反硝化聚磷菌的培养富集及处理生活污水的稳定运行

在厌氧-好氧交替运行的序批式反应器(sequencing batch reactor, SBR)中,以C/P比大于50的实际生活污水为进水,成功驯化富集聚磷菌,平均厌氧释磷量为15 mg·L~(-1),出水PO_4~(3-)-P浓度稳定小于0.5 mg·L~(-1)。在系统运行的第74 d调整运行模式为厌氧-缺氧-好氧,在缺氧开始时短期投加NO_3~--N配水以驯化培养反硝化聚磷菌。保持系统内NO_3~--N浓度不变,在进水COD浓度为250 mg·L~(-1)时,反硝化除磷效果最佳,平均反硝化除磷量占除磷量的比为87.1%。不同pH下反硝化除磷速率的小试证明,在pH=7.0时得到最大的比吸磷速率2.1 mg P·(g VSS·h)~(-1)。此时调整NO_3~--N进水为另一个全程硝化反应器的出水,并加大排水比增加缺氧初的进水量使得反应器内缺氧时的pH接近7.0,与未改变pH时对比表明前者在缺氧段反硝化除磷速率加快。反应器共运行160 d,稳定完成COD的去除与反硝化除磷过程。     

A~2/O工艺反硝化除磷试验研究

在A2/O工艺中,通过调节混合液回流比,实现了反硝化除磷菌的富集。COD和氨氮的平均去除率分别为85%和95.6%,达到稳定除磷效果时,磷酸盐的平均去除率为82.9%。缺氧段吸磷量所占比例从27.4%增至65.7%,反应后期平均比值为62.6%。污泥特性实验表明最大缺氧吸磷速率为5.79 mgP/(gMLSS.h),最大好氧吸磷速率为9.29 mgP/(gMLSS.h),两者的比值为62.3%。     

强化生物除磷系统除磷性能分析

采用厌氧/好氧和厌氧/缺氧两阶段方法培养反硝化聚磷菌,研究了第一阶段系统的除磷性能。结果表明,稳定运行的强化生物除磷系统,具有良好的除磷性能,出水磷的质量浓度小于0.5 mg/L,除磷率大于93%。通过厌氧/好氧交替方式运行,反硝化聚磷菌占聚磷菌的比例约为21.2%。缺氧段硝酸盐的消耗量与磷的摄取量成线性关系,缺氧吸磷速率约为好氧吸磷速率的49.3%。     

混合液回流比对A/A/O工艺反硝化除磷的影响

以生活污水培养驯化污泥的小试规模A/A/O工艺为研究对象,进行了混合液回流比为100%、200%和300%时对反硝化除磷的影响研究,并利用厌氧/缺氧批式试验方法对污泥特性进行单独考察。结果表明,随着混合液回流比的增大,缺氧除磷在系统除磷所起的作用、反硝化聚磷菌缺氧利用单位聚羟基链烷酸（PHAs）的吸磷量和反硝化数量出现先升高后下降,厌氧合成单位PHAs的释磷量和好氧利用单位PHAs的吸磷量并没有受到影响,以200%时反硝化除磷和系统脱氮除磷效果为最好,过高或过低NO₃-N浓度均会影响反硝化聚磷菌的缺氧吸磷速率和PHAs降解速率,但并没有影响其本身所固有的特性。     

反硝化除磷菌富集试验研究

采用A2-SBR反应器对反硝化除磷菌进行富集研究,结果表明反硝化除磷菌存在于污水处理厂活性污泥中,通过厌氧／缺氧的强化交替运行,能使反硝化除磷菌得到富集。厌氧／好氧批实验结果表明,反硝化除磷菌能够利用氧气作为电子受体进行吸磷,其比吸磷速率高于缺氧比吸磷速率。     

电子受体和碳源对氧化沟活性污泥反硝化除磷的影响

研究了电子受体和碳源对活性污泥反硝化除磷的影响。亚硝酸盐和硝酸盐都可以作为电子受体在缺氧的条件下实现对磷的吸收,但其吸磷效率比氧低。较高的亚硝酸盐浓度会严重抑制污泥的活性,当一次加入NO2-质量浓度为46 mg/L时,反硝化吸收磷不能发生;而分4次加入(每次11.5 mg/L),吸磷量可达到19.5 mg/L。电子受体浓度为0.24 mmol/L时,吸收的P和加入的N的物质的量比:NO2-为1.7,NO3-为4.7。在低的碳源浓度下,碳源可以促进反硝化磷吸收;碳源浓度过高,系统形成厌氧环境,磷反而被释放。     

