生物反应器法处理油泥污染土壤的研究

采油过程产生的油泥是整个石油烃污染源的重点。在陆地生态环境中 ,烃类的大量存在往往对植物的生物学质量产生不利影响 ,更重要的是石油中的一些多环芳烃是致癌和致突变物质 ,这些致癌和致突变的有机污染物进入农田生态系统后 ,在动植物体内逐渐富集 ,进而威胁人类的生存和健康[1 ,1 1 ] 。大量的废弃油泥 ,不仅污染农田 ,同时也给石油行业带来巨大的经济损失。污染土壤的治理主要有物理、化学和生物 (生物修复 )方法 ,生物修复方法被认为最有生命力。污染土壤生物修复技术主要有 3种 ,即原位处理、挖掘堆置处理和反应器处理。反应器处理是…     

土壤生物与土壤污染研究前沿与展望

随着社会经济发展,人类生产活动对自然环境产生越来越广泛深刻的影响,土壤污染已成为危及生态系统稳定、农产品质量安全和人体健康的突出环境问题之一。重金属、有机污染化合物、病原菌及抗性基因等各类污染物大量进入土壤后,对土壤生物系统造成毒害作用,影响到土壤生态功能;另一方面,土壤生物如细菌、真菌、土壤动物等在一定程度上能够适应土壤污染,深刻影响着污染物在土壤中的迁移转化过程,在土壤污染修复中具有潜在重要作用。从土壤污染的生态毒理效应、土壤生物对土壤污染的响应与适应机制、污染土壤修复原理与技术等三方面综述了土壤生物与土壤污染相关研究前沿,展望了重点研究方向。     

我国污染土壤生物修复技术的发展及现状

本文简要回顾了近30年来我国污染土壤生物修复技术的发展过程,主要包括生物修复技术在我国的发展阶段、生物修复的4大类型及其所适用对象与范围、生物修复用菌株的筛选与特性研究、活性菌株(菌剂)在典型污染土壤中的应用及其效果等,并针对土壤污染和生物修复技术的发展现状,简要讨论了未来生物修复技术的发展。     

污染土壤的生物修复治理技术研究进展

污染土壤的生物修复技术是一种极具潜力的土壤污染绿色修复治理方法,具有高效低耗、环境友好等特点。通过对动物修复、植物修复、微生物修复及联合修复等土壤生物修复治理技术进行分析,探讨了各种工艺技术对重金属、有机物等目标污染物的修复性能及优缺点,旨在为我国土壤污染修复治理技术的选择提供参考。     

多环芳烃和重金属复合污染土壤生物修复研究进展

多环芳烃(PAHs)和重金属是土壤环境中有机和无机污染物的典型代表，二者来源广泛且能在土壤中长期存在，极易造成复合污染。研究表明，PAHs和重金属共存时会发生复杂的相互作用，使复合污染土壤修复往往比单一污染土壤修复更加困难。生物修复具备成本低、不造成二次污染、适用于大范围修复等优势，是极具应用前景的PAHs和重金属复合污染土壤修复技术。本文总结了土壤中PAHs和重金属复合污染的分布特点及交互作用，对PAHs和重金属复合污染土壤生物修复技术作用机理及研究进展进行了综述，并对PAHs和重金属复合污染土壤生物修复技术的发展提出了展望。     

生物反应器法处理PAHs污染土壤的研究

利用自行设计的生物泥浆反应器研究了多环芳烃 (PAHs)污染土壤生物修复技术 .结果表明 ,在相同环境条件下 ,污染物自身的理化性质是影响生物修复的关键因素 ,苯环越多、分子量越大 ,越难以被微生物利用 ,故菲 (PHE)比芘 (PY)具有更高的污染可修复性 .温度、空气流量是重要的调控因子 .本实验中 ,生物泥浆反应器处理PAHs污染土壤选择的最佳运行工艺参数是 :温度 2 0～ 30℃ ,水土比 2∶1,空气流量8L·h-1·L-1,接种量 5 0g·kg-1.该工艺参数为生物泥浆反应器技术实用化及其他相关研究工作的深入开展提供了理论依据     

生物表面活性剂修复HOCs污染土壤的研究进展

简要介绍了疏水性有机污染物(HOCs)在土壤环境中积累产生的危害及应用生物表面活性剂(BS)修复HOCs污染土壤的优势.阐明了BS修复HOCs污染土壤的主要机理:BS对HOCs的增溶作用、BS促进土壤中HOCs的解吸、BS促进土壤中HOCs的生物降解.分析了BS的种类及含量、污染土壤对BS的吸附、土壤本身的理化性质等因素对土壤生物修复的影响.探讨了HOCs污染土壤生物修复的发展方向及应用前景.     

