外源微生物对共培养生物膜微生态系统的影响研究

通过外源微生物与土著微生物共培养形成生物膜,考察了外源微生物对生物膜形成过程的影响;比较了共培养生物膜与常规生物膜在生物量、生物活性、微生态系统组成与结构等方面的差异.结果表明：共培养系统微生物生物量及生物活性较大;微生物群落结构与组成和常规系统有一定的差异;PLFA谱图总峰面积较大,与脂磷法所测的生物量数据可以相互佐证.     

投加有效微生物强化SBR和SBBR除污效果的研究

将有效微生物（EM）富集培养液分别引入序批式反应器（SBR）和序批式生物膜反应器（SBBR）,构成新型的EM—SBR和EM—SBBR污水处理系统,以不接种EM的SBR和SBBR为对照,分别考察了各反应器的除污效果。结果表明,当EM在SBR中形成稳定的优势菌群后,可显著提高活性污泥的浓度,并可改善污泥的沉降性能;EM—SBR在曝气时间为4 h时对COD和NH4^＋-N的去除率均大于94%,EM—SBBR对COD和NH4^＋-N的去除率比对照组均高出7%左右;EM—SBR因菌种随出水流失造成除污效果下降而需要周期性投菌,EM—SBBR因附着性生物膜的存在有效减少了菌种的流失量,从而使其投菌周期较EM—SBR的大为延长,EM—SBBR除污效果周期性下降的主要原因为菌种退化。     

悬浮生态岛净化氮污染河水及其微生物种群结构

采用一种新型的生物膜载体材料构建复合悬浮生态岛,考察其对氮污染河水的净化效果及载体上的微生物特征,并与普通生态浮岛进行对比。结果表明,在相同条件下,复合悬浮生态岛对河水的净化效果更好,COD、氨氮、TN平均去除率分别为26. 77%、92. 86%、30. 83%。对载体生物膜样品的高通量测序发现,与普通的纤维丝载体相比,新型载体生物膜中的菌群种类更多、微生物结构更复杂;另外,其微生物群落多样性更高(Shannon指数高、Simpson指数低)。     

上海市供水管网内壁生物膜的微生物特征分析

采用富集培养、分离纯化等微生物学方法对上海市供水管网生物膜中的微生物特征进行了分析。结果表明：直接采用电镜观察管壁上的生物膜样品，难以看到微生物的明显生长；经富集培养和分离纯化后，所观察到的生物膜中的微生物以细菌尤其是杆菌居多，且阀门上生物膜中的微生物种群较管壁上的丰富；从所取生物膜样品中还分离出了放线菌和真菌，这些微生物不是管网生物膜中微生物种群的主体，但它们的存在增加了微生物种群的复杂性。     

水平流生物膜反应器处理村镇污水的运行特性

分别采用聚乙烯平板和无纺布负载平板作为水平流生物膜反应器(HFBR)的载体,考察了不同载体对HFBR除污效果的影响。中试结果表明,采用聚乙烯平板和无纺布负载平板作为HFBR的载体时对COD和氨氮均有较好的去除效果。但聚乙烯平板上的生物量相对较低,与无纺布负载平板相比,处理同样污水所需的载体平板数较多。当进水COD为150 mg/L、氨氮为22mg/L时,以无纺布负载平板作为生物膜载体的HFBR对COD和氨氮的去除率分别为85.0%和99.5%。通过测定污染物浓度的沿程变化及对主要功能微生物的荧光原位杂交分析可知,污染物的浓度随着流程而逐层下降,主要功能菌群所占比例随着对应基质浓度的改变而相应变化。     

微污染北江源水的深度处理工艺优选

采用预氧化＋常规处理＋深度处理工艺对微污染北江源水进行了中试研究，考察了在预臭氧、预氯化和无预处理方式下，GAC和O3-BAC深度处理工艺的除污效果。结果表明：采用预臭氧氧化方式可大大改善常规处理工艺对CODMn、UV254的去除效果；在预臭氧氧化方式下，O3-BAC和GAC深度处理工艺均能在长时间内保持对有机物的高效去除，且前者的去除效果及其活性炭的使用周期均优于后者；活性炭吸附对氨氮无明显去除效果，而生物降解能较好地去除氨氮；预臭氧氧化能有效去除原水中的THMFP，但生成的CHCl3不能通过生物降解被去除，只能被活性炭所吸附，在活性炭吸附饱和后出水CHCl3浓度比进水的高；从长远角度考虑，对于北江源水，预臭氧＋常规处理＋O3-BAC是一种较优的组合工艺，它能够有效去除饮用水中的有毒、有害物质，并保障饮用水的安全性。     

