Debugging Of Raw Water In Steel Mill By Coagulation-Two Stages Biological Aeration Fliters-Automatic Water Purififcharacteristics Of Lactic Acid Bacterica And Its Ication Device Process

In most cases, the treated effluent of the traditional coking wastewater has not met the second national discharged standard of the water pollutants in steel industry. Therefore, the further treatment of the treated coking wastewater has been studied by many scholars. In this research a new process that"coagulation-air Flotation, two stages biological aeration filters and automatic water purification"were used treat the effluent of a steel factory in Jiangsu province. The outlet quality of the treated coking wastewater not only meets the discharged standard but also can be reused. The new process can achieve the aim of saving energy resources and reducing pollutant. Meanwhile, it provides a new way for the advanced treatment of further treated coking wastewater.In this thesis, the process of the treated coking wastewater is mainly composed by biological aeration filters. The biodegradability of the wastewater is improved by water distribution. The debugging mainly studies the control of air flotation's running parameter, two stage BAF running parameter and the influencing factors of BAF treatment, etc, and plenty of running and controlling parameters are obtained.The running results show that when COD of the influent is no more than 200 mg/L and SS is no more than 200 mg/L, the COD of the effluent is no more than 60 mg/L and SS is no more than 15 mg/L, which not only reach the second national discharged standard for industrial water but also it meet water quality standard of reuse water proposed by the steel factory.The main influencing factor of air flotation is the dosage of the coagulation. When BAF operates for a short time, the quality of the effluent is influenced by the concentration of influent. The outlet water is stable after operation stability, and it is influenced by the organic loading capability. The concentration of COD of the effluent increases as the loading capability increases, and the NH3-N is greatly influenced by the organic loading capability of the discharging water. The water temperature changes between 14.7~26℃, and it does not influence the discharging water. The outlet water quality of the effluent is influenced by backwash strength and backwash period too.The main factor of air flotation is the dosage of the coagulation. The outlet water quality of BAF is influenced by inlet water quality in short-term operation, and it has stronger resist once impact load capability in stable operation. The COD outlet concentration increased with increasing COD organic loading, and the removal of NH3-N greatly influenced by the COD organic loading. It is little effect of COD outlet water quality when the water temperature ranges from 14.7℃to 26℃. The effluent quality of BAF is also influenced by backwash strength and period.The running parameters of the process are: the optimized dosage of PAC and PAM are 20 mg/L and 2.5 mg/L ,respectively; water backwash strength is 5.83 L/m~2·s; the air backwash strength is 16 L/m~2·s; the first backwash period is 5 days, and the second one is 6 days.