AM真菌对重金属污染土壤生物修复的应用与机理

土壤重金属污染威胁人类健康和整个生态系统,而高效、低耗、安全的生物修复技术显示出了极大的应用潜力,特别是利用植物-微生物共生体增强生物修复效应的应用.丛枝菌根(Arbuscular Mycorrhizae,AM)真菌是一类广泛分布于土壤生态系统中的有益微生物,能与90％以上的陆生高等植物形成共生体.研究发现,AM真菌能够增强宿主植物对土壤中重金属胁迫的耐受性.当前,利用AM真菌开展重金属污染土壤的生物修复已经引起环境学家和生态学家的广泛关注.基于此,围绕AM真菌在重金属污染土壤生物修复作用中的最新研究进展,从物理性防御体系的形成、对植物生理代谢的调控、生化拮抗物质的产生、基因表达的调控等角度探究AM真菌在重金属污染土壤生物修复中的作用机理,以期为利用AM真菌开展重金属污染的生物修复提供理论依据,并对本领域未来的发展和应用前景进行了展望.     

石油污染土壤的生物降解研究

石油工业迅速的发展带来了许多环境问题。在原油生产与输送过程中[1] ,井喷、泄露及沉降排放等引起的原油进入土壤造成的土壤污染 ,很难治理。原油在环境中残留时间长 ,对土壤微生物和土壤 植物生态系统 ,甚至地下水都产生危害 ,影响土壤肥力 ,破坏土壤生产力 ,严重影响当地的粮食产量及产品质量。当前 ,治理土壤石油污染的方法主要有物理法、化学法和生物治理技术[2 ] 。污染土壤生物清洁技术就是利用微生物将土壤中有害有机污染物降解为无害无机物 (ＣＯ2 和Ｈ2 Ｏ)的过程。降解过程可以由改变土壤理化条件 (包括土壤ｐＨ ,温度、湿度、…     

石油污染土壤堆制微生物降解研究

采用异位生物修复技术堆式堆制处理方法 ,对辽河油田原油污染土壤进行了生物修复处理研究 .处理工程设 4个处理料堆单元 ,每个处理单元长 118.5cm ,宽 6 5 .5cm ,高 12 .5cm .研究结果表明 ,当进行处理的石油污染土壤中石油烃总量为 5 .2 2 g·10 0 g-1土时 ,利用黄孢原毛平革菌 (Phanerochaetechrysospori um) ,经过 5 5d的运行 ,石油烃总量去除率达 5 4.2 % .堆制处理中影响污染土壤石油烃总量生物降解的主要变化因子为污染土壤的O2 和CO2 含量、降解石油烃微生物的数量、污染土壤pH的变化 .通过监测这些数据的变化 ,可直接反映该工程的处理石油污染土壤的效果 .本处理工程采用定期通风措施 ,操作简单、运行费用低廉 ,为石油污染土壤生物修复实用化提供了一种简单易行的污染土壤清洁技术 .     

Bioremediation of pentachlorophenol-contaminated soil by bioaugmentation using activated soil

The use of an indigenous microbial consortium, pollutant-acclimated and attached to soil particles (activated soil), was studied as a bioaugmentation method for the aerobic biodegradation of pentachlorophenol (PCP) in a contaminated soil. A 125-l completely mixed soil slurry (10% soil) bioreactor was used to produce the activated soil biomass. Results showed that the bioreactor was very effective in producing a PCP-acclimated biomass. Within 30 days, PCP-degrading bacteria increased from 10⁵ cfu/g to 10⁸ cfu/g soil. Mineralization of the PCP added to the reactor was demonstrated by chloride accumulation in solution. The soil-attached consortium produced in the reactor was inhibited by PCP concentrations exceeding 250 mg/l. This high level of tolerance was attributed to the beneficial effect of the soil particles. Once produced, the activated soil biomass remained active for 5 weeks at 20 °C and for up to 3 months when kept at 4 °C. The activated attached soil biomass produced in the completely mixed soil slurry bioreactor, as well as a PCP-acclimated flocculent biomass obtained from an air-lift immobilized-soil bioreactor, were used to stimulate the bioremediation of a PCP-impacted sandy soil, which had no indigenous PCP-degrading microorganisms. Bioaugmentation of this soil by the acclimated biomass resulted in a 99% reduction (from 400 mg/kg to 5 mg/kg in 130 days) in PCP concentration. The PCP degradation rates obtained with the activated soil biomass, produced either as a biomass attached to soil particles or as a flocculent biomass, were similar. Received: 31 March 1997 / Received revision: 22 July 1997 / Accepted: 25 August 1997     

