改进型A_(2)NSBR工艺参数及其除磷脱氮特性

PARAMETERS AND PERFORMANCE OF AN IMPROVED A_(2)NSBR PROCESS ON PHOSPHORUS AND NITROGEN REMOVAL

以模拟生活污水为处理对象,在常规A_(2)NSBR工艺厌氧释磷后插入一段曝气吸磷过程,通过运行条件的优化,寻求解决后续缺氧段中硝酸盐与磷酸盐浓度的匹配问题,并在此基础上研究了改进后A_(2)NSBR工艺的除磷脱氮特性及其缺氧段的运行控制问题。结果表明:在厌氧释磷后插入一段曝气吸磷过程,控制后续的缺氧搅拌初始ρ(NO_(3)^(-)-N)/ρ(PO_(4)^(3-)-P)为1.15~1.3时,可以提高系统反硝化除磷过程的稳定性,可避免因ρ(NO_(3)^(-)-N)/ρ(PO_(4)^(3-)-P)过低而出现“二次无效释磷”现象,并可将pH在线参数由上升转为下降的峰值点,作为在线控制缺氧段反硝化除磷过程结束的依据;取SBR池的充排水比为0.67时,系统能为其缺氧段初提供的NO_(3)^(-)-N量仅约为进水NH_(4)^(+)-N的40%;优化后改进型A_(2)NSBR工艺典型周期的出水ρ(COD)为15.3 mg/L,出水ρ(PO_(4)^(3-)-P)、ρ(NO_(3)^(-)-N)、ρ(NH_(4)^(+)-N)和ρ(TN)的均值分别为0.27,0.36,12.81,13.17 mg/L,相应的COD、PO_(4)^(3-)-P和TN去除率依次为96.7%、96.8%和78.3%。

An aeration phosphorus-absorption process was inserted after the anaerobic phosphorus release of the conventional A_(2)NSBR process for the treatment of simulated domestic sewage.Through the optimization of operating condition,the matching problems of nitrate and phosphate concentration in the subsequent anoxic section were solved,and then the phosphorus and nitrogen removal characteristics of the improved A_(2)NSBR process and operation control of the anoxic section were studied.The results showed that the stability of the denitrification phosphorus removal process could be improved by inserting a stage of aeration phosphorus-absorption process after anaerobic phosphorus release,and controlling the concentration ratio of NO_(3)^(-)-N and PO_(4)^(3-)-P at the beginning of the subsequent anoxic stage to be 1.15~1.3,so as to avoid the phenomenon of secondary ineffective phosphorus release,due to the low ratio of NO_(3)^(-)-N/PO_(4)^(3-)-P;and the peak point at which the on-line pH parameter changed from rising to falling could be used as the basis for on-line controlling the end of denitrification and phosphorus removal process in the anoxic section.When the water filling and drainage ratio of the SBR tank was 0.67,the amount of NO_(3)^(-)-N that the system could initially provide for its anoxic section was only about 40% of NH_(4)^(+)-N in the influent.The effluent COD in the typical cycle of the improved A_(2)NSBR process after optimization was 15.3 mg/L,and the average values of PO_(4)^(3-)-P,NO_(3)^(-)-N,NH_(4)^(+)-N and TN in the effluent were 0.27,0.36,12.81,13.17 mg/L,respectively,and the corresponding removal rates of COD,PO_(4)^(3-)-P and TN were 96.7%,96.8%,78.3% respectively.