Profiles and removal efficiency of polycyclic aromatic hydrocarbons by two different types of sewage treatment plants in Hong Kong

Sewage discharge could be a major source of polycyclic aromatic hydrocarbons(PAHs) in the coastal waters. Stonecutters Island and Shatin Sewage Treatment Works(SCISTW and STSTW)in Hong Kong, adopted chemically enhanced primary treatment and biological treatment,respectively. This study aimed at(1) determining the removal efficiencies of PAHs,(2) comparing the capabilities in removing PAHs, and(3) characterizing the profile of each individual PAHs, in the two sewage treatment plants(STPs). Quantification of 16 PAHs was conducted by a Gas Chromatography. The concentrations of total PAHs decreased gradually along the treatment processes(from 301 ± 255 and 307 ± 217 ng/L to 14.9 ± 12.1 and 63.3 ± 54.1 ng/L in STSTW and SCISTW, respectively). It was noted that STSTW was more capable in removing total PAHs than SCISTW with average total removal efficiency 94.4% ± 4.12% vs. 79.2% ± 7.48%(p 0.05). The removal of PAHs was probably due to sorption in particular matter, confirmed by the higher distribution coefficient of individual and total PAHs in solid samples(dewatered sludge contained92.5% and 74.7% of total PAHs in SCISTW and STSTW, respectively) than liquid samples(final effluent-total contained 7.53% and 25.3% of total PAHs in STSTW and SCISTW, respectively).Despite the impressive capability of STSTW and SCISTW in removing PAHs, there was still a considerable amount of total PAHs(1.85 and 39.3 kg/year, respectively for the two STPs) being discharged into Hong Kong coastal waters, which would be an environmental concern.     

厌氧污泥降解萘动力学与生物多样性研究

为对工业废水中的萘进行高效的生物处理,采集某石油工业废水处理装置的厌氧活性污泥,以萘和萘与乳酸钠为电子供体进行驯化培养.当一个驯化周期中萘去除率达到90%以上时,研究间歇反应条件下分别以萘和萘与乳酸钠为电子供体时的降解动力学,并提取去除率高的污泥中微生物总DNA,构建16S rDNA基因片段克隆文库分析细菌群落结构.结果表明,以单一萘为电子供体时萘的降解率远远小于萘与乳酸钠共代谢时的降解率;两种驯化模式下萘浓度与时间符合一级反应动力学,动力学常数K分别为3.5×10-3h-1和16×10-3h-1.萘与乳酸钠共代谢污泥中细菌类群主要为Deltaproteobacteria、Thermotogae、Bacteroidetes、Chloroflexi和Unclassified bacteria,其中Deltaproteobacteria类细菌占主导地位.在成熟的厌氧活性污泥中Desulfobulbus sp.所占比例为24.2%;Kosmotoga占21.0%.此外,反应器中还存在Smithella、Syntrophobacter、Levilinea等细菌.对厌氧活性污泥中细菌多样性的研究有利于优化反应条件,从而提高污泥中萘的去除率.     

Microbial community changes in aquifer sediment microcosm for anaerobic anthracene biodegradation under methanogenic condition

The widespread distribution of polycyclic aromatic hydrocarbons (PAHs) in groundwater has become an important environmental issue. Knowledge of microbial community changes could aid in identification of particular microorganisms that are capable of degrading PAHs in contaminated aquifers. Therefore, 16S rRNA gene clone library analysis was used to identify the archaeal and bacterial communities in an aquifer sediment microcosm used for anaerobic anthracene degradation under methanogenic conditions. A remarkable shift of the archaeal community structure occurred after anaerobic anthracene degradation, but the types of the abundant bacterial phyla did not change. However, a decrease of both archaeal and bacterial diversity was observed. Bacterial genera Bacillus, Rhodococcus and Herbaspirillum might have links with anaerobic anthracene degradation, suggesting a role of microbial consortia. This work might add some new information for understanding the mechanism of PAH degradation under methanogenic conditions.     

