Three Different Topics for Bioremediation Application on Soils and Waters Contaminated with Aromatic Compounds, by Using Immobilized Bacteria

Molecular techniques and modelling are presented as powerful tools required in the performance of efficient soil and water bioremediation systems. An Escherichia coli CC118-D strain was constructed by inserting the Klebsiella pneumoniae hpa B gene, coding for the unstable 3,4-dihydroxyphenylacetate 2,3-dioxygenase, into its chromosome. When the constructed strain was immobilized, both enzyme stability and viability increased along the studied period, in absence of antibiotic. We proposed this strategy as an approach to overcoming plasmid instability and to enhance enzyme activity and stability, avoiding antibiotic utilization. A model was developed to understand and predict the behaviour of bacteria and pollutants in a bioreactor system, considering: fluid dynamics, molecular/cellular scale processes and biofilm formation.     

城市土壤污染研究现状与趋势

城市土壤是城市生态环境系统的有机组成部分,对城市的可持续发展有着重要的意义.城市化和工业化进程的加快,造成城市土壤污染、侵蚀、酸化和硬化以及土壤生物和植被退化等一系列较为严重的城市环境问题,直接危及到城市居民的健康和安全;因此,城市土壤污染问题已经引起人们的高度重视.近10多年来,国内外有关城市土壤重金属污染,微有机物污染,生源要素污染和城市土壤污染的环境与健康风险评价等诸多研究取得了一系列的研究成果.本文主要就以上研究成果进行了较为系统地总结与阐述,并且在此基础上提出了今后有关城市土壤污染研究的发展重点与趋势,以期为改善城市生态环境质量提供重要的科学依据.     

近岸海域石油污染生物修复技术的研究进展

生物修复技术是治理大面积污染区域的一种有价值的修复方法。对国内外最新的生物刺激和生物强化技术进行调研,总结了该技术对治理近岸海域石油污染的研究进展,分析总结了施加营养盐技术对海洋环境的影响,以及生物修复技术尚存在的一些局限性。     

土壤和地下水中多环芳烃生物降解研究进展

多环芳烃是一类普遍存在于环境中的难降解的危险性"三致"有机污染物。受污染的土壤和地下水中的多环芳烃,生物降解是其归宿的主要途径。研究表明,对于土壤中低分子量多环芳烃类化合物,微生物一般以唯一碳源方式代谢;而大多数细菌和真菌对四环或四环以上的多环芳烃的降解作用一般以共代谢方式开始。文章重点论述了多环芳烃的来源、降解多环芳烃的微生物、生物降解机理、影响生物降解的因素以及生物修复方法。认为今后的研究方向是高分子量多环芳烃的降解机理与降解途径,基因工程技术在多环芳烃生物降解方面的应用,以及生物表面活性剂产生的机理及其在实际处理中的应用等。     

农药污染地下水的微生物治理及含水层渗透性变化研究

采用了从农药厂阿特拉津生产车间排污口污泥中分离出的菌种AT菌 ,进行了农药阿特拉津污染地下水微生物治理的模拟实验研究 ,在实验条件 (T =10℃ ,pH =7.5 )与野外含水层的条件基本一致情况下 ,难于生物降解的污染质阿特拉津的一次投菌降解率可达 3 1.0 8% ;设计了两种有效细菌的投放方式以模拟野外条件下的菌种投加条件。另外 ,AT菌的作用会造成被治理含水层的渗透性能降低 ,两种投菌方式下 ,实验后含水层的渗透系数分别下降 60 .5 4%和 3 4 5 6%。清水冲洗 10d的渗透性恢复率分别为 48.96%及 81.3 6% ,说明清水渗透恢复的方法效果明显     

Trimethylbenzoic acids as metabolite signatures in the biogeochemical evolution of an aquifer contaminated with jet fuel hydrocarbons

