Combination Process Of "Micro Electrolysis/bio Enhancement/ozonation"for Pigment Wastewater Treatment

Pigment wastewater consists of mother liquor and washing liquid.This wastewater is highly colored,difficult to biodegrade,anti light,anti oil and contains high CODcr,anilines,while its quality changes,therefore,the pigment wastewater is a major problem in industrial wastewater treatment.Wastewater in this research from a company is acid,which generated during the process of azo pigment production.The company is ready to move to the new industrial park,its new plant's wastewater output is expected to reach 2000 t/d and the effluent water quality needs to reach "Wastewater quality standards for discharge to municipal sewers,(CJ343-2010).The effluent water quality can not meet this standard by using the old factory's treatment process of "grille/air flotation/bio-treatment".Therefore,the purpose of this study is to determine the new treatment process,to ensure that the new plant drainage can meet the emission standards.According to the wastewater quality,The combination process of "micro electrolysis/bio enhancement/ozone oxidation"was used to treat this wastewater.The optimum technique parameters and the kinetic equation of ozone degradation of aniline were determined.The high treatment efficiency of the micro electrolysis was achieved under the conditions of pH?5,the dosage of dissolved oxygen(DO)=3 mg/L,reaction time=30 min,The effluent pH was adjusted to 9.00 for the precipitation reaction.As a result,the B/C of micro electrolysis effluent increased from 0.18 to 0.58,concentration of CODcr and aniline were reduced from 1483 mg/L to 1342 mg/L and 60.6 mg/L to 49.74 mg/L,respectively.Then,the most amount of CODcr was removed by the functional bacteria in the biological reaction unit.After 2 days,the concentration of CODcr,color and aniline was reduced from 1342 mg/L to 200-300 mg/L,from 1000 to 100,from 49.74 mg/L to 20 mg/L or so,respectively.In the subsequent ozone oxidation process,the optimum conditions were pH of 5,reaction temperature of 298.15 K,ozone dosage of 9.16 mg/(L·min).After 13 min,the concentration of CODcr and color reduced to 100-150 mg/L and 40,respectively.The aniline was below 1 mg/L.The degradation of aniline by ozone accorded with pseudo first-order kinetic reaction.By this combination process,the maximum CODcr,color and total aniline removal efficiencies were more than 89.89%,96%and 98.35%,respectively.The effluent quality meets the B standard of "Wastewater quality standards for discharge to municipal sewers"(CJ343-2010).