Removal of veterinary antibiotics from anaerobically digested swine wastewater using an intermittently aerated sequencing batch reactor

A lab-scale intermittently aerated sequencing batch reactor(IASBR)was applied to treat anaerobically digested swine wastewater(ADSW)to explore the removal characteristics of veterinary antibiotics.The removal rates of 11 veterinary antibiotics in the reactor were investigated under different chemical organic demand(COD)volumetric loadings,solid retention times(SRT)and ratios of COD to total nitrogen(TN)or COD/TN.Both sludge sorption and biodegradation were found to be the major contributors to the removal of veterinary antibiotics.Mass balance analysis revealed that greater than 60%of antibiotics in the influent were biodegraded in the IASBR,whereas averagely 24%were adsorbed by sludge under the condition that sludge sorption gradually reached its equilibrium.Results showed that the removal of antibiotics was greatly influenced by chemical oxygen demand(COD)volumetric loadings,which could achieve up to 85.1%±1.4%at 0.17±0.041 kg COD/m-3/day,while dropped to 75.9%±1.3%and 49.3%±12.1%when COD volumetric loading increased to 0.65±0.032 and1.07±0.073 kg COD/m-3/day,respectively.Tetracyclines,the dominant antibiotics in ADSW,were removed by 87.9%in total at the lowest COD loading,of which 30.4%were contributed by sludge sorption and 57.5%by biodegradation,respectively.In contrast,sulfonamides were removed about 96.2%,almost by biodegradation.Long SRT seemed to have little obvious impact on antibiotics removal,while a shorter SRT of 30–40 day could reduce the accumulated amount of antibiotics and the balanced antibiotics sorption capacity of sludge.Influent COD/TN ratio was found not a key impact factor for veterinary antibiotics removal in this work.     

典型油田多环芳烃污染对土壤反硝化微生物群落结构的影响

油田区土壤具有潜在的PAHs(polycyclic aromatic hydrocarbons)污染风险,而以硝酸根为电子受体的反硝化作用可能在PAHs的厌氧代谢中起到重要作用.以具有50多年历史的江汉油田区域为对象,从该油田的油井口附近采集了9个土壤样品,编号为JH-1~JH-9,以反硝化相关的nir K(Cu-亚硝酸还原酶基因)和nirS(细胞色素cd1-亚硝酸还原酶基因)为分子标识,通过定量PCR及克隆文库结合T-RFLP(terminal-restriction fragment length polymorphism)的方法,研究典型油田区土壤反硝化微生物的群落结构,并探讨其与土壤环境因子之间的关系.结果表明,该油田区土壤中nirK基因的丰度高于nirS基因,PAHs含量最高的土壤样品(JH-4)中反硝化功能基因nir K和nir S的丰度均最低,相关性分析表明,土壤nir K及nirS基因的丰度均与土壤PAHs含量呈显著负相关(nirK:R2=0.54,P0.05;nirS:R~2=0.58,P0.05).克隆文库及T-RFLP的结果则表明,该油田土壤中nirK基因的群落组成在不同样品间的变异较大,且PAHs含量最高的JH-4中该基因的群落组成与其它各样品有明显的不同,RDA(redundancy analysis)的分析结果进一步表明除有效氮、有效磷外,土壤PAHs含量也是影响nirK型反硝化微生物群落组成的重要因子.相较于nirK,该油田区土壤中nirS基因的群落组成在不同样品间的差异较小,但发现nirS型假单胞菌的丰度与土壤PAHs含量呈正相关,表明具备较强有机污染物降解能力的假单胞菌属可能在该区域土壤PAHs的反硝化代谢中起到重要作用.     

重庆青木关地下河流域水中多环芳烃的污染和迁移特征

为探究典型岩溶槽谷区重庆青木关地下河流域水中多环芳烃(PAHs)的含量、组成、来源及污染特征,于2014年对青木关地下河流域中3种不同类型水体进行了连续7个月的采样监测,并利用气相色谱-质谱联用仪(GC-MS)测定了水中16种优控多环芳烃含量.结果表明,地下河水、表层岩溶泉水和地表水中∑PAHs含量变化范围分别为73.9~339.0、76.2~212.0和81.9~272.0 ng·L-1,平均值分别为134、138和173ng·L-1;PAHs组成以2~3环为主,平均占总含量的82%.通过对PAHs的组成对比分析表明,PAHs在迁移过程中地下环境介质对PAHs存在吸附作用.燃烧源是流域内水中PAHs的主要来源,PAHs污染水平较低,个别中低环PAHs含量超过水质标准,高环PAHs超标仅出现在2014年11月的地表水和地下河出口水样中.     