驯化后的聚糖菌对NO_2~--N和NO_3~--N内源反硝化速率的影响

在序批式(sequencing batch reactor,SBR)反应器中,通过分段厌氧-好氧(厌氧后排水)运行方式,在以葡萄糖为碳源、P/C比小于2/100的条件下,成功实现了聚糖菌(glycogen accumulating organisms,GAOs)的驯化富集,厌氧段磷酸盐的释放量(phosphorus release amounts,PRA)稳定在1.0 mg·L-1以内,胞内糖原(glycogen,gly)含量是初始阶段的1.2倍。驯化后的GAOs分别以NO_2~--N、NO_3~--N为电子受体经厌氧-缺氧运行方式,可进行内源反硝化反应过程。GAOs在内源反硝化过程中依次利用胞内的聚β-羟基戊酸酯(poly-β-hydroxyvalerate,PHV)、聚β-羟基丁酸酯(poly-β-hydroxyvalerate,PHB)和gly作为内碳源。在22℃时,反硝化聚糖菌(denitrifying glycogen accumulating organisms,DGAOs)以NO_2~--N、NO_3~--N为电子受体平均比内源反硝化速率分别为0.067 g N·(g VSS)-1·d-1、0.023 g N·(g VSS)-1·d-1,常温短程内源反硝化速率约是全程内源反硝化速率的3倍。     

强化生物除磷系统中聚磷菌菌群特性

为了研究强化除磷系统中聚磷菌(PAOs)菌群特性,通过批次试验分别考察了厌氧/好氧(A/O)污泥和厌氧/缺氧(A/A)污泥吸磷特性。试验结果表明:A/O污泥好氧吸磷速率(qPo)大于缺氧吸磷速率(qPa),而A/A污泥qPo却小于qPa。基于此试验结果可得出目前普遍应用qPa与qPo的比值表征反硝化聚磷菌(DPAOs)占PAOs的相对百分比的方法不合理。聚磷菌菌群构成与电子受体类型有关,根据电子受体类型可将PAOs分为三种,即:PON(既能以氧作为电子受体,也能以硝态氮作为电子受体)、PO(只能以氧作为电子受体)和PN(只能以硝态氮作为电子受体)。     

序批式活性污泥法反硝化聚磷菌的培养驯化研究

以某污水处理厂活性污泥作为种泥,采用序批式活性污泥法(SBR)进行反硝化聚磷菌(DPB)培养驯化研究。结果表明,经过厌氧-好氧,厌氧-换水-缺氧,厌氧-缺氧,厌氧-缺氧-短时曝气4个阶段培养驯化,系统出水效果良好:出水PO43--P的质量浓度稳定在0.5 mg.L-1以下,平均除磷率达96%;出水COD稳定在50 mg.L-1以下,平均去除率达77%。DPB占聚磷菌的比例约为65.02%。当投加不同含量的NO3--N时,硝酸盐的含量只影响吸磷速率而不影响吸磷量。当缺氧段DPB体内的PHB为限制因素时,缺氧吸磷过程在不同NO3--N含量下基本相同。     

A2O工艺处理低C/N比生活污水的试验研究

采用52.5 L的A²O试验装置处理实际生活污水,研究了A²O工艺在处理低C/N比生活污水时的脱氮除磷特性,并探讨了如何通过强化缺氧吸磷来提高系统的脱氮除磷效率。试验结果表明：在厌氧/缺氧/好氧体积比为1/1/2、HRT为8 h、污泥回流比为70%、内回流比为300%的工况下处理C/N为7.89的生活污水,TN和SOP去除率分别能够达到85.4%和93.3%,系统中存在反硝化除磷,缺氧吸磷占总吸磷量的25.3%。同样的运行条件下处理C/N为4.20的生活污水时,SOP去除几乎不受影响,但TN去除率降低至62.2%,平均出水TN浓度也超过20 mg•L^-1。维持厌氧区体积不变,增大缺氧区体积,使得缺氧/好氧体积比为5/8时,TN去除率可上升到70.7%,缺氧吸磷占总吸磷量的55.2%。同时改变内回流比的试验表明250%的内回流比能最大程度地强化反硝化除磷的作用,此时TN去除率可提高至77.3%。强化A²O工艺中的反硝化除磷,能克服碳源不足对脱氮除磷的影响,显著提高低C/N比污水的脱氮除磷效率。     

