Reduction of tofu industry liquid waste pollutants using the electrocoagulation method, with the influence of the distance between electrodes and contact time

Tofu production produces solid waste and liquid waste which can pollute the environment. Industrial wastewater treatment has been carried out using various methods, one of which is the electrocoagulation method. The purpose of this study was to analyze the effect of distance between electrodes and contact time on reducing TSS, TDS, turbidity, and pH levels of tofu industrial wastewater and to obtain the best treatment in reducing pH, TSS, TDS, turbidity, and COD levels. The research was conducted using a Factorial Randomized Block Design with 3 replications. The electrocoagulation process was carried out using variations of distance between electrode of 1.0, 1.5, and 2.0 cm and contact times of 30, 45, and 60 minutes. The experimental data were analyzed using Analysis of Variance (ANOVA) and Honestly Significant Difference (HSD) test at a significance level of 5%. Based on the results of the study, it was concluded that the distance between electrodes and contact time affected the reduction of wastewater pollutants. The results showed that a distance between electrodes of 1.0 cm with a contact time of 60 minutes was the best treatment, which resulted in the largest reduction in TSS, TDS, and turbidity values of up to 69.05 percent, 59.34 percent, and 98.15 percent, respectively, the largest increase in pH of up to 28.45 percent, and reduction of COD of up 48.90 percent. Keywords: electrocoagulation; electrode distance; contact time