Yangtze Three Gorges Reservoir, China: A holistic assessment of organic pollution, mutagenic effects of sediments and genotoxic impacts on fish

Besides obvious benefits,the Three Gorges Dam's construction resulted in new pollution scenarios with the potentials to threaten the Three Gorges Reservoir(TGR) ecosystem.In order to record organic contamination,to find links to ecotoxicological impacts and to serve as reference for ensuing monitoring,several sites in the TGR area were screened applying the triad approach with additional lines-of-evidence as a holistic assessment method.Sediments and the benthic fish species Pelteobagrus vachellii were sampled in 2011 and 2012 to determine organic pollution levels,mutagenic potentials and genotoxic impacts.Two regional hot-spots near the cities of Chongqing and Kaixian were identified and further investigated in 2013.Only polycyclic aromatic hydrocarbons(PAHs) could be detected in sediments in 2011(165–1653 ng/g),emphasizing their roles as key pollutants of the area.Their ubiquity was confirmed at Chongqing(150–433 ng/g) and Kaixian(127–590 ng/g) in2013.Concentrations were comparable to other major Chinese and German rivers.However,the immense sediment influx suggested a deposition of 216–636 kg PAH/day(0.2–0.6 mg PAH/(m2·day)),indicating an ecotoxicological risk.PAH source analysis highlighted primary impacts of combustion sources on the more industrialized upper TGR section,whereas petrogenic sources dominated the mid-low section.Furthermore,sediment extracts from several sites exhibited significant activities of frameshift promutagens in the Ames fluctuation assay.Additionally,significant genotoxic impairments in erythrocytes of P.vachellii were detected(Chongqing/Kaixian),demonstrating the relevance of genotoxicity as animportant mode of action in the TGR's fish.PAHs,their derivatives and non-target compounds are considered as main causative agents.     

Influence of microbial community structure of seed sludge on the properties of aerobic nitrifying granules

In order to evaluate the influence of microbial community structure of seed sludge on the properties of aerobic nitrifying granules, these granules were cultivated with different seed sludge, and the variation of microbial community and dominant bacterial groups that impact the nitrogen removal efficiency of the aerobic nitrifying granules were analyzed and identified using 16s rDNA sequence and denaturing gradient gel electrophoresis (DGGE) profiles. The results presented here demonstrated that the influence of the community structure of seed sludge on the properties of aerobic nitrifying granules was remarkable, and the granules cultivated by activated sludge from a beer wastewater treatment plant showed better performance, with a stable sludge volume index (SVI) value of 20 mL/g, high extracellular polymeric substance (EPS) content of 183.3 mg/L, high NH₄⁺-N removal rate of 89.42% and abundant microbial population with 10 dominant bacterial groups. This indicated that activated sludge with abundant communities is suitable for use as seed sludge in culturing aerobic nitrifying granules.     

Feasibility of bioleaching combined with Fenton oxidation to improve sewage sludge dewaterability

A novel joint method of bioleaching with Fenton oxidation was applied to condition sewage sludge. The specific resistance to filtration (SRF) and moisture of sludge cake (MSC) were adopted to evaluate the improvement of sludge dewaterability. After 2-day bioleaching, the sludge pH dropped to about 2.5 which satisfied the acidic condition for Fenton oxidation. Meanwhile, the SRF declined from 6.45 × 10¹⁰ to 2.07 × 10¹⁰ s²/g, and MSC decreased from 91.42% to 87.66%. The bioleached sludge was further conditioned with Fenton oxidation. From an economical point of view, the optimal dosages of H₂O₂ and Fe^2 + were 0.12 and 0.036 mol/L, respectively, and the optimal reaction time was 60 min. Under optimal conditions, SRF, volatile solids reduction, and MSC were 3.43 × 10⁸ s²/g, 36.93%, and 79.58%, respectively. The stability and settleability of sewage sludge were both improved significantly. Besides, the results indicated that bioleaching-Fenton oxidation was more efficient in dewatering the sewage sludge than traditional Fenton oxidation. The sludge conditioning mechanisms by bioleaching-Fenton oxidation might mainly include the flocculation effects and the releases of extracellular polymeric substances–bound water and intercellular water.     

