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.

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.

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.

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.

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.

氧化铁改性石英砂的复合挂膜与氨氮去除试验研究

采用自制的氧化铁改性石英砂滤料(简称"改性砂"),对生物改性砂联合处理微污染物氨氮的复合挂膜启动性能以及滤料表面形态进行了试验研究,并与生物普通砂联用效果进行对比。结果表明,生物普通砂和生物改性砂在挂膜初期的生物量分别为15.46、13.79 nmol/g(n(P)/m(滤料)),稳定运行期分别为18.75、20.09 nmol/g;挂膜初期,生物普通砂与生物改性砂对质量浓度为1～2 mg/L氨氮的去除效果分别达到92%和95%;挂膜稳定期,前者对氨氮的去除效果约60%,后者稳定在80%左右;在不同氨氮质量浓度(0.5～4 mg/L)下,生物普通砂对氨氮去除率从60%上升至80%,生物改性砂的去除率从70%增至95%;过滤前后2种滤料表面形态均发生变化,生物改性砂表面孔隙更小,结构更加复杂多孔,表面粗糙程度进一步增加,对氨氮去除率高。

啤酒废水改良Bardenpho工艺除磷脱氮技术研究

Bardenpho工艺内循环和污泥均回流至A1池,使A1池和A2池均含有较多的NO3—N,对高氮的啤酒废水除磷效果有所影响。在Bardenpho工艺缺氧段前增设厌氧池,并分流70%回流污泥至缺氧池,保证了磷的有效释放及好氧段磷的吸收能力,提高了除磷效果。第二缺氧-好氧段延长污泥龄至10～16d,提高了脱氮处理效果。出水的氮磷水质均有明显提高(NH3—N2.15mg/L、TP2.40mg/L)。

复合倒置A^2/O工艺优化运行参数研究

结合污水处理厂升级改造开展中试研究,考察水力停留时间(HRT)、污泥龄(SRT)和回流比等运行参数对复合倒置A2/O工艺处理性能的影响,优化工艺运行参数。试验结果表明,在常温和低温条件下,复合倒置A2/O工艺所需泥龄较短,当SRT为12 d时,既可保证良好的硝化水平,又可提高除磷效果;当回流比为200%时,可获得良好的同步脱氮除磷效果。

荷兰DSM化工厂生物除氮技术简介

本文主要介绍了荷兰DSM化工厂生物除氮技术

硝化菌的分离鉴定及多菌复配处理医药化工废水

氨氮是水体污染主要原因之一,单一菌常常难以有效去除。本研究从活性污泥中分离筛选出一株氨氮去除能力强的异养硝化细菌(Aquabacterium olei)。探究该菌株硝化特性,并优化菌株接种方式与培养方式。将该异养硝化细菌XTT与好氧反硝化菌LX 1-3混合培养共同处理医药污水,通过优化复合菌株培养方式、配比后,其氨氮去除率明显提高。当XTT与LX 1-3以1:3的比例接种,摇床培养84 h后,氨氮去除率高达95.6%。结果表明复合菌在污水处理方面有重要意义及应用前景。

复合微生物菌剂处理高浓度氨氮废水的强化作用

依托传统A/O工艺,采用短程硝化-反硝化处理人工高浓度氨氮废水,并投加新型复合微生物菌剂BMc-1强化废水处理效果,研究菌剂对污水脱氮的强化效果并分析对功能菌带来的变化。结果表明,投加菌剂后可以强化脱氮性能,实验组氨氮、总氮(TN)去除率达98.8%、82.0%,比较对照组氨氮、TN去除率97.3%、75.5%,分别提高1.7%、6.5%。16sRNA测序结果表明,投加菌剂使得活性污泥中微生物量、丰度以及多样性提高,菌剂对系统原微生物环境稳定性无影响,系统中Proteobacteria、Bacteroidetes、Chloroflexi为优势门未改变。投加菌剂后主要反硝化菌Thauera和氨氧化菌Nitrosomonas数量稳定,Pseudomonas、Thiopseudomonas、Terrimonas、Nitrosomonas脱氮功能菌占比提升。检测出Acinetobacter、Pedobacter等原系统不存在脱氮相关功能菌。实验结果表明复合菌剂BMc-1具有强化生物工艺脱氮能力的作用。

假单胞菌复合菌剂对高浓度废水中氨氮总氮浓度降解的研究

在修复工程中,利用微生物处理高浓度氨氮废水。通过对填埋场渗滤液坑底活性污泥驯化,筛选出复合菌剂,在异养硝化培养基或基坑废水中培养25 d后,氨氮平均质量浓度从830.42 mg/L降至38.28 mg/L,去除率最高达95.4%;总氮平均质量浓度从930.03 mg/L降至330.68 mg/L,去除率最高达66.2%。该复合菌剂主要成分为假单胞菌,对氨氮总氮降解效果显著,持续时间长,在高浓度污染水体修复领域中具有良好的应用前景。