Study of the production of Volatile Fatty Acids in a municipal wastewater treatment plant

Abstract

This study has carried out a literature review to see what are the optimal operating conditions for the production of VFAs for the mono- and co-fermentation of WAS, PS, OFMSW and FW. For WAS mono-fermentation, the optimal operating conditions found are neutral-basic pH (7-8) and thermophilic temperature (55 C). In addition, the best pretreatment of WAS in terms of VFA yield and pretreatment cost is believed by the author to be the pretreatment of 1.54 mg/L FNA + RL. For PS mono-fermentation, the optimal operating conditions found are at basic pH (9) and thermophilic temperature (55 C). Finally, for OFMSW fermentation, the optimal operating conditions found were pH 6-7 and mesophilic temperature (40 C). For co-fermentation, the highest yield from the data collected in this study was (0.867 g CODVFA/ g VS fed) with a substrate with a FW/WAS=5 ratio that was fermented at the following operating conditions: SRT 7 d, OLR 9 g VS/L·d, T 40 °C and uncontrolled pH (5.2-6.4). For the implementation of acidogenic fermentation in a WWTP, the author of this work proposed to work with co-fermentation of mixed sludge and FW at the optimal conditions found in a CSTR reactor using the produced methane to maintain the temperature of the system