Simultaneous nitrification and denitrification of municipal wastewater in aerobic membrane bioreactors.

Simultaneous nitrification-denitrification (SND) of municipal wastewater was investigated in a laboratory-scale membrane bioreactor (MBR) operated at two different hydraulic retention times (HRTs), 0.5 and 1 day, dissolved oxygen 3.0 to 0.5 mg/L, and solids retention time (SRT) between 28 and 120 days. The organic loading rate (OLR) (0.11 to 0.64 kg chemical oxygen demand [COD]/m3/d) and influent soluble COD (SCOD)/ total Kjeldahl nitrogen (TKN) ratio (5 to 19) were varied by the addition of glucose. The ammonia-nitrogen and TKN removals were over 97%, and total nitrogen removal was approximately 89% in the MBR. The maximum specific nitrification rates (98 mg N/d/g VSS) and specific denitrification rates (81 mg N/d/g VSS) occurred at an SCOD/TKN ratio of 9.1. The optimum conditions for maximum total nitrogen removal by SND in a single reactor MBR have been found to be low dissolved oxygen (< 0.6 mg/L) and high OLR (approximately 0.64 kg COD/m3/d) at an HRT of 0.5 day and SRT of approximately 85 days.     

Performance investigation of membrane bioreactor systems during municipal wastewater reclamation.

Four commercially available membrane bioreactor (MBR) systems were operated at the pilot scale, to investigate performance during the reclamation of municipal wastewater. The MBR performance was evaluated under a variety of operating conditions, including two types of feed wastewater (raw and advanced primary effluent), hydraulic retention times (HRTs) ranging from 2 to 6 hours, and permeate fluxes between 20 and 41 lmh. Test results showed that MBR systems were capable of operating on advanced primary effluent, despite the possible presence of coagulant and/or polymer residual, with minimal membrane fouling. Membrane performance data generated during this study was also used to quantify the relationship between permeate flux and membrane fouling. Cleaning intervals at various flux conditions were estimated as follows: 69 days at 20 lmh, 58 days at 25 lmh, and 30 days for operation between 31 and 41 lmh. It was also demonstrated that the MBR process could be optimized to operate with minimal fouling under high hydraulic (flux = 37 lmh) and organic loading (HRT = 2 hours and food-to-microorganism ratio = 0.33 g COD/g VSS x d) conditions. Water quality monitoring conducted throughout the study showed that each MBR system consistently produced an oxidized (5-day biochemical oxygen demand < 2 mg/L) and nitrified (ammonia < 1 mg-N/L) effluent low in particulate matter (turbidity < 0.1 NTU), under all conditions tested.     

Treatment of food industry waste by bench-scale upflow anaerobic sludge blanket-anoxic-aerobic system.

An upflow anaerobic sludge blanket (UASB)-anoxicaerobic system was used for treatment of tomato and bean processing wastewater. At various hydraulic retention times, ranging from 0.7 to 5 days, excellent removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD), total suspended solids (TSS), ammonia-nitrogen (NH4-N), and total Kjeldahl nitrogen was achieved with final effluent BOD/TSS/NH4N concentrations of less than 15/15/1 mg/L. Biogas yield in the UASB reactor varied from 0.33 to 0.44 m3/kgCODremoved. The kinetics of anaerobic treatment were investigated. The yield coefficient was 0.03 gVSS/gCOD; maximum specific growth rate was 0.24 day(-1); Monod half velocity constant was 135 mgCOD/L; and specific substrate utilization rate was 3.25 gCOD/gVSS x d. Nitrification and denitrification kinetics were studied in batch experiments, and the rates were comparable with those in the continuous flow system.     

Treatment of domestic wastewater by an hydroponic NFT system

The objectives in this work were to investigate a conceptual layout for an inexpensive and simple system that would treat primary municipal wastewater to discharge standards. A commercial hydroponic system was adapted for this study and the wastewater was used to irrigate Datura innoxia plants. Influent and effluent samples were collected once a month for six months and analysed to determine the various parameters relating to the water quality. The legal discharge levels for total suspended, biochemical oxygen demand and chemical oxygen demand were reached with the plant system after 24 h of wastewater treatment. Total nitrogen and total phosphorus reduction were also obtained. NH4(+)-N was reduced by 93% with nitrification proving to be the predominant removal process. Significant nitrification occurred when the BOD5 level dropped 45 mg/l. Similar results were obtained for six months although the sewage composition varied widely. D. innoxia develops and uses the wastewater as the unique nutritive source.     