Molecular characterization of methanogenic microbial communities for degrading various types of polycyclic aromatic hydrocarbon

Knowledge on methanogenic microbial communities associated with the degradation of polycyclic aromatic hydrocarbons (PAHs) is crucial to developing strategies for PAHs bioremediation. In this study, the linkage between the type of PAHs and microbial community structure was fully investigated through 16S rRNA gene sequencing on four PAH-degrading cultures. Putative degradation products were also detected. Our results indicated that naphthalene (Nap)/2-methylnaphthalene (2-Nap), phenanthrene (Phe) and anthracene (Ant) sculpted different microbial communities. Among them, Nap and 2-Nap selected for similar degrading bacteria (i.e., Alicycliphilus and Thauera) and methanogens (Methanomethylovorans and Methanobacterium). Nap and 2-Nap were probably activated via carboxylation, producing 2-naphthoic acid. In contrast, Phe and Ant shaped different bacterial and archaeal communities, with Arcobacter and Acinetobacter being Phe-degraders and Thiobacillus Ant-degrader. Methanogenic archaea Methanobacterium and Methanomethylovorans predominated Phe-degrading and Ant-degrading culture, respectively. These findings can improve our understanding of natural PAHs attenuation and provide some guidance for PAHs bioremediation in methanogenic environment.     

Optimization of CO2 adsorption capacity and cyclical adsorption/desorption on tetraethylenepentamine-supported surface-modified hydrotalcite

The objective of this research was to investigate CO_2adsorption capacity of tetraethylenepentamine-functionalized basic-modified calcined hydrotalcite(TEPA/b-c HT)sorbents at atmospheric pressure formed under varying TEPA loading levels,temperatures,sorbent weight to total gaseous flow rate(W/F)ratios and CO_2concentrations in the influent gas.The TEPA/b-c HT sorbents were characterized by means of X-ray diffraction(XRD),Fourier transform infrared spectrometry(FT–IR),thermal gravimetric analysis(TGA),Brunauer–Emmet–Teller(BET)analysis of nitrogen(N_2)adsorption/desorption and carbon–hydrogen–nitrogen(CHN)elemental analysis.Moreover,a full 2~4factorial design with three central points at a 95%confidence interval was used to screen important factor(s)on the CO_2adsorption capacity.It revealed that85.0%variation in the capacity came from the influence of four main factors and the15.0%one was from their interactions.A face-centered central composite design response surface method(FCCCD–RSM)was then employed to optimize the condition,the maximal capacity of 5.5–6.1 mmol/g was achieved when operating with a TEPA loading level of 39%–49%(W/W),temperature of 76–90°C,W/F ratio of 1.7–2.60(g·sec)/cm~3and CO_2concentration of 27%–41%(V/V).The model fitted sufficiently the experimental data with an error range of±1.5%.From cyclical adsorption/desorption and selectivity at the optimal condition,the 40%TEPA/b-c HT still expressed its effective performance after eight cycles.     

无机废水硝化过程中原生动物群落结构特征及其变化规律

研究了处理人工氨氮配水的反应器硝化过程中原生动物种群结构特征及其变化规律.研究发现,来自城市污水厂的接种污泥随着运行时间的延长,原生动物的种群多样性不断降低.在亚硝酸盐积累阶段,表壳虫(Arcella)成为优势种;在硝酸盐成为主要硝化产物时,原生动物的优势种主要为累枝虫(Epistyli)和匣壳虫(Centropyxis);污泥粒径大小是决定匣壳虫成为优势种的主要原因.     

Development and preliminary application of a method to assess river ecological status in the Hai River Basin, north China

The river ecosystem in the Hai River Basin(HRB), an important economic region in China, is seriously degraded. With the aim of river restoration in the HRB, we developed a method to assess the river's ecological status and conducted a preliminary application of the method.The established method was a predictive model, which used macroinvertebrates as indicator organisms. The river's ecological status was determined by calculating the ratio of observed to expected values(O/E). The method included ecoregionalization according to natural factors, and the selection of reference sites based on combinations of habitat quality and macroinvertebrate community. Macroinvertebrate taxa included Insecta,Crustacea, Gastropoda, and Oligochaeta, with 39 families and 95 genera identified in the HRB. The HRB communities were dominated by pollution tolerant taxa, such as Lymnaeidae, Chironomus, Limnodrilus, Glyptotendipes, and Tubifex. The average Shannon–Wiener index was 1.40 ± 0.5, indicating a low biodiversity. In the river length of 3.31 × 10~4 km, 55% of the sites were designated poor, with a bad ecological status. Among nine secondary river systems, Luan and Zi-ya had the best and worst river conditions,respectively. Only 17 reference site groups were selected for river management in the 41 ecoregions examined. This study lays the foundation for river restoration and related research in the HRB, and we anticipate further developments of this novel method.     

