砂土中柴油的微生物降解研究

从加油站污染土壤中筛选出对柴油具有较强降解能力的菌株,比较研究菌株及菌群降解柴油的差异,探讨植物苜蓿和芥菜对菌株降解柴油污染物的影响.结果表明:①菌株Q18和菌群对砂土中柴油都具有较强的降解能力,菌群对柴油的降解率明显高于菌株Q18.菌株Q18 和菌群在5 d内对柴油的总降解率分别为40.29%和54.15%.与菌株Q18降解柴油相比,菌群主要是强化了中、长链烷烃化合物的降解.②在砂土中,苜蓿和芥菜都能显著地强化菌株Q18对柴油的降解,但苜蓿强化菌株Q18降解柴油的能力强于芥菜. 5 d内菌株Q18-芥菜和菌株Q18-苜蓿复合体系对柴油总降解率分别达到60.05%和56.68%.③菌群和苜蓿及芥菜复合体系降解柴油的能力也有显著提高,但芥菜强化菌群降解柴油的能力强于苜蓿.5 d内菌群-芥菜和菌群-苜蓿复合体系对柴油总降解率分别为75.53%和70.50%.      

低温条件下硝基苯降解菌的筛选及鉴定

在低温(15℃)条件下,从东北制药总厂曝气池和氯霉素生产废水集水池污泥中驯化、分离得到1株以硝基苯为唯一碳源的高效降解菌株cc-2,并通过菌体形态、生理生化反应特性及16S rDNA测序对其进行分析.同时,对菌株cc-2的生长和降解硝基苯的特性进行了研究.结果表明,菌株cc-2为鲍曼不动杆菌(Acinetobacter baumannii),该菌株利用硝基苯生长的最佳条件分别是:接种量为10%,生长温度为15℃,pH值为7.菌株cc-2可在硝基苯质量浓度低于400 mg.L-1的无机盐培养基中生长代谢,当硝基苯初始浓度为200 mg.L-1时,菌株48h的降解率可达66.84%.     

不同类型土壤和植物对柴油微生物降解的影响

本研究拟从加油站油污染土壤中筛选出对柴油具有较强降解能力的菌株,研究不同类型土壤和植物对菌株降解柴油的影响。实验主要结论如下:①通过富集培养的方法分离得到1株对柴油具有较强降解能力的菌株Q18,经鉴定分析,初步确定其为红球菌(Rhodococcus sp.);②菌株Q18对柴油的降解率在砂壤土中最高,达到46.28%,其次为砂土,在粘土中降解率最低。③苜蓿和芥菜都能显著强化菌株Q18对柴油的降解,但其能力在不同类型土壤中不尽相同,在砂土中,苜蓿强化菌株Q18降解柴油的能力强于芥菜;而在砂壤土和粘土中,芥菜强化菌株Q18降解柴油的能力强于苜蓿。     

汽油降解菌的分离及降解研究

从泄漏污染的加油站土壤中筛选出对汽油具有较强降解能力的菌株,研究该菌株最适宜的生长条件,探讨紫外线诱导及投加表面活性剂等强化手段对该菌株降解汽油的影响.结果表明:①通过富集培养的方法分离得到的菌株Q18,经形态特征及生理生化特征鉴定,初步确定其为红球菌(Rhodococcus sp.).②菌株Q18在培养液中适宜生长的温度,pH和底物质量浓度分别为35 ℃,6.0和1 000 mg/L.③通过紫外线照射诱变后的菌株降解能力强于原始菌株,且15 W紫外灯对菌株的诱变效果优于30 W;氯化锂单独诱变效果不明显;经紫外灯照射和氯化锂复合诱变的菌株QY4对汽油的降解率达到了52.2%,在所有诱变菌中最高,效果最显著. ④表面活性剂能增强汽油的生物可利用性,强化菌株Q18对汽油的降解,但阴离子和非离子的混合表面活性剂SDS+TX-100和SDS+TW-80比单一表面活性剂更能有效提高菌株Q18对汽油的降解率.      

