Impact of nitrite on aerobic phosphorus uptake by poly-phosphate accumulating organisms in enhanced biological phosphorus removal sludges

Impact of nitrite on aerobic phosphorus (P) uptake of poly-phosphate accumulating organisms (PAOs) in three different enhanced biological phosphorus removal (EBPR) systems was investigated, i.e., the enriched PAOs culture fed with synthetic wastewater, the two lab-scale sequencing batch reactors (SBRs) treating domestic wastewater for nutrient removal through nitrite-pathway nitritation and nitrate-pathway nitrification, respectively. Fluorescence in situ hybridization results showed that PAOs in the three sludges accounted for 72, 7.6 and 6.5 % of bacteria, respectively. In the enriched PAOs culture, at free nitrous acid (FNA) concentration of 0.47 × 10^?3 mg HNO₂-N/L, aerobic P-uptake and oxidation of intercellular poly-β-hydroxyalkanoates were both inhibited. Denitrifying phosphorus removal under the aerobic conditions was observed, indicating the existence of PAOs using nitrite as electron acceptor in this culture. When the FNA concentration reached 2.25 × 10^?3 mg HNO₂-N/L, denitrifying phosphorus removal was also inhibited. And the inhibition ceased once nitrite was exhausted. Corresponding to both SBRs treating domestic wastewater with nitritation and nitrification pathway, nitrite inhibition on aerobic P-uptake by PAOs did not occur even though FNA concentration reached 3 × 10^?3 and 2.13 × 10^?3 mg HNO₂-N/L, respectively. Therefore, PAOs taken from different EBPR activated sludges had different tolerance to nitrite.     

反硝化除磷菌筛选及其特性研究

【目的】研究反硝化除磷菌特性。【方法】通过微生物筛选和生物学特性研究方法,从对虾养殖池塘中筛选出多株可在有氧条件下同时具有反硝化除磷功能的菌种。【结果】菌株LY-1可在18 h内将初始量为10 mg/L的亚硝酸盐氮降低至0.04 mg/L,PO43?-P降低至0.05 mg/L。在DO浓度为5.0?5.9 mg/L时,该菌反硝化除磷率近100%。试验选取具有反硝化除磷功能的枯草芽孢杆菌为阳性对照菌,大肠杆菌为阴性对照菌,比较研究了菌株LY-1在不同pH、温度、盐度、PO43?-P浓度、亚硝酸盐浓度时反硝化除磷的强弱,在pH为5?9范围时,该菌亚硝酸盐氮去除率近99%,PO43?-P去除率86%;温度为30°C时,该菌反硝化除磷率近100%;盐度为5‰?15‰、PO43?-P浓度为10 mg/L、亚硝酸盐氮浓度为20 mg/L时,该菌亚硝酸盐氮和PO43?-P去除率均可达99%。【结论】菌株LY-1反硝化除磷性能显著高于对照菌(P<0.05)。通过菌株LY-1形态学观察、生理生化及16S rRNA基因序列分析,初步鉴定为蜡样芽孢杆菌(Bacillus cereus)。     

Simultaneous nitrification,denitrification, and phosphorus removal in a lab-scale sequencing batch reactor

Simultaneous nitrification and denitrification (SND) via the nitrite pathway and anaerobic-anoxic-enhanced biological phosphorus removal (EBPR) are two processes that can significantly reduce the energy and COD demand for nitrogen and phosphorus removal. The combination of these two processes has the potential of achieving simultaneous nitrogen and phosphorus removal with a minimal requirement for COD. A lab-scale sequencing batch reactor (SBR) was operated in alternating anaerobic-aerobic mode with a low dissolved oxygen (DO) concentration (0.5 mg/L) during the aerobic period, and was demonstrated to accomplish nitrification, denitrification, and phosphorus removal. Under anaerobic conditions, COD was taken up and converted to polyhydroxyalkanoates (PHAs), accompanied by phosphorus release. In the subsequent aerobic stage, PHA was oxidized and phosphorus was taken up to <0.5 mg/L by the end of the cycle. Ammonia was also oxidized during the aerobic period, but without accumulation of nitrite or nitrate in the system, indicating the occurrence of simultaneous nitrification and denitrification. However, off-gas analysis showed that the final denitrification product was mainly nitrous oxide (N(2)O), not N(2). Further experimental results demonstrated that nitrogen removal was via nitrite, not nitrate. These experiments also showed that denitrifying glycogen-accumulating organisms (DGAOs), rather than denitrifying polyphosphate-accumulating organisms (DPAOs), were responsible for the denitrification activity.     

