Enhanced biological nutrients removal using an integrated oxidation ditch with vertical circle from wastewater by adding an anaerobic column

Compared to conventional oxidation ditches, an integrated oxidation ditch with vertical circle （IODVC） has the characters of concise configuration, simple operation and maintenance, land saving and automatical sludge returning. By the utilization of vertical circulation, an aerobic zone and an anoxic zone can be unaffectedly formed in the IODVC. Therefore, COD and nitrogen can be efficiently removed. However, the removal efficiency of phosphorus was low in the IODVC. In the experiment described, a laboratory scale system to add an anaerobic column to the IODVC has been tested to investigate the removal of phosphorus from wastewater. The experimental results showed that the removal efficiency of TP with the anaerobic column was increased to 54.0% from 22.3% without the anaerobic column. After the acetic sodium was added into the influent as carbon sources, the mean TP removal efficency of 77. 5 % was obtained. At the same time, the mean removal efficiencies of COD, TN and NH3-N were 92.2%, 81.6% and 98.1%, respectively, at 12 h of HRT and 21-25 d of SRT. The optimal operational conditions in this study were as follows： recycle rate = 1.5-2.0, COD/TN 〉 6, COD/TP 〉 40, COD loading rate = 0.26-0.32 kgCOD/（kgSS· d）, TN loading rate = 0. 028-0. 034 kgTN/（ kgSS·d） and TP loading rate = 0.003-0.005 kgTP/（kgSS· d）, respectively.

Performance evaluation of a modified step-feed anaerobic/anoxic/oxic process for organic and nutrient removal

A pilot scale modified step-feed process was improved to increase nutrient(N and P)and organic removal operations from municipal wastewater.It combined the step-feed process and a method named "University of Cape Town(UCT)".The effect of nutrient ratios and inflow distribution ratios were studied.The highest uptake efficiency of 95% for chemical oxygen demand(COD)has been achieved at the inflow distribution ratio of 40/35/25.However,maximum removal efficiency obtained for total nitrogen(TN)and phosphorus at 93% and 78%,respectively.The average mixed liquor suspended solids(MLSS)was 5500 mg·L^(-1).In addition,convenient values for dissolved oxygen(DO)concentration,and p H were obtained throughout different stages.The proposed system was identified to be an appropriate enhanced biological nutrient removal process for wastewater treatment plants owing to relatively high nutrient removal,sturdy sludge settle ability and COD removal.

Fluidized-Bed Bioreactor Applications for Biological Wastewater Treatment： A Review of Research and Developments

污水处理是保护环境和人类健康的重要过程。目前,最经济有效的污水处理方法为生物处理法,如运行时间较长的活性污泥法。然而,随着人口的增长,对新型高效污水处理技术的需求越来越迫切,流态化技术虽然已展示出能够提高许多化学与生化处理过程的效率,但尚未在大型污水处理过程中得到广泛的应用。循环流化床生物反应器(CFBBR)污水处理技术的研究始于加拿大西安大略大学,在该技术中,载体颗粒表面会形成一层含细菌与其他微生物的生物膜,并在反应器中呈流化状态;流态化固有的良好混合和质量传递特性,使得该技术在生活污水和工业污水处理过程中均具优势。实验室阶段和中试阶段的研究均证实了CFBBR可去除污水中90%以上的碳源、80%以上的氮源,且污泥产量少于活性污泥法的1/3。由于该技术的高效性,CFBBR还可被用于传统方法难以处理的高有机碳污水处理,且具有占地面积小的优势。同时,CFBBR在动态负荷试验(进水量和进水浓度变化)中也展现了良好的抗冲击和恢复性能。总的来说,CFBBR是一种高效的污水处理方法,可在较短的水力停留时间和较小的反应器体积内处理更多的污水。此外,该反应器的紧凑设计将有助于在偏僻地区建造独立的污水处理系统。

Biological nutrient removal by internal circulation upflow sludge blanket reactor after landfill leachate pretreatment

