Investigating Wastewater Disposal Technics And Reuse Water Technology For Printing Wastewater Of Flag Awning Factory

Someone flag awning Limited company is situated in Xujing Town Qingpu area Shangha, but the whole will move to the Jinshan area textile industry campus in 2010. Experiment takes the moving flag awning factory as the research background, and takes wastewater from the original flag awning factory as object of study. After investigating wastewater quality of the original flag awning factory, the experiment chooses hydrolytic acidification + biological contact oxidation for the second-level biochemistry subject technics disposing printing wastewater of the moving flag awning factory. At the same time, the leader of the flag awning factory hopes that it can reduce tap water amount and discharged the wastewater amount from the flag awning factory through realizesing a great lot of reuse water, which will debase production cost of the flag awning factory and strives the biggest economic interest for the factory. Wherefore, the experiment has researched advanced treatment for printing waste water coming form the second-level biochemistry. The technics of advanced treatment choose coagulation and sedimentation + sand filtration +biology activated charcoal filter tank. The experiment researched advanced treatment in basic of guaranteed that the effluent from the second-level biochemistry system accord with Sewage Synthesis Emission Standard (DB31/199-2009) and Sewage Disperses Into Cities Sewer Water Standard (DB31/425-2009).Startup of the Second-level biochemical system consumes 26 days, and the Best water power resident time is 22.5 hour. In steady operation period of the second-level biochemical system, C0D_Cr,BOD₅,NH₃-N in the effluent from the second-level biochemistry system are between 209.38～221.67mg/L,21.37～27.86mg/L and 5.76～6.25mg/L respectively, and the chroma of the effluent from the second-level biochemistry system is about 60 tiems. The water qualities of the effluent from the second-level biochemistry system are lower than the discharged limit in Sewage Synthesis Emission Standard (DB31/199-2009) and Sewage Disperses Into Cities Sewer Water Standard (DB31/425-2009).Coagulant used in the experiment is Polyaluminium Chloride. The amount of the coagulant is 250mg/L, and under the condition that pH of the wastewater is 9 the coagulant is added into the wastewater. The quartz sand is selected as the material of the sand leach. The water qualities including COD_Cr,NH₃-N,the chroma of the effluent from the coagulation and sedimentation + the sand filtration are about 90mg/L,3.5mg/L, 6tiems.The vaccination sludge of the biological activated charcoal filter tank comes from the effluent from the biological contact oxidation. The research discoveres that adopting the effluent from the biological contact oxidation can reduces the startup time of the biological activated charcoal filter tank greatly, and the startup time of the biological activated charcoal filter tank are only about 16 days. After starting successfully, the elimination rate of COD_Cr is above 65% , and COD_Cr in the effluent from the biological activated charcoal filter tank is under 40 mg/L. Then, the elimination rate of NH₃-N is above 70%, and NH₃-N in the effluent from the biological activated charcoal filter tank is under 1 mg/L. The best operating condition of the biological activated charcoal filter tank is that gas-water ratio is 3:1, that the optimum hydraulic loading is 0.5m～3/( m～2·h), and that the optimum carbon layer height is 60cm. That the filter tank adopts backwash method is gas wash first, then gas-water wash, last water rinse. The backwash periods of the filter tank is 6 days, and the restoring time of the filter tank is 7 hours after backwash. In steady operation period of the filter tank, COD_Cr,BOD₅,NH₃-N,SS,DO,浊度,色度,pH in the effluent from the filter tank are about 18～23mg/L, 2.1～3.6mg/L, 0.2～0.8mg/L,6mg/L, 5～7mg/L, 3.8～5NTU, 0, 6.7～7.5.The effluent of the advanced treatment technics can use in the workshop of printing and washing, and it can be used as miscellaneous water in the factory, but it can't use boiler room. The test indicates that it is without the essential influence for chromatic aberration and color fastness of the product after reuse water. When the wastewater is reused, the nexus of the salts density in the reuse wate and the reuse rate of the wastewater is , and B figures the salts density in the reuse water. According to , the nexus of the salts density in the reuse wate and the reuse rate of the wastewater is positive correlation. If the reuse rate of the wastewater is 75%, the amount of the reuse water is 450t/d. The amount of the reuse water in the workshop of printing is 168.75t/d. The amount of the reuse water in the workshop of washing is 225t/d. The amount of the reuse water used as the miscellaneous water is 56.25t/d.The total investment of project of the reuse water is 460, 500 Yuan, and the processing cost of the reuse water is 1.39 Yuan/ton. The cost may be possible to take back after going into production for 30 months. After 30 months, the economic efficiency reclaimed is 15,240 Yuan every month, and the water fee may save 213,525 Yuan every year. It is more important for reducing 31.2075tCOD which is efflux every year.