Effect of nitrite from nitritation on biological phosphorus removal in a sequencing batch reactor treating domestic wastewater

Although nitrite effect on enhanced biological phosphorus removal (EBPR) has been previously studied, very limited research has been undertaken about the effect of nitrite accumulation caused by nitritation on EBPR. This paper focused on nitrite effect from nitritation on EBPR in a sequencing batch reactor treating domestic wastewater. Results showed that nitrite of below 10 mg/L did not inhibit P-uptake and release; whereas EBPR deterioration was observed when nitrite accumulation reached 20 mg/L. Due to P-uptake prior to nitritation, nitrite of 20 mg/L has no effect on aerobic P-uptake. The main reason leading to EBPR deterioration was the competition of carbon source. Batch tests were conducted to investigate nitrite effect on anaerobic P-release. Under sufficient carbon source, nitrite of 30 mg/L had no impact on poly-β-hydroxyalkanoate (PHA) storage; contrarily, under insufficient carbon source, denitrifiers competing for carbon source with phosphorus accumulating organisms resulted in decrease of PHA synthesis and P-release.     

The effect of propionic to acetic acid ratio on anaerobic-aerobic (low dissolved oxygen) biological phosphorus and nitrogen removal

In this paper, three lab-scale sequencing batch reactors (SBR-A, B, and C) operated with anaerobic/aerobic (low dissolved oxygen, 0.15-0.45 mg L(-1)) configuration were long-term cultured, respectively with single acetic acid and propionic/acetic acid of 1/1 and 2/1 (carbon molar ratio), and the comparisons of anaerobic and aerobic transformations of phosphorus and nitrogen among them were made. With the increase of propionic/acetic acid, lower anaerobic phosphorus release and higher phosphorus release to short-chain fatty acids uptake ratio were observed, and less anaerobic and aerobic transformations of glycogen and poly-3-hydroxybutyrate as well as total polyhydroxyalkanoates occurred, but the transformations of poly-3-hydroxyvalerate and poly-3-hydroxy-2-methyvalerate increased. The phosphorus removal efficiency was respectively 81, 94 and 97% in SBR-A, B and C. Almost all ammonium was removed and no significant nitrite was accumulated at different propionic/acetic acid ratios. However, the nitrate accumulation and total nitrogen removal were observed to be affected by propionic/acetic acid ratio. The total nitrogen removal efficiency was 61, 68 and 82%, and the aerobic end nitrate concentration was 8.05, 6.40 and 3.54 mg L(-1) in three SBRs, respectively. All the above studies indicated that the sole acetic acid caused more nitrate accumulation than propionic and acetic acids mixture, and a pertinent increase of wastewater propionic/acetic acid ratio was of benefit to both nitrogen and phosphorus removal in an anaerobic/aerobic (low dissolved oxygen) biological wastewater treatment process.     

一株海洋好氧反硝化细菌的鉴定及其好氧反硝化特性

【目的】从处理海洋养殖循环水的生物滤器生物膜中分离到1株具有好氧反硝化活性的细菌(菌株2-8),并进一步研究了该菌的分类地位及反硝化特性。【方法】采用16S rRNA基因序列分析对菌株进行初步鉴定,采用好氧培养技术,探讨了碳源种类、起始pH、NaCl浓度、C/N、温度和摇床转速对菌株2-8好氧反硝化活性的影响。【结果】该菌株的16S rRNA基因序列与Pseudomonas segetis FR1439T(AY770691)的相似性最高,达到99.9%,因此初步鉴定菌株2-8属于假单胞菌属(Pseudomonas sp.2-8)。碳源类型和C/N对其好氧反硝化作用的影响最为显著,以柠檬酸钠为唯一碳源,C/N为15时脱氮效率最高,低C/N导致亚硝酸盐的积累;其好氧反硝化的最适温度和pH分别为30℃和7.5;菌株2-8在摇床转速为160r/min下脱氮效果最好;NaCl浓度对其反硝化活性的影响不明显。【结论】在初始硝酸氮浓度为140mg/L,以柠檬酸钠为唯一碳源、C/N为15、pH为7.5、NaCl浓度为30g/L,30℃以及160r/min摇床培养的条件下,菌株2-8在48h内脱氮率可达92%且无亚硝酸盐积累。     

Enhanced denitrifying phosphorous removal in a novel anaerobic/aerobic/anoxic (AOA) process with the diversion of internal carbon source

