低C/N比水产养殖废水生物脱氮实验研究

Experimental study on biological nitrogen removal process of low C/N aquaculture

随着短程硝化-反硝化理论研究的发展,在低C/N比条件下,实现污水的生物脱氮处理已成为可能。为此,设计了水产养殖用水的三级生物膜短程硝化-反硝化处理工艺,并对该工艺在去除模拟水产养殖废水主要污染物的作用进行了初步研究。研究结果表明,在进水pH值7.5~8.5,温度为28~32℃,溶解氧为0.5~1 mg/L,游离氨浓度为5~10 mg/L的条件下,模拟废水的COD、NH4＋-N和TN的平均去除率分别达到94.4%、91.6%和70.1%;并且低C/N比对出水氨氮NH4＋-N的去除率影响不大,NO2--N的平均浓度控制在5.2 mg/L以下,低于鱼类的耐受浓度。表明该短程硝化-反硝化工艺设计,可用于低C/N比水产养殖废水主要污染物的生物处理,尤其是可消除NO2--N对水产养殖的潜在威胁,基本达到养鱼回用标准。

A new type short-cut nitrification denitrification biofilter with multi-stage biofilm treatment system was designed,and its efficiency of bio-denitrification was researched under laboratory conditions.The results showed that when the pH was 7.5～8.5,the temperature of water was at 28～32 ℃,dissolved oxygen was 0.5～1 mg/L and ammonia was 5~10 mg/L in artificial aquaculture wastewater,COD,nitrite and total nitrogen average removal rates were 94.4%,91.6% and 70.1%,respectively.That influence on the effluent removal rate of NH＋4-N with low C/N ratio was little,and the concentration of nitrite was limited to less than 5.2 mg/L in artificial aquaculture wastewater,that was below the tolerance levels of fish.The results indicate that removing nitrite from aquaculture wastewater with the short-cut nitrification denitrification multi-stage biofilm biofilter is a feasible approach,and the water quality is suitable to recycling into the aquaculture system.