Characteristics of particulate-bound polycyclic aromatic hydrocarbons emitted from industrial grade biomass boilers

Polycyclic aromatic hydrocarbons(PAHs) are carcinogenic or mutagenic and are important toxic pollutants in the flue gas of boilers. Two industrial grade biomass boilers were selected to investigate the characteristics of particulate-bound PAHs: one biomass boiler retro-fitted from an oil boiler(BB1) and one specially designed(BB2) biomass boiler. One coal-fired boiler was also selected for comparison. By using a dilution tunnel system, particulate samples from boilers were collected and 10 PAH species were analyzed by gas chromatography–mass spectrometry(GC–MS). The total emission factors(EFs) of PAHs ranged from 0.0064 to0.0380 mg/kg, with an average of 0.0225 mg/kg, for the biomass boiler emission samples. The total PAH EFs for the tested coal-fired boiler were 1.8 times lower than the average value of the biomass boilers. The PAH diagnostic ratios for wood pellets and straw pellets were similar.The ratio of indeno(1,2,3-cd)pyrene/[indeno(1,2,3-cd)pyrene + benzo(g,h,i)perylene] for the two biomass boilers was lower than those of the reference data for other burning devices, which can probably be used as an indicator to distinguish the emission of biomass boilers from that of industrial coal-fired boilers and residential stoves. The toxic potential of the emission from wood pellet burning was higher than that from straw pellet burning, however both of them were much lower than residential stove exhausts.     

Ozone concentrations, flux and potential effect on yield during wheat growth in the Northwest-Shandong Plain of China

Ozone (O₃) concentration and flux (F_o) were measured using the eddy covariance technique over a wheat field in the Northwest-Shandong Plain of China. The O₃-induced wheat yield loss was estimated by utilizing O₃ exposure-response models. The results showed that: (1) During the growing season (7 March to 7 June, 2012), the minimum (16.1 ppbV) and maximum (53.3 ppbV) mean O₃ concentrations occurred at approximately 6:30 and 16:00, respectively. The mean and maximum of all measured O₃ concentrations were 31.3 and 128.4 ppbV, respectively. The variation of O₃ concentration was mainly affected by solar radiation and temperature. (2) The mean diurnal variation of deposition velocity (V_d) can be divided into four phases, and the maximum occurred at noon (12:00). Averaged V_d during daytime (6:00–18:00) and nighttime (18:00–6:00) were 0.42 and 0.14 cm/sec, respectively. The maximum of measured V_d was about 1.5 cm/sec. The magnitude of V_d was influenced by the wheat growing stage, and its variation was significantly correlated with both global radiation and friction velocity. (3) The maximum mean F_o appeared at 14:00, and the maximum measured F_o was − 33.5 nmol/(m²·sec). Averaged F_o during daytime and nighttime were − 6.9 and − 1.5 nmol/(m²·sec), respectively. (4) Using O₃ exposure-response functions obtained from the USA, Europe, and China, the O₃-induced wheat yield reduction in the district was estimated as 12.9% on average (5.5%–23.3%). Large uncertainties were related to the statistical methods and environmental conditions involved in deriving the exposure-response functions.     

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.     

Start-up of the anammox process from the conventional activated sludge in a hybrid bioreactor

The anaerobic ammonium oxidation (anammox) process was successfully started up from conventional activated sludge using a hybrid bioreactor within 2 months. The average removal efficiencies of ammonia and nitrite were both over 80%, and the maximum total nitrogen removal rate of 1.85 kg N/(m³.day) was obtained on day 362 with the initial sludge concentration of 0.7 g mixed liquor suspended solids (MLSS)/L. Scanning electron microscope (SEM) observation of the granular sludge in the hybrid reactor clearly showed a high degree of compactness and cell sphericity, and the cell size was quite uniform. Transmission electron microscope photos showed that cells were round or oval, the cellular diameter was 0.6--1.0 μupm, and the percentage of the anammoxosome compartment was 51%--85% of the whole cell volume. Fluorescence in situ hybridization analysis (FISH) indicated that anammox bacteria became the dominant population in the community (accounting for more than 51% of total bacteria on day 250). Seven planctomycete 16S rRNA gene sequences were present in the 16S rRNA gene clone library generated from the biomass and affiliated to Candidatus Kuenenia stuttgartiensis and Candidatus Brocadia sp., a new anammox species. In addition, the average effluent suspended solid (MLSS) concentrations of outlets I (above the non-woven carrier) and II (below the non-woven carrier) were 0.0009 and 0.0035 g/L, respectively. This showed that the non-woven carrier could catch the biomass effectively, which increased biomass and improved the nitrogen removal rate in the reactor.     

