Poultry carcasses are contacted with water treated with one or more specified dihalodialkylhydantoin biocides in a processing operation downstream from a scalding tank. The aqueous effluent from that downstream operation or from any location further downstream is recycled to the scalding tank. Surprisingly, the bromine residues from the dihalodialkylhydantoin biocides are much more thermally unstable than, for example, the commonly used microbiocide, sodium hypochlorite. Thus, the effluent from the scalding tank has its active bromine content significantly reduced before it is sent to a water purification facility wherein microbial action is used to reduce the BOD of the waste water before its release to the environment. Thus, injury to this desired microbial action is reduced. In addition, the recycle reduces water consumption in the overall poultry processing operation.