THEORETICAL AND EXPERIMENTAL STUDY OF A SEQUENTIAL BATCH REACTOR TREATMENT OF LIQUID SWINE MANURE
ABSTRACT A laboratory scale sequential batch reactor (SBR) was used to digest liquid swine manure containing 1 to 2% suspended solids. Hydraulic retention time, biological solid retention time and influent concentration were varied during the tests. The treated effluent was analyzed for suspended solids, chemical oxygen demand, ammonia, and nitrate plus nitrite. In addition, a mathematical model was developed to describe the changes in concentration with time of chemical oxygen demand, ammonia, and nitrate plus nitrite in the SBR reactor. Results of the experimental study showed that the single reactor SBR process is capable of reducing the potential polluting carbon and nitrogen components of a concentrated wastewater to a high degree when it is operating at 7 to 9 days HRT and a BSRT around 20 days. The mathematical model developed followed quite closely the changes in COD, ammonia, and oxides of nitrogen on a laboratory scale, and should be useful for assessment of SBR system designs for commercial swine manure treatment.