in an upflow anaerobic sludge bed (UASB) reactor – Part 3: Performance at 20°C and 35°C

The performance of 2 biological sulphate reduction (BSR) upflow anaerobic sludge bed (UASB) reactors fed primary sewage sludge (PSS) and sulphate, one at 20oC (R2) and one at 35oC (R1) is described. To maintain the effluent sulphate concentration below 250 mgSO 4 2-/ℓ, the hydraulic retention time (HRT) and bed solids retention time (SRT or sludge age) both needed to be longer and the feed primary sewage sludge (PSS) COD to SO 4 2- ratio higher at 20oC than at 35oC, viz. 20.