低温条件下硝基苯降解菌的分离及降解特性

低温条件下,从东北制药总厂的曝气池与氯霉素生产废水集水池污泥中分离、筛选得到6株以硝基苯为唯一碳源的降解菌,对6株菌进行降解能力研究得知,菌株cc-2为低温高效硝基苯降解菌。经形态特征和生理生化特征分析,初步鉴定属于不动杆菌属(Acinetobacter sp.)。菌株cc-2降解性能研究结果表明:菌株最佳条件为生长温度15℃、培养基pH值为7、摇床转速为140 r/min。最佳降解条件下,当硝基苯初始浓度为200 mg/L时菌株48h降解率达66.84%。外加葡萄糖和乙酸钠促进了菌株cc-2对硝基苯的生物降解,降解率分别为80.44%和78.57%,该菌株的生长降解性能研究为低温环境中硝基苯的修复提供了技术支撑。     

一株中度耐盐硝基苯降解菌的鉴定及降解特性

在高盐度(1%NaCl)条件下,从某制药厂曝气池的活性污泥中驯化、分离得到1株以硝基苯为唯一碳源的高效降解菌株N18,并通过菌体形态、生理生化反应特性、全细胞脂肪酸组分分析及16SrRNA基因测序分析对其进行初步鉴定.结果表明,菌株N18为蜡样芽胞杆菌(Bacilluscereus).该菌株利用硝基苯生长的最佳条件为接种量10%、生长温度30℃、pH=7.外加葡萄糖或乙酸钠可使硝基苯降解率分别由72.70%提高到82.62%和79.25%(硝基苯初始浓度为200mg.L-1,72h).在盐度为1%～3%时,硝基苯的降解情况基本不变,甚至在盐度为10%时仍能降解硝基苯,说明菌株N18为中度耐盐细菌.当150mg.L-1的苯酚或75mg.L-1的苯胺与200mg.L-1的硝基苯共存时,菌株仍能有效降解硝基苯.菌株对硝基苯的最大耐受浓度为400mg.L-1.     

阿特拉津降解菌株的分离、鉴定及降解特性研究

通过贫营养原水曝气培养法,以SBR方式驯化和稳定运行2个月,分离得到1株能够降解除草剂阿特拉津的降解菌株,命名为L-6.在以阿特拉津为唯一氮源(500 mg.L-1)的无机盐液体培养基中培养96 h后,降解率达到89.2%.扫描电镜观察发现该降解菌株细胞呈长杆状.提取菌株的DNA,进行16S rRNA基因序列分析,并构建系统进化树.结果表明该菌株与GenBank数据库中多株Pseudomonas菌株16S rRNA基因的同源性在99%以上.结合生理生化检测,判断该降解菌为假单胞菌属(Pseudomonas sp.).碳源利用实验发现,降解菌株L-6可以利用葡萄糖、果糖和柠檬酸钠生长,不能利用蔗糖、乳糖和淀粉.环境因素对降解效率的影响实验表明,温度在30℃,初始pH 7～9条件下,降解效率最佳.     

一株多氯联苯降解菌的筛选鉴定及降解性能研究

从长期受有机污染的土壤中驯化、分离出1株高效多氯联苯降解菌,经生理生化和16S r DNA测序鉴定为铜绿假单胞菌(Pseudomonas aeruginosa),用其对PCB77进行降解性能研究.结果表明,该菌株能够以PCB77为唯一碳源生长,在培养温度为30℃、p H值7.5、PCB77浓度1.0 mg·L-1、接菌量2 m L(OD600=1.0)、摇床转速150 r·min-1的培养条件下,7 d后PCB77的降解率为49.6%;菌株在外加相同浓度联苯和邻苯二甲酸时,降解效率分别提高到58.5%和53.8%,而加入苯甲酸时,降解率为40.8%;外加重金属Cr6+和Pb2+对菌株降解PCB77均有显著的抑制作用;当重金属浓度较低时抑制作用不显著,而浓度较高时有明显的抑制作用,且Cr6+对菌株降解能力的抑制强于Pb2+.     

砷胁迫下石油烃降解菌的分离、鉴定及其降解特性

以湖北省某砷-石油烃复合污染场地的土壤为研究对象，分离纯化砷胁迫下石油烃降解菌，采用16S rDNA测序技术进行菌种鉴定，分析降解菌的生长特性与降解特征，验证降解菌对复合污染土壤的实际修复效果。结果表明：从耐As高效石油烃降解菌株系列中筛选出菌株JYZ-03,其鉴定结果为不动杆菌(Acinetobacter sp.);菌株JYZ-03最佳生长和降解条件为pH=7、温度30℃、盐度0.1%和初始接种量2%;此条件下菌株JYZ-03对石油烃的降解效率为84.05%,对石油烃各组分降解能力存在差异，难易程度表现为长链烷(C26—C38)>多环芳烃>支链烷烃>中长碳链烷烃(C11—C25),石油烃降解效果显著，具有较好的实际修复效果。该研究丰富了石油烃污染修复功能菌株库，可为复合污染场地修复提供更多选择。     

