膜—生物反应处理工艺中微生物对系统的影响

膜—生物反应器是近年来污水处理研究的热点,但受膜污染因素的影响,使其在实际应用中发展缓慢。由于膜—生物反应器的运行机理不是在生物反应器和膜组件的基础上简单叠加,并且由于生物特性和种类的改变,因此对系统的影响也不同于传统的活性污泥法。由于其独特的运行方式使微生物种类、数量发生变化,微生物在膜—生物反应器中不仅仅只起到去除有机物和脱氮、除磷的作用,对系统的运行也产生了一定的影响,尤其是对膜污染的影响。该文从微生物角度对其进行阐述,以期为膜污染治理提供一份参考。     

一体式膜-生物反应器污水处理特性及膜污染机理研究

本文介绍了一体式膜 生物反应器处理生活污水和含难降解有机物废水的试验研究 ,取得了以下主要结果 :(1 )采用一体式膜 生物反应器处理实际生活污水 ,系统地考察了不同ＳＲＴ和ＨＲＴ对污染物去除效果的影响。结果表明 ,一体式膜 生物反应器在不同的ＳＲＴ和ＨＲＴ下均表现出良好的污染物去除效果和运行的稳定性。但在长ＳＲＴ的条件下 ,生物反应器内出现了微生物代谢产物的积累。污泥龄过短时 ,反应器料液会对膜过滤造成极其不利的影响。(2 )对生物反应器微生物和混合液特性的研究表明 ,随着污泥龄的增长 ,生物反应器内的污泥活性有降低的…     

膜生物反应器的技术经济分析

膜生物反应器 (MBR)是通过膜分离技术强化污水生物处理的新技术。综述了该技术在我国的应用现状 ;并对MBR进行初步的技术经济分析。研究结果表明 :影响膜生物反应器运行费用的关键因素为膜通量和使用寿命     

三种型式膜-生物反应器工艺运行特性研究

研究了三种不同型式的生物反应器即活性污泥反应器（ＡＳＲ）、生物膜反应器（ＢＲ）和复合式反应器（ＨＲ）分别与膜分离相组合时的运行特性。结果表明不同膜－生物反应器组合工艺之间，污染物去除效率相差不大，但膜通透量却存在明显差异。膜－复合式反应器组合工艺的产水率最高。膜面污染物及其影响因素分析表明，膜面污染物主要为固体污泥和溶解性有机物，分别与生物反应器混合液中悬浮污泥浓度和上清液有机物浓度相关。膜－复合式生物反应器膜面沉积的污泥量和吸附的有机物量均居中。因而膜通透量最大。     

MBR在污水处理中的应用与研究进展

膜生物反应器(MBR)是近年来受到广泛关注的污水处理与回用领域的新技术之一.综述了膜生物反应器水处理技术在国内外的应用及研究进展,分析了膜组件性能、混合液特性与操作参数等方面对膜污染形成的影响,指出了预防和控制膜污染的措施,其中包括膜组件自身优化设计、改善工艺运行条件及其膜污染的清洗,最后展望了膜生物反应器技术的前景.     

膜生物反应器在医院污水处理中的应用

通过膜生物反应器在陕西省森林工业职工医院污水处理中的应用实例,对其工艺流程、运行参数进行介绍,分析其运行特点。运行表明,其处理效果达到《医疗机构水污染物排放标准》(GB18466-2005)中综合医疗机构和其他医疗机构水污染物排放限值,且该系统运行稳定、维护费用低,出水水质优良,值得在医院污水处理中推广。     

膜生物反应器中膜污染机理与应对

膜生物反应器是将膜分离技术和生物反应器结合而成的一种新型污水处理工艺,文章主要针对膜生物反应器中膜污染进行了综述,分析了膜污染途径,并提出了应对措施。     

膜生物反应器运行条件的优化及膜污染的控制

初步讨论了膜生物反应器MBR运行条件的优化和膜污染的控制 ,提出低压操作不仅有利于提高能量利用效率 ,而且有利于膜通量长时间保持较高水平。试验结果表明 :膜的污染是造成膜生物反应器能耗较高的主要原因 ;采用恒通量操作方式 ,在运行初期控制初始膜通量 ,有利于控制膜污染的产生 ;反冲洗是保持恒定膜通量 ,维持系统长期稳定运行的有效措施     

基于生物安全风险控制的重力流超滤参数优化及水质安全保障策略

针对中空纤维膜重力流超滤(Gravity-Driven Membrane, GDM)长期运行过程中出现的微生物超标问题,对GDM设计参数(膜丝材质、膜丝孔径和膜丝长度)与出水菌落总数相关性进行了评估。研究结果表明,GDM在长期运行过程中,其超滤膜表面变形菌门微生物相对丰度显著增加,该类微生物的突破行为可能是造成出水微生物超标的主要因素。中空纤维膜的不同设计参数对GDM出水微生物指标具有显著影响,其中亲水性较强(改性PVDF)、膜孔较小(20 nm)的超滤膜对微生物具有较强的吸附能力、筛分能力,而长度相对较短的超滤膜表面水力分布更加均匀,因此上述GDM反应器出水中的微生物数量明显降低。不同设计参数对稳定通量和浊度、色度的去除效率影响较小。因此,可通过优化GDM设计参数,降低GDM出水生物安全风险。进一步提出通过利用紫外消毒及加热煮沸等方式对出水中微生物进行灭活,保障GDM出水水质安全。     

