Removal of organic matter from tofu wastewater using a combination of adsorption, Fenton oxidation, and ultrafiltration membranes

Abstract

The production of tofu results in wastewater from the soaking, washing, and pressing processes. Owing to its unique composition and quality, tofu wastewater treatment involves a complex set of challenges. Wastewater from tofu production has a significantly high organic content because it contains many soybean residues and other products. This study aimed to determine the removal efficiency of tofu wastewater contaminants for a combination of adsorption, Fenton oxidation, and ultrafiltration membrane processes. The best strategy for turbidity removal, with a removal value of 99.78%, was an integrated system combining adsorption and ultrafiltration membranes. The most optimal method for reducing organic matter contained in tofu wastewater is Fenton oxidation with TSS, COD and turbidity removal values of 81.11%, 95.13% and 62.42%. Moreover, microphotography analysis using scanning electron microscopy showed an irregularly shaped surface layer with the particles spaced far apart when granular active carbon adsorption was integrated with an ultrafiltration membrane. The results were inversely proportional when Fenton oxidation was integrated with ultrafiltration membranes. After granular active carbon adsorption, the spacing between the granules or crystals increased, whereas the granular dimensions decreased.