膜生物反应器中新型无纺布膜过滤特性及膜污染特征

通过无纺布和聚偏氟乙烯平板膜组件在相同操作条件下的对比实验,研究无纺布膜的过滤特性。结果表明,2种膜的膜生物反应器COD、氨氮平均去除率均＞90%。过膜压力变化表明在长期运行条件下,无纺布可适于作为膜生物反应器的过滤介质,其过滤机理为膜表面滤饼层形成动态膜,从而增强了膜截留能力。膜污染研究表明,无纺布膜阻力主要来自滤饼层（占总阻力的83.6%）,经清洗后膜通量可恢复至94%。扫描电镜显示膜表面滤饼层较厚,结合膜阻力分析结果认为,该滤饼层对膜污染和可逆性影响较大。对膜表面和膜孔中胞外聚合物（EPS）的红外分析证实,其中含有蛋白质和多糖物质,而且组分分析表明蛋白质是膜污染物EPS中的主要组分,在膜孔中的含量比滤饼层中还高。     

Electrocoagulation-integrated hybrid membrane processes for the treatment of tannery wastewater

Three different combinations of treatment techniques, i.e. electrocoagulation combined with microfiltration (EMR), membrane bioreactor (MBR) and electrocoagulation integrated with membrane bioreactor (hybrid MBR, (HMBR)), were analysed and compared for the treatment of tannery wastewater operated for 7 days under the constant trans-membrane pressure of 5 kPa. HMBR was found to be most suitable in performance as well as fouling reduction, with 94 % of chemical oxygen demand (COD) removal, 100 % chromium removal and 8 % improvement in percentage reduction in permeate flux compared to MBR with only 90 % COD removal and 67 % chromium removal. The effect of mixed liquor suspended solids on fouling was also investigated and was found to be insignificant. EMR was capable of elevating the flux but was not as efficient as HMBR and MBR in COD removal. Fouling reduction by HMBR was further confirmed by SEM-EDX and particle size analysis.     

A comparison of membrane bioreactor and conventional-activated-sludge mixed liquor and biosolids characteristics.

Characteristics and behavior of raw and digested mixed liquor derived from a membrane bioreactor (MBR) and a full-scale activated-sludge (FSAS) facility were compared. The accumulation of nondegradable chemical oxygen demand in the MBR appears to play an important role in increasing the observed biological yield coefficient (Y(obs)), reducing average floc size, decreasing total suspended solids/total solids and volatile suspended solids/volatile solids (VS) ratios, and reducing specific-oxygen-uptake rates of the mixed liquor relative to FSAS-derived biological solids. Membrane bioreactor sludges exhibited lower VS destruction following 30 days mesophilic-anaerobic and aerobic digestion when compared to FSAS sludges. Significant deterioration in dewatering behavior was observed for the FSAS biosolids after anaerobic digestion and, to a lesser extent, following aerobic digestion. In comparison, digestion had a small affect on dewatering efficiency and conditioner requirements for MBR biosolids. Full-scale facilities using membrane separation may need to tailor digestion and dewatering processes to the specific characteristics of MBR sludges.     

SMBR处理含油废水出水COD数学模型

根据微生物生长动力学特征以及膜分离特征,建立恒通量下运行的一体式膜生物反应器系统出水COD数学模型,提出膜生物反应器处理效率的数学模型。以实验及模型为基础,分别对进水COD浓度控制在300、400、500 mg/L附近时经过反应器后COD的去除效率进行了比较。通过公式计算的数据和实验数据分析可得:COD去除率的公式计算值与实验结果比较吻合,相对偏差仅为0.0223,为膜系统有机物的去除效果估算提供了基础,可为该类工艺的参数选择与优化提供参考。     

2-Chlorobenzoate biodegradation by recombinant Burkholderia cepacia under hypoxic conditions in a membrane bioreactor.

