Sequencing batch operation consists of fill, react, settle and decant phases in the same reactor. Operation consists of anaerobic, anoxic and oxic (aerobic) phases when nutrient removal from the wastewater is desired. Since the same reactor is used for biological oxidation (or mixing) and sedimentation in aerobic and anaerobic SBR operations, capital and operating costs are lower than conventional activated sludge process and conventional anaerobic digestion process, respectively. Therefore, Aerobic SBR and Anaerobic SBR operations may be more advantageous far treatment of small volume animal wastewater in rural areas.