An innovative combined on-site process for the remote rural solid waste treatment--a pilot scale case study in China

The aim of this study was to find a feasible method for the treatment of solid waste generated in the remote rural, where the transportation costs are prohibitive and the resources to construct and maintain conventional treatment plants are not available. This process, consisted of two types of simulated bioreactor landfill (one was recirculated bioreactor landfill, and the other was comprised of fresh and aged refuse reactor) and a soil infiltration system, was operated in ambient temperature for 180 days all together. After treated by the system of fresh and aged refuse reactor, the refuse and leachate reached a strongly degraded and stable state. The remaining leachate can be treated by the soil infiltration system, and 87.5 ± 2.1%, 98.6 ± 1.0% and 95.7 ± 1.7% were achieved by 60 cm soil depths for organic matter, ammonium nitrogen and total nitrogen removal, respectively.     

In situ nitrogen removal in phase-separate bioreactor landfill

The feasibility of in situ nitrogen removal in phase-separate bioreactor landfill was investigated. In the experiment, two sets of bioreactor landfill systems, namely conventional two-phase and in situ nitrogen removal bioreactor landfills, were operated. The in situ nitrogen removal bioreactor landfill (NBL) was comprised of a fresh-refuse filled reactor (NBLF), a methanogenic reactor (NBLM) and a nitrifying reactor (NBLN), while the two-phase bioreactor landfill (BL) used as control was comprised of a fresh-refuse filled reactor (BLF) and a methanogenic reactor (BLM). Furthermore, the methanogenic and nitrifying reactors used aged refuse as bulk agents. The results showed that in situ nitrogen removal was viable by phase-separation in the bioreactor landfill. In total 75.8 and 47.5 g of nitrogen were, respectively, removed from the NBL and the BL throughout the experiment. The methanogenic reactor used the aged refuse as medium was highly effective in removing organic matter from the fresh leachate. Furthermore, the aged refuse was also suitable to use as in situ nitrification medium. The degradation of fresh refuse was accelerated by denitrification in the initial stage (namely the initial hydrolyzing stage) despite being delayed by denitrification in a long-term operation.     

膜生物反应器的研究进展

膜生物反应器是近年来发展的废水处理新技术,具有活性污泥浓度高、污泥龄长、占地面积小、投资省的特点。利用膜生物反应器进行污水处理不仅可以大大节约水资源,还可以大大节约能源,节省设备和运行费用,已成为二十一世纪研究热点。膜生物反应器是通过高效膜分离技术与活性污泥相结合,增大污泥中的特效菌来加快生化反应速率,提高废水处理效果。目前处理对象已从生活污水扩展到高浓度的有机废水和难降解的工业废水。本文综述了膜生物反应器在废水中的应用研究情况,并分析比较了各种膜材质的特点、适用范围以及膜的污染因素和清洗方法,展望了膜生物反应器的应用前景及进一步研究方向。     

Inhibitory role of root hairs on transport within root culture bioreactors

An experimental system was developed to produce root cultures of Hyoscyamus muticus with and without the profuse root hairs. Growth in the presence of 7.6 microM pyrene butyric acid (PBA) and 2.2 mM phosphate virtually eliminated root hairs, whereas growth rate, general morphology and nutrient yields remained unchanged in well-mixed flask culture. These root cultures were used to demonstrate decreased flow resistance in a tubular reactor as a result of root hair removal. To assess the impact on bioreactor performance, hairy and hairless root cultures were grown in a highly characterized 15-L bubble column bioreactor. In the absence of root hairs, the mixing was greatly enhanced; mixing times became shorter for the hairless culture at roughly 100 g (fresh weight)/L. By the end of the 3-week culture period, the mixing time of the hairy culture was 29 times longer than that of the hairless culture. The growth rate of the hairless culture in the bioreactor was as much as 2.4 times greater than growth of the hairy culture under the same conditions. The improved reactor performance was reflected in greater biomass accumulation and respiratory activity. These results show that the root hairs-which facilitate nutrient uptake in a static soil environment-are detrimental to growth in a liquid environment as an effect of their stagnating fluid flow and limiting oxygen availability.     