The feasibility of applying bacterial hemoglobin technology to degrade 2-chlorobenzoate (2-CBA) through co-metabolism under hypoxic conditions in a membrane bioreactor (MBR) process has been studied in the laboratory. 2-chlorobenzoate removal and chloride release rates in the MBR system varied from 99 to 78% and 98 to 73%, respectively, depending on the operation conditions. Chemical oxygen demand (COD) removal efficiencies were more than 90% at food-to-microorganism ratios ranging from 0.32 to 0.62 g/g/d, and the observed yield was 0.13 to 0.20 g biomass/g COD. The bacterial cell-floc size-distribution analysis showed that there is a significant change in bacterial floc size due to high shear stress during operation of the MBR. To characterize growth kinetics of Burkholderia cepacia strain dinitrotoluene, a mathematical model that describes co-metabolic oxidation of 2-CBA in an MBR has been developed.     

有机负荷对膜-生物反应器硝化性能的影响

采用厌氧动态膜-生物反应器(AnDMBR)组合自养膜-生物反应器(MBR)工艺,研究冬季低温条件下系统的硝化效果以及TP的去除效果,并与单级MBR工艺进行对比。结果表明:(1)AnDMBR对COD的去除率基本保持在50%～60%,AnDMBR组合自养MBR工艺对COD的去除率为80%～85%;单级MBR工艺对COD的去除率为80%左右。(2)总体上,AnDMBR组合自养MBR工艺对NH4+-N的去除率大于95%;单级MBR对NH4+-N的去除效果比AnDMBR组合自养MBR工艺差。(3)AnDMBR组合自养MBR工艺中,出水NO2--N与NO3--N均有积累;单级MBR工艺中,出水NO2--N积累不明显。(4)相对于亚硝酸盐氧化菌(NOB),氨氧化菌(AOB)对有机负荷更敏感,当有机负荷高时,AOB更易受到异养菌活动的抑制;当有机负荷降低、异养菌活性减弱时,AOB活性明显增强,系统的硝化效果得到明显改善。(5)AnDMBR组合自养MBR工艺对TP的去除率高于80%,单级MBR工艺稳定后对TP的去除率仅为20%～30%。(6)从呼吸速率和硝化速率可知,自养MBR的硝化效果优于单级MBR。     

Treatment of bleach pulp mill effluent by MF-MBR

The types of treatment most commonly used by pulp mills are biological treatments in combination with sedimentation or coagulation/flocculation as pretreatment. The main issues faced by these types of treatment are low efficiency in the removal of organic matter and the loss of aggregate value for the recovered fiber. Therefore, this study aims to evaluate the use of microfiltration (MF) combined with a membrane bioreactor (MBR) for the treatment of bleach pulp mill effluents. The results showed that the use of the MF-MBR system was an excellent alternative for the treatment of bleach pulp mill effluents with an average COD removal of 95%. The microfiltration allowed the recovery of fibers, which can be returned to the production process without losing economic value, and produced a better quality effluent for further treatment in the MBR. The MBR presented high efficiency removal of organic matter.     

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.     

Evaluation of membrane bioreactor process capabilities to meet stringent effluent nutrient discharge requirements.

A six-stage membrane bioreactor (MBR) pilot plant was operated to determine and demonstrate the capability of this process to produce a low-nutrient effluent, consistent with the nutrient reduction goals for the Chesapeake Bay. Biological nitrogen removal was accomplished using a multistage configuration with an initial anoxic zone (using the carbon in the influent wastewater), an aerobic zone (where nitrification occurred), a downstream anoxic zone (where methanol was added as a carbon source), and the aerated submerged membrane zone. The capability to reliably reduce effluent total nitrogen to less than 3 mg/L as nitrogen (N) was demonstrated. A combination of biological (using an initial anaerobic zone) and chemical (using alum) phosphorus removal was used to achieve effluent total phosphate concentrations reliably less than 0.1 mg/L as phosphorus (P) and as low as 0.03 mg/L as P. Alum addition also appeared to enhance the filtration characteristics of the MBR sludge and to reduce membrane fouling. Aeration of the submerged membranes results in thickened sludge with a high dissolved oxygen concentration (approaching saturation), which can be recycled to the main aeration zone rather than to an anoxic or anaerobic zone to optimize biological nutrient removal. Biological nutrient removal was characterized using the International Water Association Activated Sludge Model No. 2d. The stoichiometry of chemical phosphorus removal was also consistent with conventional theory and experience. The characteristics of the solids produced in the MBR were compared with those of a parallel full-scale conventional biological nitrogen removal process and were generally found to be similar. These results provide valuable insight to the design and operating characteristics of MBRs intended to produce effluents with very low nutrient concentrations.     