A novel anaerobic/aerobic/anoxic (AOA) process is proposed to realize denitrifying phosphorous removal in this study, and the characteristic of the AOA process is transferring part of the anaerobic mixed liquor to the post-anoxic zone for providing the carbon source needed for denitrification. The AOA process was operated for 3 months, and the average removal efficiencies of NH4+-N, TN and PO4(3-)-P were 93.0±3.1%, 70.3±2.9% and 87.3±11.8%, respectively. A mass balance analysis indicated that 0.49±0.02 g VSS(-1) d(-1) of PO4(3-)-P and 0.23±0.04 g VSS(-1) d(-1) of NO3--N were simultaneously removed in the anoxic zone, and it is speculated that denitrifying phosphorous removal occurred in the AOA process. Furthermore, 0.24±0.06 g VSS(-1) d(-1) of TN was removed in the aerobic zone via simultaneous nitrification and denitrification (SND). The results demonstrate that the multi-zone structure of the AOA process favors the enhancement of denitrifying phosphorous removal and SND for municipal wastewater treatment.     

Free nitrous acid inhibition on anoxic phosphorus uptake and denitrification by poly-phosphate accumulating organisms

Nitrite has been found in previous research an inhibitor on anoxic phosphorus uptake in enhanced biological phosphorus removal systems (EBPR). However, the inhibiting nitrite concentration reported varied in a large range. This study investigates the nitrite inhibition on anoxic phosphorus uptake by using four different mixed cultures performing EBPR with pH considered an important factor. The results showed that the protonated species of nitrite, HNO(2) (or free nitrous acid, FNA), rather than nitrite, is likely the actual inhibitor on the anoxic phosphorus uptake, as revealed by the much stronger correlation of the phosphorus uptake rate with the FNA than with the nitrite concentration. All the four EBPR sludges showed decreased anoxic phosphorus uptake rates with increased FNA concentrations in the studied range of 0.002-0.02 mg HNO(2)-N/L. The phosphorus uptake by all four cultures was completely inhibited at 0.02 mg HNO(2)-N/L. Granular sludge appeared to be more tolerant to HNO(2) than flocular sludge likely due to its stronger resistance to the transfer of nitrite into the bacterial aggregates. Furthermore, denitrification by the phosphorus-accumulating organisms (PAOs) was also found to be inhibited by HNO(2). The denitrification rate decreased by approximately 40% when the FNA concentration was increased from 0.002 to 0.02 mg HNO(2)-N/L.     

Enhanced biological nutrient removal using MUCT-MBR system

Biological nutrient removal was investigated in a combined modified University of Cape Town and membrane bioreactor system. When the influent nutrient mass ratio (COD/TN/TP) was 28.5/5.1/1 to 28.5/7.2/1, average removal efficiencies of COD, TN and TP were 90%, 81.6%, 75.2%. Obvious denitrifying phosphorus removal occurred with C/N ratio 3.98. When nitrite was the main electron acceptor, the ratio of denitrifying phosphate uptake to the total phosphate uptake were 99.8% and the sludge yield was 0.28kg VSS/kg COD; when nitrate was the main electron acceptor, the ratio was 92% and the yield was 0.32kg VSS/kg COD. In case of nitrite, the system not only kept TP and TN removal at 89.1% and 82.2%, but also ensured less sludge production. Batch tests showed that the proportion of denitrifying phosphorus-accumulating organisms in the total phosphorus-accumulating organisms in the system was higher than 80%.     

基于好氧反硝化及反硝化聚磷菌强化的低温低碳氮比生活污水生物处理中试研究

【背景】低碳氮比生活污水很难达标处理,多级A/O工艺、生物强化技术及生物膜技术的有机结合可有效解决这一问题。【目的】开发出一种泥膜共生多级A/O工艺并进行中试研究,驯化出高效脱氮除磷菌剂并对系统进行生物强化。【方法】通过测定中试设备出水及污水处理厂出水化学需氧量(Chemical oxygen demand,COD)、氨氮(NH_4~+-N)、硝氮(NO_3~--N)、总氮(Total nitrogen,TN)、总磷(Total phosphorus,TP)对比分析两种工艺的污染物去除效能,利用高通量测序技术对比生物强化技术对系统微生物群落结构的影响。【结果】中试设备对COD、NH_4~+-N、NO_3~--N、TN、TP的去除效果均优于污水处理厂的处理工艺;驯化的低温好氧反硝化菌TN去除率最大值可达84.21%,驯化的低温反硝化聚磷菌群对磷的去除率最高可达85.75%;利用驯化菌群对中试设备进行生物强化后较好地改善了系统NH_4~+-N、NO_3~--N、TN、TP的去除效果;经生物强化后,具有好氧反硝化和反硝化聚磷功能的Pseudomonas菌群明显增多。【结论】泥膜共生多级A/O工艺对于低碳氮比生活污水的处理具有很好的效果,利用生物强化技术可有效提高低温条件下系统污染物去除效能。     

