ENHANCEMENT OF ANAEROBIC DIGESTION OF HIGH-SOLID WASTE ACTIVATED SLUDGE WITH LOW ORGANIC CONTENT AT DIFFERENT ORGANIC LOADING RATES BY PRETREATMENT.

Anaerobic digestion of high-solid waste activated sludge (HS-WAS) with low organic content at different organic loading rates (OLR) by various pretreatments (thermal, alkaline and thermal-alkaline) was investigated in this study. Experimental results showed that no matter whether pretreatment methods were employed or not, the daily biogas production from HS-WAS with low organic content increased in the OLR range of 1.5-3.0 kg/m3·day. The biogas production and volatile solids (VS) reduction at different OLRs by different pretreatments had the same conclusion as follows: thermal-alkaline > thermal > alkaline > control. Further exploration revealed that the solubilization of organic matters in sludge was improved by various pretreatments, resulting in the enhancement of anaerobic digestion. Also, the accumulation of volatile fatty acids (VFAs) and ammonia nitrogen did not gave negative influences on the stability or the overall performance of HS-WAS anaerobic digestion. [ABSTRACT FROM AUTHOR]