Study On Utilization System Of BaoSteel’s Water Resource And Treatment Technology For Recycled Water Of Factory Moat

At the background of water resource shortage, the development of iron and steel industry is limited by water supply insufficiency. According to the current situation of large quantity of wastewater discharge, low efficiency of water resource recycling and high water consumption per ton steel, the study on water recycling system and key technology for water reuse to increase the utilization efficiency in iron and steel industry has been urgent affairs.The study focuses on research on water utilization system and recycled wastewater treatment technology in Baosteel, which can offer technical support for water saving work and construct high efficient water resource utilization system for other large-scale iron and steel enterprises in our country, or provide reference for fresh water consumption decrease per ton steel.The result shows, in Baosteel the efficiency for water recycling could be more than 98% through the way of water supply based on quality, step and water recycling. And the water consumption could be decreased through water balance test, water losing decrease, increase condense degree and reuse discharge water resource （the factory moat）., as the accepting water for production wastewater, living wastewater and rain, The factory moat water resource is very flush, it has high potential to reuse water. Through the investigation for the factory moat, Fe、 Mn、 Cl^-、 SO₄^2-、 Conductance and Rigidityare are the important targer to removal for water reuse.The study had done the experiment of iron and manganese removal by manganese mineral biological filtration and manganese mineral filled constructed wetland. The result illustrates, when the granularity of manganese mineral is 2～3mm, filtering speed is 5m/h, work period is 4 days, expanding proportion for backwash is 10%, backwash time is 6 minutes, the residual condition of Fe、 Mn in effluent after manganese mineral biological filtration could be lower than 0.3mg/L and 0.1mg/L, which meets the requirement for water reuse. When the HRT of manganese mineral filled constructed wetland is 2 days, the residual condition of Fe、 Mn in effluent is less than 0.05mg/L respectively, meeting the water quality of reverse osmosis inffluent.The study also had done the experiment of the constructed wetland’s outflow water advance treatment by reverse osmosis. The result shows, when the reclaim efficiency is 75% and Conductance is 900～1800us/cm, the average stress is 1.06Mpa. salt removal efficiency is more than 98%, the Cl^-、SO₄^2- and Rigidity could be decreased from 300mg/L, 80mg/L�'�354mg/L to trace, the Conductance in outflow is less than 30μs/cm, meeting the demand for industry water quality of Baosteel.The study puts forward some treatment technology course and reuse method for the factor), moat water, effluent of manganese mineral biological filtration could be mixed with industry water as the reuse water in industry water system, the wastewater of factory moat could be used as industry water、filtration water and intenerating water directly after treatment by constructed wetland and reverse osmosis.