The combination of anaerobic-aerobic and coagulation-flocculation method using tamarind seed as natural coagulant for tofu wastewater treatment

Abstract

The high demanding for tofu as a food containing high protein’s source in Indonesia is followed by the increasing number of the waste produced in this industry, both for solid and liquid waste. The high amount of organic material measured as COD (9,880 mg/L) of this wastewater makes it potential to be treated biologically. To enhance the process efficiency and the better quality of effluent, biological process was combined with coagulation and flocculation process as the finishing processes in this study. The research’s purposes were firstly to evaluate the more effective method between two biological process that were the aerobic process (method 1) and the combination of anaerobic-aerobic process (method 2) and secondly to determine the best dose of tamarind seed as the natural coagulant. Doses variant used were 1,000 ppm, 2,000 ppm, 3,000 ppm, and 4,000 ppm. The result showed that method 1 has the slightly better performance of COD removal compared to the second method, which was about 89.744%. At the coagulation and flocculation process, 2,000 ppm of tamarind seed as natural coagulant gave the best result on decreasing turbidity level of method 1 (63.745%) while the highest dose (4,000) was needed to reduce turbidity level of method 2 effluent as much 26.41%.