Enhanced biogas production from modified tapioca starch wastewater

Modified tapioca starch wastewater (MTSW) contains organic and inorganic matters that affected on biological wastewater treatment and biogas production. Especially, the wastewater from chemical modification processes contains high salinity that can inhibit microorganism activities. Zero valent iron is expected to be helpful for creating an enhanced anaerobic environment that might improve the performance of the anaerobic process. The bio-electrochemical system can promote microbial metabolism thereby leading to higher biochemical performance. Result in this study aimed at enhancing performance of upflow anaerobic sludge blanket reactors a treatment for biogas production from MTSW. Three improving methods were compared that included of bio-electrochemical system (BES-UASB), zero-valent iron (ZVI-UASB) and salt tolerance microbial systems (STM-UASB). The experiments were operation by varying hydraulic loading rate HLR) and organic loading rate (OLR) with values of HLR 0.02, 0.25 m3/m2-h and OLR 7.5, 25 kgCOD/m(3)-day, respectively. Overall organic removal efficiencies were more than 70% of COD removed for three methods. The highest COD removal was found in BES-UASB that was about 82% of COD removed. The biogas production yields were about 0.33, 0.32 and 0.28 m3/kg-COD removed for BES-UASB, ZVI-UASB and STM-UASB, respectively. As well as, the highest bio-methane production was found in BES-UASB reactor with more than 60% of biogas compositions. (C) 2019 Published by Elsevier Ltd.