A comprehensive study for characteristics, acidogenic fermentation, and anaerobic digestion of source separated organics.

In this research, the physiochemical characteristics of source separated organics (SSO) throughout a long-term period, along with their possible effects on anaerobic digestion (AD), acidogenic fermentation, and hydrolysis processes were investigated. Seasonal characteristics of SSO revealed significant differences in some factors demonstrating that eating habits, waste handling, and collection techniques would lead to the variation in SSO characteristics. The SSO collected during the summer months revealed a significantly higher yield for soluble COD based on the mass of volatile suspended solids (VSS) (428 mg/g-VSS) and volatile fatty acids (VFAs) production (292 mg COD VFAs/g-VSS) compared to those of the winter samples. The results revealed that 65–68% of the produced SCOD during the acidogenic fermentation process belonged to VFAs. It was also revealed that 85% of the VFAs was produced during the first two days of the fermentation process. The mesophilic batch AD process achieved based on the mass of volatile solids (VS) an average methane yield of 555 mL CH 4 /g VS, which was significantly higher than the range of 350–480 mL CH 4 /g-VS reported for food waste in the literature. Considering the results of the present study, the SSO has a significant potential to produce biomethane and VFAs at the industrial scale. The cost-benefit analysis of a full-scale AD plant with a capacity of processing 75,000 tonnes SSO/year revealed that the revenue from selling the SSO-derived CH 4 (∼400,000 $/year) could compensate for about 20% of the operating cost of the plant. Image 1 • The maximum volatile fatty acid (VFAs) yield of 292 mg/g VSS was achieved. • Up to 85% of the VFAs was produced during the first 2 days of the fermentation process. • An average methane yield of 555 mL CH 4 /g VS was obtained through the SSO digestion. • SSO revealed higher potential for methane production compared to food waste. • Selling biomethane could compensate for about 20% of the digester operating cost. [ABSTRACT FROM AUTHOR]