Analysis of the efficiency of UASB reactors in a municipal wastewater treatment plant

Abstract

The UASB (Upflow Anaerobic Sludge Blanket) reactors efficiency of a municipal wastewater treatment plant (WWPT) was evaluated over a period of 9 years. The WWTP treated an average flow of 500 l/s, with removal efficiencies of biochemical oxygen demand (BOD5), chemical oxygen demand (COD), and suspended solids (SS) of 66 %, 52 %, and 60 %, respectively. The biogas production reached 37541 m3/month (82.4 % of methane), with a sludge production of 334 m3/month. The hydraulic retention time was among 7 and 8 hours, typical interval of UASB systems for a temperature of 26 °C. Removal of nitrogen and phosphorous was not found. The efficiencies, and similar results in Indonesia and Latin America, served to conclude that anaerobic digestion was a promising process for the pretreatment of wastewater in tropical countries.