Operation performance and microbial community dynamics of phosphorus removal sludge with different electron acceptors

Operation performances of phosphorus removal sludge with different electron acceptors in three parallel SBRs were firstly compared in the present study, and the effect of post-aeration on denitrifying phosphorus removal was also studied. Moreover, community dynamics of different phosphorus removal sludge was systematically investigated with high-throughput sequencing for the first time. TP removal rates for nitrate-, nitrite-, and oxygen-based phosphorus removal sludge were 84.8, 78.5, and 87.4 %, with an average effluent TP concentration of 0.758, 0.931, and 0.632 mg/l. The average specific phosphorus release and uptake rates were 20.3, 10.8, and 21.5, and 9.43, 8.68, and 10.8 mgP/(gVSS h), respectively. Moreover, electron utilization efficiency of denitrifying phosphorus removal sludge with nitrate as electron acceptor was higher than nitrite, with P/e^? were 2.21 and 1.51 mol-P/mol-e^?, respectively. With the assistance of post-aeration for nitrate-based denitrifying phosphorus removal sludge, settling ability could be improved, with SVI decreased from 120 to 80 and 72 ml/g when post-aeration time was 0, 10, and 30 min, respectively. Moreover, further phosphorus removal could be achieved during post-aeration with increased aeration time. However, the anoxic phosphorus uptake was deteriorated, which was likely a result of shifted microbial community structure. Post-aeration of approximately 10 min was proposed for denitrifying phosphorus removal. Nitrate- and nitrite-based denitrifying phosphorus removal sludge exhibited similar community structure. More phosphorus accumulating organisms were enriched under anaerobic–aerobic conditions, while anaerobic–anoxic conditions were favorable for suppressing glycogen-accumulating organisms. Significant differences in pathogenic bacterial community profiles revealed in the current study indicated the potential public health hazards of non-aeration activated sludge system.     

Simultaneous nitrification, denitrification, and phosphorus removal from nutrient-rich industrial wastewater using granular sludge

The biological removal of nitrogen and phosphorus from nutrient-rich abattoir wastewater using granular sludge has been investigated. A lab-scale sequencing batch reactor, seeded with granular sludge developed using synthetic wastewater, was operated for 13 months under alternating anaerobic and aerobic conditions. It is demonstrated that the granules could be sustained and indeed further developed with the use of abattoir wastewater. The organic, nitrogen, and phosphorus loading rates applied were 2.7 gCOD L(-1) day(-1), 0.43 gN L(-1) day(-1), and 0.06 gP L(-1) day(-1), respectively. The removal efficiency of soluble COD, soluble nitrogen and soluble phosphorus were 85%, 93%, and 89%, respectively. However, the high suspended solids in the effluent limited the overall removal efficiency to 68%, 86%, and 74% for total COD, TN, and TP, respectively. This good nutrient removal was achieved through the process known as simultaneous nitrification, denitrification, and phosphorus removal, likely facilitated by the presence of large anoxic zones in the center of the granules. The removal of nitrogen was likely via nitrite optimizing the use of the limited COD available in the wastewater. Accumulibacter spp. were found to be responsible for most of the denitrification, further reducing the COD requirement for nitrogen and phosphorus removal. Mineral precipitation was evaluated and was not found to significantly contribute to the overall nutrient removal. It is also shown that the minimum HRT in a granular sludge system is not governed by the sludge settleability, as is the case with floccular sludge systems, but likely by the limitations associated with the transfer of substrates in granules.     

