不同C/P下低耗EBPR的脱氮除磷及侧流磷回收性能

Performance of nitrogen and phosphorus removal and sidestream phosphorus recovery by low-consumption EBPR under different C/P ratio

采用厌氧交替好氧(A/O)模式下运行的SBR反应器,考察低耗(DO=1.0 mg/L)条件下不同进水m(COD)/m(P)(记作C/P)对主流强化生物除磷(Enhanced biological phosphorus removal,EBPR)系统脱氮除磷效果及其相应的厌氧磷回收性能的影响。结果表明,当进水P浓度保持不变,C/P逐步降低(C/P=400/8、350/8、300/8)时,系统厌氧末期释磷量随进水碳源浓度的降低而逐步减小,相应的侧流磷回收率从61.5%降至45.3%,而磷去除率和出水磷达标率分别从96.7%和93.3%降至87.7%和30.0%,说明侧流系统的磷回收率和主流系统的除磷效率均受进水碳源浓度的影响,期间,NH_(4)^(+)-N去除性能一直良好,TN去除率变化不大。继续降低C/P至400/12,在NH_(4)^(+)-N去除性能不受影响而TN去除率提升3.8%的同时,主流EBPR系统的除磷率和出水磷达标率分别上升至97.4%和69.2%,相应的厌氧磷回收率达62.6%,说明影响主流系统除磷性能及侧流系统磷回收性能的主要因素是进水碳源浓度和磷源浓度,而与C/P关系不大。研究还发现,前3个实验阶段的污泥胞内多聚磷酸盐(Polyphosphate,poly-P)含量都有缓慢降低的趋势,最后1阶段呈上升趋势,这与污泥吸磷性能的趋势相一致,在整个实验阶段污泥沉降性能则始终变化不大。

A sequencing batch reactor(SBR)was operated with anaerobic alternating oxic(A/O)condition to investigate the effect of different m(COD)/m(P)(C/P ratio)on nitrogen and phosphorus removal performance of a mainstream EBPR(Enhanced biological phosphorus removal)under low consumption(DO=1.0 mg/L)and anaerobic side-stream phosphorus recovery efficiency.The results showed that the amount of phosphorus released at the end of the anaerobic phase gradually decreased due to the reduction of the influent carbon source when influent P concentration kept constant and C/P ratio gradually decreased(C/P=400/8,350/8,300/8).The corresponding anaerobic side-stream phosphorus recovery rate decreased from 61.5%to 45.3%.Besides,the phosphorus removal rate and effluent phosphorus reaching standard rate dropped from 96.7%and 93.3%to 87.7%and 30.0%,respectively.It suggested that both side-stream phosphorus recovery performance and mainstream phosphorus removal rate were influenced by the concentration of carbon source.While NH_(4)^(+)-N removal performance kept well and TN removal rate had little change during this period.As C/P decreased to 400/12,mainstream EBPR phosphorus removal rate and effluent phosphorus reaching standard rate increased to 97.4%and 69.2%,respectively.At the same time,TN removal rate increased by 3.8%but NH_(4)^(+)-N removal performance not be affected.The corresponding anaerobic phosphorus recovery rate reached 62.6%.It showed that the main factors that affected the phosphorus removal performance of the mainstream system and the phosphorus recovery performance of the side-stream system were the influent carbon source concentration and the phosphorus source concentration,but had little relationship with the C/P ratio.It was also observed that poly-P(polyphosphate)content in cells during the first three stages displayed a slow decreasing trend and the last stage showed an upward trend,which was consistent with the phosphorus uptake performance of the sludge.The sludge settling performance kept stable in the whole test stage.