Process Of Printing And Dyeing Wastewater Treatment Plant Upgrading

The study was based on upgrading reconstruction of Anqing municipal waste water treatment plant. After the investigation and analysis of the operation situation, finding problems of treatment tank, and taking the corresponding measures to improve the removal of pollutants, so that the effluent concentration of COD reached the original design value, the effluent concentration of NH3-N, TP and SS reached the latest national emission standards (GB 4287-2012), and on this basis, selecting the advanced treatment process, so that the effluent concentration of COD and chroma also meets the latest national emission standards. The main findings showed:(1) The dyeing wastewater treatment plant was designed reasonable and operated stable, having higher pollutant removal. The average removal rate of COD, chroma, NH3-N, TP and SS were 81.24%,45.67%,60.28%,61.33% and 84.83%; The effluent concentration of COD is slightly higher than the (GB 4287-1992) standard, because the high water pH and hydraulic retention time is short, and the effluent TP is much higher than the design value due to TP changed much and PAC dosage was less, biochemical process for the removal of chroma is not very good, so that the chroma is long-term excessive;(2) By adjusting the reactor operating conditions, so that the removal of pollutants has increased significantly. Lowering the pH of the water, an appropriate extension of structures HRT, cleaning up the reactor to decrease the accumulation of silt and increasing PAC dosage, the average removal rate of COD increased to 86.63% and the water reached the original design value; The average removal rate of NH3-N, TP and SS increased to 77.56%,85.08% and 92.46%, the effluent concentration meet (GB 4287-2012) standards;(3) In this paper, the object studied is second effluent of the dyeing wastewater treatment plant. The princip、 characteristic 、 effect factor and application of Fenton reagent oxidation is studied, the optimal operating parameters are determined by single factor experiment; The study of Fenton reagent oxidation indicates that the optimal operating parameters are as follows:when pH value is 5, reaction time is 30 minutes, the dosage of H2O2 and FeSO4 are 3.63g Fe2+ /L and 2mL H2O2/L, the optimal result is obtained, and the removal efficiency of COD and chroma are 65.38% and 91.89%, and the effluent values are 55.39 mg/L and 25 times, reaching (GB 4287-2012) direct emissions standards; While Fenton method is very well to the removal of COD and chroma, but the processing cost is higher, reaching 3.774 yuan/ tons, which is difficult for enterprises;(4)This research used biological aerated filter(BAF) which is widely used in the field of wastewater treatment to deal with dyeing wastewater, by adjusting gas-water ratio, hydraulic loading and other factors, analyzed the operation change rule of BAF process, optimized the BAF optimal parameters. gas-water ratio of 4:1,hydraulic loading of 0.071 m3/(m2·h) around, the optimal result is obtained, and the removal efficiency of COD and chroma are 55.52% and 48.34%, so that the effluent values of COD reaches (GB 4287-2012) direct emissions standards, while the chroma is not.(5) We use sodium hypochlorite to further deal with chroma, the optimal operating parameters are determined by single factor experiment. Sodium hypochlorite for the removal of chroma is firstly drastically improving until remaining unchanged. Taking account of the cost, the dosage of sodium hypochlorite is 1.2mL/L, and the removal efficiency of chroma is 75% and the effluent values is 40 times, reaching t(GB 4287-2012) direct emissions standards;...