Tofu Industrial Wastewater Treatment by Electrocoagulation Method

Abstract

Tofu waste liquid contains high levels of organic impurities, such as protein and amino acids. These organic compounds cause the tofu industrial wastewater to contain high biological oxygen demand (BOD), chemical oxygen demand (COD), pH and total suspended solid (TSS) which can pollute the environment. In general, the liquid waste from the tofu factory is discharged directly into rivers through sewers and rivers. Most of the tofu wastewater contains various kinds of pollutants which may be produced in the form of organic pollutants (foul smelling), inorganic pollutants (spicy and colored), so they are dangerous to the surrounding environment and need to be treated. One alternative to tofu liquid waste treatment is electrocoagulation. The electrocoagulation method has the potential to purify tofu wastewater and reduce the content of BOD, COD, TSS and neutralize pH without the addition of certain chemical coagulants. The purpose of this study was to obtain the characteristics and levels of pollutants contained in tofu industrial wastewater before and after processing, and to determine the effectiveness of the electrocoagulation method with various variations in voltage and reaction time. The electrocoagulation tub is attached with a cable connected to the power supply, then connected to a current source with a variable voltage (8; 10; 12 V) and a variable reaction time (30; 60; 90; 120; 150 minutes). The optimum conditions were obtained at a voltage variation of 12 volts and a reaction time of 150 minutes, with a percentage increase in pH of 72.33% to 5.98, a decrease in COD of 28.57% to 10 mg/L, a decrease in BOD5 of 46.87% to 2, 29 mg/L, and TSS from 11.47% to 21.6 mg/L.