Nitrogen and phosphorus removal in pilot-scale anaerobic-anoxic oxidation ditch system

To achieve high efficiency of nitrogen and phosphorus removal and to investigate the rule of simultaneous nitrification and denitrification phosphorus removal （SNDPR）, a whole course of SNDPR damage and recovery was studied in a pilot-scale, anaerobicanoxic oxidation ditch （OD）, where the volumes of anaerobic zone, anoxic zone, and ditches zone of the OD system were 7, 21, and 280 L, respectively. The reactor was fed with municipal wastewater with a flow rate of 336 L/d. The concept of simultaneous nitrification and denitrification （SND） rate （rSND） was put forward to quantify SND. The results indicate that： （1） high nitrogen and phosphorus removal efficiencies were achieved during the stable SND phase, total nitrogen （TN） and total phosphate （TP） removal rates were 80% and 85%, respectively; （2） when the system was aerated excessively, the stability of SND was damaged, and rSND dropped from 80% to 20% or less; （3） the natural logarithm of the ratio of NOx to NH4^＋ in the effluent had a linear correlation to oxidation-reduction potential （ORP）; （4） when NO3^- was less than 6 mg/L, high phosphorus removal efficiency could be achieved; （5） denitrifying phosphorus removal （DNPR） could take place in the anaerobic-anoxic OD system. The major innovation was that the SND rate was devised and quantified.

Removal of nitrogen and phosphorus in a combined A^2/O-BAF system with a short aerobic SRT

A bench-scale anaerobic/anoxic/aerobic process-biological aerated filter （A^2/O-BAF） combined system was carded out to treat wastewater with lower C/N and C/P ratios. The A^2/O process was operated in a short aerobic sludge retention time （SRT） for organic pollutants and phosphorus removal, and denitrification. The subsequent BAF process was mainly used for nitrification. The BAF effluent was partially returned to anoxic zone of the A^2/O process to provide electron acceptors for denitrification and anoxic P uptake. This unique system formed an environment for reproducing the denitdfying phosphate-accumulating organisms （DPAOs）. The ratio of DPAOs to phosphorus accumulating organisms （PAOs） could be maintained at 28% by optimizing the organic loads in the anaerobic zone and the nitrate loads into the anoxic zone in the A^2/O process. The aerobic phosphorus over-uptake and discharge of excess activated sludge was the main mechanism of phosphorus removal in the combined system. The aerobic SRT of the A^2/O process should meet the demands for the development of aerobic PAOs and the restraint on the nitrifiers growth, and the contact time in the aerobic zone of the A^2/O process should be longer than 30 min, which ensured efficient phosphorus removal in the combined system. The adequate BAF effluent return rates should be controlled with 1--4 mg/L nitrate nitrogen in the anoxic zone effluent of A^2/O process to achieve the optimal nitrogen and phosphorus removal efficiencies.

Enhanced Nutrient Removal with Upflow Biological Aerated Filter for Reclaimed Water

A two-stage upflow biological aerated filter was designed as an advanced treatment process to optimize the operating parameters and study the correlative factors influencing the efficiency of nitrification, denitrification and phosphorus removal. The experimental results showed that the final effluent of the two-stage upflow biofilter process operated in series could meet the stringent limits of the reclaimed water for the total nitrogen of 2 mg/L, and total phosphorus of 0.3 mg/L. The high treatment efficiency allowed the reactor operating at very high hydraulic loadings and reaching nearly complete nitrification and denitrifieation.

Research on polyhydroxyalkanoates and glycogen transformations: Key aspects to biologic nitrogen and phosphorus removal in low dissolved oxygen systems

In this paper,a study was conducted on the effect of polyhydroxyalkanoates(PHA)and glycogen transformations on biologic nitrogen and phosphorus removal in low dissolved oxygen(DO)systems.Two laboratory-scale sequencing batch reactors(SBR1 and SBR2)were operating with anaerobic/aerobic(low DO,0.15-0.45 mg·L^(-1))configurations,which cultured a propionic to acetic acid ratio(molar carbon ratio)of 1.0 and 2.0,respectively.Fewer poly-3-hydroxybutyrate(PHB),total PHA,and glycogen transformations were observed with the increase of propionic/acetic acid,along with more poly-3-hydroxyvalerate(PHV)and poly-3-hydroxy-2-methyvalerate(PH2MV)shifts.The total nitrogen(TN)removal efficiency was 68%and 82%in SBR1 and SBR2,respectively.In the two SBRs,the soluble ortho-phosphate(SOP)removal efficiency was 94%and 99%,and the average sludge polyphosphate(poly-P)content(g·g-MLVSS^(-1))was 8.3%and 10.2%,respectively.Thus,the propionic to acetic acid ratio of the influent greatly influenced the PHA form and quantity,glycogen transformation,and poly-P contained in activated sludge and further determined TN and SOP removal efficiency.Moreover,significant correlations between the SOP removal rate and the(PHV+PH2MV)/PHA ratio were observed(R^(2)>0.99).Accordingly,PHA and glycogen transformations should be taken into account as key components for optimizing anaerobic/aerobic(low DO)biologic nitrogen and phosphorus removal systems.

