The Analysis of Pollutant Parameters in Tofu Wastewater after being Treated by Contact Glow Discharge Electrolysis

Abstract

There are many Small, Micro, and Medium Enterprises engaged in tofu processing in Indonesia. Some of them still dumped their waste directly into the river, causing the stream to become turbid, had a bad odor, and many aquatic organisms in the water died. Tofu wastewater contained high pollutant parameters, such as COD, BOD, TOC, and TSS; therefore, we need an effective wastewater treatment that could reduce the level of these parameters below the government's standards. Contact Glow Discharge Electrolysis (CGDE) was used to treat the wastewater. Besides these four parameters, pH solutions were also measured at several CGDE process voltage variations (such as 650 V, 700 V, and 750 V). The content of compounds contained in the initial tofu wastewater and the waste that had been treated by using CGDE were analyzed. From this study, it was known that the higher the voltage applied, the more acidic the solution would become due to hydrogen peroxide emersion, which is a weak acid. In the same operating condition, the percentage of TOC degradation was lower than that of COD degradation. The voltage of 750 V gave the lowest COD and TOC values, respectively 446.6 mg/L and 320 mg/L. Also, the best voltage that could reduce BOD and TSS degradation by 37% and by 80.2% respectively, was 650 V. Although CGDE process was able to decrease COD, BOD, TOC, and TSS, the decrease of these pollutant parameters still could not reach the standards set by the government, except for TSS. Besides having the ability to reduce pollutant parameters, it is also powerful in degrading complex compounds in tofu wastewater into compounds with simpler molecular structures, such as Tris (2,4-di-tert-butyl phenyl) phosphate and eicosane.