Tofu industrial wastewater treatment with ozonation and the adsorption method using natural zeolite

Tofu industrial wastewater is usually disposed of directly without undergoing waste treatment, a process that endangers the environment. The amounts of chemical oxygen demand (COD) and total suspended solids (TSS) in the wastewater exceed the maximum levels determined by the government of Indonesia. Ozonation and adsorption are well-known methods that can effectively degrade organic and inorganic compounds in wastewater. In this research, the removal of COD and TSS from tofu industrial wastewater was examined through the use of the ozonation method, the adsorption method using natural zeolite, and both methods combined. The sample was passed into a packed-bed column containing natural zeolite and ozone used for about 60 minutes. The effectiveness of the method was evaluated by COD and TSS degradation, with varying dosages of ozone and amounts of natural zeolite (50 g, 75 g, and 100 g). The best result was achieved by using a combination of ozonation and adsorption, with 100 g of zeolite and an ozone dosage of 155.1 mg/h, which achieved 219.4 mg/L and 25 mg/L removal COD and TSS, respectively.