Efficiency of suspended solid removal from tofu production using Rotating Biological Contractor (RBC)

Abstract

Tofu is a common food in Indonesia, made from soybean, and needs gigantic water for the process. The liquid waste of the tofu industry is usually directly discharged into the river without being processed. Liquid wastes of tofu have high organic content and become a problem in water pollution. Rotating Biological Contactor (RBC) is efficient method to treat waste with a high organic matter load by utilizing microorganisms to consume organic matter through biofilms. Biofilm will degrade organic matter aerobically. The purpose of the study is to determine the capability of RBC to reduce the organic content of tofu wastewater with different rotations of the disk. Rotation was experimentally varied from 30, 40, 50, 60 RPM and control. Results were considered in percentage decrease from the untreated waste: TSS of 87.56 ± 6.48%, BOD of 99.13 ± 0.21 %, and COD of 98.53 ± 0.08%. To conclude, the optimum rotation is 50 RPM for decreasing BOD and COD, otherwise 40 RPM for reducing TSS. The results effluent RBC on three parameters passed the quality standards legally for the soybean processing company or activity.