Performance of a Field Scale Combined Biofilters System for the Purification of Micro-polluted Urban Shallow Lake

Combined biofilters system was developed to purify a micro-polluted urban shallow lake. The performance of the system was investigated from January 2007 to December 2011. The results showed that the effluent concentration of COD dropped below 20 mg /L, NH4-N dropped below 0.2 mg /L, TN decreased below 1.0 mg/L, and TP decreased below 0.2 mg/L, all of the water quality indexes reached the class III standard of “Surface Water Quality Standards” (GB 3838-2002) except TP. The combined system showed strong anti-shock load and provided an option for the treatment of micro-polluted urban lake.