MBBR两种填料对养猪废水脱氮除磷效果对比

为了探讨移动床生物膜反应器中不同填料对废水脱氮除磷效果的影响,采用碳纤维球和聚乙烯塑料两种不同悬浮填料进行对比试验。在不同运行条件下,分别测定氨氮、总氮、总磷、COD等指标,对比挂膜和脱氮除磷效果。结果表明,碳纤维球填料挂膜速度快,在不同运行条件下均比聚乙烯塑料填料对COD、NH4+-N、TN、TP等的去除效果好,去除率分别可达91.2%、98.0%、77.5%、68.1%。这说明比表面积大、孔隙率高的填料挂膜更快,挂膜量更多,更有利于实现同时生物脱氮除磷。     

微生物燃料电池生物阴极

微生物燃料电池(microbial fuel cells, MFCs)利用微生物处理废水的同时产电,是一种清洁可再生能源技术。近年来新兴起的生物阴极是指阴极室中的功能微生物附着在电极表面形成生物膜,电子由电极传递给微生物并发生相应的生物电化学反应;是微生物燃料电池研究的一个重要方向。本文根据厌氧、好氧操作体系的不同将生物阴极进行分类;归纳总结了微生物组成、电极和分隔材料的研究进展,探讨了生物阴极在去除污染物和生成高附加值产品中的实际应用,并提出了其将来发展的可能方向。     

厌氧悬浮填料生物膜反应器处理费托合成废水

采用厌氧悬浮填料生物膜反应器工艺对费托合成废水进行处理,考察了高有机负荷条件下系统的运行情况.有机负荷小于31.1g/(L·d)时,COD去除率达97%以上;当有机负荷从39.7g/(L·d)增加至56.3g/(L·d)时,厌氧反应对COD的去除率从88%降至6l%.实验结果表明,填料生物膜比悬浮污泥具有更高的活性,M...     

离子交换膜对采用生物膜电极法降解五氯酚的影响

以五氯酚（PCP）为目标污染物,在隔膜式电解槽中研究了不同离子交换膜对采用生物膜电极法处理五氯酚的影响. 结果表明,阴离子交换膜有利于五氯酚在生物膜电极上的转化和中间产物的去除;与生物法和电化学法降解五氯酚相比,采用以钛基二氧化铅为阳极（Ti/PbO₂）、生物膜电极为阴极、阴离子交换膜为隔膜的电解槽处理时,五氯酚的降解效果明显优于生物法和电化学方法,经24 h处理后五氯酚的去除率和化学需氧量（COD）去除率均可达到96%（质量分数）.     

聚硅硫酸铁絮凝剂去除市政污水磷的研究

将自制复合絮凝剂聚硅硫酸铁(PFSS i)用于市政污水除磷,考察了影响PFSS i除磷效果的一些因素,确定了PFSS i复合絮凝剂除磷的优化配比和用量。在优化条件下,对模拟污水中磷的去除率为96.7%,浊度去除率为92%;对实际污水中磷的去除率为82.3%,浊度去除率为96.5%。结果表明该复合絮凝剂有良好的除磷、除浊性能。     

A/O固定生物膜系统处理焦化废水的研究

中国是一个用煤大国, 而焦化废水是一种有害、难处理的工业废水. 因此, 焦化废水的处理问题在中国就显得尤为重要. A/O固定生物膜系统结合了A/O处理工艺与固定化微生物技术, 是一种较为先进的废水处理系统. 文中通过大量的试验, 研究了A/O固定生物膜系统这一技术处理焦化废水的可行性. 在试验系统中, 缺氧反应器和好氧反应器中均安装了半软性填料. A/O固定生物膜系统的处理效率受许多参数的影响, 例如: HRT, C/N比, OLR, 以及回流比R. 文中研究了这些参数对系统废水处理效率的影响程度. 试验结果表明, 充足的碳源对于生物降解系统而言, 是非常重要的. 将碳氮比C/N从2.5提高到5, 焦化废水的COD去除率相应地将从 64.15%上升到83.28%. 为更好地提高出水的水质, 在混凝技术对废水进行废水处理领域, 也作了一定的尝试. 试验结果还表明, 用A/O固定生物膜系统处理焦化废水, NH4-N的去除率是非常令人满意的, 最高去除率可高达99%. 由此可见, 采用A/O固定生物膜系统处理焦化废水是可行的.     

