THE EFFECT OF CURRENT AND TIME ON COD (CHEMICAL OXYGEN DEMAND) AND COLOR DEGRADATION IN THE ELECTROCOAGULATION PROCESS OF BATIK WASTEWATER

Abstract

The development of the batik industry is very high after being recognized as a world cultural heritage by UNESCO in 2009. The development of the batik industry is directly proportional to the waste generated. The batik industry produces liquid waste that can pollute the environment, especially from leftover dyes, washing and rinsing residues, and pelorodan (wax relieve) water. The contaminants found in the batik industry are organic materials, heavy metals, suspended solids, oils and fats. The liquid waste can have a negative impact on the ecosystem, so it needs to be treated before being discharged into the environment. There are various wastewater treatment processes that can be resolved the negative impacts that caused by the pollution of the batik industry wastewater, and one of it is electrocoagulation. Electrocoagulation is a process of destabilizing suspensions, emulsions, and solutions containing contaminants by flowing direct current which causes flocs so they are easily precipitated. The electrocoagulation process does not use chemicals so it is environmentally friendly and need faster time. In this study, the batik industry located in Bandung City use electrocoagulation process for the wastewater treatment. Processing is using an electrocoagulation reactor capacity of 6 liters. Variations in the experiments carried out were current and time. The varied currents were 0.5 A, 1 A, 1.5 A, 2 A, and 2,5 A and the time varied were 10, 15, 20, and 25 minutes. Based on the results of these experiments, it was shown that the optimum condition of the electrocoagulation process for batik wastewater treatment was with a current of 2.5 A for 25 minutes. These conditions was decrease COD value and color absorbance of the treated waste. The COD value of the effluent decreased to 81.6 mg/l with a treatment efficiency of 95.04% and  color absorbance 0.231 at a maximum wavelength of 284 nm with a processing efficiency of 46%.