ANAEROBIC DIGESTION OF DOMESTIC WASTEWATER

Abstract

Treatment of domestic wastewater is one of the serious problems. Various treatment technologies such as physico-chemical treatment and biological treatment are available for the treatment of domestic wastewater. Owing to the presence of high organic matter, domestic wastewater is well suited for biological treatment. As such in recent years there has been increasing interest in anaerobic treatment of wastewater. Compared to aerobic treatment, anaerobic digestion produces less biomass for the same amount of COD removal compared to aerobic treatment and produces methane up to 95% of the organic matter in the waste stream. The laboratory bench scale experiments were carried out treating domestic wastewater of Gulbarga city in fabricated anaerobic batch reactor of 10 Lts working volume. The domestic wastewater has the following characteristics (average values) pH= 6.9 to 7.95, Total solids = 1140 mg/L, Dissolved solids = 1020 mg/L, Suspended solids = 120 mg/L, Alkalinity = 120 mg/L, Total volatile solids = 890 mg/L, Chloride = 262.2 mg/L, BOD 5 = 285 mg/L, COD = 945 mg/L. The experiments were carried out for three months with the initial organic loading rate = 0.945 kg of COD/m 3 day. From the study it is concluded that the anaerobic digestion has the efficiency in removal of COD by 90.25% and Total solids removal of 67.27%.