处理BPA模拟废水的SBR工况参数对污泥有机毒性的影响研究

在处理双酚A(BPA)模拟废水的序批式活性污泥系统(SBR)反应器中,保持进水COD含量均为300 mg·L-1左右,通过改变水力停留时间HRT从12~8 h,污泥龄SRT从20~10 d,考察污泥有机毒性和其他水质指标的变化.试验分析了空白组和40 mg·L-1初始浓度BPA对照组在不同工况条件下周期末出水COD值、污泥有机毒性分布规律以及稳定期单周期内COD值和污泥有机毒性的变化趋势.结果表明,缩短水力停留时间和污泥龄有利于活性污泥降解BPA,并消减稳定期污泥的有机毒性;出水COD稳定在50 mg·L-1左右,且水相和泥相均无BPA残留.在应用PCR-DGGE技术分析SBR系统内微生物菌群多样性和不同样品间的相似性过程中,得出污泥总毒性抑制率与微生物多样性呈负相关性关系,进水成分的不同和运行参数改变是导致污泥总毒性差异的主要原因.     

Fungal diversity in major oil-shale mines in China

As an insufficiently utilized energy resource,oil shale is conducive to the formation of characteristic microbial communities due to its special geological origins.However,little is known about fungal diversity in oil shale.Polymerase chain reaction cloning was used to construct the fungal ribosomal deoxyribonucleic acid internal transcribed spacer(r DNA ITS)clone libraries of Huadian Mine in Jilin Province,Maoming Mine in Guangdong Province,and Fushun Mine in Liaoning Province.Pure culture and molecular identification were applied for the isolation of cultivable fungi in fresh oil shale of each mine.Results of clone libraries indicated that each mine had over 50% Ascomycota(58.4%–98.9%)and 1.1%–13.5%unidentified fungi.Fushun Mine and Huadian Mine had 5.9% and 28.1% Basidiomycota,respectively.Huadian Mine showed the highest fungal diversity,followed by Fushun Mine and Maoming Mine.Jaccard indexes showed that the similarities between any two of three fungal communities at the genus level were very low,indicating that fungi in each mine developed independently during the long geological adaptation and formed a community composition fitting the environment.In the fresh oil-shale samples of the three mines,cultivable fungal phyla were consistent with the results of clone libraries.Fifteen genera and several unidentified fungi were identified as Ascomycota and Basidiomycota using pure culture.Penicillium was the only genus found in all three mines.These findings contributed to gaining a clear understanding of current fungal resources in major oil-shale mines in China and provided useful information for relevant studies on isolation of indigenous fungi carrying functional genes from oil shale.     

有机物特性对AAO系统污泥沉降性能的影响

研究了不同进水混合型有机物组成下AAO系统中活性污泥菌群结构演替规律以及微生物胞内、胞外聚合物的变化对污泥沉降性能的影响.结果表明,当进水中有机物全部为溶解态时,污泥沉降性能最佳,污泥体积指数(sludge volume index,SVI)为70 m L·g-1,且优于进水有机物以溶解态为主(SVI=120 m L·g-1)和以颗粒态为主(SVI=280 m L·g-1)的系统.根据菌群结构分析可知Thiothrix、Chryseolinea和Trichococcus这3种菌属对污泥沉降性能的影响至关重要.其中颗粒态有机物可促进Trichococcus的生长,而溶解态有机物可促进Thiothrix和Chryseolinea的生长.此外,菌群结构的改变也对胞内及胞外聚合物的变化有重要影响,从而加剧污泥沉降性能改善或恶化的进程.较高的溶解态有机物含量可提高胞内聚合物贮存能力,并改善污泥沉降性能.同时,污泥沉降性能也与松散附着胞外聚合物(loosely bound extracellular polymeric substances,LB-EPS)中多糖、蛋白质和Zeta电位呈显著负相关关系.