Evolution of trimethylbenzoic acids in the KC-135 aquifer at the former Wurtsmith Air Force Base (WAFB), Oscoda, MI was examined to determine the functionality of trimethylbenzoic acids as key metabolite signatures in the biogeochemical evolution of an aquifer contaminated with JP-4 fuel hydrocarbons. Changes in the composition of trimethylbenzoic acids and the distribution and concentration profiles exhibited by 2,4,6- and 2,3,5-trimethylbenzoic acids temporally and between multilevel wells reflect processes indicative of an actively evolving contaminant plume. The concentration levels of trimethylbenzoic acids were 3-10 orders higher than their tetramethylbenzene precursors, a condition attributed to slow metabolite turnover under sulfidogenic conditions. The observed degradation of tetramethylbenzenes into trimethylbenzoic acids obviates the use of these alkylbenzenes as non-labile tracers for other degradable aromatic hydrocarbons, but provides rare field evidence on the range of high molecular weight alkylbenzenes and isomeric assemblages amenable to anaerobic degradation in situ. The coupling of actual tetramethylbenzene loss with trimethylbenzoic acid production and the general decline in the concentrations of these compounds demonstrate the role of microbially mediated processes in the natural attenuation of hydrocarbons and may be a key indicator in the overall rate of hydrocarbon degradation and the biogeochemical evolution of the KC-135 aquifer.     

油泥废弃物的生物修复技术研究

本文利用正交试验 ,探讨了堆腐法处理油泥废弃物过程中调控因子 (肥料、客土、水分和 pH)的影响。结果发现 ,投加一定量的客土是影响处理效果的重要因子。通过正交试验选择和确定的最佳处理条件为 :在自然温度 >2 0℃的情况下 ,客土投加量 2 0 %、肥料 10 %、菌剂 5 %、控制水分 30 % (烘干基 )和pH 7。优化条件的建立为油泥废弃物的深度处理提供了理论依据     

生物修复剂在清除海滩石油污染中的应用

介绍了生物修复石油污染海滩时常用的修复剂类型及其特点.当实验室环境条件能较好控制时,生物强化剂一般是有效的;然而污染现场得出的证据不能表明其对生物降解有促进作用.实验室和现场的研究均表明营养型生物促进剂能有效促进石油的生物降解.水溶性营养易被波浪和潮汐冲刷掉;缓释型营养盐面临的主要挑战是如何控制其释放速率,以保证孔隙水中能较长时间维持理想的营养浓度;亲油型肥料中含有有机碳,有可能在微生物降解石油之前被优先降解.建议根据污染环境的特点选用适合的生物促进剂.     

Isolation of Cr(VI) reducing bacteria from industrial e uents and their potential use in bioremediation of chromium containing wastewater

The present study is aimed at assessing the ability of Bacillus sp.JDM-2-1 and Staphylococcus capitis to reduce hexavalent chromium into its trivalent form.Bacillus sp.JDM-2-1 could tolerate Cr(Ⅵ) (4800 μg/mL) and S.capitis could tolerate Cr(Ⅵ) (2800 μg/mL).Both organisms were able to resist Cd2+ (50 μg/mL),Cu2+ (200 μg/mL),Pb2+ (800 μg/mL),Hg2+ (50 μg/mL) and Ni2+ (4000 μg/mL).S.capitis resisted Zn2+ at 700 μg/mL while Bacillus sp.JDM-2-1 only showed resistance up to 50 μg/mL.Bacillus sp.JDM-2-1 and S.capitis showed optimum growth at pH 6 and 7,respectively,while both bacteria showed optimum growth at 37℃.Bacillus sp.JDM-2-1 and S.capitis could reduce 85% and 81% of hexavalent chromium from the medium after 96 h and were also capable of reducing hexavalent chromium 86% and 89%,respectively,from the industrial effluents after 144 h.Cell free extracts of Bacillus sp.JDM-2-1 and S.capitis showed reduction of 83% and 70% at concentration of 10 μg Cr(Ⅵ)/mL,respectively.The presence of an induced protein having molecular weight around 25 kDa in the presence of chromium points out a possible role of this protein in chromium reduction.The bacterial isolates can be exploited for bioremediation of hexavalent chromium containing wastes,since they seem to have the potential to reduce the toxic hexavalent form to its nontoxic trivalent form.     

生物修复技术在白海面黑臭河涌治理中的应用

利用人工曝气、水体生物修复和河道生态恢复等技术,对广州市白海面黑臭水体进行治理。结果表明,在污水进水流量3000～4000m^3／d的条件下,通过生物治理,消除了水体黑臭现象,从上游到下游,水色由暗黄逐步转为黄、黄绿;在上游不断流入污水情况下,CODcr除去率达55％以上,NH3-N除去率为35％,TP除去率达25％以上。本研究为城市黑臭河道,特别是暂时无法截污的城郊河道的治理和养护提供了一套切实可行的方法。