基于甲烷氧化菌的城镇污水厂尾水极限脱氮系统构建及机制

好氧甲烷耦合反硝化（AME-D）在城镇污水厂尾水深度脱氮方面具有巨大的应用潜力,研究采用改良型反硝化生物滤池,利用低浓度甲烷构建出AME-D极限脱氮系统.研究发现该系统在间歇式运行方式下,出水中总氮和氨氮的平均浓度能达到1.05 mg·L^-1和0.54 mg·L^-1,其平均去除率分别为94.77%和93.30%.拉曼光谱分析结果显示,由NO₃^-对称伸缩引起的峰明显消失,由醇COH面外弯曲或C—H面外弯曲振动吸收引起峰明显增强,甲烷被氧化形成的中间产物可能主要为醇类物质.16S rRNA基因测序结果表明,系统中的甲烷氧化菌主要为Methylocystis（0.27%）、Methylosarcina（0.10%）和Methyloparacoccus（0.12%）,反硝化菌主要为Pseudomonas（56.92%）、Paenibacillus（3.52%）和Lysinibacillus（3.00%）,硝化菌主要为Nitrospira（0.1%）,说明AME-D极限脱氮系统的脱氮功能是由好氧甲烷氧化菌、反硝化菌和硝化菌协同实现.     

Comparison of a plant based natural surfactant with SDS for washing of As(Ⅴ) from Fe rich soil

This study explores the possible application of a biodegradable plant based surfactant, obtained from Sapindus mukorossi, for washing low levels of arsenic （As） from an iron （Fe） rich soil. Natural association of As（Ⅴ） with Fe（Ⅲ） makes the process difficult. Soapnut solution was compared to anionic surfactant sodium dodecyl sulfate （SDS） in down-flow and a newly introduced suction mode for soil column washing. It was observed that soapnut attained up to 86% efficiency with respect to SDS in removing As. Full factorial design of experiment revealed a very good fit of data. The suction mode generated up to 83 kPa pressure inside column whilst down-flow mode generated a much higher pressure of 214 kPa, thus making the suction mode more efficient. Micellar solubilisation was found to be responsible for As desorption from the soil and it followed 1st order kinetics. Desorption rate coefficient of suction mode was found to be in the range of 0.005 to 0.01, much higher than down-flow mode values. Analysis of the PT-IR data suggested that the soapnut solution did not interact chemically with As, offering an option for reusing the surfactant. Soapnut can be considered as a soil washing agent for removing As even from soil with high Fe content.     

Effect of acid solutions on plants studied by the optical beam deflection method

The optical beam deflection method was applied to study the effects of acid solution on both a terrestial and aquatic plants Egeria and Cerastium, which are common aquatic plant and terrestial weed respectively. A probe beam from a He-Ne laser was passed through a vicinity of a leaf of the plants, which were put in culture dishes filled with acid solutions. Deflection signals of the probe beam were monitored and compared for acid solutions with different pH values. The results of Egria showed that the deflection signals changed dramatically when pH values of acid solutions were 2.0 and 3.0, while little at pH of 4.0 and 5.0. For Cerastium when pH were below 3.0, deflection signals changed greatly with time at the begining. After a certain period of time, deflection signals changed little with time. When pH value was above 4.0, deflection signals of Cerastium were still changing with time even after 20 hours. The results suggested that the damage threshold of pH was between 3.0 and 4.0 for both the land and aquatic plants.     

Screening of endophytic bacteria against fungal plant pathogens

Bacterial endophytes were found from 6 plant leaves among 35 plant leaves screened. Two of the isolated bacteria showed antagonistic activity against fungal plant pathogens. An isolate named KL1 showed the clear inihibition against plant pathogens, Fusarium oxysporum and Rhizoctonia solani, on PDA as well as TSA plate. Supernatant of the bacterial culture also showed the clear inhibition against the fungal growth on the plate and the antibiotic substance was identified as iturin A by HPLC analysis. KL1 was identified as Bacillus sp. from the 16S rRNA gene analysis. Very thin hyphae of R. solani was miccroscopically observed when the fungus was co-cultivated with KL1.     

Combined effects of cadmium and fluoranthene on germination, growth and photosynthesis of soybean seedlings

The single and combinational effects of cadmium (Cd) and fluoranthene (FLT) on germination, growth and photosynthesis of soybean seedlings were investigated. Exposure to 5, 10, or 15 mg Cd/L or 1, 5, or 10 mg FLT/L individually or in combination significantly decreased germination vigor (3 days) and final germination rate of soybean seeds, except at 1 and 5 mg FLT/L. The results of two-way ANOVA analysis and the Bliss independence model showed that at lower concentrations of FLT (1 mg/L), the interaction between Cd and FLT on germination was antagonistic, whereas the interaction was synergistic when the concentration of FLT was 5 or 10 mg/L and the concentration of Cd was 15 mg/L. Growth, expressed as dry weight, length of shoot and root, leaf area, and photosynthesis, expressed as net photosynthetic rate, intercellular CO2 concentration, chlorophyll contents and fluorescence of soybean seedlings were also reduced by exposure to 5 or 10 mg Cd/L or 1 or 5 mg FLT/L, singly or jointly. Significant antagonistic effects of exposure to 5 or 10 mg Cd/L or 1 or 5 mg FLT/L on shoot growth and photosynthesis were observed, whereas synergy and antagonism of Cd and FLT were both observed for root growth.     