生物膜电极法降解水中2-萘酚的影响因素

以2-萘酚为目标污染物,在对比电化学法和微生物法降解效果的基础上,研究了隔膜式电解体系中基体材料性质、电解池隔膜种类、温度和电流密度对生物膜电极法降解2-萘酚作用效率的影响.结果表明,生物膜电极法相比传统的电化学法和微生物法对2-萘酚类污染物的去除有一定优势,其作用效果与微生物生长状态有直接关系.以碳毡为基体的生物膜电极降解效果起始阶段优于钛网基生物膜电极,但一段时间后钛网基生物膜电极降解性能更稳定.阴离子交换隔膜电解池体系对2-萘酚的降解效果优于阳离子交换隔膜电解池体系,35℃条件下0.5 mA/cm²电流密度是最佳作用条件.     

废水生物处理过程中微生物胞外聚合物与污染物的分子间相互作用

生物处理是废水处理的主要技术手段,其中微生物在新陈代谢过程中会分泌一种复杂的高分子混合物——胞外聚合物(EPS),覆盖在微生物表面,它们是影响微生物表面特性的关键物质,在水体环境和废水处理系统中对污染物的迁移转化和去除起着至关重要的作用.研究结果表明,EPS能够利用其丰富的官能团吸附水体中的重金属和有机污染物,还可以通过氢键与氮、磷等营养元素发生相互作用.另外EPS具有一定的氧化还原特性,可以通过氧化还原反应改变污染物的存在形式.因此EPS在废水生物处理过程中具有重要的作用,可以影响重金属和有机污染物在废水生物处理过程中的去除和转化.发展高灵敏的分析方法,深入研究和理解EPS与不同污染物的分子间相互作用,对于阐明不同污染物在废水生物处理过程中的去除机制具有重要的指导意义.     

隔膜式电解槽生物膜阴极降解苯酚的过程及其条件的优化

以炼油废水中的主要污染物苯酚为目标污染物, 采用不同生物膜电极反应器对苯酚进行降解, 从而寻找出降解苯酚的最佳反应途径. 研究结果表明, 运用隔膜式电解槽生物膜阴极区域对苯酚废水进行处理, 其苯酚的去除效果虽然没有在生物膜阴极与阳极相混合的混合式反应器中处理效果好, 但在18 h内苯酚浓度降解到0, 并且其化学需氧量(COD)去除率最高, 在16 h内COD去除率达到80%. 对于隔膜式电解槽生物膜阴极区域的降解条件优化后发现, 电流设定为5 mA, 初始苯酚质量浓度低于200 mg/L, 温度为35 ℃时, 苯酚降解效果最佳.     

利用原子力显微镜和分子技术研究海水微生物腐蚀(英文)

生物膜在自然界无处不在,但生物膜造成的腐蚀却基本上被忽视.本文展示了几种化学和微生物学新方法在海水微生物腐蚀研究中的应用.原子力显微镜用来揭示生物最初形成的机理和钢在受污染海水中的腐蚀程度,16SrDNA/RNA技术则用来分析生物膜中的微生物组成.试验结果表明,微生物腐蚀在6d内就已经开始了,腐蚀体积与时间的2.83次方成正比;腐蚀生物膜中的微生物以硫酸还原菌(脱硫弧菌科)为最多,其次是梭状芽孢杆菌.     