好氧聚磷污泥反硝化除磷特性研究

以培养成功的好氧聚磷污泥为研究对象,考察其在硝酸盐或亚硝酸盐存在下的反硝化除磷特性。结果表明,好氧聚磷污泥在在未经厌氧/缺氧驯化条件下已具有良好反硝化聚磷特性。好氧聚磷污泥可利用硝酸盐作为电子受体进行脱氮除磷,在硝酸盐耗尽后停止聚磷,在一定的浓度范围内聚磷量与硝酸盐消耗量具有线性关系。在以亚硝酸盐作为电子受体的条件下,好氧聚磷污泥与反硝化聚磷污泥具有相似特点:在初始亚硝酸盐浓度较低情况下可少量聚磷,在其浓度较高时聚磷受到抑制。亚硝酸盐有可能为解偶联剂,在其还原的过程中并不耦合发生聚磷。反硝化速率随着其硝酸盐或亚硝酸盐初始浓度的升高而降低。     

序批式反应器中反硝化除磷脱氮的研究

为了提高污水脱氮除磷的效率,研究采用序批式反应器(SBR工艺)厌氧、好氧和缺氧(AOA)的运行方式富集反硝化聚磷菌(DPB),实现同步脱氮除磷。结果表明:在好氧段投加甲醇作为碳源(25—40 mg/L)可有效抑制好氧吸磷,对硝化反应影响较小,能够在缺氧段实现同时反硝化脱氮除磷。SBR反应器稳定运行10个月,当进水NH4+-N、PO43--P分别为30,15 mg/L时,总氮(TN)和PO43--P的平均去除率分别为82.5%和92.1%。聚磷菌能够利用硝酸盐作为电子受体,DPB占总聚磷菌的比例达到44.8%。与A2O运行方式相比,AOA运行方式更有利于实现DPB的富集。     

Denitrifying phosphorus removal with nitrite by a real‐time step feed sequencing batch reactor

BACKGROUND: Nitrite is toxic to anoxic phosphorus uptake when it exceeds a threshold concentration. In this study, denitrifying phosphorus removal with nitrite as electron acceptor was investigated in a sequencing batch reactor (SBR) operated using a real‐time step feed strategy. RESULTS: The nitrite pulse concentration was initially determined by batch experiments. pH increased with use of nitrite for phosphate uptake, and decreased when the nitrite was used up. Nitrite was added promptly after the pH reached the peak value, and phosphate uptake continued, driven by the nitrite addition. The pH was adjusted to 7.50 using HCl with each pulse of nitrite addition. ORP could be used to determine the endpoint of denitrifiying phosphorus removal. However, the variation of second derivative of ORP with time was much more sensitive and should be a more suitable control parameter than ORP itself to determine the endpoint of denitrifying phosphorus removal. CONCLUSION: Compared with denitrifying phosphorus removal with nitrate as electron acceptor, denitrifying phosphorus removal with nitrite using real‐time step feed can save 22.3% of polyhydroxyalkanoate (PHA) for phosphorus removal and 49.4% of PHA for nitrogen removal. In addition, the reaction time could be shortened. Copyright © 2010 Society of Chemical Industry     

改进型分段进水厌氧/缺氧/好氧工艺强化营养物去除

In order to enhance phosphorus removal in traditional step-feed anoxic/oxic nitrogen removal process,a modified pilot-scale step-feed anaerobic/anoxic/oxic (SFA²/O) system was developed,which combined a reactor similar to UCT-type configuration and two-stage anoxic/oxic process.The simultaneous nitrogen and phosphorus removal capacities and the potential of denitrifying phosphorus removal,in particular,were investigated with four different feeding patterns using real municipal wastewater.The results showed that the feeding ratios(Q₁)in the first stage determined the nutrient removal performance in the SFA²/O system.The average phosphorus removal efficiency increased from 19.17% to 96.25% as Q₁ was gradually increased from run 1 to run 4,but the nitrogen removal efficiency exhibited a different tendency,which attained a maximum 73.61% in run 3 and then decreased to 59.62% in run 4.As a compromise between nitrogen and phosphorus removal,run 3 (Q₁=0.45Q_total) was identified as the optimal and stable case with the maximum anoxic phosphorus uptake rate of 1.58mg·(g MLSS)^-1·h^-1.The results of batch tests showed that ratio of the anoxic phosphate uptake capacity to the aerobic phosphate uptake capacity increased from 11.96% to 36.85% with the optimal influent feeding ratio to the system in run 3,which demonstrated that the denitrifying polyP accumulating organisms could be accumulated and contributed more to the total phosphorus removal by optimizing the inflow ratio distribution.However,the nitrate recirculation to anoxic zone and influent feeding ratios should be carefully controlled for carbon source saving.     

