[Treatment of micro-polluted river water by immobilized microorganism technique]

The effect of immobilized microorganism technique on the micro-polluted river water was studied by four kinds of gaia-biological aerated filter (G-BAF), which were formed by special microorganism (BP35) and four different carriers, including haydite, FPUFS, aquamats flexible carrier and artificial aquatic mat. The removal rates of NH4(+) -N, chlorophyll and turbidity were 83.0%-89.0%, 77.5%-89.0% and 84.4%-95.2%, respectively, and they were all higher than the removal rates of COD, UV254 and TP. The FPUFS contained reactive groups, such as hydroxyl, epoxy and acylamide groups, which made FPUFS load a great amount of enzymes and microorganisms. Therefore, the removal rates of pollutants for FPUFS-G-BAF were higher than those for the other three kinds of G-BAF. Hydraulic retention time (HRT) had little effect on the removal rate of NH4(+) -N, while affected the removal rate of COD significantly. When the concentration of dissolved oxygen (DO) increased from < 2 mg/L to > 4 mg/L, for the four kinds of G-BAF, the removal rates of COD and NH4(+) -N increased 11.9%-18.0% and 12.7%-16.1%, respectively. The result of GC-MS showed that the technique of G-BAF could effectively degrade the macro-molecule refractory organics into small-molecule substance.