<![CDATA[Some industries produce wastewatercontaining heavy metals, such as chromium, that can pollutethe environment and is harmful to the living things. An alternativewayto treat such wasteis electro-coagulationwhichis an integration of both electrochemical andcoagulation processes by passing a direct electrical current. This research was aimed to treat wastewater containing chromium from a leather tanning industry by applying electro-coagulation process and to obtain the optimum voltage and time, as well. This laboratory work was carried outon the wastewaterfromPTAdiSatriaAbadiBantul withhigh content ofchromium(about761.504ppm). It was conducted in a batch mode by processing 7.5liters of waste in a glass tuband by using an electrode of aluminum (Al) plate (20cmx30cmx0.12cm). The electrical voltagewas variedat 2,4, 6, and 8volts,while thetime of electro-coagulation was variedfor 1, 2, 3, 4, and5hours. Content of chromium in the wastewater was therefore analyzed byAAS(atomic adsorptionspectroscopy) method. This study concluded that theelectro-coagulationprocess was effectively able to reduce the contentof chromiumin the wastewater. In addition, the variations ofvoltage and processing time significantly influenced on the decreasing of content ofchromium. The optimum voltageandtimeofelectro-coagulationwas obtained at 6volts and 8 volts for 3hours and 2 hours, respectively. The best result of electro-coagulation process of the wastewater performed on the voltage of 8 volts for 5 hours yielded the chromium content of 1.76 ppm. Such condition has promisingly reduced the content of chromium until 99.77% ofthe initial waste.]]>