牡丹区池塘微生态制剂水质底质调控技术分析

微生态制剂是利用经过特殊筛选的微生物进行基因调控和驯化，具有快速降解、吸收和转化水产养殖环境中的有机污染物（残饵、粪便和生物死体）和氮、磷等，并能形成优势种群，有效抑制有害微生物和有害藻类的生长繁殖等作用。该项技术在我省部分地区应用以来，达到了优化养殖环境、增强养殖生物抗病能力、促进快速生产等综合效果，显著提高了产量、减少了疾病的发生，增加了养殖效益，是一项绿色、高效、生态型的实用技术。2014年为充分反映微生态制剂的使用效果，我们选择有20多年历史，主养草鱼的刘寨水产养殖小区作为这次对比试验的养殖场。通过筛选我们选取了2个条件相近的池塘作为试验池和对照池，使用的微生态制剂为山东君德生物科技有限公司生产的EM原液。通过对比试验和广大养殖户反馈的信息来看，使用微生态制剂可以显著改善水体环境，即提高水体透明度和溶解氧，同时减少鱼病发生。     

铁离子促进悬浮载体挂膜的机理研究

从铁离子影响生物膜中胞外聚合物形成的角度,通过对比试验研究了铁离子促进填料挂膜的机理。结果表明,含较多铁离子的污水可提高填料上的生物膜量,并使生物膜具有更高的除污能力。铁离子可增加生物膜中胞外聚合物的含量,特别是蛋白质的含量,而胞外聚合物的凝聚作用可提高填料的挂膜速度及填料上附着的生物量;又因蛋白质中含有大量生物催化酶,故可增强生物膜的除污能力。铁离子作为胞外聚合物的连接剂,更多地与糖类官能团连接在一起,胞外多糖可能与生物膜的附着性能有关。     

输水管道生物膜的生长过程及其对水质的影响

运用生物膜反应器(BAR)模拟实际原水输水管道,研究了管道运行时间对生物膜微生物群落结构及出水微污染物浓度的影响。结果表明,随着BAR反应器运行时间的延长,出水p H值和CODMn浓度变化较小,溶解氧、氨氮和总氮浓度逐渐降低,运行180 d时,对氨氮和总氮的去除率最高,分别为41.3%和30.3%,浊度呈曲线变化;采用454高通量测序对运行90、120、180和240 d的四个生物膜样品中微生物群落结构进行分析,发现其微生物群落结构存在较大差异,90d的生物膜的微生物多样性最高,而240 d的生物膜具有最高的微生物丰度;BAR系统水质影响生物膜微生物的群落结构,同样,生物膜中的微生物净化了出水。     

具有生物活性的炭砂双层滤池的研究与展望

普通滤池主要通过滤料与颗粒间的接触凝聚作用实现对悬浮颗粒、胶体杂质和细菌等的去除,但对于日益增多的可溶性的有机和无机污染物的作用甚微。生物过滤通过活性炭滤料拦截捕捉水中的微生物产生生物膜,发挥生物膜的生物降解作用和活性炭的吸附作用使水中污染物得以有效去除,是一种将常规过滤、颗粒活性炭吸附与生物膜氧化技术结合在一起的新型过滤工艺。将传统的常规滤池升级改造为具有生物活性的炭砂双层滤池是一种经济实用、适合现阶段我国国情的改善饮用水水质的重要途径,有着可观的应用前景。     

Discriminating and assessing adsorption and biodegradation removal mechanisms during granular activated carbon filtration of microcystin toxins

Microcystins are cyanobacterial toxins that are problematic for water authorities due to their resistance to conventional water treatment. Granular activated carbon (GAC) filtration has been shown to be effective in removing microcystin from water using both adsorption and biodegradation removal mechanisms; however, little is known regarding which removal mechanism predominates and to what extent. In this study, microcystin removal due to adsorption and biodegradation in GAC filtration were discriminated and assessed by commissioning three parallel laboratory columns, including a sterile GAC column, a conventional GAC column and a sand column. The results demonstrate that biodegradation is an efficient removal mechanism once it commences and that the rate of biodegradation was dependent upon temperature and initial bacterial concentration. Adsorption of microcystins was prevalent during the initial stages of the GAC columns and was modelled using the homogeneous surface diffusion model (HSDM). The HSDM provided evidence that an active biofilm present on the surface of the conventional GAC hindered adsorption of microcystin compared with the sterile GAC with no active biofilm. Up to 70% removal of microcystin-LR was still observed after 6 months of operation of the sterile GAC column, indicating that adsorption still played a vital role in the removal of this toxin.     