Free nitrous acid (FNA) inhibition on denitrifying poly-phosphate accumulating organisms (DPAOs)

Free nitrous acid (FNA) has been identified to be a ubiquitous inhibitor of a wide range of microorganisms, including bacteria involved in wastewater treatment. The FNA-induced inhibition on the anoxic (nitrite as electron acceptor) metabolism of denitrifying poly-phosphate accumulating organisms (DPAOs) was investigated using sludge from a sequencing batch reactor performing carbon, nitrogen, and phosphorus removal from synthetic wastewater. We found that FNA had a much stronger inhibitory effect on phosphorus (P) uptake and glycogen production than on poly-β-hydroxyalkanoate degradation and nitrite reduction. The intracellular adenosine triphosphate levels decreased sharply during the FNA incubation, and the decreasing rates were positively correlated with increasing FNA concentrations. The electron transport activity of DPAOs when exposed to FNA displayed a similar trend. Further, at FNA concentrations above 0.044 mg HNO₂-N/L, the anaerobic metabolism of DPAOs was initiated despite of the presence of nitrite, as evidenced by the release of phosphorus and the consumption of glycogen. DPAO metabolism did not recover completely from FNA inhibition in the subsequent FNA-free environment. The recovery rate depended on the concentration of FNA applied in the previous anoxic period. These results suggest that the inhibitory effects are diverse and may be attributable to different mechanisms operating simultaneously.     

A metabolic model for biological phosphorus removal by denitrifying organisms

A metabolic model for biological phosphorus removal under denitrifying conditions has been established. The model is based on previous work with aerobic phosphorus removal. The form of the kinetic equations used is the same as for the aerobic model. The main difference is the value of P/NADH(2) ratio in the electron transport phosphorylation with nitrate (delta(N)). This value was determined independently from batch tests with an enriched culture of denitrifying phosphorus-removing bacteria. The measured delta(N) was approximately 1.0 mol ATP/mol NADH(2). This indicates that the energy production efficiency with nitrate compared to oxygen is approximately 40% lower. These batch tests were also used to identify a proper set of kinetic parameters. The obtained model was subsequently applied for the simulation of cyclic behavior in an anaerobic-anoxic sequencing batch reactor at different biomass retention times. The simulation results showed that the metabolic model can be used successfully for the denitrifying dephosphatation process. The obtained kinetic parameters for denitrifying enrichment cultures, however, deviated from those obtained for the aerobic enrichment cultures. (c) 1996 John Wiley & Sons, Inc.     

An integrated metabolic model for the aerobic and denitrifying biological phosphorus removal

In this work, an integrated metabolic model for biological phosphorus removal is presented. Using a previously proposed mathematical model it was shown to be possible to describe the two known biological phosphorus removal processes, under aerobic and denitrifying conditions, with the same biochemical reactions, where only the difference in electron acceptor (oxygen and nitrate) is taken into account. Though, apart from the ATP/NADH ratio, the stoichiometry in those models is identical, different kinetic parameters were found. Therefore, a new kinetic structure is proposed that adequately describes phosphorus removal under denitrifying and aerobic conditions with the same kinetic equations and parameters. The ATP/NADH ratio (delta) is the only model parameter that is different for aerobic and denitrifying growth. With the new model, simulations of anaerobic/aerobic and anaerobic/denitrifying sequencing batch reactors (A(2) SBR and A/O SBR) were made for verification of the model. Not only short-term behavior, but also steady state, was simulated. The results showed very good agreement between model predictions and experimental results for a wide range of dynamic conditions and sludge retention times. Sensitivity analysis shows the influence of the model parameters and the feed substrate concentrations on both systems. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 54: 434-450, 1997.     

Simultaneous nitrogen and carbon removal in a packed A/O reactor: effect of C/N ratio on microbial community structure

In this research, a novel packed anoxic/oxic moving bed biofilm reactor (MBBR) was established to achieve high-organic matter removal rates, despite the carbon/nitrogen (C/N) ratio of 2.7–5.1 in the influent. Simultaneous nitrification–denitrification (SND) was investigated under a long sludge retention time of 104 days. The system exhibited excellent performance in pollutant removal, with chemical oxygen demand and total nitrogen (TN) enhanced to 93.6–97.4% and 34.4–60%, respectively. Under low C/N conditions, the nitrogen removal process of A/O MBBR system was mainly achieved by anaerobic denitrification. The increase of C/N ratio enhanced SND rate of the aerobic section, where dissolved oxygen was maintained at the range of 4–6 mg/L, and resulted in higher TN removal efficiency. The microbial composition and structures were analyzed utilizing the MiSeq Illumina sequencing technique. High-throughput pyrosequencing results indicated that the dominant microorganisms were Proteobacteria and Bacteroidetes at the phylum level, which contributes to the removal of organics matters. In the aerobic section, abundances of Nitrospirae (1.12–29.33%), Burkholderiales (2.15–21.38%), and Sphingobacteriales (2.92–11.67%) rose with increasing C/N ratio in the influent, this proved that SND did occur in the aerobic zone. As the C/N ratio of influent increased, the SND phenomenon in the aerobic zone of the system is the main mechanism for greatly improving the removal rate of TN in the aerobic section. The C/N ratio in the aerobic zone is not required to be high to exhibit good TN removal performance. When C/NH₄⁺ and C/TN in the aerobic zone were higher than 2.29 and 1.77, respectively, TN removal efficiency was higher than 60%, which means that carbon sources added to the reactor could be saved. This study would be vital for a better understanding of microbial structures within a packed A/O MBBR and the development of cost-efficient strategies for the treatment of low C/N wastewater.

