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05/2612009 13:16 9518273 49 DOUGLAS KUNEV PAGE 04/10 e ANAEROBIC IAGOONS Desirtn Anaerobic lagoons are most commonly uaad for you try waste tr#.ermPnr.. Anaerobic bacteria can decompose more organic matter p�r unit lagoon volume than aerobic bacteria and are predominantly used for treatment of concentrated organic wastes: Since the anaerobic process is n,ot deendeut on maintaining dissolved oxygen, lagoons can be much deeper and requl a less surface Area. Anaerobic decompo i tion of poultry wast, can roc,alt in the production and emission of odorous gases, primarily hydrogen sulfide, ammonia, and intermediate organic acids. An anaerobic lagoon can properly sized and i managed, however, to operate with a minimum of disagreea le odu.t. Ligiiirl volume, rather than surface area, is the basis for anaerobic lagoon design. Sizing criteria should emphasize major operational needs to control odor, minimize sludge buildup and manage nitrogen. As lagoon capacity increases, odor potential, xaLC of sludge buildup and pathogenic organiame decrease while nitrogen losses increase. Table 1 gives suggested poultry lagoon design treatment capacities for mild climates. The minimum total capacity of an anaerobic lago6n should include the appropriate design treatment capacity given in Tah1e 11, additional surface storage for a 25-year, 24-hour rainfall, and an additional foot of freeboard to prevent embankment overtopping. Some producers ) desire extra lagoon capacity for temporary storage of rainfall and wast�watex inputs and for r, sludge accumulation. Providing this additional storake extends the lagoon sludge life axpactancy, provides hAtter and more uniform waste treatment, and decreases the frequency of irrigation. Table 1 estimates poultry lagoon liquid accumulation rates. The normal wastewater stor4ge capacity should be figured for at .least 90 days. Sludge accumu2aLiva rates given in Table 1 should be utilized to design a lagoon life expectancy of 15-20 years. Because bacterial activity increases at higher timperatures, anaerobic M lagoons work best in areas without cold winters. Lai goons in colder areas require more desLgr,i treatment volume. Lagoon loading rates are detArmined by the amount of volatile solids (VS) in manure. Table 2 shows the maximum Table 1. North Carolina Poultry Anaerobic LagoonlDesign Criteria Bird type Unit* Average Lagoon Contents Recommended Lagoon Bird Accumulation Deign Treatment Capacity Live - --------------------- vTeight liquid** sludge*** -minimum mean maximum lbs gala/clay ft3/yr ft3 ft3 ft3 Layer------ per bird.....--4.0_. .--0,07 __---0,63- I-14.0---a 12,5 15.0 Pullet per bird 1.5 0,03 0.22 I 3.6 4.7 5.6 * one-time bird capacity. ' ;; ** Does not include fresh flush water or accountifor lagoon seepage. No manure solids removal prior to lagoon inpu�. i