Removal of iron, manganese and high ammonia from groundwater by biofilter

A pilot-scale biological filter was constructed to removal of iron, manganese and high ammonia simultaneously from groundwater. The results indicated that the failure of manganese and ammonia oxidation when the influent ammonia concentration was above 2.0 mg/L without extra aeration. Oxidation of iron, manganese and ammonia could be completed by downflow filtration with the aeration at the bottom of the filter bed, while the processing capacity was affected significantly and was not suitable for application of the biofilter. The upflow filtration with the same aeration mode could also met the oxygen demands of the oxidation process, however, the oxidized iron and manganese were easily taken out filter bed, causing high iron and manganese concentration in the effluent. For the upflow filtration with extra aeration at the bottom of the filter bed, the experiments demonstrated that the intercepting capacity of filter was damaged significantly by disturbance of aeration compared to the case of upflow filtration without aeration and was inversely correlatedwith the aeration intensity.