Study On The Treatment Of Schoolyard Domestic Sewage By Bioflocculation

All kinds of flocculating agents are widely used in industrial process including drinking water processing, industrial wastewater treatment, sewage treatment, sludge dewatering, and food and fermentation process. Bio-flocculants can be produced by a variety of microorganism. Bio-flocculants are also highly effective , safety and harmless to the ecosystem.Flocculants producing strain were isolated from activated sludge by combining conventional with mutating method. Various flocculants culture mediums were used by different kind of microorganism. Three floc-producing strains with high flocculating activity are obtained: V₃, V₁₁, V₁₃. All strains can produce strong-activity flocculants , with flocculating rate of 80% for kaolin suspension.The results of flocculating experiment of schoolyard domestic sewage with these bio-flocculants show good flocculanting. The results show that while aerial time is 3h in SBR, bacteria is 50g/L, temperature ranges from 28°C to 30°C, to V3, the removal efficiencies of OD₅₅₀- NH3-N. COD. turbidity is 91.5 percent, 82 percent, 91.3 percent, 93.5 percent;to V₁₁, the removal efficiencies of OD₅₅₀ COD, turbidity is 89.1 percent, 91.5 percent, 95.1 percent, the removal effieiencies of NH3-N is low, to V₁₃ the removal efficiencies of OD₅₅₀, COD, turbidity is 90.7 percent, 93.3 percent. 92.1 percent, the removal effieiencies of NH3-N is zero. When V₃ , V₁₁ , V₁₃ are mixed together in the experiments, the results show that three germ are not mutually restraint and they become a kind of living the relation with each other. Meanwhile, the results show better flocculating in the treatment of wastewater than one of bacteria, the results show while aerial time is 3h in SBR, bacteria is 50g/L , temperature ranges from 28°C°C to 30°C, the removal efficiencies of OD₅₅₀, NH₃-N,COD, turbidity is 93.3 percent, 86.7 percent, 93.5 percent, 96 percent. Meanwhile flocculant can strengthen sludge function in the experiment.Some factors of microbial flocculants producing were studied by selecting different of miedia:bacteria 50g/L,temperature ranges from 28°C to 30°C,COD volumetric loading bearing 1.57kg/(m3.d), the removal efficiencies is the highest .the results show the removal efficiencies of OD₅₅₀,NH₃-N, COD, turbidity is 92.5 percent, 84.5 percent, 93.3 percent, 96.2 percent.The large scale experiment is done in the experiment, volumetric loading bearing is strengthened. When COD volumetric bearing is 2.95 kg/(m3.d), the highest efficiencies is obtained.