In order to achieve simultaneous nitrogen and phosphorus removal in the biological treatment process,denitrifying phosphorus accumulation(DNPA)and its affecting factors were studied in a sequencing batch reactor(SBR)w...In order to achieve simultaneous nitrogen and phosphorus removal in the biological treatment process,denitrifying phosphorus accumulation(DNPA)and its affecting factors were studied in a sequencing batch reactor(SBR)with synthetic wastewater.The results showed that when acetate was used as the sole carbon resource in the influent,the sludge acclimatized under anaerobic/aerobic operation had good phos-phorus removal ability.Denitrifying phosphorus accumulation was observed soon when fed with nitrate instead of aeration following the anaerobic stage,which is a vital premise to DNPA.If DNPA sludge is fed with nitrate prior to the anaerobic stage,the DNPA would weaken or even disappear.At the high concen-tration of nitrate fed in the anoxic stage,the longer anoxic time needed,the better the DNPA was.Induced DNPA did not disap-pear even though an aerobic stage followed the anoxic stage,but the shorter the aerobic stage lasted,the higher the proportions of phosphorus removal via DNPA to total removal.展开更多
This study was conducted to verify and discuss the denitrifying dephosphatation under different levels of nitrate concentration and retention time of anoxic/aerobic process in a Sequencing Batch Reactor (SBR). The res...This study was conducted to verify and discuss the denitrifying dephosphatation under different levels of nitrate concentration and retention time of anoxic/aerobic process in a Sequencing Batch Reactor (SBR). The results of tests demonstrated that there were two kinds of phosphorus-accumulating organisms (PAOs) in the biological excess phosphorus removal (BEPR) system. One was non-DNPAOs that could only use oxygen as terminal electron acceptors, the other was denitrifying PAOs (DNPAOs) that could use both nitrate and oxygen as terminal electron acceptors. Phosphorus uptake efficiency could be attained under anoxic period ranging from 28.7%-96.7% in an anaerobic/anoxic/aerobic system. Experimental results showed that nitrate concentration and retention time of anoxic/aerobic process were the key factors affecting the course of denitrifying dephosphatation.展开更多
Simultaneous biological phosphorus and nitrogen removal with enhanced anoxic phosphate uptake via nitrite was investigated in an anaerobic-aerobic-anoxic-aerobic sequencing batch reactor((AO)2 SBR). The system showed ...Simultaneous biological phosphorus and nitrogen removal with enhanced anoxic phosphate uptake via nitrite was investigated in an anaerobic-aerobic-anoxic-aerobic sequencing batch reactor((AO)2 SBR). The system showed stable phosphorus and nitrogen removal performance, and average removals for COD, TN and TP were 90%, 91% and 96%, respectively. The conditions of pH 7.5—8.0 and temperature 32℃ were found detrimental to nitrite oxidation bacteria but favorable to ammonia oxidizers, and the corresponding specific oxygen uptake rates(SOUR) for phase 1 and 2 of nitrification process were 0.7 and 15 mgO 2/(gVSS·h) in respect, which led to the nitrite accumulation in aerobic phase of(AO)2 SBR. Respiratory tests showed that 40 mgNO 2-N/L did not deteriorate the sludge activity drastically, and it implied that exposure of sludge to nitrite periodically enabled the biomass to have more tolerance capacity to resist the restraining effects from nitrite. In addition, batch tests were carried out and verified that denitrifying phosphorus accumulation organisms(DPAOs) could be enriched in a single sludge system coexisting with nitrifiers by introducing an anoxic phase in an anaerobic-aerobic SBR, and the ratio of the anoxic phosphate uptake capacity to aerobic phosphate uptake capacity was 45%. It was also found that nitrite(up to 20 mgNO 2-N/L) was not inhibitory to anoxic phosphate uptake and could serve as an electron acceptor like nitrate, but presented poorer efficiency compared with nitrate.展开更多
基金This study was supported by the National Natural Science Foundation of China(Grant No.5008014).
文摘In order to achieve simultaneous nitrogen and phosphorus removal in the biological treatment process,denitrifying phosphorus accumulation(DNPA)and its affecting factors were studied in a sequencing batch reactor(SBR)with synthetic wastewater.The results showed that when acetate was used as the sole carbon resource in the influent,the sludge acclimatized under anaerobic/aerobic operation had good phos-phorus removal ability.Denitrifying phosphorus accumulation was observed soon when fed with nitrate instead of aeration following the anaerobic stage,which is a vital premise to DNPA.If DNPA sludge is fed with nitrate prior to the anaerobic stage,the DNPA would weaken or even disappear.At the high concen-tration of nitrate fed in the anoxic stage,the longer anoxic time needed,the better the DNPA was.Induced DNPA did not disap-pear even though an aerobic stage followed the anoxic stage,but the shorter the aerobic stage lasted,the higher the proportions of phosphorus removal via DNPA to total removal.
基金Sponsored by the National Natural Science Foundation of China(Grant No50008014)
文摘This study was conducted to verify and discuss the denitrifying dephosphatation under different levels of nitrate concentration and retention time of anoxic/aerobic process in a Sequencing Batch Reactor (SBR). The results of tests demonstrated that there were two kinds of phosphorus-accumulating organisms (PAOs) in the biological excess phosphorus removal (BEPR) system. One was non-DNPAOs that could only use oxygen as terminal electron acceptors, the other was denitrifying PAOs (DNPAOs) that could use both nitrate and oxygen as terminal electron acceptors. Phosphorus uptake efficiency could be attained under anoxic period ranging from 28.7%-96.7% in an anaerobic/anoxic/aerobic system. Experimental results showed that nitrate concentration and retention time of anoxic/aerobic process were the key factors affecting the course of denitrifying dephosphatation.
文摘Simultaneous biological phosphorus and nitrogen removal with enhanced anoxic phosphate uptake via nitrite was investigated in an anaerobic-aerobic-anoxic-aerobic sequencing batch reactor((AO)2 SBR). The system showed stable phosphorus and nitrogen removal performance, and average removals for COD, TN and TP were 90%, 91% and 96%, respectively. The conditions of pH 7.5—8.0 and temperature 32℃ were found detrimental to nitrite oxidation bacteria but favorable to ammonia oxidizers, and the corresponding specific oxygen uptake rates(SOUR) for phase 1 and 2 of nitrification process were 0.7 and 15 mgO 2/(gVSS·h) in respect, which led to the nitrite accumulation in aerobic phase of(AO)2 SBR. Respiratory tests showed that 40 mgNO 2-N/L did not deteriorate the sludge activity drastically, and it implied that exposure of sludge to nitrite periodically enabled the biomass to have more tolerance capacity to resist the restraining effects from nitrite. In addition, batch tests were carried out and verified that denitrifying phosphorus accumulation organisms(DPAOs) could be enriched in a single sludge system coexisting with nitrifiers by introducing an anoxic phase in an anaerobic-aerobic SBR, and the ratio of the anoxic phosphate uptake capacity to aerobic phosphate uptake capacity was 45%. It was also found that nitrite(up to 20 mgNO 2-N/L) was not inhibitory to anoxic phosphate uptake and could serve as an electron acceptor like nitrate, but presented poorer efficiency compared with nitrate.