固定化膜生物反应器处理含抗生素污水

采用细菌固定化技术包埋活性污泥浓缩液,并利用A/O膜生物反应器处理含抗生素生活污水,考察了膜生物反应器在抗生素存在条件下降解有机物及氮素的性能,并对土霉素为代表的抗生素的去除效果进行分析。结果表明,人工模拟抗生素污水的COD、TOC、NH4+-N、TN及土霉素浓度分别为325～413、101.35～206.10、15.51～24.54、15.00～25.30和0.17～0.47 mg/L,水力停留时间为6、12和24 h的条件下,系统的出水平均COD、TOC、NH4+-N和TN分别维持在50、20、1和3 mg/L以下,对土霉素的平均去除率分别达到64%、72%和75%;研究还发现固定化膜生物反应器对进水中氨氮的波动具有良好的抗冲击负荷能力且可以延缓膜污染,正确调整水处理工艺的运行工序可以在提高水处理效率的同时有效降低水环境中的抗生素药物含量。     

Toward a high-rate enhanced biological phosphorus removal process in a membrane-assisted bioreactor.

A membrane enhanced biological phosphorus removal (MEBPR) process was studied to determine the impact of hydraulic retention time (HRT) and solids retention time (SRT) on the removal of chemical oxygen demand (COD), nitrogen, and phosphorus from municipal wastewater. The MEBPR process was capable of delivering complete nitrification independent of the prevailing operating conditions, whereas a significant improvement in COD removal efficiency was observed at longer SRTs. In the absence of carbon-limiting conditions, the MEBPR process was able to achieve low phosphorus concentrations in the effluent at increasingly higher hydraulic loads, with the lowest HRT being 5 hours. The MEBPR process was also able to maintain optimal phosphorus removal when the SRT was increased from 12 to 20 days. However, at higher suspended solids concentrations, a substantial increase was observed in carbon utilization per unit mass of phosphorus removed from the influent. These results offer critical insights to the application of membrane technology for biological nutrient removal systems.     

改良型A2／O-MBR工艺的反硝化除磷性能研究

重点考察了-种改良型膜生物反应器（A2／O—MBR）的脱氮除磷性能。该工艺主要特点在于对膜池硝化回流液进行了固液分离，并将上清液和浓缩污泥分别回流至缺氧池和厌氧池，这种改进提高了系统对氮、磷的同步去除效率。实验结果表明，在水力停留时间（HRT）为12h，污泥龄（SRT）为30d，混合液回流比为200％的运行条件下，进水COD、NH4＋-N、TN和TP平均浓度分别为（225±38）、（24．8±3．9）、（26．7±2．9）和（2．90±0．53）mg／L时，增加膜池硝化回流液固液分离装置前后，系统对COD和NH4＋-N的去除都维持在较高水平，而系统对TN和TP的去除效果显著提高，出水TN和TP平均浓度分别由（14．9±3．3）mg／L和（1．95±0．72）mg／L下降到（9．4±1．9）mg／L和（0．91±0．38）mg／L，表明增加膜池硝化回流液固液分离装置显著改善了A2／O-MBR系统的脱氮除磷效果。反硝化除磷活性实验结果进一步表明，改进后系统中反硝化除磷活性占总除磷活性的比例由51．5％上升至61．7％，说明增加膜池硝化回流液固液分离装置强化了系统的反硝化除磷性能。     

