固定化包埋颗粒对二级出水深度脱氮特性研究

Nitrogen removal of the secondary effluent by embedded immobilized bacteria in moving-bed

采用包埋固定化颗粒对北京市某污水处理厂的二沉池出水进行深度脱氮处理,研究了驯化启动及稳定运行的条件和脱氮特性,对比了不同水力停留时间(HRT)、不同进水TN负荷的脱氮效能.结果表明,在水温为25℃、pH=7.2、水力停留时间为70min、包埋颗粒填充率为30%时,投加碳源驯化一周后包埋固定化颗粒即能保持稳定高效的脱氮率,并具有良好的耐冲击负荷能力;进水TN负荷从0.5kg·m-·3d-1逐渐提高至2.0kg·m-·3d-1时,TN平均去除率达到86.6%.进水TN负荷为2.5kg·m-·3d-1时,TN平均去除率仍能达到70%;在HRT为20min时,出水硝氮<1mg·L-1,TN<5mg·L-1;填充率由30%逐渐降低到20%时,TN去除率均能达到80%以上;填充率低于20%时,TN去除率随着填充率的减少而下降.试验确定包埋固定化菌的最佳填充率为20%.

Embedded immobilized bacteria particles are used to treat the secondary effluent from the wastewater treatment plant of Beijing. The effects of hydraulic retention time, TN loading rate and the particle filling ratio on the culture process of embedded immobilized bacteria and nitrogen removal efficiency were investigated here. The results showed that a stable and high nitrogen removal efficiency was achieved in the condition of temperature 25 ℃, pH 7.2, hydraulic retention time 70 min and filling ratio 30% after adding the carbon sources for one week. An excellent resilience to the load shock was observed in our operating system. The average TN removal efficiency reached 86.6%,when the TN loading rate varied from 0.5 kg · m^-3 · d^-1 to 2.0 kg · m^-3 · d^-1. The TN can be removed by 70% with the TN loading rate 2.5 kg · m^-3 · d^-1. The effluent concentration of nitrate nitrogen and total nitrogen were less than 1 mg·L^-1 and 5 mg·L^-1 respectively at HRT 20 min. A TN removal efficiency higher than 80% was achieved when the filling ratio changed from 30% to 20%. However, the TN removal efficiency decreased with the filling ratio when the filling ratio was less than 20%. The optimized filling ratio of embedded immobilized bacteria was 20% in the experiment.