Chromium Plating Waste contain of hexavalent chrome waste that dissolve on waste water. Wastewater then treat by final slurry that mix among chrome and little bit of organic fibers. Hexavalent of chromium acid have pH = 2 this low pH can be neutralize by sodium sulfite. The chromium substance then floculate and can be prcipitated by adding NaOH until the pH about 8.5. This pH already fulfill the government rule about wastewater that should have pH about 6 to 9.
The difficulties on continuous process, the pH after add sodium sulfite can increase and the floculate dissolve again because the pH increase. If the adding of sodium sulfite to much the chromium precipitation can screwed up. This problem still make difficult on waste treatment of chromium electroplating, may other theory of water treatment on removing this heavy metal from water can be implemented better.