一株高效原油降解不动杆菌的筛选及降解特性分析

为得到高效原油降解菌,从天津大港油田废弃钻井附近的油污染土壤中筛选出一株高效原油降解菌YQJ-1.经生理生化实验、16S rDNA基因序列及系统发育树对该菌株鉴定分析,采用单因素实验研究环境因素对该菌株生长和原油降解特性的影响,并对动力学和烷烃降解进行了探讨。结果表明:该菌株为醋酸钙不动杆菌(Acinetobacter calcoaceticus);在35℃,pH为8,接种量为10mL,氮源为酵母浸粉时降解效果最佳;且1～5 g/L的原油降解与一级动力学模型一致,原油浓度为5g/L时的降解率高达77. 58%,石油降解半衰期仅为4. 93d; GC-FID分析发现,YQJ-1对链长C_(11)—C_(25)的烷烃平均降解率达到87. 84%。该研究为未来高浓度石油污染土壤环境修复提供了良好的候选菌株。     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

Removal of cadmium using MnO2 loaded D301 resin

MnO2 loaded weak basic anion exchange resin D301 （Anion exchange resin, macroreticular weak basic styrene） as adsorbent has been prepared and applied to the removal of cadmium. The adsorption characteristics have been investigated with respect to effect of pH, equilibrium isotherms, removal kinetic data, and interference of the coexisting ions. The results indicated that the Cd^2＋ could be efficiently removed using MnO2 loaded D301 resin in the pH range of 3-8 from aqueous solutions with the co-existence of high concentration of alkali and alkaline-earth metals ions. The saturate adsorption capacity of the Cd^2＋ was 77.88 mg/g. The adsorption process followed the pseudo first-order kinetics. The equilibrium data obtained in this study accorded excellently with the Langmuir adsorption isotherm.     

Effect of coagulation pretreatment on the fouling of ultrafiltration membrane

The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）. A relatively higher molecular weight （MW） of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.     

Penetration analysis of elements and bioleaching treatment of spent refractory for recycling

Acidithiobacillus ferrooxidans ATCC23270 and Acidithiobacillus thiooxidans TM-32 were used for bioleaching of spent refractories of aluminium and copper melting furnaces for their recycling.Firstly,penetration of elements into aluminium melting furnace refractory was investigated and it was found that up to 7 cm from surface was contaminated.Comparison on leaching efficiency by the strains ATCC23270 and TM-32 found that the strain ATCC23270 could treat larger amount of the refractories than the strain TM-32 could do.In the experiment of bioleaching of spent refractory aluminium melting furnace by the strain ATCC23270,high leaching efficiency were obtained on Al,Si,and Ca,and extremely low leaching performance was,however,shown on the rest of elements i.e.,Na,Mn,and Zn.Under the strain TM-32 use,relatively high leaching performance was recognized on Al,Si,Ca,Na,Mn,and Zn.In the experiment of bioleaching for spent refractory copper melting furnace,almost the same leaching trends were shown on Cu,Zn,Al,and Si under the strains ACTT23270 and TM-32 uses.     

Simultaneous removal of ammonium and phosphate by zeolite synthesized from coal fly ash as influenced by acid treatment

Zeolite synthesized from fly ash （ZFA） without modification is not efficient for the purification of NH4＋ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacity. To develop an effective technique to enhance the removal efficiency of ammonium and phosphate at low concentrations, ZFA was modified with acid treatment and the simultaneous removal of ammonium and phosphate in a wide range of concentration was investigated. It was seen that when compared with untreated ZFA, only the treatment by 0.01 mol/L of H2SO4 significantly improved the removal efficiency of ammonium at low initial concentrations. The behavior was well explained by the pH effect. Treatment by more concentrated H2SO4 led to the deterioration of the ZFA structure and a decrease in the cation exchange capacity. Treatment by 0.01 mol/L H2SO4 improved the removal efficiency of phosphate by ZFA at all initial P concentrations, while the treatment by concentrated H2SO4 （≥0.9 mol/L） resulted in a limited maximum phosphate immobilization capacity （PIC）. It was concluded that through a previous mild acid treatment （e.g. 0.01 mol/L of H2SO4）, ZFA can be used in the simultaneous removal of NH4＋ and P at low concentrations simulating real effluent.