短程硝化-反硝化生物滤池脱氮机制研究

Mechanism of Nitrogen Removal by Partial Nitrification-Denitrification Biological Filter

研究了短程硝化生物滤池的调控因素以及短程硝化-反硝化生物滤池的脱氮机制.结果表明,针对城市污水处理厂二级出水中的氨氮和总氮,在水温为(30±1)℃的条件下,提高进水pH值有助于硝化生物滤池中亚硝酸盐的积累,较好地实现短程硝化过程,当进水pH值平均为8.5时,亚硝酸盐的积累达到最大.沿硝化生物滤池水流方向,pH和DO的变化呈相反趋势,亚硝酸盐的积累呈增加趋势,在反应器出水口较好地实现了亚硝酸盐的积累.短程硝化-反硝化生物滤池对NH4+-N有较好的去除效率(90%以上);当反硝化生物滤池进水COD/TN为3.0时,出水TN的浓度降低到8～9 mg.L-1的范围,去除率稳定在79%～81%.

The controlling factors for nitrite accumulation in partial nitrification and mechanism of nitrogen removal from the secondary effluent of wastewater treatment plant by partial nitrification-denitrification biological filter were investigated.The results showed that nitrite accumulated with increasing of pH value in the influent under the condition of temperature was（30±1）℃.The nitrite accumulation achieved to the highest at a pH value of 8.5 in this batch experiments.In addition,the nitrite accumulation presented increasing tendency through the up-flow nitrifying biological filter,which can be adjusted by the changes of pH and DO through the filter.The removal efficiency of NH＋4-N was over 90% by the partial nitrification-denitrification biological filter.Meanwhile,carbon sources were supplied for the denitrifying bacteria to accomplish denitrification process.Under the condition of COD/TN at a value of 3.0,the concentration of TN in the effluent of denitrifying biofilter was 8-9 mg·L-1 and the removal efficiency achieved 79%-81%,stably.