Treatment of septage using an upflow anaerobic sludge blanket reactor

This study examined the feasibility of applying an upflow anaerobic sludge blanket (UASB) reactor to treat septage. The UASB reactor was operated at 3 5 +/- 1 degreesC, and the substrate septage had a total solids (TS) concent ration of 13 200 mg/L. Reactor operation was initiated at a hydraulic resid ence time (HRT) of 10 days; thereafter, the HRT was shortened stepwise to 1 .5 days. The TS, volatile solids (VS), and organic loading rates were 1.4 t o 9.4 kg TS/m(3).d, 5.6 to 8.5 kg VS/m(3).d, and 1.1 to 6.7 kg chemical oxy gen demand (COD)m(3).d, respectively. At the organic loading rate of 6.7 kg COD/m(3).d (the HRT of 1.5 days), the total COD, soluble COD, and TS and V S removal efficiencies were 68, 74, and 66 and 73%, respectively. The avera ge granule diameter and volatile suspended solids concentration were approx imately 0.89 mm and 32000 mg/L, respectively. Based on results obtained fro m 7 months of constant methane production and removal efficiencies, which a re comparable to values previously reported in the literature for wastewate r, it was concluded that a UASB reactor can successfully treat septage.