序批式反应器用于牛场污水的处理

对序批式反应器 (SBR)用于牛场污水的处理进行了试验研究 ,主要研究了三个水力停留时间 (HRT)和有机负荷率对污染物去除率、出水水质和污泥特性的影响。试验结果表明 ,对 10 0 0 0mg/LCOD牛场污水 ,使用 1dHRT ,相应有机负荷率为 10gCOD/L·d时 ,混合出水COD、TS、VS、TKN和TN的去除率分别为 45 %、2 1.4%、34 .2 %、5 3.2 %和 2 2 .2 % ,上清液出水的分别为 80 .2 %、6 3.4%、6 6 .2 %、75 %和 38.3% ;两种出水的SCOD和NH3 N去除率相同 ,分别为 5 0 .0 %和 76 .5 %。经SBR处理后 ,污泥的沉降浓缩性能也有了比较明显的改善。     

Treatment of coke-plant wastewater by biofilm systems for removal of organic compounds and nitrogen

Coke-plant wastewater was treated by an anaerobic-anoxic-aerobic (A(1)-A(2)-O) biofilm system and an anoxic-aerobic (A/O) biofilm system, respectively. At same or similar levels of hydraulic retention time (HRT), the two systems had almost identical chemical oxygen demand (COD) and NH(3) removals, but a different organic-N removal. Set-up of an acidogenic stage benefited for the removal of organic-N and the A(1)-A(2)-O system was more useful for total nitrogen removal than the A-O system. HRT did not have a substantial effect on the COD and NH(3)-N removal efficiencies, but considerably influenced the organic-N removal and distribution of oxidized nitrogen in the final effluent. The GC/MS analysis demonstrated that some refractory compounds were decomposed at the acidogenic stage and resulted in the production of some intermediates, which were more readily degraded in the subsequent aerobic stage. Hence, the A(1)-A(2)-O system had better effluent quality than the A-O system in terms of effluent composition.     

曝气生物滤池处理农村污水的中试研究

采用研制的曝气生物滤池对农村污水进行处理，研究其性能特点和影响因素。结果表明：在气水比为5∶1，水力停留时间（HRT）为15 h，进水COD浓度在250 mg/L以下时，COD和氨氮的去除率分别在80％和90％以上，出水COD和氨氮值达到国家《城镇污水处理厂污染物排放标准》一级A标准；反应器在冬季水温12℃以上运行时出水COD和氨氮值比在夏季运行时有所上升，但去除率仍在80%和90%以上，可以达到排放标准。     

改良型一体化氧化沟工艺在低碳源条件下脱氮除磷

针对在低碳源条件下脱氮除磷效果不佳,将倒置A2/O工艺的思想运用于一体化氧化沟工艺中,构建一种新型污水处理系统,即改良型一体化氧化沟工艺。实验考查了系统在低碳源条件下的脱氮除磷能力;结果表明:当缺氧区进水分配比r=0.8,泥龄SRT=10 d,好氧区水力停留时间HRT=12 h时,该系统对COD、NH4+-N和TP的去除率分别达70.8%、89.3%和72.1%,出水NOx--N为1.65 mg/L,同时处理效果稳定,出水水质达到了《城镇污水处理厂污染物排放标准》(GB 18918-2002)一级B标准的要求。     

Application of a constructed wetland for industrial wastewater treatment: a pilot-scale study

The main objective of this study was to examine the efficacy and capacity of using constructed wetlands on industrial pollutant removal. Four parallel pilot-scale modified free water surface (FWS) constructed wetland systems [dimension for each system: 4-m (L)x1-m (W)x1-m (D)] were installed inside an industrial park for conducting the proposed treatability study. The averaged influent contains approximately 170 mg l(-1) chemical oxygen demand (COD), 80 mg l(-1) biochemical oxygen demand (BOD), 90 mg l(-1) suspend solid (SS), and 32 mg l(-1) NH(3)-N. In the plant-selection study, four different wetland plant species including floating plants [Pistia stratiotes L. (P. stratiotes) and Ipomoea aquatica (I. aquatica)] and emergent plants [Phragmites communis L. (P. communis) and Typha orientalis Presl. (T. orientalis)] were evaluated. Results show that only the emergent plant (P. communis) could survive and reproduce with a continuous feed of 0.4m(3)d(-1) of the raw wastewater. Thus, P. communis was used in the subsequent treatment study. Two different control parameters including hydraulic retention time (HRT) (3, 5, and 7d) and media [vesicles ceramic bioballs and small gravels, 1cm in diameter] were examined in the treatment study. Results indicate that the system with a 5-d HRT (feed rate of 0.4m(3)d(-1)) and vesicles ceramic bioballs as the media had the acceptable and optimal pollutant removal efficiency. If operated under conditions of the above parameters, the pilot-plant wetland system can achieve removal of 61% COD, 89% BOD, 81% SS, 35% TP, and 56% NH(3)-N. The treated wastewater meets the current industrial wastewater discharge standards in Taiwan.     