城市污水生物脱氮提质增效技术现状与展望

随着国家和地方污水排放标准的提升,已建城市污水处理厂普遍面临提标改造的重要挑战,且出水总氮达标是提标改造任务的重点和难点。基于此,本文阐述了双碳时代下低碳氮比城市污水生物脱氮提质增效的技术路径,展望了未来研究方向。首先系统综述了城市污水厂强化生物脱氮效能的常规路径,立足深度挖掘原有生物处理工艺脱氮潜力和增设反硝化生物滤池深度处理工艺两个方面进行了总结;其次全面介绍了新型低碳自养生物脱氮工艺(如厌氧氨氧化、硫自养反硝化和铁自养反硝化)的研究进展和应用前景,为构建绿色、高效的自养生物脱氮系统以及异养-自养耦合深度脱氮系统提供理论依据与技术支撑;最后展望了未来城市污水生物脱氮的发展方向与趋势,通过与生物技术、材料技术和信息技术等多学科的交叉融合,推动污水生物脱氮领域的技术变革与科技创新。本文以期为城市污水脱氮的减污降碳协同增效提供参考。

A/A/O微曝氧化沟工艺提标改造效果分析

采用固定式填料对A/A/O微曝氧化沟工艺进行提标改造,可提升系统的脱氮除磷性能。在生化池固定式填料填充体积比为10%的条件下,出水COD、NH_(4)^(+)-N、TN及TP平均质量浓度分别为28.7、2.42、6.86和0.32 mg/L,满足GB 18918—2002《城镇污水处理厂污染物排放标准》一级A排放标准,且处理水量提升了17.43%。高通量测序结果表明,提标改造后在门水平优势菌群主要为绿湾菌门(Chloroflexi)、放线菌门(Actinobacteriota)及拟杆菌门(Bacteroidota),三者相对丰度之和大于60%,且Chloroflexi相对丰度大于30%。在属水平优势菌群为硝化菌属(norank_f_Saprospiraceae、Nitrospira、Mycobacterium)、反硝化菌属(Rhodoplanes)及聚磷菌属(Acinetobacter及Tetrasphaera)。固定式填料-泥膜复合A/A/O微曝氧化沟中填料生物膜有利于菌群结构优化和功能微生物的富集。

BDP(生物倍增)工艺应用于污水处理厂的提标改造

采用BDP(生物倍增)工艺对某污水处理厂进行提标扩建改造工程,工程运行结果表明,该工艺处理效果良好,出水水质稳定,抗冲击负荷能力强,其中COD、BOD5、NH_(3)-N和TP等污染物达到《地表水环境质量标准》(GB3838-2002)中的IV类水标准,TN和SS则满足《城镇污水处理厂污染物排放标准》(GB 18918-2002)中的一级A排放标准。工程实际运行费用为0.94元/m^(3),与国内同类工程相比有一定的运行成本优势。

多级AO+MBR工艺在污水处理厂高排放标准提标改造中的应用

由于排放标准的提高和进水水质的变化,河北省K污水处理厂需进行提标改造,改造后处理规模不变,出水水质满足《大清河流域水污染物排放标准》(DB 13/2795—2018)中的重点控制区排放限值。基于来水中含有部分工业废水、进水水质波动范围大、占地受限等因素,采用了多级AO生物池+膜生物反应器(MBR)工艺;通过对原工艺单元进行充分挖潜利旧,对原连续进水循环式活性污泥(CASS)出水池局部加高增加了总停留时间,改造后的处理工艺运行稳定,满足出水要求,达到提高后的排放标准[COD_(Cr)≤30 mg/L、氨氮≤1.5 mg/L(水温≤12℃时,氨氮≤2.5 mg/L)、总氮≤15 mg/L、总磷≤0.3 mg/L],可为高排放标准下的污水处理厂提标改造提供借鉴经验。

