曝气生物滤池铝盐化学强化与生物协同除磷

Phosphorus removal by biochemical synergistic precipitation in upflow biological aerated filter by using aluminum chloride

为了解投加铝盐后曝气生物滤池的除磷效果及其对去碳、硝化功能和生物膜、生物相的影响,通过同步比较在投加药剂和不投加药剂情况下小试曝气生物滤池的净化效果和生物膜结构特征、生物相组成.结果表明,当反应器水力负荷和进水总磷(TP)负荷分别为1.3m3·m-2·h-1和0.12～0.13kg·m-3·d-1时,TP的去除随铝盐投加量的增加而增加,但并不成正比例增加.投加铝盐后TP去除率可提高70%～86%.当投加系数≤1.5时,适当加大气水比有利于除磷,但当投加系数≥1.75时,加大气水比对TP的去除没有影响.当气水比为(3～5)∶1、投加系数≥1.75时,曝气生物滤池出水TP<0.5mg·L-1;若气水比增加到7∶1时,投加系数可进一步降低至1.5.投加铝盐对浊度、COD去除的贡献率分别只有4%～7%和5%～13%,而对氨氮的去除影响甚微.投加铝盐后反应器进水端陶粒表面发现大量网状絮体,出水端却较少.投加铝盐对生物膜中微生物的种类和数量的影响很小.

To compare with the removal efficiency of total phosphate （TP） and the influence of chemical dosed onto the reactors on the removal of organic matter, ammonia nitrogen （NH4^＋ -N） and biofilm, two pilot-scale upflow biological aerated filters （UBAF）, UBAF-1 with aluminum chloride and UBAF- 2 without chemical agent, at hydraulic loading rate （HLR） of 1.3m^3·m^-2·h^-1 and TP loading rate of 0. 12 kg-0.13kg·m^-3·d^-1 were operated synchronously using artificial water. The removal efficiency of TP in UBAF-1 was 70%-86% more than the one in UBAF-2. The results demonstrate that the removal efficiency of TP increases gradually disproportionatly with the increase of chemical dosing ratio （Al/P mol ratio）. The suitable increase of gas/liquid ratio was in favor of removing TP as chemical dose ratio was less than or equal to 1.50. But the increase of gas/liquid ratio had almost no influence on the removal of TP when the chemical dosing ratio was higher than or equal to 1.75. The TP effluent concentration was less than 0.5 mg. L-when the chemical dose ratio was more than 1.75 with gas/liquid ratio in range of 3-5. The same result could be achieved when chemical dose ratio was 1.50 with gas/liquid ratio of 7. The chemical dosing was advantageous to the removal of turbidity and COD, which contributed respectively 4%-7% and 5%-13% reduction, but it had little influence on the removal of NH4^＋-N. Many mesh-structure flocs were observied on the surface of the media near the inlet, but few on the surface of the media near the outlet of UBAF-1. Aluminum chloride precipitations have little effect on the species and quantities of microorganism.