This project was started up for disposing 60,000t waste water daily, and mainly draining the wastes from Plant Areas 1 and 2 and pressure draining of sewage pump station at new zone for units upstream ironmaking. Pretreatment and advanced treatment systems constituted the project, in which, the pretreatment system employed such internationally-leading technologies as enhanced flocculation with sludge external circulation, highly-efficient settling tank with inclined tube sedimentation and sludge thickening, plus MBBR moving bed biofilm reactor and TGV filter, and the advanced treatment system utilized dual processing technology. The disposed waste water would be recovered for makeup of raw water for desalted water station, makeup of circulating water for thermoelectricity and air separation. Moreover, the soft water as produced from the systems in the flow rate of 1,000m³/h would feed users wherever needed. The concentrated saline water could be used for granulation of BF slag. That’s the actualization of zero discharge of industrial waste water. To that end, at least 3,000t COD could be abated every year.
 

In practice, this project implemented advanced treatment of plant-wide waste water and took it as source water to process into industrial fresh water and soft water. In this process, waste water was no way to be discharged for pollution and more importantly, reclaimed for saving consumptions of industrial fresh water. It would exert great impacts on China in need of environmental protection and severe scarcity of water resources. It was built by following the concept of garden-like works, embellishing Bayi Steel with green coverage of over 20% and manmade lake.
 

Under the circumstances of demanding treasuring water resources and control environmental pollutions, this project set a good model in this profession and worthwhile to promote. In its operation as in designed capacity, the reclaimed water would cost per unit in less than 1 yuan/m³, soft water cost per unit in less than 4 yuan/m³. Enormous benefits could be brought forward economically, socially and environmentally.