好氧硝化颗粒污泥膜生物反应器性能和膜污染研究

实验研究了好氧硝化颗粒污泥膜生物反应器AGMBR的处理性能,并将其与活性污泥膜生物反应器ASMBR进行对比,考察了颗粒污泥在减缓膜污染中所起的作用.好氧硝化颗粒污泥膜生物反应器AGMBR连续稳定运行102 d,系统具有良好的去除有机物和同时硝化反硝化能力,在进水COD和NH+4-N浓度分别为500和200 mg/L时,COD、NH+4-N和TN的去除率分别稳定在86%、94%和45%以上.颗粒污泥有效减缓了膜污染,延长了膜清洗的周期,AGMBR中的膜污染以膜孔堵塞为主,占总阻力的64.81%;滤饼层的阻力为2.1×1012m-1,远小于ASMBR中的16.07×10"m-1;膜清洗周期是相同条件下ASMBR的2.43倍以上;而且AGMBR内不断有新颗粒生成,维持了AGMBR系统性能和运行的稳定.     

纳米材料对膜生物反应器影响的试验研究

通过向一体式膜生物反应器中投加纳米材料来改变料液性质,预防膜污染和提高膜生物反应器对污染物的去除效率,并利用扫描电镜分析中空纤维膜的表观结构的变化情况,通过红外光谱分析活性污泥性质的变化,以探讨防治膜污染的机理。试验结果表明,纳米材料的投加对COD和NH₃-N的去除无明显影响,提高了TP的去除率,TP去除率达70%。而且投加纳米材料可改变活性污泥的性质和生物膜的表观结构,减缓膜污染。     

微曝气Fenton氧化法处理模拟双酚A废水的效果及其生物验证

研究了微曝气Fenton氧化法关键工艺参数对模拟双酚A（BPA）废水处理效果的影响,并从活性污泥性质和污染物去除率两方面,采用膜生物反应器(membrane bioreactor, MBR)对微曝气Fenton氧化法的处理效果进行了实验验证,为实现BPA废水的生物处理奠定基础。结果表明,初始pH值、反应时间、H₂O₂/COD(质量浓度比)、H₂O₂/Fe²⁺ (摩尔浓度比)、反应温度及曝气量均对预处理效果有较大影响,在最佳条件下,COD去除率可达70%,BOD/COD值则由原废水的0.02提高到0.50以上。MBR处理上述出水的结果表明,经微曝气Fenton氧化处理BPA的废水,可较好地适应后续的生化处理。     

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.     

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。     

Simultaneous nitrification and denitrification with anoxic phosphorus uptake in a membrane bioreactor system.

The performance of an innovative membrane bioreactor (MBR) process using anoxic phosphorus uptake with nitrification and denitrification for the treatment of municipal wastewater with respect to operational performance and effluent quality is addressed in this paper. The system was operated at steady-state conditions with a synthetic acetate-based wastewater at a hydraulic retention time (HRT) of 12 hours and on degritted municipal wastewater at a total system HRT of 6 hours. The MBR system was able to achieve 99% biochemical oxygen demand (BOD), chemical oxygen demand (COD), and ammonia-nitrogen (NH4(+)-N); 98% total Kjeldahl nitrogen (TKN); and 97% phosphorus removal, producing effluent BOD, COD, NH4+-N, TKN, nitrate-nitrogen, nitrite-nitrogen, and phosphate-phosphorus of <3, 14, 0.2, 0.26, 5.8, 0.21, and <0.01 mg/L, respectively, at the 6-hour HRT. The comparison of the synthetic and municipal wastewater run is presented in this paper. Steady-state mass balance on municipal wastewater was performed to reveal some key features of the modified MBR system.     

