一组中温厌氧消化菌群高温启动过程中的菌群多样性变化研究

该研究利用37℃培养的中温厌氧消化菌群为菌源,直接提温至50℃驯化培养,获得连续处理高浓度糖蜜废水的厌氧消化产甲烷菌群,并考察高温驯化过程中菌群结构及多样性的变化特征.结果表明,中温厌氧消化菌群直接转入高温培养后,在高浓度有机废水连续进料的条件下,厌氧消化过程能够快速启动生成甲烷,并在22 d后形成稳定的高温厌氧消化产甲烷菌群,平均甲烷生成效率为162.3 m L CH_4/g COD.乙酸和丙酸是厌氧发酵液内的2类主要有机酸,产气稳定期间的质量浓度分别为25.3和145.3 mg·L~(-1).转入高温培养后,菌群结构产生巨大变化,细菌变异程度强于古菌,并逐渐稳定成为以代谢糖、多种有机酸的细菌和产甲烷古菌为主要优势菌群的高温厌氧消化菌群.克隆结果显示细菌菌群以Thermacetogenium和Acetomicrobium faecal为主要优势菌群,分别占细菌克隆文库的33.44%和20.99%;古菌菌群以Methanosaeta和Methanoculleus为主要优势菌群,占古菌克隆文库的56.40%和39.75%.转入高温培养后,产甲烷古菌的总生物量下降,含量约为7.6×106拷贝/g活性污泥.研究结果对阐明温度选择压力对厌氧消化菌群结构与功能影响,改进高温厌氧消化菌群富集方法具有重要意义.     

多相内循环厌氧反应器内颗粒污泥特性分析

该文对处理柠檬酸废水的多相内循环厌氧反应器中颗粒污泥的理化特性和微生物特性进行了实验研究。扫描电镜下厌氧颗粒污泥呈黑色、球形、表面光滑且有空隙;筛分法得到90%的污泥粒径分布在0.45~2.0 mm范围内;重力沉降法得到90%以上颗粒污泥的沉降速度大于50 m/h,沉降性能良好;高温灼烧法测得颗粒污泥的挥发分占总固体的64.56%,有机物含量高。采用454高通量测序的方法对厌氧颗粒污泥中的微生物进行鉴别,细菌中共有约30个菌门和100个菌属,其中Anaerofustis、Anaerolineae、Spirochaeta和Longilinea是优势菌属,分别占细菌总量的4.91%、4.78%、4.41%、3.98%。这些细菌的共同特征是可以将大分子有机物水解并转化成酸。古生菌中广古菌门(Euryarchaeota)占92.48%,其中甲烷鬃菌属(Methanosaeta)占7.81%,甲烷杆菌属(Methanobacterium)占49.35%,主要作用是产甲烷。微生物的多样性指数较高,表明厌氧颗粒污泥中微生物种类丰富,有利于厌氧反应器的稳定运行。     

高通量测序研究酒精废水治理中厌氧活性污泥的微生物菌群

厌氧消化是治理酒精生产废水的主要技术,本实验基于Illumina Mi Seq高通量测序研究了厌氧活性污泥的微生物菌群,在属(genus)水平上分析了污泥中细菌和古菌的种类和相对丰度,探讨了细菌和古菌的功能.结果表明:高温厌氧活性污泥(TAS)中相对丰度≥1.0%的细菌属有10个,包括Coprothermobacter、Longilinea、Levilinea等,它们的主要功能是分解蛋白质、代谢碳水化合物生成有机酸、乙酸氧化、硫酸盐还原.中温厌氧活性污泥(MAS)中相对丰度≥1.0%的细菌属有21个,包括Acinetobacter、Succinibibrio、Meniscus、Longilinea等,它们的主要功能是代谢碳水化合物生成有机酸、脂肪酸和有机酸氧化、分解结构顽固化合物.TAS中古菌属主要是产甲烷古菌Methanosaeta、Methanobacterium和Methanothermbacter,它们的相对丰度分别为57.72%,28.35%和9.90%.MAS中古菌属主要是产甲烷古菌Methanobacterium、Methanosarcina、Methanosaeta和Methanosphaera,它们的相对丰度分别为33.21%、23.70%、16.63%和11.77%.高通量测序研究充分展示了厌氧活性污泥的微生物菌群,可为阐释酒精废水治理中厌氧消化技术的生物机制及其技术改良提供参考.     

