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Characterization of food waste-recycling wastewater as biogas feedstock

Shin, Seung Gu, Han, Gyuseong, Lee, Joonyeob, Cho, Kyungjin, Jeon, Eun-Jeong, Lee, Changsoo, Hwang, Seokhwan
Bioresource technology 2015 v.196 pp. 200-208
acetates, biodegradability, biogas, butyrates, chemical oxygen demand, ethanol, feedstocks, fermentation, methane, propionic acid, seasonal variation, solubilization, volatile fatty acids, wastewater
A set of experiments was carried out to characterize food waste-recycling wastewater (FRW) and to investigate annual and seasonal variations in composition, which is related to the process operation in different seasons. Year-round samplings (n=31) showed that FRW contained high chemical oxygen demand (COD; 148.7±30.5g/L) with carbohydrate (15.6%), protein (19.9%), lipid (41.6%), ethanol (14.0%), and volatile fatty acids (VFAs; 4.2%) as major constituents. FRW was partly (62%) solubilized, possibly due to partial fermentation of organics including carbohydrate. Biodegradable portions of carbohydrate and protein were estimated from acidogenesis test by first-order kinetics: 72.9±4.6% and 37.7±0.3%, respectively. A maximum of 50% of the initial organics were converted to three major VFAs, which were acetate, propionate, and butyrate. The methane potential was estimated as 0.562L CH4/g VSfeed, accounting for 90.0% of the theoretical maximum estimated by elemental analysis.