     

反硝化聚磷菌及其脱氮除磷机理研究进展

水体富营养化是当前水环境保护工作的重点关注问题,微生物修复富营养化水体具有高效、低耗且不产生二次污染等特点,已经成为富营养化水体生态修复的一种重要方式。近年来,对反硝化聚磷菌的研究及其在污水处理工艺中的应用越来越广泛。不同于传统的反硝化细菌联合聚磷菌去除氮磷工艺,反硝化聚磷菌在交替厌氧、缺氧/好氧条件下能同时进行脱氮除磷而被广泛关注与研究。值得注意的是,近几年报道的部分微生物仅在好氧条件下就可进行同时脱氮除磷,但是其脱氮除磷机理仍未理清。基于此,文中总结了目前发现的反硝化聚磷菌和同时硝化反硝化聚磷微生物的种类及特点,并对其脱氮与除磷的关系及其机理进行了系统性分析,对目前反硝化除磷存在的问题进行了梳理,最后对今后的研究方向进行了展望,以期为完善反硝化聚磷菌的脱氮除磷机理及工艺改进提供参考。     

Effects of acetate and nitrite addition on fraction of denitrifying phosphate-accumulating organisms and nutrient removal efficiency in anaerobic/aerobic/anoxic process

The effects of acetate and nitrite on the performance of sequencing batch reactors (SBRs) employing an anaerobic/aerobic/anoxic (AOA) process were investigated. Three types of SBR operations were used: sodium acetate addition at the start of anoxic condition for heterotrophic denitrification (Type 1); sodium acetate addition at the start of aerobic condition for anoxic phosphate removal by denitrifying phosphate-accumulating organisms (DNPAOs) (Type 2: conventional AOA process); and nitrite addition at the start of aerobic condition for inhibition of phosphate-accumulating organisms (PAOs) (Type 3). A track experiment shows that Type 2 led to the best performance of SBRs among the three types. An analysis by fluorescence in situ hybridization (FISH) revealed that nitrite addition decreased the ratio of PAOs with a decrease in phosphorus removal efficiency. The fraction of DNPAOs in Type 2 was the highest at 13%, indicating that Type 2 is suitable for the simultaneous nitrogen and phosphorus removal in the AOA process.     

亚硝酸盐对污水生物除磷影响的研究进展

亚硝酸盐作为生物硝化和反硝化的中间产物, 存在于污水生物脱氮除磷系统中。对于生物强化除磷工艺亚硝酸盐既是电子受体用于反硝化除磷, 同时又是抑制剂影响生物除磷过程。本文综述了聚磷菌在厌氧、好氧和缺氧环境中的代谢机理, 在此基础上分别从好氧除磷和反硝化除磷两方面介绍了亚硝酸盐对污水生物除磷影响的研究, 同时概述了亚硝酸盐对生物除磷的抑制机理, 并对该领域的研究提出了个人见解。     

Effect of prefermentation on denitrifying phosphorus removal in slaughterhouse wastewater

An anaerobic-anoxic sequencing batch reactor (A2 SBR) coupled with a fixed-bed nitrification reactor for simultaneous carbon, nitrogen and phosphorus removal was evaluated using slaughterhouse wastewater. Whereas the treatment could not be successfully carried out on the raw wastewater, the process showed very good nutrient removal performances after prefermentation. The removals of COD, N-NH4 and P-PO4 achieved were 99%, 85% and 99%, respectively. The increase in volatile fatty acid (VFA) and phosphate concentrations in the effluent after prefermentation may explain the high levels of biological carbon, nitrogen and phosphorus removal observed. A simple prefermentation is, therefore, necessary but sufficient to ensure good performances of the denitrifying enhanced biological phosphorus removal (EBPR) process.