高效厌氧产甲烷颗粒污泥中微生物多样性及定量化研究

以小试高效厌氧反应器不同运行阶段的颗粒污泥为对象,利用变性梯度凝胶电泳(DGGE)、荧光原位杂交(FISH)和实时定量链式聚合酶反应(RTQ-PCR)等技术研究了其中微生物种群的多样性、特征微生物的空间分布和定量关系,结果表明:随着反应器有机负荷逐渐提高,颗粒污泥中古菌的群落结构的变化较细菌更为明显;细菌多分布在颗粒外层,而古菌则主要分布在颗粒内层;古菌含量略少于细菌,但有逐渐增多的趋势;产甲烷丝菌在古菌中的含量增加明显.     

阿维菌素废水工业化UASB颗粒污泥产甲烷菌群分析

产甲烷菌群是厌氧颗粒污泥的重要功能菌群,采用荧光原位杂交(fluorescencein situhybridization,FISH)技术对阿维菌素废水处理工业化UASB颗粒污泥产甲烷菌群进行分析.结果表明,不同形成阶段(不同粒径)颗粒污泥表面和内部剖面,一般产甲烷菌(methanogens)、产甲烷杆菌(Methanobacteriales)和产甲烷八叠球菌(Methanosarcinales)的分布形态相同,但相对丰度存在差异.颗粒污泥内部剖面产甲烷菌群相对丰度大于表面;产甲烷杆菌相对丰度大于产甲烷八叠球菌;颗粒污泥表面和内部剖面产甲烷菌群相对丰度范围为(25.50±8.63)%~(48.67±8.87)%;1.0~2.0 mm粒径颗粒污泥产甲烷菌群相对丰度最大,内部剖面和表面一般产甲烷菌的相对丰度分别为(47.08±8.26)%和(48.67±8.87)%.废水阿维菌素残留可能对产甲烷菌群具有抑制作用.不同粒径颗粒污泥最大比产甲烷活性范围为1.311~1.562 g/(g.d),变化趋势与COD去除率变化趋势相同,而且与产甲烷菌群相对丰度变化趋势一致,表明颗粒污泥生物活性与产甲烷菌群密切相关.     

序批式接触氧化反应器中细菌多样性及其功能

采用分子生物学手段,通过构建16S rDNA基因文库,对新型剩余污泥减量化处理系统——序批式生物砾间接触氧化反应器中细菌多样性进行了系统发育分析,并讨论了多种细菌共存对剩余污泥减量化的贡献.共有72个克隆子用于细菌系统发育分析. 结果表明:填料表面附着细菌与孔隙内细菌由变型菌属、噬纤维菌-屈挠杆菌-拟杆菌组(CFB)、硝化杆菌科、低G+C革兰氏阳性细菌、高G+C革兰氏阳性细菌、疣微菌科和绿菌科等七大类细菌组成. 其中,优势菌群分别是以兼具呼吸/发酵代谢方式的β变形菌纲(分别占生物膜和内泥中克隆子总量的18%和35%)和δ变形菌纲,以及以呼吸/发酵为主要代谢方式的CFB(分别占克隆子总量的24%和23%). 多种细菌对剩余污泥减量化的主要功能可归纳为能量解偶联、共代谢作用、生物溶胞作用和慢性生长种群的影响.      

活性炭在中高温条件下对玉米秸秆厌氧发酵的影响

为提高玉米秸秆厌氧发酵的产气效果,本文研究活性炭在中温(38℃)和高温(50℃)条件下对玉米秸秆厌氧发酵产甲烷的效果及微生物学机制.结果表明,添加活性炭能显著促进秸秆厌氧发酵产甲烷,中、高温试验组(添加活性炭)的累积产甲烷量分别比对照提高了63%和96%;DGGE的结果显示,高温试验组(添加活性炭)和对照组(未添加活性炭)的发酵液中的优势细菌菌群分别是Clostridiale bacterium和Bacillus,中温对照组发酵液和中温试验组发酵液未发现明显优势菌种.添加活性炭分别有利于氢营养型的甲烷鬃毛菌(Methanosaeta concilii strain)和乙酸营养型的醋酸甲烷八叠球菌(Methanosarcina acetivorans strain),在中温、高温试验组的发酵液中形成优势古菌菌群.中温试验组活性炭载体上的优势古菌菌群为甲烷鬃毛菌(Methanosaeta concilii strain),而高温试验组活性炭载体上的优势古菌菌群主要为甲烷八叠球菌嗜高温菌属(Methanosarcina thermophila strain).     