燃煤电厂烟尘铅排放状况外场实测研究

选取30台燃煤电厂锅炉开展燃料铅含量及烟尘铅排放浓度的系列外场测试.结果表明,燃煤电厂燃料铅含量均值为8.50 mg·kg-1,烟尘铅平均排放浓度为0.0081 mg·m-3,排放因子为0.0643 g·t-1.不同机组容量及有无选择性催化还原(SCR)装置状况下烟尘铅排放因子无显著性差异(p＞0.1),不同除尘设施类型下烟尘铅排放因子有显著性差异(p＜0.1),布袋除尘(Fiber Filter,FF)电厂烟尘铅排放因子低于静电除尘(Electrostatic Precipitator,ESP)电厂.本研究中铅排放因子低于国内估算值,与AP 42燃煤电厂铅排放因子处于同一水平.基于本研究排放因子计算的全国2011年燃煤电厂烟尘铅排放量为126.76 t.     

植物滞留系统中草本植物对磷的去除效果研究

以黑麦草、地毯草、高羊茅和早熟禾为研究对象,研究4种草本植物在植物滞留系统中不同介质、不同入口浓度下对城市非点源(人工降雨径流)中污染物磷的富集能力和去除效果。结果表明:4种草本植物对人工降雨径流中的磷均有明显的去除效果,TP平均去除率在60.24%～83.56%。不同草本植物去除人工降雨径流中TP的能力,从强到弱的顺序依次为:早熟禾>黑麦草>地毯草>高羊茅。其中,对于同一种草本植物同样的入口浓度情况下,沙土Ⅱ为最佳土壤介质,具有最佳的去除磷能力。4种草本植物对磷的去除率随入口浓度的增加,去除率也随之增加。4种草本植物地上部和地下部磷累积量分别为2.27～5.92 mg和4.33～6.46 mg;其中黑麦草磷累积总量最高,其次是地毯草,最低的是早熟禾。综合考虑污染物去除率和磷在植物体内的累积量,交替种植早熟禾和黑麦草可提高植物滞留系统去磷能力且有利于延长系统寿命。     

化石燃料电厂CO2俘获方案研究

论述了CO2俘获的重要性和紧迫性,介绍了4种适用于化石燃料电厂的CO2俘获方案：煤粉燃烧中的CO2分离和俘获处理、气化CO2分离和俘获处理、氧燃烧CO2分离和俘获处理和化学环燃烧处理。     

城市污水处理厂生成的微生物气溶胶的污染特性

为探明城市污水厂生成的微生物气溶胶的污染特性,于2011年6～7月利用Andersen六级撞击式采样器对西安市第三污水处理厂不同污水处理单元的微生物气溶胶进行现场采样,利用平皿培养和菌落计数法检测分析了细菌、真菌和放线菌这3类微生物气溶胶的浓度、粒径分布和中值直径.结果表明,污水处理厂污泥脱水车间的细菌和放线菌气溶胶浓度最高,分别为7 866 CFU.m-3±960 CFU.m-3和2 139 CFU.m-3±227 CFU.m-3,而真菌气溶胶浓度最高出现在氧化沟,为2 156 CFU.m-3±119 CFU.m-3.细菌、真菌和放线菌气溶胶粒径分布均呈偏态型,其中细菌和真菌的粒径分布峰值出现在2.1～3.3μm范围,而放线菌气溶胶粒径分布峰值出现在1.1～2.1μm范围.总体上,污水厂中细菌气溶胶中值直径>真菌气溶胶中值直径>放线菌气溶胶中值直径.另外,微生物气溶胶的空间变化特征表现为粒径大的微生物气溶胶浓度减少率大.3类微生物气溶胶浓度减少率的变化程度从大到小依次为细菌>真菌>放线菌.     

铬胁迫对3种草本植物生长及铬积累的影响

为了阐明铬胁迫对白花三叶草（Trifolium repens）、高羊茅（Festuca arundinacea）、紫花苜蓿（Medicago sativa）3种草本植物的毒害机制,为铬污染土壤植物修复提供理论依据,采用盆栽试验,在土壤中添加不同浓度的铬[Cr（Ⅵ）]（K2Cr2O7为0、100、200、300和400 mg.kg-1）,研究重金属铬对3种草本植物生长、生理特性、重金属铬累积与分布的影响.结果表明,白花三叶草、高羊茅和紫花苜蓿的平均耐性指数分别为62.5、48.3和36.33.在铬浓度为400 mg.kg-1处理条件下,白花三叶草和高羊茅叶绿素含量、SOD和POD活性分别为对照的57.14%、51.51%、35.76%和63.27%、52.96%、41.36%,而紫花苜蓿无法生存.在铬胁迫下,3种草本植物的株高、根长、地上（下）部干重均表现降低,其降低大小顺序为紫花苜蓿〉高羊茅〉白花三叶草,但MDA含量增加,并且紫花苜蓿增加幅度最大,高羊茅次之,白花三叶草最小.三者对铬的耐受性表现为白花三叶草〉高羊茅〉紫花苜蓿.3种草本植物叶片积累的铬主要贮存于细胞壁,其次是细胞质,而在叶绿体和线粒体中含量较低.叶绿体和线粒体中铬含量与叶绿素、MDA含量、SOD和POD活性存在明显的相关性.随着铬浓度增加,3种草本植物叶片亚细胞组分中铬含量增加,并且总是紫花苜蓿〉高羊茅〉白花三叶草.当铬处理浓度为300 mg.kg-1时,与白花三叶草、高羊茅相比,紫花苜蓿叶片富集铬浓度最高,达51.44 mg.kg-1,其中分配于叶绿体（19.09%）和线粒体（18.04%）中铬的比例也明显较高.白花三叶草、高羊茅和紫花苜蓿地上部和地下部富集系数平均值分别为1.22、1.54;1.16、1.44和1.26、1.62,转运系数平均值分别为0.78、0.78和0.74.在重金属铬污染土壤治理中,白花三叶草和高羊茅有一定的潜在应用价值.