Performance of a submerged membrane bioreactor system for biological nutrient removal.

A pilot submerged membrane bioreactor coupled with biological nutrient removal was used to treat the primary effluent at a municipal wastewater treatment plant. Long-term experiments were conducted by varying hydraulic retention time from 6 to 8 hours and solids retention time from 20 to 50 days, respectively. The performance was assessed by monitoring key wastewater parameters, including chemical oxygen demand (COD), nitrogen, and phosphorus concentration in individual anoxic, anaerobic, aerobic, and membrane separation zones. Results showed that the tested system can consistently achieve COD, nitrogen, and phosphorus removal efficiencies at 80 to 98%, 70 to 93%, and 89 to 98%, respectively. Effluent COD remained low as a result of efficient solid retention, even though there was great variation in influent quality. However, total nitrogen increased proportionally with influent concentration. At a 50-day solids retention time, higher COD and nitrogen oxides specific utilization rates in the anoxic zone resulted in a high production of nitrogen oxides in the subsequent aerobic zone.     

农户庭院型人工湿地对农村生活污水的净化效果

为了探讨人工湿地在农村生活污水处理应用中的可行性,通过在广东省珠海市上洲村建立农户型水平潜流和垂直流人工湿地系统各一套,比较2种人工湿地对农村生活污水净化效果的差异。在运行稳定阶段,2套系统处理出水中COD、BOD5、TP、NH4+-N和TN的平均浓度均达到了城镇污水处理厂排放标准(GB18918-2002)一级A标准。2套系统对农村生活污水的各污染物都具有很好的去除效果。其中,垂直流湿地对COD、BOD5、TP、TN和NH4+-N平均去除率分别为96.10%、96.01%、85.32%、91.18%和82.44%;水平潜流湿地则分别为93.29%、94.41%、86.52%、85.95%和77.46%。统计分析结果表明,垂直流湿地对NH4+-N的去除率高于水平潜流湿地,且其差异达到显著水平;水平潜流湿地对TP的去除率高于垂直流湿地,但其差异未达到显著水平。     

A comparison of swine wastewater treatment using real-time and fixed-time two-stage sequencing batch reactors

This study compared the swine wastewater treatment of two identical lab-scale two-stage sequencing batch reactors (TSSBR) under similar conditions except that one was operated on a fixed-time mode and the other on a real-time mode. While both TSSBR systems performed very well, the real-time TSSBR performed far better then the fixed-time TSSBR, in every aspect of carbon, nitrogen, and phosphorous removal. The removals of COD, TOC, were at 97% and for BOD5 even at 99.7%. In terms of NH4-N and TKN removals, the real-time TSSBR achieved removal of over 98%. For phosphorus removals (Ortho-P and total P) the results from the real-time TSSBR was quite remarkable at 97.7%.     

Decolorization and biodegradation of dye wastewaters by a facultative-aerobic process