A2O工艺缺氧生物磷去除

A lab-scale anaerobic-anoxic-oxic (A2O) process used to treat a synthetic brewage wastewater was investigated. The objectives of the study were to identify the existence of denitrifying phosphorus removing bacteria (DPB), evaluate the contribution of DPB to biological nutrient removal and enhance the denitrifying phosphorus removal in A2O bioreactors. Sludge analysis confirmed that the average anoxic P uptake accounted for approximately 70% the total amount of P uptake, and the ratio of anoxic P uptake rate to aerobic P uptake rate was 69%. In addition, nitrate concentration in the anoxic phase and different organic substrate introduced into the anaerobic phase had significant effect on the anoxic P uptake. Compared with conventional A2O processes, good removal efficiencies of COD, phosphorus, ammonia and total nitrogen (92.3%, 95.5%, 96% and 79.5%, respectively) could be achieved in the anoxic P uptake system, and aeration energy consumption was saved 25%. By controlling the nitrate recirculation flow in the anoxic zone, anoxic P uptake could be enhanced, which solved the competition for organic substrates among poly-P organisms and denitrifiers successfully under the COD limiting conditions. Therefore, in wastewater treatment plants the control system should be applied according to the practical situation to optimize the operation.     

A2O工艺缺氧生物磷去除

A lab-scale anaerobic-anoxic-oxic （A^2O） process used to treat a synthetic brewage wastewater was investigated. The objectives of the study were to identify the existence of denitrifying phosphorus removing bacteria （DPB）, evaluate the contribution of DPB to biological nutrient removal and enhance the denitrifying phosphorus removal in A^2O bioreactors. Sludge analysis confirmed that the average anoxic P uptake accounted for approximately 70% the total amount of P uptake, and the ratio of anoxic P uptake rate to aerobic P uptake rate was 69%. In addition, nitrate concentration in the anoxic phase and different organic substrate introduced into the anaerobic phase had significant effect on the anoxic P uptake. Compared with conventional A^2O processes, good removal efficiencies of COD, phosphorus, ammonia and total nitrogen （92.3%, 95.5%, 96% and 79.5%, respectively） could be achieved in the anoxic P uptake system, and aeration energy consumption was saved 25%. By controlling the nitrate recirculation flow in the anoxic zone, anoxic P uptake could be enhanced, which solved the competition for organic substrates among poly-P organisms and denitrifiers successfully under the COD limiting conditions. Therefore, in wastewater treatment plants the control system should be applied according to the practical situation to optimize the operation.     

Identification and Metabolic Mechanism of Non-fermentative Short-cut Denitrifying Phosphorus-removing Bacteria

To investigate the characteristics and metabolic mechanism of short-cut denitrifying phosphorus-removing bacteria (SDPB) that are capable of enhanced biological phosphorus removal (EBPR) using nitrite as an electron acceptor, an aerobic/anoxic sequencing batch reactor was operated under three phases. An SDPB-strain YC was screened after the sludge enrichment and was identified by morphological, physiological, biochemical properties and 16S rDNA gene sequence analysis. Denitrifying phosphorus-removing experiments were conducted to study anaerobic and anoxic metabolic mechanisms by analyzing the changes of chemical oxygen demand (COD), phosphate, nitrite, poly-β-hydroxybutyrate (PHB), and glycogen. The results show that strain YC is a non-fermentative SDPB similar to Paracoccus denitrificans. As a kind of non-fermentative bacteria, the energy of strain YC was mainly generated from phosphorus release (96.2%) under anaerobic conditions with 0.32 mg P per mg synthesized PHB. Under anoxic conditions, strain YC accumulated 0.45 mg P per mg degraded PHB, which produced most of energy for phosphate accumulation (91.3%) and a little for glycogen synthesis (8.7%). This metabolic mechanism of strain YC is different from that of traditional phosphorus-accumulating organisms (PAOs). It is also found that PHB, a kind of intracellular polymer, plays a very important role in denitrifying and accumulating phosphorus by supplying sufficient energy for phosphorous accumulation and carbon sources for denitrification. Therefore, monitoring ΔP/ΔPHB and? ΔNO₂^--N/ΔPHB is more necessary than monitoring ΔP/ΔCOD,?ΔNO₂^--N/ΔCOD, or ΔNO₂^--N.