Theoretical investigation of particle deposition in biofilm systems

Experience has shown that the performance of biofilm reactors is strongly influenced by the size distribution of the constituents being biologically oxidized. Processes of diffusion, interception, and sedimentation that affect the transport of solid particles are presented and applied to biofilm systems. Biofilm systems with media of small diameter or long hydraulic residence time (fixed-bed, soil treatment, and fluidized-bed) can be effective for removing submicron particles through diffusion and interception. In systems with horizontal biofilm surface area, large particles (> 10–50 μm) can be removed by sedimentation. The slow mass transfer of particulate BOD can cause biodegradation rates to be much slower than for soluble species. An understanding of particle behavior will facilitate development of better models of biofilm systems. Areas that merit further research are indicated.     

Fate of antibiotics in activated sludge followed by ultrafiltration (CAS-UF) and in a membrane bioreactor (MBR)

The fates of several macrolide, sulphonamide, and trimethoprim antibiotics contained in the raw sewage of the Tel-Aviv wastewater treatment plant (WWTP) were investigated after the sewage was treated using either a full-scale conventional activated sludge (CAS) system coupled with a subsequent ultrafiltration (UF) step or a pilot membrane bioreactor (MBR) system. Antibiotics removal in the MBR system, once it achieved stable operation, was 15-42% higher than that of the CAS system. This advantage was reduced to a maximum of 20% when a UF was added to the CAS. It was hypothesized that the contribution of membrane separation (in both systems) to antibiotics removal was due either to sorption to biomass (rather than improvement in biodegradation) or to enmeshment in the membrane biofilm (since UF membrane pores are significantly larger than the contaminant molecules). Batch experiments with MBR biomass showed a markedly high potential for sorption of the tested antibiotics onto the biomass. Moreover, methanol extraction of MBR biomass released significant amounts of sorbed antibiotics. This finding implies that more attention must be devoted to the management of excess sludge.     

Short-term tests with a pilot sewage plant and biofilm reactors for the biological degradation of the pharmaceutical compounds clofibric acid,ibuprofen, and diclofenac

The biodegradation of three active compounds of pharmaceuticals clofibric acid, ibuprofen, and diclofenac was investigated in short-term tests with a pilot sewage plant (PSP) and biofilm reactors (BFR, oxic and anoxic) as model systems for municipal sewage treatment. The PSP was characterized with respect to mixing behavior, the BFR with respect to biofilm content and sorption of the pharmaceutical compounds. The short-term experiments were carried out for 55 h in the PSP and for 48 h in the BFR. The concentration of the pharmaceuticals was in the microgram per liter range in presence of readily biodegradable substances in the milligram per liter range. Therefore, a too short time period and too low concentration to promote adaption of the microorganisms were applied. Under the operating conditions applied the biodegradation of the lipid lowering agent clofibric acid and the analgesic agents ibuprofen and diclofenac in the oxic BFR resembled that in the PSP. Clofibric acid and diclofenac were not eliminated and reached a level of approximately 95% of their initial concentration, whereas the concentration of ibuprofen was decreased to approximately 40% in the PSP and to approximately 35% in the oxic BFR. Both systems showed, therefore, an inherent ability for ibuprofen biodegradation. Elimination in the anoxic BFR resulted in a decrease of the concentration of all three substances to values between 60 and 80% of their initial concentration. In contrast to the PSP acetone revealed as inhibitor in the BFR. In both systems acetone was not degraded in the short-term tests.     

Modeling of aerobic biodegradation of feces using sawdust as a matrix

Composting in the bio-toilet system is a continuous thermophilic-aerobic biodegradation process. Unlike to the traditional composting systems, biodegradation rates of organic matter are very important because feces are daily added into the composting reactor of the bio-toilet and an accelerated decomposition is aimed. The models developed for conventional composting processes include simple formulations of biodegradation kinetics and deal mainly with energy and water balances. Therefore, formulation of kinetics that can reasonably describe the biodegradation process in the bio-toilet system is required for better modeling predictions. In this work, a bio-kinetic model was introduced to describe the aerobic biodegradation of feces in the bio-toilet system. This model includes three processes for carbonaceous material degradation and is prepared by using the activated sludge modeling techniques and formulations. Stoichiometric parameters were adopted from literature on activated sludge processes. Kinetic parameters were estimated by conducting batch tests for several organic loadings and by using respirometry, curve-fitting techniques, and sensitivity analysis. Feasibility and applicability of these parameters were assessed by conducting feces intermittent-feeding tests and by simulating the experimental respiration rates. Model, stoichiometric and kinetic parameters proved to be affordable for describing the biodegradation of feces in the bio-toilet system.     