一体化超滤-膜混凝吸附生物反应器饮用水除污染效能

为了提高超滤-膜生物反应器(UF-MBR)的饮用水除污染效果,在其反应器中直接投加粉末活性炭进行吸附和聚氯化铝进行混凝,构建一体化超滤-膜混凝吸附生物反应器(UF-MCABR)。试验结果表明,在投药量为粉末活性炭8mg/L、聚氯化铝10mg/L时,UF-MCABR对TOC和CODMn的去除率比UF-MBR分别提高了37.1个百分点和29.8个百分点;对DOC和UV254的去除率分别提高了40.6个百分点和61.4个百分点,并取得了几乎100%的硝化效率和PO34-—P去除效率。UF-MCABR的膜污染速率较之UF-MBR显著降低。     

Microflora evaluation of two agro-industrial effluents treated by the JACTO jet-loop type reactor system.

Jet-loop type reactors developed in our group have been successfully used for biological treatment of winery and olive oil wastewaters. The objective of the present work was to study the influence of the reactor hydrodynamics, causing high shear stress applied on the nozzle and its influence on the composition of the microbial population. Winery and olive oil industry effluents were treated and analysed. Microbial consortia were enriched and selected under different bio-treatment conditions of the effluents. In the case of the winery wastewaters, the isolates identified belong to the genera of Pseudomonas and Bacillus. Saccharomyces cerevisiae was also present in the consortia but no filamentous fungi were detected. In the case of the olive oil wastewaters, Bacillus megaterium 2 was the predominant microorganism. It was not detected any type of fungi.     

Comparison of linear alkylbenzene sulfonates removal in conventional activated sludge systems and membrane bioreactors.

The potential of a membrane bioreactor (MBR) and a conventional activated sludge (CAS) system to remove polar micropollutants was evaluated using linear alkylbenzene sulfonates (LAS) as model components. Removal efficiencies over 97% were achieved in both reactor systems. The appearance of biological breakdown metabolites and the respirometric response of the sludges to LAS addition indicated that LAS removal was due to biodegradation, rather than sorption phenomena. The effect of operational variables, such as hydraulic retention time, LAS composition and hydrophobicity of the membrane used in the MBR, was negligible in the range tested. A stepwise increase in LAS influent concentration resulted in higher residual effluent concentrations but did not change the procentual removal efficiency. Because an increase in LAS and SPC effluent concentration occurred to a larger extent in the CAS than in the MBR under similar operating conditions, MBRs may turn out to be be more robust with respect to biological degradation of micropollutants than CAS.     

地表水锰污染在水处理中去除研究进展

近年来,我国地表水锰污染现象日趋严重,呈现出季节性、突发性的特点。其主要成因包括外来污染源、岩石土壤的条件、地下水补给和内源性污染。相比于地下水,地表水除锰的研究长期以来未受到足够重视．但可以借鉴鞍为成熟的地下水除锰理论和技术,主要有沉淀法、氧化法、生物法等。其中沉淀法较为简单,处理效果不佳;氧化法技术成熟,应用广泛;生物法环保高效,但大多尚停留在实验阶段,是重点研究方向;其他诸如离子交换法、膜过滤法、吸附法在应用中也都存在一定的局限性。     

Modelling of the extractive membrane bioreactor process based on natural fluorescence fingerprints and process operation history.

A method for non-mechanistic and non-linear modelling of complex biological processes is presented, using the example of the extractive membrane bioreactor (EMB). The model is based on artificial neural networks (ANN), which are able to predict the state of the process from a combination of reactor operational parameters and natural fluorescence fingerprints. Current as well as historic process operation is included in the ANN input vector, in order to account for lag-times within the reactor system and for biofilm dynamics that are dependent on process history. The model is especially relevant for practitioners, as it does not require assumptions on underlying process mechanisms, and it relies on routinely available operational data and on an easy-to-install, non-invasive, in-situ, on-line monitoring method. Moreover, it focuses on the prediction of overall process performance parameters, which are of immediate relevance in practice. The developed model was able to predict the process state very well. Sensitivity analysis revealed that the main impact on process performance stems from process operation rather than the physiological state of the biological culture, and that in the EMB configuration employed process operation history decisively impacts on the process outcome.     

