EFFECT OF RICE STRAW ADDITION ON HIGH SORID THERMOPHIRIC DIGESTION OF SEWAGE SLUDG FROM AN OXIDATION DITCH PLANT

Abstract

 To apply anaerobic digestion for small scale municipal wastewater treatment plant, the effects of rice straw addition on thermophilic digestion of dewatered sludge produced in an oxidation dich plant were examined in a laboratory scale digestor. In the thermophilic digestion experiment of the dewatered sludge (TS 6%) at HRT 15 days, organic acids were accumulated and methane yield was lower than the methane production potential of the sludge. On the other hand, stable methane production could be maintained by the addition of rice straw (3%). Significant differences were observed in both bacterial and archaeal community among mono-digestion and co-digestion sludge. In the digested sludge of co-digestion, higher abundance of Clostridiaceae was detected, estimating that the bacterial group related to decomposition of cellulose. Acetoclastic methane production archaea, Methanosarcina was occupied 59.6 % in detected total archaea. High resistance of Methanosarucina was estimated to achieve stable methane production.