The effects of UV disinfection on distribution pipe biofilm growth and pathogen incidence within the greater Stockholm area, Sweden

An assessment of the effects of the transition from conventional chlorination to UV disinfection on potable water biofilm growth and pathogen incidence was made. Two hydraulic systems were tested, one a 1.0 km polyethylene pilot-scale system within the Lov? waterworks, Stockholm, Sweden, as well as H?sselby and Nockeby municipal distribution systems within the greater Stockholm area. Biofilms were propagated on coupons and the amount of biomass analysed by standard culture and molecular methods. There was no measurable difference in biofilm biomass or pathogen incidence in the transition from conventional chlorination to UV-treatment in any system examined. With the exception of aeromonads, frank (salmonellae, enterobacteria) and opportunistic (legionellae) pathogens as well as indicator bacteria (E. coli, coliforms, enterococci) could not be detected within biofilms in either the pilot-scale or large-scale municipal system. Free-living protozoa were detected almost ubiquitously in biofilm samples in either experimental system though their exact significance and impact remains unknown and warrants further investigation.     

低温条件下生物转盘处理低浓度污染地表水

为实现低温条件下(冬季水温为8~15℃)快速启动生物转盘处理低浓度污染地表水,采用自然挂膜法G1、活性污泥挂膜法G2和硝化菌挂膜法G3这3种方式进行生物转盘挂膜,并对出水指标与生物膜表观形貌、群落组成进行对比研究。结果表明,从启动速率与抗冲击负荷能力来看,G3>G2>G1;25 d后接种硝化菌的生物转盘对氨氮的去除率即可达到88.78%。稳定运行后,3种挂膜方式的生物转盘对低浓度污染地表水的处理效果相近,对NH4+-N和COD的去除率均可稳定在90%和20%。3种挂膜方式的微生物丰度与种类相似,与硝化反应有关的细菌主要有Nitrosospira、Candidatus nitrotoga、Nitrosomonas,在3种挂膜方式中分别占比15.85%、12.04%、12.47%;与COD降解有关的细菌主要有Reyranella、Thermomonas、Polymorphobacter、Sphingomonas与Arenimonas,在3种挂膜方式中分别占比10.69%、12.39%、15.02%。微生物多样性和均匀度呈现出后端生物转盘盘片大于前端的趋势,说明微生物种类和均匀度与污染物种类和浓度有关。     

Determination of nutrients limiting biofilm formation and the subsequent impact on disinfectant decay.

Understanding the contribution of both organic and inorganic nutrients to biofilm development and the subsequent impact of developed biofilms on disinfectant decay are important requirements for distribution system management strategies. Nutrient limitation may be one way to control biofilm development without increasing disinfectant dosing. Little is known, however, of the nutrient requirements of biofilms in distribution systems. Indeed, the effects on biofilm development due to the addition of nutrients to distribution systems and what impact biofilm development may have on disinfectant decay is still poorly understood. This study used annular reactors to determine the nutrients limiting for biofilm development in drinking water from two different Sydney sources and the subsequent effects of biofilm development on disinfectant decay. It was found that biofilm development in Sydney water was limited by organic carbon and that biofilm development promoted chloramine decay. Moreover, biofilm development occurred in the presence of chloramine. The ability of biofilms to respond to increases in disinfectant concentrations was dependent on the biomass of the biofilms. In a comparative study using chlorinated drinking water containing very low levels of organic carbon, biofilm development was not detected. Removal of organic carbon resulted in greater persistence of chlorine, which led to greater biofilm control. It was also shown that biofilms could contribute cells to the aqueous phase. The results of the study indicate that treatment and system management strategies should incorporate organic carbon removal to limit biofilm development through a combination of retarding bacterial growth and enhancing disinfectant persistence.     

Nitritation performance in membrane-aerated biofilm reactors differs from conventional biofilm systems

Nitrogen removal via nitrite has gained increasing attention in recent years due to its potential cost savings. Membrane-aerated biofilm reactors (MABRs) are one potential technology suitable to achieve nitritation. In this study we compared lab scale MABRs with conventional biofilm reactors to evaluate the influence of environmental conditions and operational parameters on nitritation performance. The oxygen mass transfer rate is postulated as a crucial parameter to control nitritation in the MABR: Clean water measurements showed significant underestimation of the total oxygen mass transfer, however, accurate determination of the oxygen mass transfer coefficient (k_m) of the system could be achieved by adjusting the liquid-phase mass transfer resistance in the constructed model. Batch experiments at different initial ammonium concentrations revealed that the conventional biofilm geometry was superior for nitritation compared to MABRs. These differences were reflected well in estimates of the oxygen affinity constants of the key microbial players, AOB and NOB (K_O,AOB < K_O,NOB (in both systems) and K_O,NOB values smaller in the MABR vs. the conventional biofilm system). It also appeared that – in addition to oxygen limitation – the absolute and relative substrate concentrations in the biofilm (esp. of oxygen) are very important for successful nitritation. Initial biomass composition, furthermore, impacted reactor performance in the MABR systems indicating the need for appropriate inoculum choice.