The Research On Affecting Factors Of Iron Removal By Contact-Oxidation Filtration In The Dongting Lake Groundwater

On the basis of summarizing the related references home and abroad, through medium experiments we researched the effect of filter media and operation conditions on iron removal by contact oxidation from groundwater, and investigated the mechanism of iron removal by aerated filtration and the rate of iron removal by contact oxidation. The results showed that when the iron content increased from 16 mg/L to 20 mg/L, the technology of aeration and primary contact oxidation could be operated on iron removal. The filter media's diameter could adopt 1.6-2.0mm, and the thickness could adopt 1.00m. Except a little difference in filter maturity, manganese sand, anthracite coal, ceramisite agitator and quartz sand almostly had the same effect on iron removal, when DO was < 1mg/L, the effect of iron removal by contact oxidation was very bad, but when DO content exceeded 34% theoretical oxygen demand, DO had no effect on iron removal, and the effluent iron content could reach the criterion of the drinking water quality. when pH was>6.5, the filter had better effect on iron removal, and the iron content of the effluent may maintain below 0.3mg/L. But when pH was <6.5, the iron content of the effluent rised steeply with the decrease of pH, and even effluent iron content was higher than influent iron content. When filtration rate was <12m/h, the effect of iron removal by contact oxidation was better, and the effluent iron content was at trace level. But when filtration rate was >12m/h, the effluent iron content increased rapidly and exceeded admissable iron content. Under the conditions that pH was >6.5, DO was >5mg/L and iron content was higher, the main action of iron removal was contact oxidation effection, and the effection of the microorganism was smaller. When pH was 6.65, filtration rate was 8m/h and Do was 6.5mg/L, there existed the function relation between ferrous ions concentration and filter bed depth. Using the function relation, we can predict ferrous ions concentration at any depth of the filter or count the minimal depth of the filter bed...