Recycling of sewage sludge using microwave pretreatment and elutriated acid fermentation

Abstract

This work elucidates the effects of pretreatment on primary and secondary sludge using microwave irradiation before the application of elutriated acid fermentation (EAF) systems conducted under different temperature conditions. The EAF used water to elutriate volatile free acids generated in the fermenter which thickened the sludge generated. The results of this study focus on sludge reduction conducted under different temperatures. The SCOD production utilizing a microwave pretreatment method (MW) followed by EAF, with 35 degrees C after the microwave as pretreatment, and from only the EAF at 35 and 55 degrees C was 0.33, 0.11, and 0.22 g SCODprod./g VSfed. Volatile fatty acids (VFAs) production was found to be similar to that of the results of SCOD production. Coliforms and Escherichia coli were not detected after pretreatment with microwave irradiation for time over 5 min.