Design And Operation Of Wastewater Reuse Project Of Steel And Iron Plant

Nowadays, industrial wastewater reuse has become an effective method to alleviate the water crisis, which is an important path for large-scale enterprise development. Meanwhile, it can reduce the emission of pollutants, reduce the environmental pressure, and be beneficial to economic and environmental remarkably.Basing on the Baotou iron and Steel Group new factory new sewage reuse project, the mixture of industrial production wastewater and domestic sewage was treated. The design value of wastewater treatment capacity was 3600m3/h. The advantages and disadvantages were analysed between traditional technology and membrane separation technology for determination of treatment process in this article. The research work was completed as following:(1) The wastewater treatment process for the mixture of production sewage and living sewage in Baogang new factory was determined, the capacity value was 3000m3/h. The various construction engineering was designed by 3600m3/h. The concentrated water from advanced treatment reverse osmosis plant was used for blast furnace cinder flushing, the freshwater was delivered to the steel plant, power plant, hot rolling mill and cold rolling plant as the production process water and cooling water. The water quality index was accorded with the iron and steel industry wastewater treatment and reuse engineering technical specifications "(HJ2019-2012), satisfied to the demand of BaoGang new plant sewage.(2) According to the quality of reclaimed water requirements, the process was selected as the combination of traditional process and membrane method. the preprocessing part consists of a grid, regulation pool, high-efficiency clarifier, V type filter composition, depth treatment using the combination of PVDF submerged ultrafiltration and reverse osmosis system, using to remove the suspended solids and sewage CODCr, salt etc..(3) In the operation of the system, the problems were identified and solved to ensure the normal operation of various structures. It was found that the water pump system immersed ultrafiltration was not stable in the operation process, and the other interference factors were excluded, the vacuum pump problem was identified, the problem with cancellation of the link by the first recoil water production after operation mode was solved. Reverse osmosis system was contaminated by microbial activity, after flux recovery cleaning in the pool, the pollution problem on membrane was thoroughly solved, which could be the operating experience for the actual project.(4) As the system running, the system was stable, the effluent quality could meet the water quality index with the back to the steel mill wastewater. Saving fresh water resource could improve the utilization of sewage recycling rate, and reduce the pollution of water environment, and had obvious social benefit and environmental benefit.(5) Through the statistics of the entire process of investment and operating costs, electricity, chemicals and other aspects of the analysis showed that the wastewater reuse project annual saved of water charges and sewage discharge fee 40000000 yuan, created new profits for the steel mills, and accounted for the cost of engineering design.