The removal of biological nutrient from mature landfill leachate with a high nitrogen load by an internal circulation upflow sludge blanket （ICUSB） reactor was studied. The reactor is a set of anaerobic-anoxic-aerobic （A^2/O） bioreactors, developed on the basis of an expended granular sludge blanket （EGSB）, granular sequencing batch reactor （GSBR） and intermittent cycle extended aeration system （ICEAS）. Leachate was subjected to stripping by agitation process and poly ferric sulfate coagulation as a pretreatment process, in order to reduce both ammonia toxicity to microorganisms and the organic contents. The reactor was operated under three different operating systems, consisting of recycling sludge with air （A^2/O）, recycling sludge without air （low oxygen） and a combination of both （A^2/O and low oxygen）. The lowest effluent nutrient levels were realised by the combined system of A^2/O and low oxygen, which resulted in effluent of chemical oxygen demand （COD）, NH3-N and biological oxygen demand （BOD5） concentrations of 98.20, 13.50 and 22.50 mg/L. The optimal operating conditions for the efficient removal of biological nutrient using the ICUSB reactor were examined to evaluate the influence of the parameters on its performance. The results showed that average removal efflciencies of COD and NH3- N of 96.49% and 99.39%, respectively were achieved under the condition of a hydraulic retention time of 12 hr, including 4 hr of pumping air into the reactor, with dissolved oxygen at an rate of 4 mg/L and an upflow velocity 2 m/hr. These combined processes were successfully employed and effectively decreased pollutant loading.

污水生化处理工艺发展阶段化技术特征及未来趋势

百余年来,伴随人类社会和科技日新月异,污水生化处理技术也在实现快速发展与不断迭代,新工艺与新反应器、新功能微生物与新生化代谢途径不断被提出、发现和解析,并进一步推动了污水处理技术的进步与升级。回顾了过去百余年污水生化处理技术发展历程,就典型污水生化工艺,结合技术研发进展、技术成熟度及案例应用情况,给出了不同生化处理工艺代际划分与技术发展期“S曲线”,分析了近些年来新涌现出的一些革新性污水生化处理工艺的技术原理、技术特征,结合实际案例分析了工艺技术特征、技术优势与总体效能,从工艺强化、绿色低碳与集约高效等方面总结了未来污水处理发展的技术趋势,以期为“双碳背景”下排水系统提质增效工作、未来国内前瞻性污水厂工艺设计与运行提供参考和借鉴。

Operation of three parallel AN/AO processes to enrich denitrifying phosphorus removing bacteria for low strength wastewater treatment

Three parallel anaerobic-anoxic/anaerobic-aerobic （AN/AO） processes were developed to enrich denitrifying phosphorus removal bacteria （DPB） for low strength wastewater treatment. The main body of the parallel AN/AO process consists of an AN （anaerobic-anoxic） process and an AO （anaerobic-aerobic） process. In the AO process, the common phosphorus accumulating organisms （PAOs） was dominate, while in the AN process, DPB was dominate, The volume of anaerobic zone（Vana）：anoxie zone（Vano） ： aerobic zone （Vaer） for the parallel AN/AO process is 1：1：1 in contrast with a Vana：Vaer and Vano：Vaer of 1：2 and 1：4 for a traditional biological nutrient removal process （BNR）. Process 3 excels in the 3 processes on the basis of COD, TN and TP removal. For 4 month operation, the effluent COD concentration of process 3 did not exceed 60 mg/L; the effluent TN concentration of process 3 was lower than 15 mg/L; and the effluent TP concentration of process 3 was lower than 1 mg/L.

Enhanced biological phosphorus removal using thermal alkaline hydrolyzed municipal wastewater biosolids

This study reports the feasibility of using municipal wastewater biosolids as an alternative carbon source for biological phosphorus removal.The biosolids were treated by a lowtemperature,thermal alkaline hydrolysis process patented by Lystek International Inc.(Cambridge,ON,Canada)to produce short-chain volatile fatty acids and other readily biodegradable organics.Two sequencing batch reactors(SBRs)were operated with synthetic volatile fatty acids(Syn VFA)and readily biodegradable organics produced from the alkaline hydrolysis of municipal wastewater biosolids(Lystek)as the carbon source,respectively.Municipal wastewaters with different strengths and COD:N:P ratios were tested in the study.The reactors’performances were compared with respect to nitrogen and phosphorus removal.It was observed that phosphorus removal efficiencies were between 98%–99%and 90%–97%and nitrogen removal efficiencies were 78%–81%,and 67%for the Syn VFA and Lystek,respectively.However,the kinetics for phosphorus release and uptake during the anaerobic and aerobic stages with Lystek were observed to be significantly lower than Syn VFA due to the presence of higher order VFAs(C4 and above)and other fermentable organics in the Lystek.

N2O emission from a sequencing batch reactor for biological N and P removal from wastewater

Nitrous oxide （N2O） is a greenhouse gas that can be released during biological nitrogen removal from wastewater. N2O emission from a sequencing batch reactor （SBR） for biological nitrogen and phosphorus removal from wastewater was investigated, and the aims were to examine which process, nitrification or denitrification, would contribute more to N2Oemission and to study the effects of heterotrophic activities on N2O emission during nitrification. The results showed that N2O emission was mainly attributed to nitrification rather than to denitrification. N2O emission during denitrification mainly occurred with stored organic carbon as the electron donor. During nitrification, NaO emission was increased with increasing initial ammonium or nitrite concentrations. The ratio of N2O emission to the removed ammonium nitrogen （N2O- N/NH4-N） was 2.5% in the SBR system with high heterotrophic activities, while this ratio was in the range from 0.14% to 1.06% in batch nitrification experiments with limited heterotrophic activities.

