Study On Coagulation With Loading Materials And Biochemical Treatment Of Printing And Dyeing Wastewater

China is one of the largest textile producing countries, in recent years, China's printing industry with an unprecedented situation of rapid development. China has become the world's largest printing and dyeing industry country. Textile industry is not only one of China's economic pillars of the industry, but also an industry with a large water consumption and pollutant emissions.Printing and dyeing wastewater has many characteristics, more material difficult to degradate, complicated organic matter, high density, heave toxicity and so on. After the preprocessed and discolored, there are a lot of difficult biodegradable substances. such as the residual dyestuffs, the dyeing auxiliaries, acid-base. Direct emission will not meet environmental protection standards and will cause serious environmental pollution, access to municipal sewage treatment plant which will also damage the microbial systems. Therefore,studying printing and dyeing wastewater treatment technology is of great significance.Coagulation with loading materials and biochemical technology is studied. The results of flocculant screening and selection of experimental conditions show that the PAM associated with PAV ferric chloride has more better effect than aluminum sulfate, ferric chloride and other flocculants. Optimal treatment conditions are concluded that the dosage of PAC is 500 mg/L, the dosage of PAM is 20 mg/L, Magnetite Powder dosage of 1% (w%) of wastewater volume, temperature is room one,pH is 7. Biochemical treatment technology opts activated sludge, anaerobic phase temperature is 28.6°C deposition time of 24h and aerobic phase temperature is 28°C deposition time of 24h. Under these conditions, the CODCr of the tested wastewater can be from 1083 mg/L down to 182 mg/L and color can be from 4000 times down to 1000 times. Then by Ozone-oxygen treatment, the CODCr of the tested wastewater can be from 182mg/L down to 95mg/L and color down to 32.Which achieve the fist emission standard of GB4287-92. The studying results of Mechanism of coagulation with loading materials that Magnetite Powder is hydrophilic material,which can absorb PAHs. And the addition of Magnetite Powder enhanced coagulation in the side of the electrical double layer compression, adsorption and bridging etc. Sedimentation rate is 110cm/min that is 4.6 times traditional coagulation. This is conducive to settlement and separation, to reduce the processing cycle and improve wastewater treatment efficiency.