Experimental Research On Treatment Of Printing And Dyeing Wastewater Of Soluble Dyestuff With Hydrolytic Acidification-biological Contact Oxidation Processes

Printing and dyeing wastewater is a kind of organic industrial wastewater that is difficult to deal with. It has got the feature of high concentration of pollutant, complex component and frequent change with water quality and quantity. In this experiment, we use hydrolytic acidification-biological contact oxidation process to deal with simulative wastewater confected by myself. The effect of this process can be tested and a valid control parameter of the model can be found out by analyzing the result and variety regulations of COD, BOD₅, pH, NH₃-N and chromaticity in the whole processes.Experimental water is simulative wastewater. Hydrolytic acidification cell in the first part is to improve biodegradability and wipe off chromaticity, making good condition for the later part. Two biological contact oxidation stages aim at reduction of COD, BOD₅ and NH₃-N.This process starts up by the method of culturing bio-film of hydrolytic acidification column and two biological contact oxidation columns. Culturing bio-film uses the vaccination method. With 20-day-long alimentation liquid and 51 day-long wastewater domestication, the bio-film both in hydrolytic acidification column and two biological contact oxidation columns grow well, the biofacies microscopic exam is normal and the removing rate of COD is nearly 90%. The result of this experiment shows that the removing rate of COD by hydrolytic acidification column is 20%-40%; Two biological contact oxidation columns contribute most of the COD removal, which are 40% or so and 10% or so respectively, accounting for 50% of the total COD removal efficiency in the system. COD, BOD₅, chromaticity and NH₃-N of the water handled by the process fulfill standardâ…¡of《Discharge standard of water pollutants for dyeing and finishing of textile industry(GB4287-92)》.Thus we can determine that the bio-film has been mature and the process of culturing bio-film has been succeeded.Through the model orthogonal experiment, we evaluate possible factors that may affect the reactor movement to get the best movement condition. The factors we pick up include: the water flux and proportionment of air vs. water in the two biological contact oxidation columns. In the experiment we mainly focus on the removal effect of COD and chromaticity. The final result shows the water flux is the most prominent factor to affect the effect, proportionment of air vs. water of the 1st stage of biological contact oxidation column affects less than water flux, proportionment of air vs. water of the 2nd stage of biological contact oxidation column influences the least. We also obtain the best condition of the model: water flux=5L/h, proportionment of air& water of the 1st stage of biological contact oxidation column=11.1:1, proportionment of air vs. water of the 2nd stage of biological contact oxidation column=8.9:1.