典型BNR工艺污泥中温和高温厌氧消化特征对比

针对我国城市污水处理厂生物营养物去除(BNR)工艺目前产生的大量污泥,以典型BNR工艺氧化沟和A/A/O工艺产生的污泥为研究对象,考察中温[(36±1)℃]和高温[(52±1)℃]厌氧消化时BNR工艺污泥的水解、产气及减量特征。结果表明,在中温和高温厌氧消化条件下,氧化沟工艺污泥的最大比产甲烷速率(R_(max))和最大产甲烷潜力(P_(0))均明显低于A/A/O工艺污泥,且其消化时间更长。此外,高温厌氧消化大幅提高了BNR工艺污泥的R_(max)和P_(0),并缩短了消化时长,如高温下氧化沟工艺污泥的R_(max)、P_(0)和消化时长分别为中温下的2.47倍、1.33倍和53.8%。高温厌氧消化可明显提高BNR工艺污泥的有机物降解率,可满足《城镇污水处理厂污泥处理处置污染防治最佳可行技术指南(试行)》(HJ—BAT—002)对污泥中有机物降解率的要求。

折流式A^(2)O-MBR工艺启动过程及影响因素研究

针对MBR工艺的改进和优化,构建了小试规模的折流式A^(2)O-MBR工艺装置,将好氧池分为第一好氧池(O_(1))和第二好氧池(O_(2)),考察了溶解氧(DO)和水力停留时间(HRT)对处理性能的影响。进水COD、NH4+-N和PO_(4)^(3-)-P分别为400 mg/L、50 mg/L和5 mg/L。在HRT分别为24 h和12 h条件下,COD、NH4+-N和TN的去除效果保持稳定,平均去除率为90.2%、99.4%、84.8%,平均出水分别为38.1 mg/L、0.3 mg/L和7.6 mg/L。除磷性能受好氧区DO影响较大,将O_(1)池DO浓度从6 mg/L下降至3.5 mg/L,除磷效果明显改善,PO_(4)^(3-)-P去除率从45.0%提高至79.5%;在HRT缩短至12 h后,除磷效果保持稳定,出水平均浓度保持在1.0 mg/L。适当降低DO浓度、缩短HRT可避免聚磷菌体内PHB等内碳源过度消耗,有利于除磷效果的改善。

Simulation of long-term nutrient removal in a full-scale closed-loop bioreactor for sewage treatment： an example of Bayesian inference

In this study, the performance of nitrogen and phosphorus removal in a full-scale closed-loop bioreactor （oxidation ditch） system was simulated using the ASM2d model. Routine data describing the process for two years were compiled for calibration and validation. To overcome the identifiability problem, the classic Bayesian inference approach was utilized for parameter estimation. The calibrated model could describe the long-term trend of nutrient removal and short-term variations of the process performance, showing that the Bayesian method was a reliable and useful tool for the parameter estimation of the activated sludge models. The anoxic phosphate uptake by polyphosphate accumulating organisms （PAO） contributed 71.2% of the total Poly-P storage, which reveals the dominance of denitrifying phosphorus removal process under the oxygen limiting conditions. It was found that 58.7% of the anoxic Poly-P storage and denitrification by PAO in the reactor was achieved in the aerated compartment, implying that the PAO＇s anoxic activity was significantly stimulated by the low dissolved oxygen （DO） level in this compartment due to the oxygen gradient caused by brush aerator.

Study on the effect of landfill leachate on nutrient removal from municipal wastewater

In this study, landfill leachate with and without pre-treatment was co-treated with municipal wastewater at different mixing ratios. The leachate pre-treatment was achieved by air stripping to removal ammonia. The objective of this study was to investigate the effect of landfill leachate on nutrient removal of the wastewater treatment process. It was demonstrated that when landfill leachate was co-treated with municipal wastewater, the high ammonia concentration in the leachate did not have a negative impact on the nitrification. The system was able to adapt to the environment and was able to improve nitrification capacity. The readily biodegradable portion of chemical oxygen demand（COD）in the leachate was utilized by the system to improve phosphorus and nitrate removal.However, this portion was small and majority of the COD ended up in the effluent thereby decreased the quality of the effluent. The study showed that the 2.5% mixing ratio of leachate with wastewater improved the overall biological nutrient removal process of the system without compromising the COD removal efficiency.

