farms are exempt from the ples include covers and enclosures used to storm water permitting requirements of isolate composting and curing pads, and the CWA, yet some of those facilities rival product storage areas from rainfall; the more “industrial-scale” facilities found swales, dikes and berms to divert up-gra- elsewhere in size, scale and potential wa- dient runoff from the facility; and storm ter quality impact. water detention basins, vegetative filter Storm water discharge general permits strips, rain gardens (or bioretention issued to multi-sector SIC code industries ponds) and constructed wetlands to man- (like composters in the SIC 2875 category), age collected runoff. while called NPDES permits, do not have Part I (February 2008) of this series on the same effluent limitations on pollutant storm water management at composting concentration, pollutant loading and flow facilities discussed methods for quantify- that is found in traditional end-of-pipe ing storm water runoff and some of the NPDES permits for point sources. These constituents in the runoff that are of con- general permits are based on periodic cern in water pollution control. Part II monitoring of key pollutants (correlated (April 2008) focused on storm water treat- with the typical storm water contamina- ment options. Part III reviews regulations tion profile of that particular SIC Code) in seven states. and the preparation and implementation of pollution prevention programs. STATE REGULATORY STRATEGIES The monitoring parameters are called States vary widely with regard to how “benchmarks,” and the permitted party is storm water from composting facilities is

BIOCYCLE MAY 2008 39 regulated. Regulators from several states Stormwater Permitting Unit Supervisor were contacted for information about how at North Carolina DENR. “Based on the compost facility storm water was regulated: analytical data we’ve seen, pollutant lev- Kansas: Ken Powell, an Environmental Oregon DEQ els in storm water are more characteristic Scientist with the Kansas Department of developed a specific of wastewater. It is also now clear that Health notes, “Compost facilities are split leachate from composting operations is a into five categories in our regulations: permit for wastewater and poses water quality con- yard waste, manure, livestock (which cerns without adequate treatment. We are means dead animals), source-separated composters focused also concerned about leachate from fin- organic waste and municipal solid waste. ished compost storage piles. Leachate and Leachate and storm water controls are re- on the use of BMPs runoff from these piles can still introduce quired at all composting facilities. All of concentrated amounts of oxygen demand, the facilities in Kansas are currently to treat storm water. nutrients, solids and other pollutants into windrow facilities. Any leachate would surface waters. We have decided, unlike mix with the storm water. With the excep- other states, that runoff from finished tion of MSW composting, all of our facili- compost piles is not storm water, it is a ties use either a grass filter strip alone or leachate, and should be regulated as a in combination with a storm water reten- wastewater.” tion structure. Excess water in the control North Carolina DENR’s wastewater structures can be used for watering the rule requires that all nondischarge alter- windrows or irrigated on crop fields. We do natives be fully explored before a wastew- not currently have any MSW composting ater discharge permit is issued. Alterna- facilities, but they would be required to be tives include: eliminate exposure to rain connected to a municipal sewer system or by enclosing the facility; internal recycling to haul the leachate to a municipal sewer as irrigation water for compost process system. MSW facilities are also required to control; spray application on land; diver- be covered, so they should generate very sion to a wastewater treatment plant little leachate. In Kansas we have not re- (WWTP) through the sanitary sewer sys- quired NPDES permits since no unfiltered tem; diversion to a WWTP through a runoff should leave the facility. “pump-and-haul;” or treatment on-site Missouri: Missouri uses the SIC 2875 in- through a permitted treatment system dustrial MSGP to regulate storm water (i.e. a “package” WWTP, a constructed from composting facilities. Missouri uses wetlands, an evapotranspiration drain- two different categories of composting fa- field, etc., or some combination of tech- cilities under this SIC Code, one for oper- nologies). Only after demonstrating that ations of less than 20 acres composed of none of the preceding is feasible, will feedstocks from agricultural, wood and DENR entertain an application for a dis- food product sources (Permit No. MO- charge. Discharges will