FATE OF RESIDUALS IN NITRIFICATION DENITRIFICATION TREATMENT OF PIGGERY WASTEWATERS

A careful appraisal of piggery wastewaters should be made mainly becau se of their high content of organic constituents together with the nit rogen and stringent effluent limitations involved. Specific emphasis s hould be given to the COD of the wastewater as it contains, aside from a biodegradable portion, a residual fraction which persists throughou t the treatment process. Experimental evaluations indicated that the e ffluent of a laboratory-scale SBR contained significant amounts of non -biodegradable COD. Since SBR was primarily operated to achieve nitrif ication-denitrification, a method previously developed for the assessm ent of the influent soluble inert COD, S(I) was modified in a way to r eflect the possible impact of the nitrification and denitrification pr ocesses. The paper also summarizes the performance of SBR with respect to its nitrogen removal potential from piggery wastewaters.