| abstract |
PROBLEM TO BE SOLVED: To provide a treatment method for effectively removing hexavalent and tetravalent selenium, hexavalent and trivalent chromium in wastewater. SOLUTION: A ferrous compound and a ferric compound are added to waste water containing selenium to adjust the liquidity to alkaline, and together with the produced ferrous hydroxide and ferric hydroxide, tetravalent selenium is added. A wastewater treatment method comprising precipitating hexavalent selenium. |