16S rDNA克隆文库方法分析好氧颗粒污泥细菌组成

采用构建16S rDNA克隆文库方法对好氧颗粒污泥的细菌种群多样性进行研究. 随机测定了82个克隆子序列(700 bp),Blast比对结果表明,好氧颗粒污泥中微生物群落具有高度多样性,可分为7个主要类群,其中,β变形菌(β-Proteobacteria)类群和鞘脂杆菌(Sphingobacteria)类群在文库中所占比例最大,分别为34.16%和30.50%;其次是Candidate division TM7类群、黄杆菌(Flavobacteria)类群和γ变形菌(γ-Proteobacteria)类群,分别为9.76%,7.32%和7.32%;放线菌(Actinobacteria)类群和α变形菌(α-Proteobacteria)类群所占比例相对较小,分别为4.88%和1.22%. 序列分析结果表明,好氧颗粒污泥中不仅含有对好氧颗粒污泥形成和稳定运行具有重要作用的食酸菌属(Acidovorax)细菌、假单胞菌(Pseudomonas)等细菌,还含有对CODCr和氨氮具有很好去除能力的Micropruina glycogenica,丛毛单胞菌科(Comamonadaceae)等细菌.      

高钙废水颗粒污泥中古菌菌群结构变化的分析

为了解高浓度Ca~(2+)与颗粒污泥中古菌菌群结构的关系,利用高通量测序分析IC(Internal Circulation)反应器(以废纸造纸废水为处理对象)内不同高度处颗粒污泥中古菌菌群组成,并利用SEM(Scanning Electron Microscope)和EDS(Energy Dispersive X-ray Spectroscopy)分析颗粒污泥的形态结构和元素组成,同时借助红外光谱和XRD(X-ray diffraction)分析不同高度处颗粒污泥化学结构中各官能团的分布情况和无机成分.结果表明,随着反应器高度的增加,颗粒污泥中的无机成分CaCO_3也随着增加,而种泥中钙含量只有1.81%.种泥和ICR反应器内的颗粒污泥中古菌在门分类水平上主要包括Euryarchaeota和Bathyarchaeota,两者之和占90%以上.在属分类水平上,主要包括Methanosaeta、Methanoregula、Methanobacterium、Methanosarcina、Methanolinea、Methanospirillum等.种泥中古菌的物种多样性要明显高于IC反应器中,在IC反应器中不同高度处古菌生物多样性由高到低的顺序是5 m2 m7 m,5 m处的古菌物种更加丰富.随着反应器高度的增加,乙酸营养型甲烷菌的相对丰度呈现递增趋势,氢营养型甲烷菌则呈现递减趋势,而种泥中氢营养型甲烷菌相对丰度较大.这表明颗粒污泥在高钙废水的长期作用下,氢营养型甲烷菌的相对丰度减少,乙酸营养型甲烷菌的相对丰度增多,系统中古菌物种的相对丰度和多样性有所下降.CaCO_3沉淀使颗粒污泥的产甲烷活性降低,主要表现为其对氢营养型甲烷菌具有较大的抑制作用.     

污泥性质对微波预处理-厌氧消化的影响及古菌群落结构分析

污泥性质对预处理强化厌氧消化工艺的效果有较大影响.本研究对比了某实际污水厂A~2O工艺和A~2O-MBR工艺产生的剩余污泥在微波预处理-厌氧消化过程中污泥性质的变化与产气效果,并考察了在预处理和厌氧消化过程中污泥的古菌群落结构变化.结果表明,A~2O工艺剩余污泥有机质含量比A~2O-MBR污泥高出16. 4%(分别为66. 4%和50. 0%),SCOD、溶解性蛋白质和多糖分别为后者1. 24、2. 02和4. 84倍,具有更好的可生物降解性.虽然预处理对生物降解性差的A~2O-MBR污泥有机物释放效果更好,但A~2O污泥在微波预处理-厌氧消化后产甲烷量比相应处理后的A~2O-MBR污泥多26. 1%.两种剩余污泥的古菌群落结构差异较大,A~2O-MBR污泥中甲烷丝菌属和甲烷八叠球菌属丰度分别比A~2O污泥多3. 68%和19. 73%.预处理对古菌群落的丰富度和均匀度影响相对较小,但厌氧消化后波动较大.污泥中有机组分不同是引起古菌群落结构变化的重要影响因素.     

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.