Nutrient Removal and Biomass Production in an Outdoor Pilot-Scale Phototrophic Biofilm Reactor for Effluent Polishing

An innovative pilot-scale phototrophic biofilm reactor was evaluated over a 5-month period to determine its capacity to remove nitrogen and phosphorus from Dutch municipal wastewater effluents. The areal biomass production rate ranged between 2.7 and 4.5 g dry weight/m²/day. The areal nitrogen and phosphorus removal rates averaged 0.13 g N/m²/day and 0.023 g P/m²/day, which are low compared to removal rates achieved in laboratory biofilm reactors. Nutrient removal increased during the day, decreased with decreasing light intensity and no removal occurred during the night. Additional carbon dioxide supply was not requisite as the wastewater was comprised of enough inorganic carbon to sustain microalgal growth. The study was not conclusive for the limiting factor that caused the low nutrient removal rate, possibly the process was limited by light and temperature, in combination with pH increases above pH 9 during the daytime. This pilot-scale study demonstrated that the proposed phototrophic biofilm reactor is not a viable post-treatment of municipal wastewater effluents under Dutch climate conditions. However, the reactor performance may be improved when controlling the pH and the temperatures in the morning. With these adaptations, a phototrophic biofilm reactor could be feasible at lower latitudes with higher irradiance levels.     

基于稳定的膦叶立德合成2(5H)-呋喃酮和2(5H)-吡咯酮作为细菌群体感应抑制剂的研究

利用稳定的乙酸乙酯基膦叶立德与含羰基化合物反应,合成了不同的2(5H)-呋喃酮,然后将获得的部分2(5H)-呋喃酮与醋酸铵反应转化为2(5H)-吡咯酮类化合物.所合成化合物均经1H NMR、13C NMR和MS等确认.通过测定所得到的化合物对于绿脓杆菌的最低抑菌浓度(MIC)来检验其抑菌活性;利用细莆生物膜染色实验来检测所得到的化合物对细菌群体感应系统和细菌生物膜的影响.活性实验结果表明,所得到的2(5H)-呋喃酮类化合物和2(5H)-吡咯酮类化合物均具有一定的抑制细菌群体感应的能力.     

Quantitative and morphological analysis of biofilm formation on self-assembled monolayers

In spite of intensive studies over the past two decades, the influence of surface properties on bacterial adhesion and biofilm formation remains unclear, particularly on late steps. In order to contribute to the elucidation of this point, we compared the impact of two different substrates on the formation of bacterial biofilm, by analysing bacterial amount and biofilm structure on hydrophilic and hydrophobic surfaces. The surfaces were constituted by NH₂- and CH₃-terminated self-assembled monolayers (SAMs) on silicon wafers, allowing to consider only the surface chemistry influence because wafers low roughness. A strain of Escherichia coli K12, able to produce biofilm on abiotic surfaces, was grown with culture durations varying from 4 h to 336 h on both types of substrates. The amount of adhered bacteria was determined after detachment by both photometry at 630 nm and direct counting under light microscope, while the spatial distribution of adhered bacteria was observed by fluorescence microscopy. A general view of our results suggests a little influence of the surface chemistry on adherent bacteria amount, but a clear impact on dynamics of biofilm growth as well as on biofilm structure. This work points out how surface chemistry of substrates can influence the bacterial adhesion and the biofilm formation.     

Improved procedure for wastewater biofilm removal and analysis

Fixed-film processes for wastewater treatment are becoming widely used. Their efficiency is usually estimated only from substrate removal rate measurements. A better understanding of fixed culture composition and activity is needed to optimize processes in which they are involved. These analyses often require that biofilms are removed from their substrata, but this procedure is one of the most limiting steps in biofilm investigations, especially when cell counts are involved.

The main objective of the study was to develop an optimal removal procedure based on sonication for analysis of biofilm parameters such as total and active bacterial counts by epifluorescent microscopy (4',6-diamidino-2-phenylindole (DAPI) and 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) stainings) and total organic content as estimated by total proteins determination and chemical oxygen demand measurements. Experiments were carried out on nitrifying biofilms developed on a plastic granular substratum.

Results confirmed that the removal step is crucial in biofilm analysis. The repeatability of bacterial enumeration was evaluated as well as the efficiency of sonication treatment and optimal conditions for attached cell removal. Within the studied range of sonication conditions, the sonication time and the duty cycle improved the removal efficiency of active bacteria, whereas the sonication power had the opposite effect.     