be subject to wa- G090000); and the other for operations un- ter-quality based effluent limits as needed der 20 acres handling any sort of feedstock (i.e., Total Maximum Daily Loads, whole (Permit No. MO-G920000). Facilities per- effluent toxicity, etc.), and would have ef- mitted under this SIC Code category must fluent limitations much like a regular be nondischarging, except in the event of point-source municipal or industrial “emergency discharges during catastroph- wastewater discharge. ic rain events.” This is defined as the 1 in “Since the policy went into effect, Wal- 25 year, 24-hour rainfall, which ranges lace Farms (a multi-feedstock industrial from 5.6 to 7 inches of rain in Missouri. composter) has decided to divert to the Permits issued under the MO-G920000 sanitary sewer system, Brooks (a multi- category require composters to test feed- feedstock industrial composter) is working stocks for heavy metals (not just compost). on a plan for an on-site treatment system, Benchmark monitoring requirements in- the City of Durham (a yard waste com- clude BOD, TSS, oil and grease, fecal col- poster) is considering a pump-and-haul to iform, pH, temperature, ammonia-nitro- a WWTP and Warren Wilson College (an gen, other forms of nitrogen and institutional in-vessel composter) is con- phosphorus. Land application of the re- sidering an exclusion from coverage based tained storm water is limited to rates of on being in-vessel,” said Frank Franciosi less than 650,000 gallons per acre per of the Carolinas Composting Council. Dis- year. These general permits are tailored to cussions are underway between the Coun- a particular facility’s operation. cil and DENR about the nature and types North Carolina: Recent regulatory deci- of cost-effective on-site treatment systems sions in North Carolina have caused con- that will meet state water quality permit- siderable concern for composters, as the ting requirements. state’s Department of Environment and Oregon: One of the more progressive ap- Natural Resources (DENR) has decided to proaches to managing storm water may be deny any future requests for storm water found in Oregon. “We found that regulat- discharge permits from composting facili- ing storm water from composting facilities ties. “Over the past year, we have seen an under the Industrial General Storm Water increasing number of composting opera- Permits didn’t adequately cover all on-site tions seeking NPDES storm water dis- activities of composters,” says Jenine charge permits,” said Bradley Bennett, Camilleri, with the Water Quality Divi-

40 BIOCYCLE MAY 2008 sion of Oregon Department of Environ- mental Quality (DEQ). “So we developed a Table 1. Oregon’s proposed storm water monitoring benchmarks for composting specific storm water permit for com- operations posters, known as the 1200-CP General Storm Water Permit.” This new permit is focused on the use of BMPs to treat storm Parameter Benchmark water from compost. Quarterly monitoring will be required of BOD and phosphorus in Total copper 0.1 mg/l addition to the standard industrial storm Total lead 0.4 mg/l water monitoring parameters of copper, Total zinc 0.6 mg/l lead, zinc, pH, suspended solids and oil pH 5.5 – 9.0 SU Total suspended solids 130 mg/l and grease. This permit also requires: pub- Total oil & grease 10 mg/l lic notice and comment on the application BOD5 30 mg/l and on the storm water management plan; Total phosphorous 2 mg/l requires runoff meet in-stream water Floating solids (associated with composting activities) No visible discharge quality standards; and composting facili- Oil & grease sheen No visible sheen ties obtain an individual NPDES permit if 1Applies only to facilities not discharging to the Columbia Slough Watershed; those facilities also have an they have failed after the fourth year of E. Coli monitoring benchmark and different benchmark concentrations than those above. permit coverage to consistently meet the monitoring benchmarks. (Table 1 lists pro- posed benchmarks). Exemptions from this rule will be limited to home composting, specialist with the Washington Depart- agricultural composting of agricultural ment of Ecology. “Washington has been del- waste and institutional composting of self- egated to run EPA’s NPDES permit pro- generated wastes (and on-site use of the gram and is authorized to administer the resulting compost only). Industrial Storm Water NPDES in lieu of Under new composting rules being pre- EPA’s Multi-Sector permit.” She also noted pared by Oregon DEQ Land Quality that most facilities manage storm water on- (which include the new storm water per- site through detention and infiltration or mit rules), leachate will have to be segre- discharge storm water offsite under a per- gated from storm water and handled sep- mit. “If they manage storm