BACKGROUND: Dye wastewater is one of the main pollution sources of water bodies in China. Conventional biological processes are relatively ineffective for color removal, the development of alternative treatment methods will become important. Our subjective was that of introducing a new biotreatment technology which combined a facultative biofilm reactor (FBR) with an aerobic reactor (AR) to treat a dye wastewater. The efficiencies of color and chemical oxygen demand (COD) removal and the mechanism of dye degradation were investigated. METHODS: The anthraquinone acid dye (acid blue BRLL) concentration, organic loading rate (OLR) and hydraulic retention time (HRT) were varied in the experiments to evaluate the treatment efficiency and process stability. The biodegradation products were detected by infrared (IR) and high performance liquid chromatography and mass spectrometry (HPLC-MS). RESULTS AND DISCUSSION: The results demonstrated that the facultative biofilm process was more effective for decolorization than the anaerobic stage of an anaerobic-aerobic process. Most color removal occurred in the facultative reaction (maximum to 88.5%) and the BOD (biochemical oxygen demand): COD of the FBR effluent increased by 82.2%, thus improving the biodegradability of dyes for further aerobic treatment. The dye concentration, OLR and HRT will be the factors affecting decolorization. Color removal efficiency falls as the influent dye concentration increases, but rises with increased HRT. The infrared and HPLC-MS analyses of the effluents of FBR and AR reveal that the dye parent compound was degraded in each reactor during the process. CONCLUSION: The Facultative-aerobic (F-A) system can effectively remove both color and COD from the dye wastewater. The FBR played an essential role in the process. The average overall color and COD in the system were removed by more than 93.9% and 97.1%, respectively, at an OLR of 1.1 kg COD m(-3) d(-1) and at the HRT of 18-20 hours in the FBR and 4-5 hours in the AR. The color removal mechanism in each reactor was not only a sort of biosorption on the floc materials, but even more an effect of biodegradation, especially in the facultative process. Recommendation and Outlook. In applying the F-A system to treat a dye wastewater, the control of facultative processes and the set up of appropriate operation conditions appear to be critical factors. Also, it is suggested a moderate COD loading rate and about a 24-hour HRT will favor the F-A system.     

A/O+MBR工艺处理玉米深加工废水的中试研究

实验基于企业污水站的改造工程,研究了MBR对玉米深加工废水的处理效果并对工艺运行参数优化提出建议.结果表明,该工艺对COD的去除率可以达到90％以上,出水稳定在26 mg/L左右;出水NH4-N达到1 mg/L以下;TN去除率达到70％以上,出水TN达到10 mg/L以下,出水完全达到排放标准.通过4种工况的比较,说明在污泥浓度8 g/L左右,曝气池内DO在3 mg/L左右,MBR内DO＞4 mg/L,好氧段停留时间13.5 h,并保证3h以上的缺氧段水力停留段时间的条件下,A/O+ MBR工艺可以有效去除玉米深加工废水中的污染物.     

曝气浸没固定生物膜反应器处理化粪池出水

研究了以丝瓜络作为生物膜载体的曝气浸没固定生物膜反应器在处理化粪池出水时的可行性以及运行性能。结果表明,丝瓜络生物膜反应器可以在2周内成功启动;水力停留时间(HRT)对COD和氨氮的去除效果有显著影响,在水力停留时间为4 h的条件下,系统对COD和氨氮的去除率分别达到了78.5%和96.4%。另外,系统有较强抗有机污染物冲击负荷的能力,当COD和氨氮的进水浓度分别为59.3 mg/L和15.9 mg/L时,系统对有机污染物的去除效果较佳,去除率分别达到了80.0%和98.9%。     

垃圾压缩站污水的生物强化处理

垃圾压缩站污水是一种具有高COD、高NH3-N特点的有机污水.以厌氧/好氧组合工艺为基础,通过投加高效菌株对活性污泥系统进行生物强化.实验结果表明,与空白相比,厌氧出水COD去除率提高约30%,好氧出水NH3-N去除率提高约20%.最终出水COD《120 mg/L, NH3-N《25 mg/L,均达到《污水综合排放标准》(GB 8978-1996)二级排放标准.     

准好氧矿化垃圾反应床＋超声／芬顿联用技术处理垃圾渗滤液

针对垃圾渗滤液污染物浓度高、可生化性差等特点，采用准好氧矿化垃圾反应床＋超声／芬顿联用技术对垃圾渗滤液进行预处理。准好氧矿化垃圾床处理后渗滤液中COD、氨氮、总磷、色度的去除率分别为80％、85％、92％和85％。通过单因素实验和正交实验，确定了超声／Fenton法最佳工艺条件。经该组合工艺后，渗滤液中COD、氨氮、总磷和色度的最高去除率分别可达96％、86％、94％和95％，且出水无臭，颜色为淡黄色，BOD5／COD从0．16增至0．35左右，可生化性基本满足后续生物处理需要，且COD、总磷这2个指标达到《生活垃圾填埋场污染控制标准》（GB16889—2008）规定的排放标准。