SRB法处理酸性矿山废水的实验研究

硫酸盐酸性矿山废水是我国矿区水污染中对生态环境破坏影响最大的污染源之一,通过实验室静态实验确定高效SRB最佳生长条件参数为温度35℃,pH 7.0,COD/SO42-比值为1.3,Fe2+=150 mg/L。最后,利用自行设计、研制的内升流(流化床)外降流(生物膜滤池)式厌氧生物反应器进行同步除硫、脱氮、除磷、去除重金属离子酸性废水综合治理的可行性研究,实验表明这一研究思路和工艺设计是可行性的,废水综合处理可达到较为满意的效果。     

Influence of hydraulic retention time on UASB post-treatment with UF membranes

A pilot UASB reactor coupled with an external ultrafiltration (UF) membrane was operated under three different hydraulic retention times (HRT) for domestic wastewater treatment. The aim was to assess the HRT influence on system performance and fouling. The highest concentrations of COD, total solids, extracellular polymeric substances (EPS) and soluble microbial products (SMP) in UASB effluent and permeate were found when the UASB reactor was operated under the lowest HRT studied (4 hours); although the fulfillment of Mexican Standard for wastewater reclamation was not compromised. This fact could be attributed to the higher shear stress forces inside the UASB reactor when it was operated at low HRT, which promoted the release of biopolymeric substances in its effluent. Besides, the fouling propensity in the UASB effluent was worsened with HRT reduction, by increasing the fouling rate and the specific cake resistance. Based on these results, it is recommended to avoid operating the UASB reactor at low HRTs (less than 4 hours) in order to control SMP and EPS fouling potential. The results presented also suggest that HRT reduction has a detrimental effect on performance and fouling.     

A comparison of BNR activated sludge systems with membrane and settling tank solid-liquid separation.

Installing membranes for solid-liquid separation into biological nutrient removal (BNR) activated sludge (AS) systems makes a profound difference not only to the design of the membrane bio-reactor (MBR) BNR system itself, but also to the design approach for the whole wastewater treatment plant (WWTP). In multi-zone BNR systems with membranes in the aerobic reactor and fixed volumes for the anaerobic, anoxic and aerobic zones (i.e. fixed volume fractions), the mass fractions can be controlled (within a range) with the inter-reactor recycle ratios. This zone mass fraction flexibility is a significant advantage of MBR BNR systems over BNR systems with secondary settling tanks (SSTs), because it allows changing the mass fractions to optimise biological N and P removal in conformity with influent wastewater characteristics and the effluent N and P concentrations required. For PWWF/ADWF ratios (fq) in the upper range (fq approximately 2.0), aerobic mass fractions in the lower range (f(maer) < 0.60) and high (usually raw) wastewater strengths, the indicated mode of operation of MBR BNR systems is as extended aeration WWTPs (no primary settling and long sludge age). However, the volume reduction compared with equivalent BNR systems with SSTs will not be large (40-60%), but the cost of the membranes can be offset against sludge thickening and stabilisation costs. Moving from a flow unbalanced raw wastewater system to a flow balanced (fq = 1) low (usually settled) wastewater strength system can double the ADWF capacity of the biological reactor, but the design approach of the WWTP changes away from extended aeration to include primary sludge stabilisation. The cost of primary sludge treatment then has to be offset against the savings of the increased WWTP capacity.     

The role of fouling mechanisms in a membrane bioreactor.

The present study has aimed to quantify the role of pore blocking and cake layer in a laboratory scale hollow fibre membrane module in submerged configuration, The membrane reactor (MBR) was fed with raw wastewater, only screened with a 2-mm sieve, collected from the Palermo WWTP. The MBR was characterised by an operating volume of 190 L and equipped with an aeration system located on the bottom of the reactor. The MBR operated for 65 days. The permeate was extracted by imposing a constant flux through the membrane (21 Lh(-1) m(-2)). The results confirm the importance of pore blocking control during start-up. In particular, it provides a rapid irreversible fouling that takes place at the beginning of the filtration process, before the deposition mechanism. Therefore, low suspended solids concentration in the initial phase causes a fast irreversible fouling. This circumstance creates the need for more frequent chemical cleaning after start-up without inoculum. Finally, the results underline that the cake has a mainly reversible feature.     

基于藻类连续生长的生物慢滤池深度净化污水的研究

利用藻类连续生长的生物慢滤池开展污水深度净化实验,通过分析生物慢滤池不同深度区域污染物浓度,考察其对氮磷等污染物质的降解规律。研究结果表明:在生物慢滤池中,总氮的去除主要依靠填料表层中微生物的降解和藻类吸收作用,其降解幅度可达31.5%;总磷的去除主要依靠滤柱深层的滤料的吸附作用以及上覆水中藻类的吸收,其降解幅度可达47.0%;氨氮浓度的降低主要依靠硝化转化作用和滤池上覆水表面的挥发作用,其降解幅度为21.8%。可见,生物慢滤池的上覆水和填料表面存在有大量的微生物和藻类,其对水质的净化起到了关键作用。