water onsite, arately. If leachate is commingled with they may not need a permit,” Sullivan said. storm water, the facility is not eligible for “Depth to groundwater, runoff volume and the 1200-CP permit. “We’re considering a risk of contamination all play a role in the joint permitting process for both permits determination of needing a permit for those (Solid Waste and Water Quality) with one who retain storm water on site.” application,” notes Camilleri. The new Wisconsin: In Wisconsin, leachate is reg- rules (currently in draft form) will require ulated and is required to be segregated that leachate production be minimized, from storm water. “Leachate treatment is that it be collected and directed to an im- required to a varying extent depending on permeable containment structure, that the facility,” said Gretchen Wheat, an en- tanks used to store leachate have sec- gineer with the Wisconsin Department of ondary containment and that it be either Natural Resources (WIDNR). “It depends directed to a treatment plant, or if treated on waste types, facility size, location fac- on-site, then discharged under a NPDES tors, etc. Berms, ditches or other means permit with effluent limitations. must be used to prevent run-on of noncon- Virginia: Solid waste composting facili- tact storm water. Leachate includes water ties (which includes everything from yard that comes in contact with materials in the trimmings to commingled municipal solid composting process.” waste) are required to capture, contain Brad Wolbert, a hydrogeologist with and prevent discharge of runoff from the 1- WIDNR’s, Bureau of Waste and Materials hour, 10-year storm. Runoff above that Management, has recently taken the lead level is regulated under the Industrial Ac- on solid waste composting. Wolbert ex- tivity General Permit for SIC 2875 (Fertil- plained, “Solid waste composting facilities izers, mixing only). Benchmark monitor- with feedstocks limited to certain source ing parameters are: Total Nitrogen (2.2 segregated materials are regulated by s. mg/l), Total Recoverable Iron (1.0 mg/l), NR 502.12. The rule is mainly for yard ma- Total Recoverable Zinc (120 µg/l) and To- terials and vegetable food waste composted tal Phosphorus (2 mg/l). Facilities are also by low tech methods. Composting facilities required to conduct visual monitoring that are small or have lower nutrient ma- (recording their observations), annual terials can generally discharge leachate or monitoring and preparation and adoption run off to a vegetated filter strip area. Fa- of a SWP3 Plan. cilities that are large or have higher nutri- Washington: Composting facilities in ents need to capture leachate, and the rule Washington are required to separate specifies two management options: recircu- leachate from storm water; storm water late into the composting process, or dis- running off a compost pad is considered charge to permitted wastewater treatment leachate. “Compost facilities here usually facility. Potentially leachate could be dis- require an Industrial Storm Water NPDES charged to a wastewater treatment strip, permit,” said Chery Sullivan, a composting but a WPDES Permit may be required, and

BIOCYCLE MAY 2008 41 Reprinted With Permission From: an applicant would need to demonstrate Wheat added, “A starting place to guide May, 2008 the effectiveness of any proposed treat- compost leachate treatment design might ment option. Composting of other feed- be Natural Resource Conservation Service stocks is regulated by s. NR 502.08, Wis- (NRCS) Standards 635 Wastewater Treat- consin Administrative Code, a more ment Strip, 393 Filter Strip and 590 Nutri- ADVANCING COMPOSTING, ORGANICS RECYCLING generally written rule that allows flexibili- ent Management. Treatment strip design & RENEWABLE ENERGY ty to address processing of various solid commonly includes capture of more concen- 419 State Avenue, Emmaus, PA 18049-3097 wastes by any method shown to be envi- trated initial flow. However, manure has 610-967-4135 • www.biocycle.net ronmentally sound.” much higher nutrients than expected in Wolbert went on to note, “Storm water compost leachate, so I’m not suggesting to from a compost pad is considered leachate, directly use NRCS Standards.” and a curing pad is considered a compost pad. So, runoff from curing pads is regu- Craig Coker is a Contributing Editor to Bio- lated under the same authority, but differ- Cycle and a Principal in the firm of Coker ent (less) treatment might be needed. Composting & Consulting in Roanoke, Vir- Product storage piles may also be regulat- ginia (www.cokercompost.com). He can be ed under the same authority, but again, reached at (540) 904-2698 or by email at required treatment would be less.” [email protected].

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42 BIOCYCLE MAY 2008