Study On The Coagulation And Sludge Utilization In High Fluoride Phosphorus Wastewater Treatment

Based on the site investigation on the quantity and quality characteristics of Samsung company’s produced wastewater, the search of a large number of relevant literature, and the visit of correlative practical wastewater treatment project case, a technical route applying “calcium+coagulation sedimentation” method to treat high concentration fluorine wastewater discharged by Samsung is proposed.Some optimized experiments on the fluorine-containing wastewater treatment process are carried out in the lab. It is resulted that on the condition that 1 L of raw water contains 60 mg/L of fluorine, 15 mg/L of phosphorus, the discharged water contains only about 10 mg/L of fluorine and 0.86 mg/L of phosphorus, which reached the emission requirement when the pH is 8.5, the dosage of 30% calcium chloride is 3.47 mL, the dosage of 10% PAC is 1.2 mL and the dosage of 0.1% PAM is 12 m L. The treatment operating cost is evaluated as well.And on this basis the amount of sludge produced and its main ingredient in the process of fluorine and phosphorus removal are examined systematically. Meanwhile, it is calculated that 1.34 g/L of dried sludge will produced under the optimal reagent dosage. The content of calcium fluoride is up to 60% in the sludge, followed by a certain amount of aluminum phosphate, calcium carbonate and silica. In addition, some researches on the utilization of fluorine-containing sludge are carried out in this paper. For example, high-temperature sintering method treating fluorine-containing sludge is used to prepare new material to treat wastewater came from Samsung. And the basic properties of the material are characterized. Preliminary experimental results show that the prepared new material is stable, and has no heavy metal and fluoride ion release through the optimum firing process–the preheating temperature is 400 oC, the warm-up time is 60 min, the firing temperature 840 oC, and the firing holding time is 20 min.It is found that the removal rate of phosphorus reaches 27.8% by the preliminary experiment which is used to purify the company’s wastewater. The effect explains that the ideal material is suitable for the wastewater containing fluoride. And further, the material can also be prepared as a filter material for wastewater treatment. Not only do the result obtained in this study provides the design basis for the company to implement wastewater treatment by branching process, but also supplies a new way for the integrated utilization of fluorine-containing sludge generated from water treatment process.