ABSTRACT
540The quantity of wastewater discharged from processing operations in a poultry plant may range from 5 to 10 gal/bird, with 7 gal being a typical value. Poultry processing wastewater is typically organic in character, high in biochemical oxygen demand (BOD) than domestic wastewater, and contains high amount of suspended solids and floating material such as scum and grease. Since wastewater from poultry processing plants is typically organic, it responds well to treatment by biological methods. In biological waste treatment systems, microorganisms use the polluting constituents of the wastewater as food for survival and growth. Wastewater treatment systems in the poultry processing industry usually provide primary and secondary treatment and may or may not include tertiary treatment. The secondary treatment required for discharging wastewater to a stream may be in the form of an activated sludge or trickling filter system, a system of lagoons, or an irrigation system. Each of these methods of biological treatment has been tried with varying degrees of success. Activated sludge systems that may be applied to poultry plant wastes include conventional activated sludge, activated sludge using step aeration, high-rate activated sludge, extended aeration activated sludge, and the contact stabilization process. Anaerobic lagoons, aerobic lagoons, and a combination of an anaerobic lagoon and an aerobic lagoon may be used for secondary treatment of poultry wastes. All poultry wastewater effluents should be chlorinated before discharge into the receiving stream. All of the aforementioned processes are described in this chapter and represent the commonly used waste treatment processes. The use of other systems, such as microfiltration and certain chemical processes, while possible, is generally not prevalent due to high initial and operating costs.541