A simplified steady-state model of a hybrid bioreactor composed of a bubble column bioreactor and biofilter compartments

In a previous study, a hybrid bioreactor comprised of a bubble column bioreactor section and a biofilter section was successfully applied to the treatment of benzene. In order to design and optimize the bioreactor system for actual use in the field, simple but effective mathematical models of the two-stage system were required. Since the liquid phase in the bubble column bioreactor section was well mixed, a CSTR (continuously stirred tank reactor) model was adopted for this section, with benzene removal by both air stripping and biodegradation being considered in the model equations. The gaseous benzene degradation in the biofilter section was described using a PFR (plug flow reactor) model. The combined model was validated through independent experiments, and the simulation results were in a good agreement with measured data.     

A cell-detaching reactor for inoculation of anchorage-dependent CHD and Vero cells between stepwise-expanded bioreactors

A cell-detaching reactor was developed to collect cells growing on microcarriers for inoculation between stepwise-expanded bioreactors. It consisted of a trypsinization zone and a separation zone, which were separated by a 200-mesh stainless steel screen. The screen allowed the cells only to pass through to the next bioreactor, after the cells have been trypsinized and detached from microcarriers. The operating feasibility of the cell-detaching reactor was tested with anchorage-dependent recombinant Chinese hamster ovary (rCHO) and African green monkey kidney (Vero) cells. rCHO and Vero cells were first cultured in a small microcarrier bioreactor, and then inoculated via the cell-detaching reactor into either a packed-bed bioreactor (for rCHO cells) or a larger microcarrier bioreactor (for Vero cells). For rCHO cells, the cell density reached 1.3 × 10⁷ cells/ml in the perfusion culture, and Vero cells reached 1.3 × 10⁶ cells/ml in the batch culture.     

Performance of tapered column packed-bed bioreactor for ethanol production

A tapered column type of bioreactor system packed with immobilized Saccharomyces cerevisiae was used to study the bioreactor performance as a function of design and operating variables. The performance of tapered column bioreactor system was found to be better than that of the conventional cylindrical column reactor system for the ethanol fermentation. The new bioreactor design alleviated problems associated with carbon dioxide evolution and provided a significantly better flow pattern for both liquid and gas phases in the bioreactor without local channelling. A mathematical simulation model, which takes into account of the axial convection and dispersion, interphase mass transfer, and apparent kinetic design parameters, was developed. The effect of radial concentration gradients on the bioreactor performance was found to be insignificant. For the reactor system studied, the maximum ethanol productivity obtained was 60 g ethanol/L gel/h, and the maximum glucose assimilation rate was 140 g glucose/L gel/h. One of the most important findings from this study was that the apparent kinetic parameters change at the glucose concentration of 2 g/L This change was found to be due to the changes in yeast physiology and metabolism. The values of V(m) (') and V(m) (') decreased from 0.8 to 0.39 g ethanol/g cell/h and from 97mM to 11mM, respectively. The substrate inhibition constant was estimated as 0.76M and the product inhibition constant was determined as 113 g ethanol/L The degree of product inhibition showed practically a linear relationship with an increasing ethanol concentration. Based on the hydro-dynamic analysis of the bioreactor system, it was found that the Peclet number, N(Pe) was not a strong function of the flow velocity at low flow rates through the bioreactor system, but its value decreased somewhat at an interstitial velocity greater than 0.03 cm/s. The tapered column bioreactor system showed a much better flow pattern of gas and liquid phases within the reactor, thereby providing a more homogeneous distribution of gas-liquid-solid phases in the reactor without any phase separation.     

Bioreactor technology in marine microbiology: from design to future application

Marine micro-organisms have been playing highly diverse roles over evolutionary time: they have defined the chemistry of the oceans and atmosphere. During the last decades, the bioreactors with novel designs have become an important tool to study marine microbiology and ecology in terms of: marine microorganism cultivation and deep-sea bioprocess characterization; unique bio-chemical product formation and intensification; marine waste treatment and clean energy generation. In this review we briefly summarize the current status of the bioreactor technology applied in marine microbiology and the critical parameters to take into account during the reactor design. Furthermore, when we look at the growing population, as well as, the pollution in the coastal areas of the world, it is urgent to find sustainable practices that beneficially stimulate both the economy and the natural environment. Here we outlook a few possibilities where innovative bioreactor technology can be applied to enhance energy generation and food production without harming the local marine ecosystem.