Surfactant-induced detachment of monodispersed hematite particles adhered on glass

The effects of an anionic (sodium 4-octylbenzenesulfonate, NaOBS) and a cationic (1-dodecylpyridinium chloride, DPC) surfactant on the detachment of colloidal hematite particles adhered to glass beads was studied using the packed column technique. Both additives induced particle removal at concentrations above those necessary for the reversal of charge either on particles or on beads, in order to induce a repulsion between interacting surfaces. The amount of detached hematite was substantially increased as the surfactant concentrations exceeded the corresponding critical micellization concentrations (CMC). Particle removal was shown to follow first order kinetics with two distinctively different rate constants. The value of the constant for rapid removal, k(r), was substantially higher than that established in earlier studies for detachment of the same particles with NaOH solutions.     

Dynamic removal of oral biofilms by bubbles

A novel approach to the removal of biofilms from solid surfaces is to pass large numbers of air bubbles over the surfaces. Such a phenomenon occurs when teeth are brushed with some types of powered toothbrushes that accelerate bubbly fluid against or across teeth surfaces. Video recordings of air bubbles propelled against a mature biofilm of Streptococcus mutans showed that the bubbles removed the biofilm at the point of collision. A mathematical model of the removal process was proposed and was able to simulate the kinetics of the biofilm removal process. Removal rate was modeled to be proportional to the bubble footprint area and the number of collisions per time. The fraction of biofilm removed per bubble collision is on the order of 0.4, a value much larger than would have been expected based on previous research employing bubbles that moved slowly along a surface that was partially covered with adherent bacteria. The higher removal efficiency is attributed to fluid dynamic shear forces that occur in conjunction with the thermodynamic forces that pull bacteria from a surface as a bubble contacts the biofilm. Fast bubbly flow is expected to remove bacterial biofilm from hard surfaces such as teeth.     

Representative applications of heparin-sepharose in the removal of polyamines from biological materials

Many experimental systems would greatly benefit from the availability of a simple and effective technique to remove polyamines from biological materials. We have examined the possibility of utilizing heparin-sepharose in the removal of polyamines from rat heart mitochondria, DNA-spermine complex, and fetal calf serum. Heparin-sepharose removes 90% of spermine adsorbed to the cytoplasmic surface of rat heart mitochondria. Heparin-sepharose almost totally removes spermine from DNA-spermine complex, leaving less than 0.003 mol spermine/mol DNA phosphorus. Heparin-sepharose is highly effective in removing spermine and spermidine (99.5 and 95% adsorbed, respectively) from fetal calf serum. Under the same experimental conditions only 50% of putrescine is adsorbed. A higher amount of resin corresponding to an increased capacity for putrescine must be used to achieve a satisfactory removal of putrescine.     

A biological breadboard platform for cell adhesion and detachment studies

The dynamic nature of cell adhesion and detachment, which plays a critical role in a variety of physiological and pathological phenomena, still remains unclear. This motivates the pursuit of controllable manipulation of cell adhesion and detachment for a better understanding of cellular dynamics. Here we present an addressable, multifunctional, and reusable platform, termed the biological breadboard (BBB), for spatiotemporal manipulation of cell adhesion and detachment at cellular and subcellular levels. The BBB, composed of multiple gold electrodes patterned on a Pyrex substrate, is surface-modified with arginine-glycine-aspartic acid terminated thiol (RTT) and polyethylene glycol (PEG) to achieve a cell-adhesive surface on the gold electrodes and a cell-resistive surface on the Pyrex substrate, respectively. Cell adhesion is regulated by the steric repulsion of PEG chains, while cell detachment is controlled by the reductive desorption of a gold-thiol self-assembled monolayer (SAM) at an activation potential of -0.90 to -1.65 V. Experimental characterizations using NIH 3T3 fibroblasts are presented to demonstrate the utility of our device.