曝气生物滤池在高标准污水处理厂提标改造中的应用

江苏某市由于区域污染物排放总量的限制,当污水排放量增长后需降低污染物的排放浓度,该市某污水厂因此要进行提标改造,建设规模为1.7×10^(5)m^(3)/d,出水水质由一级A提高至地表“类Ⅲ类水标准”。文中总结了该污水厂提标的设计经验,设计采用“硝化+反硝化+滤布过滤+臭氧-生物活性炭(O_(3)-BAC)+超滤”处理工艺,脱氮处理构筑物采用曝气生物滤池,抗冲击负荷强,运行管理简单,滤池平均36~48 h反冲洗一次,硝化滤池各级出水设置导流板后,反硝化滤池进水溶解氧质量浓度可稳定在4~6 mg/L。单位用地面积为0.15 m^(2)/(m^(3)·d^(-1))。根据2020年—2021年的运行数据,当进水COD_(Cr)、BOD5、SS、氨氮、TN、TP质量浓度为12~26、3.8~7.1、1~6、0.22~2.22、5.34~11.60、0.15~0.40 mg/L时,各污染物平均去除率分别为29%、23%、44%、57%、52%、68%,通过该工艺处理后出水水质稳定达标,为未来污水厂更严格的排放标准提供了升级提标工艺思路和经验借鉴。

Advanced nitrogen and phosphorus removal in A^(2)O-BAF system treating low carbon-to-nitrogen ratio domestic wastewater

A laboratory-scale anaerobic-anoxic-aerobic process(A^(2)O)with a small aerobic zone and a bigger anoxic zone and biologic aerated filter(A^(2)O-BAF)system was operated to treat low carbon-to-nitrogen ratio domestic wastewater.The A^(2)O process was employed mainly for organic matter and phosphorus removal,and for denitrification.The BAF was only used for nitrification which coupled with a settling tank Compared with a conventional A^(2)O process,the suspended activated sludge in this A^(2)OBAF process contained small quantities of nitrifier,but nitrification overwhelmingly conducted in BAF.So the system successfully avoided the contradiction in sludge retention time(SRT)between nitrifying bacteria and phosphorus accumulating organisms(PAOs).Denitrifying phosphorus accumulating organisms(DPAOs)played an important role in removing up to 91%of phosphorus along with nitrogen,which indicated that the suspended activated sludge process presented a good denitrifying phosphorus removal performance.The average removal efficiency of chemical oxygen demand(COD),total nitrogen(TN),total phosphorus(TP),and NH_(4)^(+)-N were 85.56%,92.07%,81.24%and 98.7%respectively.The effluent quality consistently satisfied the national first level A effluent discharge standard of China.The average sludge volume index(SVI)was 85.4 mL·g^(-1)additionally,the volume ratio of anaerobic,anoxic and aerobic zone in A^(2)O process was also investigated,and the results demonstrated that the optimum value was 1:6:2.

传统活性污泥法COD去除及脱氮改造的模拟

活性污泥模型方法正逐渐成为废水处理工程领域科学研究、工艺设计和过程控制的一种重要手段 .以国际水质协会的活性污泥 1号模型 (ASM1)为基础 ,以MATLAB为工具开发模拟软件 ,对模型进行了校核与验证 .模拟了重庆市唐家桥污水处理厂COD和含N组分的降解过程 ,研究了有机物负荷、流量、温度和溶解氧浓度变化对出水COD、氨氮、硝态氮和总氮的影响 .利用所开发的模拟程序对唐家桥污水处理厂的脱氮改造方案进行了优化 ,并预测了改造后的处理效果 .

活性污泥2号模型用于城市污水处理厂脱氮除磷改造的研究

利用自行开发的活性污泥 2号模型ASMNO .2计算机模拟程序对重庆市某污水厂三种脱氮除磷改造方案 (A O ,A2 O ,倒置A2 O)进行了模拟研究 ,寻求了每一种方案的最佳运行控制参数 .结果表明 :(1)将现有曝气池前端 1 4控制为缺氧而形成A O工艺 ,缺氧区溶解氧浓度为 0 .10mg L ,混合液内回流比为 10 0 % ,可以使TN去除率达到 5 8.6 % ,提高 2 4个百分点 ,TP基本不受影响 ;(2 )将现有曝气池前端 12 %控制为厌氧区 ,2 4 %控制为缺氧区 ,缺氧区溶解氧浓度为 0 .10mg L ,混合液内回流比为 10 0 % ,可以使TN去除率达到 6 2 .1% ,提高约 2 8个百分点 ,TP去除率达到 78.3% ,提高 37个百分点 ;(3)倒置A2 O工艺与常规A2 O工艺的出水水质基本相当 ,但倒置A2 O工艺在工程实践中更易于实现 ;(4)三种工艺出水COD和氨氮均能达到国家规定的一级排放标准 .

