Effect of temperature on low-strength wastewater treatment by UASB reactor using poly(vinyl alcohol)-gel carrier

The feasibility of treating low-strength wastewater with an up-flow anaerobic sludge blanket (UASB) reactor, using a poly(vinyl alcohol)-gel carrier, at various temperatures and hydraulic retention times (HRTs) was examined. The temperature was decreased from 35 °C to 25 °C and then to 15 °C. The HRT was reduced from 2.0 h to 0.22 h. The COD removal rate reached 28 kg-COD m−3 d−1 at 35 °C, 16 kg-COD m−3 d−1 at 25 °C, and 6 kg-COD m−3 d−1 at 15 °C. The COD removal rate was reduced by half for each temperature reduction of 10 °C.