Pilot-Scale Study On Denitrification Treatment Of Low C/N Ration, High TKN Municipal Wastewater With Biofilm A/O/O System

The technological characteristics of pilot-scale biofilm A/O/O system treating low C/N ration, high TKN municipal wastewater at a constant temperature of 10-20 were studied. The denitrifying results showed that the biofilm A/O/O system was capable of achieving in 30-50 percent TN removal efficiency and excess of 70 percent TKN removal efficiency to treat such low C/N ration municipal wastewater under the condition of no external carbon source. The fundamental factors affecting A/O/O system biofilm culturing and the technological parameters and conditions of the three biofilm reactors were investigated mainly in the paper.If the second biological contact oxidation pond that processed ammonium could culture the mature biofilm as nitrifying bacteria was superior living bacteria or not, was the key procedure of A/O/O system biofilm culturing. Water temperature, air/water ration and influent ammonium loading rate (ALR), were the main effects of biofilm formation and its maturation time.The resdlts of characteristics research that the three biofilmreactors of A/O/O system treat low C/N ration, high TKN municipal wastewater at 10-20, indicated that the optimal anoxic reaction time and recycle ration were 2.1h(its nitrate loading rate was 1.2 kg/m3d) and 3 respectfully as for biofilm denitrification pond; as for the first biological contact oxidation pond, the optimal HRT was 4h(its OLR_COD was 3.6⁴.1kg/m3d, OLR_BOD was 1.62-1.85kg/m3-d), the effect was better when its air/water ration#6 and effluent D0=4.5-6mg/l; as for the second biological contact oxidation pond, the optimal HRT and air/water ration were 2.64h(its ALR 0.78 kg/m3d) and 6 respectfully, the nitrifying effect was better as effluent D0=5⁶mg/l.