STIMULATION AND DECOLORIZATION OF ANAEROBIC DIGESTION TREATING SEWAGE SLUDGE WITH THERMALLY PRE-TREATED WASTE ACTIVATED SLUDGE

Abstract

 This study evaluated microbial stimulation and decoloization of anaerobic digestion treating sewage sludge with thermally pre-treated waste activated sludge at 150°C for 1 hour. Addition of powdered activated carbon and conditioning with ferric chloride for dewatering were employed for these purposes. The results showed that the addition of activated carbon does not improve overall performance, but is able to siginificantly reduce propionate concentration in digested sludge. Also, the color of digested sludge was reduced by 29.1%. Conditioning of digested sludge by ferric chloride removed the color by approximately 75% at most, without deteriorating dewatering characteristics. Therefore, therse methods were found to be effective for microbial stimulation and decoloization of digested sludge liquor.