高氨氮对厌氧生物法处理城市垃圾渗沥液的影响

研究了高浓度氨氮对厌氧膜生物法处理城市垃圾渗沥液的影响。结果表明,COD去除率、沼气产量、沼气产率、辅酶F420和最大比产甲烷活性均随氨氮浓度的增加而减小;当氨氮浓度<3600mg/L时,不会对厌氧膜生物反应器的运行产生明显的影响;氨氮对厌氧污泥产甲烷活性的50%抑制浓度为4350mg/L;高浓度氨氮会造成系统VFA浓度增加;当氨氮浓度由4800mg/L降低到2000mg/L后,受重度抑制的厌氧微生物的活性可以在20d里恢复到未受抑制时的活性水平。     

一体式MFC-好氧MBR运行效果及膜污染特性

膜生物反应器(MBR)是一种高效的污水处理工艺,而微生物燃料电池(MFC)能利用NO-3作为电子受体进行脱氮。为解决膜生物反应器(MBR)脱氮效率低和膜污染问题,建立了一套能够进行脱氮、有效抑制膜污染的一体式MFC-好氧MBR新工艺。以开路MFC-MBR反应器为对照,对耦合系统中污水处理效果、膜污染情况进行研究。研究表明,2套系统的COD去除率均超过88%,对NH4-N的去除均达到99%。闭路MFC-MBR系统TN去除率达到69.4%,高于开路系统的55.3%。混合液的MLVSS/MLSS稳定在88%左右,同时耦合系统能够改善污泥混合液的性质,zeta电位的绝对值和粘度较开路系统有所减少,污泥颗粒平均体积粒径(233.482μm)较开路系统(94.877μm)有明显增加,膜清洗周期延长了41.17%。     

Simultaneous nitrification and denitrification in an aerobic reactor with granular sludge originating from an upflow anaerobic sludge bed reactor.

Anaerobic granular sludge, obtained from an upflow anaerobic sludge bed reactor at a brewery waste treatment station, was cultured for 3 months under aeration conditions until the diameter of sludge was in the range 1.8 to 2.6 mm. The aerobic granular sludge gathered acquired the ability of catalyzing simultaneous nitrification and denitrification (SND) and was applied in the study of the process of nitrogen removal in a bioreactor. The ratio between chemical oxygen demand (COD) and ammonium-nitrogen (NH4(+)-N) concentration in the influent was found to be an important factor influencing the process of SND. The final percentage removal of NH4(+)-N reached 100% under the optimal condition of 500 mg/L COD and 0.39 NH4(+)-N/COD. Intermediate products, such as nitrite-nitrogen and nitrate-nitrogen, were also analyzed to clarify the SND process with the aerobic granular sludge.     

一体式MFC-好氧MBR运行效果及膜污染特性

膜生物反应器（MBR）是一种高效的污水处理工艺,而微生物燃料电池（MFC）能利用N0i作为电子受体进行脱氮。为解决膜生物反应器（MBR）脱氮效率低和膜污染问题,建立了一套能够进行脱氮、有效抑制膜污染的一体式MFC-好氧MBR新工艺。以开路MFC—MBR反应器为对照,对耦合系统中污水处理效果、膜污染情况进行研究。研究表明,2套系统的COD去除率均超过88％,对NH4-N的去除均达到99％。闭路MFC—MBR系统TN去除率达到69．4％,高于开路系统的55．3％。混合液的MLVSS／MLSS稳定在88％左右,同时耦合系统能够改善污泥混合液的性质,zeta电位的绝对值和粘度较开路系统有所减少,污泥颗粒平均体积粒径（233．482μm）较开路系统（94．877μm）有明显增加,膜清洗周期延长了41．17％。     

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.