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Biogas production from bakery wastewater in two-stage anaerobic digestion system
Author(s)
Date Issued
January 1, 2017
Type
Article
Abstract
Biogas production from bakery wastewater was studied using a semi-continuous, two-stage anaerobic digestion system, consisting of 2 l-first-stage digester and 5 l-second-stage digester under temperature of 35°C. Substrate feed rates were examined in a batch experiment by varying in the range of 50 to 200 ml/l/d. Characteristics of substrate and effluent of the digester (i.e. pH, SS, TS, VS, VFAs, COD, sCOD, TN, TP, TSO 2- 4 ), biogas yields and compositions were investigated. The experimental results showed that substrate feed rate of 100 ml/l/d produced maximum yield of biogas. The biogas yield was directly proportional to concentration of VFAs in the second-stage digester. The approximate pH values in the first stage and the second stage digesters were 6.13 and 7.25, respectively. The average biogas yield of 0.481 l/ g VS removed and 0.609 l/ g sCOD removed was observed at a hydraulic retention time (HRT) of 10 days. Biogas contained 46.4%-60.8% methane. Removal efficiencies of SS, VS, COD and sCOD in this system were 85.58%, 93.35%, 87.91% and 75%, respectively. The amounts of total nitrogen and total phosphorus after digestion increased whereas that of sulfate decreased.
Citation
Current Applied Science and Technology, 17(1), 103-112, 2017