ECOSUNIDE工艺用于沂水污水处理厂的升级改造

分点进水高效脱氮除磷工艺(ECOSUNIDE)通过改变进水方式,创造了有利于硝化菌和聚磷菌生长的环境,实现了短时高效脱氮,并在沂水县城市污水处理厂升级改造中得到了成功应用。

无锡市城北污水处理厂升级改造工艺设计

无锡市城北污水处理厂升级改造工程设计规模15万m3/d,采用强化二级生物脱氮除磷以及增加三级盘片式微过滤工艺进行改造,出水达到《城镇污水处理厂污染物排放标准》(GB18918—2002)中的一级A排放标准。介绍了升级改造工程处理工艺选择、工程设计参数、设备配置情况等,总结分析了升级改造工艺设计的技术特点和要求。

基于ASM2d的MSBR工艺脱氮除磷优化运行诊断与改造

为满足较高的污水排放标准,同时考虑降低污水处理运行成本、节省基建费用等因素,通过国际水协推出的活性污泥数学模型ASM2d建立适用于污水处理厂实际运行状况的水质模型,对YT污水处理厂进行了工艺优化诊断,并提出了改造方案,确保工艺运行经济、高效,出水水质能够稳定达标。

无锡市胡埭污水处理厂升级改造工艺设计

无锡市胡埭污水处理厂升级改造工程实施规模为0.7×104m3/d,采用强化C-TECH二级生物脱氮除磷以及增加三级盘片式微过滤工艺进行工艺改造,出水达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)中的一级A标准。介绍了升级改造工程处理工艺选择、工程设计参数、设备配置情况等,总结分析了升级改造工艺设计的技术特点和要求。

MBR城市污水处理厂生物脱氮升级改造研究

昆明第四污水处理厂采用膜生物反应器(MBR)处理工艺,为了减少该厂氮污染物排放量,降低污水处理能耗,该研究对污水处理现状及存在的问题进行了分析,提出优化好氧缺氧区域设置、进水分配与内回流量等,强化系统反硝化脱氮效果,进而提出了4套升级改造方案,并进行生产性试验研究。研究结果表明在保证硝化效果的条件下,采用多点进水优化进水分配,可获得较好的脱氮效果,出水总氮(TN)平均值为9.15 mg/L,TN和氨氮的去除率分别达到68.46%和97.98%。

无锡太湖国家旅游度假区污水处理厂提标改造设计

无锡太湖国家旅游度假区污水处理厂提标改造工程实施规模为1.25×104m3/d,采用强化CAST生物脱氮、机械微过滤(盘片过滤)工艺,改造后处理出水达到了《城镇污水处理厂污染物排放标准》(GB 18918—2002)的一级A标准。介绍了该工程的工艺流程、设计参数及技术特点。

北京高碑店再生水处理厂升级改造工艺方案设计

为实现污水的资源化利用,通过改造工程将高碑店污水处理厂升级成为再生水处理厂,规模100万m3/d,出水主要水质指标要求达到《地表水环境质量标准》(GB 3838—2002)IV类水体水质标准。通过对现状污水处理厂及改造目标的分析,综合考虑技术、经济、可实施性等多方面因素,选取升级改造主体为A2/O(填料)工艺,新建的深度处理部分采用反硝化生物滤池+膜过滤+臭氧脱色工艺。介绍了水处理和污泥处理部分的工艺设计方案及设计参数,分析了工艺方案特点。

“准Ⅳ类”标准下城镇污水厂提标改造的难点与举措

近年来我国诸多地区的污水厂迎来了以“准Ⅳ类”为排放标准的新一轮提标改造任务。从新标准的变化入手,结合我国实际情况,分析了在各种因素制约下提标改造中的困难所在,建议以提高进水浓度为目的的源头控制、以优化内部碳源分配利用为核心的工艺改造,以及以强化污泥和深度处理并举的生物脱氮等措施,以期为新一轮的提标改造提供借鉴与参考。