Investigations On The Technology Of Removal Of Manganese In Surface Water

According to the characteristics of surface water, model experiment in prior period investigates two kinds of process of removal of manganese in surface water in terms of the experience of removal of manganese in ground water, which are single mixed sand biology filter tank process and pre-oxidation by potassium permanganate and quartz sand filter tank process. For optimizing the technology of manganese removal from theory perspective and able to be widely used in practice, we carried out the performance experiment for identifying these processes. In the performance experiment, the efficient methods of experiment are used for seeking the optimal parameters, which can provide plentiful experiences for popularizing the technology of manganese removal. We conclude the following results from these two performance experiments of manganese removal.1. Removal of manganese by mixed sand biology filter tankDue to the high effect of manganese removal of mixed sand biology filter tank in the first stage of experiment, the manganese concentration in effluent can be controlled below to 0.1mg/L, however the effect of the filter tank begins to decrease after nearly two months and the concentration of manganese ion is between 0.10 and 0.15 mg/L, which has no more much advantages of removal of manganese. One of reasons for it is that graduation of manganese sand is not rational, which leads to partial confusion of filter layer construction. Besides the quality of manganese sand is not very high, mass manganese dioxide in the manganese sand runs off and decreases in 70%. Additionally the equipment of backwash is not suitable for the manganese sand, which leads mixed sand filter tank not to attain the effect of manganese removal in pilot period.2. Pre-oxidation by potassium permanganateIt is found that the process of manganese removal not only effectively removes manganese ion in surface water and also has an effect on removal of ammonium nitrogen and COD, meanwhile it is able to improve on coagulation and flocculation and performance of sedimentation and to reduce the dose of chlorine. Economic analysis indicates the cost of the process is lower in operation. The optimal parameters of the process in operation are as following: the dose of potassium permanganate=0.8mg/L; the dose of aluminium chloride=8mg/L; the dose of chlorine=2.0mg/L. The addition dose ofpotassium permanganate is direct ration to the influent. The point of addition locates at the front influent pipe. The experiment indicates that the process of manganese removal takes on the characteristics that are a simple process, convenient management, low investigation and low cost of operation , has significant economic benefits and marked social benefits and is an ideal process of manganese removal in surface water.