Application of Immobilized Microorganism Pellets and Ion Exchange Resin Combined Process for Micro-Polluted Water Treatment

The oxidation of ammonia nitrogen at a low concentration in synthetic micro-polluted water by immobilized nitrobacteria pellets in inner-circulated biological fluidized bed reactor was investigated with the system operated continuously under the condition of temperature 20~30CC, DO 3~5 mg/L. The concentrations of effluent NH₄ ⁺-N and NO₂ ^--N are below 0.3 mg/L at the influent concentration of 10~15 mg/L NH₄ ⁺-N with the hydraulic retention time(HRT) controlled at 30 min. More than 90% ammonia nitrogen is oxidated to nitrate nitrogen. The removal of nitrate nitrogen by ion exchange resin in columns. The resin capacity could reach 20 g-N/L-resin, and the removal rate was about 99%. The result shows that the effluent water meets the standards of drinking water quality. This combined process is feasible for engineering applicationand will be widely used in future.