聚合铝铁对A^2/O系统EPS及生物絮凝性能的影响

Effect of Polymeric Aluminum-iron on EPS and Bio-flocculation in A^2/O System

通过向实验室构建的A2/O模型好氧池末端投加聚合铝铁(PAFC)来强化系统的生物除磷,使得出水总磷达到《城市污水处理厂污染物排放标准GB 18918-2002》中的一级A标准,并重点分析投加的PAFC对A2/O系统中活性污泥胞外聚合物(EPS)和活性污泥生物絮凝性能的影响.结果表明,随着PAFC投药量的增加,A2/O系统活性污泥EPS总量变化不大,但EPS组分中蛋白/多糖含量的比值逐渐降低,由投药前的3.30降低至投药后的2.30;EPS中金属离子含量逐渐增加,在厌氧-缺氧-好氧的运行周期内,各处理单元污泥的EPS中金属铝离子含量增加.投加PAFC后,活性污泥颗粒变大,二沉池出水的Zeta电位明显降低,由投药前-15.83 mV降低至-21.20 mV,污泥产量增加.因此,适量投加PAFC后,生物絮凝性能得到改善,出水中悬浊颗粒减少,出水水质变好.

Polymeric aluminum-iron（PAFC） was added at the end of aeration tank to enhance phosphorus removal,so that the phosphorus concentration in the effluent could meet the calss A standard in municipal sewage treatment plant pollutant discharge standard（GB 18918-2002）.The characteristics of extracellular polymer substances（EPS） and bio-flocculation for the activated sludge in the A2/O system were analyzed in the experiment.The results showed that,the gross of EPS varied little with the increase in PAFC dosage,while,the ratio of albumen to polysaccharide declined from 3.30 to 2.30.When the PAFC dosage increased,the concentration of Al3＋ in EPS increased during the whole anaerobic-anoxic-aerobic cycle.The flocs of activated sludge became larger after PAFC addition,Zeta potential of the effluent dropped significantly from-15.83 mV to-21.20 mV and sludge yield increased.Therefore,bio-flocculation of the activated sludge in the A2/O system improved when a proper amount of PAFC was added,subsequently improve the water quality of the effluent.