新型废水生物脱氮的微生物学研究进展

生物脱氮是含氮废水处理公认的最佳处理方式,随着对生物脱氮微生物学原理研究的不断深入,许多新的生物脱氮特殊菌株或菌群及微生物转化机制不断被发现.本文在传统生物脱氮过程机理上,结合最近国内外生物脱氮的新发现,就短程硝化反硝化、同时硝化反硝化、厌氧氨氧化的微生物学原理进行了阐述.

污泥龄对A/A/O工艺反硝化除磷的影响

以实际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,进行了污泥龄(SRT)为8、10、12和15 d时对反硝化除磷的影响研究.结果表明,随着污泥龄的延长,反硝化除磷对系统除磷所起的作用越大,反硝化聚磷菌缺氧利用单位PHAs的反硝化数量和吸磷量也迅速增加,聚磷菌好氧利用单位PHAs的吸磷量并没有受到影响,以SRT为12 d时反硝化除磷和系统脱氮除磷效果为最好.结果还表明,去除单位氮所需COD数量随污泥龄的延长呈减少趋势,而去除单位磷所需COD数量呈增大趋势.对于我国典型的城市污水而言,SRT为12 d和15 d时去除单位氮和磷所需的外碳源数量较8 d时要低,从而使反硝化除磷作用可真正地达到节省碳源和能源的目的.

A^2O工艺处理低C/N比生活污水的试验研究

采用52.5L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8h、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20mg·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。

连续流分段进水生物脱氮工艺研究进展

连续流分段进水生物脱氮工艺（C SF B N R）是一种串联多个缺氧和好氧区域,充分利用污水中有机碳源进行有效脱氮的污水处理技术。介绍了C SF B N R的原理,重点分析了分段数量、进水流量分配比例、缺氧区和好氧区容积比、污泥回流比和进水C O D/T N等对工艺的影响。增大C SF B N R的分段数量、污泥回流比和容积比可以提高脱氮率,适宜的分段数、容积比和污泥回流比分别是2～4、1：4～1：1和75%～1 00%。优化后的C SF B N R处理C/N低至5的污水可以达到国家一级A排放标准。通过工程应用实例,证实了C SF B N R的脱氮率高于传统生物脱氮工艺。

电子受体亚硝酸氮在反硝化除磷过程中的作用

针对先前文献提到的亚硝酸氮在反硝化除磷中存在着一定的抑制作用,以亚硝酸氮作为电子受体,对其在缺氧反硝化吸磷过程中的抑制影响进行了大量的静态烧杯试验.结果表明,在亚硝酸氮浓度大于30mg·L-1的时候,确实存在严重的抑制作用,而且该临界抑制浓度与污泥的特性和运行操作条件等因素有关;但是在亚硝酸氮浓度低于25mg·L-1的情况下不会对反硝化条件下磷的吸收产生毒害作用,相反地,它可以取代氧气、硝酸氮做为良好的电子受体用来进行缺氧段磷的生物摄取,在反硝化除磷中表现一定的积极作用.

传统生物除磷脱氮工艺和反硝化除磷工艺对比

介绍了传统生物除磷脱氮和反硝化除磷的机理,比较了几个有代表性的传统除磷脱氮工艺和反硝化除磷工艺。通过分析认为反硝化除磷菌(DPB)能够以硝态氮为电子受体,从而大大节省耗氧量,缓解常规工艺对外加碳源的需求。如何在不增加工艺流程复杂性的同时,在工艺中充分富集DPB是反硝化除磷的关键。

A^2/O污水处理工艺中基质转化机理研究

以实际污水培养驯化污泥的小试规模A2/O工艺为研究对象,对系统中基质的转化机理及硝态氮对基质转化的影响进行了批式试验研究.结果表明,在无硝态氮存在于厌氧环境的系统中,厌氧段消耗的COD有51%可被聚磷菌吸收并合成为聚羟基链烷酸(PHAs);缺氧和好氧条件下的比吸磷速率为3.87和6.54 mg/(g.h),利用单位PHAs的吸磷量(rP/PHA)分别为0.38和0.78.而在有硝态氮存在于厌氧环境的系统中,厌氧段消耗的COD仅有30.8%可被聚磷菌吸收并合成PHAs,61.5%用于还原硝态氮;缺氧和好氧条件下的比吸磷速率为2.24和4.58 mg/(g.h),rP/PHA值分别为0.35和0.77.同时,在这2个系统中厌氧阶段释放的磷和消耗的COD成良好的线性关系.硝态氮存在于厌氧环境会降低聚磷菌的厌氧释磷速率和效率,使PHAs的合成量减少,从而降低聚磷菌的缺氧和好氧吸磷速率,但并不会影响其吸磷能力.