Study on removal of organic matter from high-salt wastewater in coal chemical industry

Catalytic ozonation is a kind of advanced oxidation technology, widely used in industrial wastewater treatment process in recent years, which has the advantages of high removal efficiency of organic matter and no secondary pollution. In order to effectively remove organic matter from high-salt wastewater from coal chemical industry, the advantages of catalytic ozonation technology in refractory organic wastewater were utilized. Reverse osmosis concentrated brine was used as the source of wastewater. Four catalysts with different active components(Fe-Mn-K, Mn-MgO, Mn-Co-Cu, Mn) were investigated. The effect of ozone oxidation on high-salt wastewater was studied, and the catalyst with the best catalytic(Mn-MgO) effect was pilot tested in the Sinopec Ningxia Energy Chemical Site. The effects of gas-water ratio and cycle number on the treatment effect were studied. The results showed that after 120 min reaction, the removal rate of COD by catalyst Mn-MgO was as high as 70%, and the color of wastewater was also significantly reduced. The removal rate of COD under the other three catalysts did not exceed 65%, indicating that the best treatment effect is catalyst Mn-MgO. In the pilot test, the COD removal rate was about 25% when the gas-water ratio was 1∶4, and the COD removal rate was only about 15% when it was increased to 1∶2. The results of the test run for 3 days all showed that the COD removal rate increased with the increase of the number of cycles.