初级基质对降解菌Pseudomonas putida共代谢苯扎贝特的影响

通过对3,5-二硝基水杨酸(DNS)法测定还原糖含量各影响因素的筛选,优化确定了显色时间8 min,稳定时间10 min,最佳波长490 nm下进行吸光度测定的检测方法;分析分别以葡萄糖和麦芽糖作为外加碳源时,降解菌Pseudomonas putida B-31的生长情况和共代谢降解典型药物苯扎贝特(BZF)的过程。结果表明,降解菌只有在外加碳源的条件下才可正常生长,而且其在葡萄糖环境中生长得更好;拟合得到的葡萄糖、麦芽糖和BZF代谢动力学结果显示,葡萄糖对BZF去除的促进作用更为明显,同时从葡萄糖培养基中降解菌所提取的酶比活力要高于麦芽糖培养基,分析原因可能是葡萄糖所诱导的降解菌关键酶活力更强,而且还可能会产生不同的蛋白质点位。     

四川省不同区域高速公路环境影响评价要点

高速公路项目由于其线路长、工程量大等特点,不可避免会对生态环境、土地资源、水土流失、人居环境等造成不利影响,本文根据四川各区域的地形地貌、水文地质、生物多样性等环境特点,提出了在不同地区高速公路建设中的环境影响评价要点,从而使环境影响评价内容更具有针对性。     

膜曝气生物膜反应器生物膜影响因素分析

膜曝气生物膜反应器（MABR）是一种利用透气膜进行曝气,可以实现同步硝化反硝化的污水生物处理新工艺。本文阐述了膜曝气生物反应器生物膜的原理和特点,总结了国内外在该领域的研究成果,重点介绍了C／N、氧气压力、流速、生物膜厚度、温度和pH对生物膜性能的影响。     

流动注射法测定水中阴离子表面活性剂的探讨

本文采用流动注射分析技术在线测定水中阴离子表面活性剂,使用的仪器为德国BRAN＋LUEBBE公司自动分析仪。方法在0.050～0.400mg/L范围内,可以获得较好的线性方程,相关系数〉0.9990,检出限为0.015mg/L,水样的回收率在92%～109%,此方法符合水质测定阴离子表面活性剂的要求。并对影响阴离子表面活性剂测定的因素进行探讨。     

唐山排污权交易模式浅析

对开展排污权交易的目的、意义、关键因素进行了分析,对唐山排污权交易的工作进程以及交易指标、交易主体、交易程序、指导价格、申购数量、交易范围、优先及限制条件等模式特点进行了阐述,以期为同类型城市开展排污权交易提供参考。     

大学生英语口语交流障碍的心理因素及克服办法

目前大学生的英语口语表达能力总体很差,在口语交流上也出现各种障碍,其原因除学生英语学习能力较差以外,态度问题、动机偏差、缺乏自信、不耐挫折、缺乏热情、过于紧张、性格内向等心理因素也起着关键的作用。对于大学生英语口语交流存在的障碍,可以通过激发兴趣、心理暗示、教师鼓励、减少心理压力、结交外国朋友等有效方法,指导学生进行口语训练,提高学生口语水平。     

Molecular and physiological characterization of fluoroquinolone resistance in relation to uropathogenicity among Escherichia coli isolates isolated from Wenyu River, China

Increasing antibacterial resistance and pathogenicity in the environment is of growing concern due to its potential human risk. In the present study, 236 Escherichia coli isolates were collected from Wenyu River in China on drugless (48 isolates) and quinolone-containing plates (189 isolates). Their minimum inhibitory concentrations (MICs) were determined ranging from 0.125 μg mL⁻¹ to 128 μg mL⁻¹. Mutation points related to fluoroquinolone resistance were observed at S83 to L and D87 to N or Y in the GyrA subunit and S80 to R or I and E84 to G in the ParC subunit. Generally, MICs of LEV and GAT are dependent on the patterns of these mutation points. The profile with three mutation points was related to LEV-resistant E. coli isolates, and the (S83L, D87N + S80I) mutation profile was most prevalent (65.7%) in LEV-resistant isolates, while a large proportion of isolates, even those with three mutation points, were susceptive to GAT. The incidence of virulence factors in LEV-resistant isolates (44.7%, 59/132) was much higher than in nonresistant isolates (23.1%, 24/104) (χ² = 11.925, 1° of freedom, p < 0.001) indicating that fluoroquinolone-resistant E. coli would pose a potential risk. A similar distribution was also found in isolates resistant to GAT (χ² = 7.843, 1° of freedom, p = 0.0079).     

Identification of relevant micropollutants in Austrian municipal wastewater and their behaviour during wastewater treatment

The European Union has defined environmental quality standards (EQSs) for surface waters for priority substances and several other pollutants. Furthermore national EQSs for several chemicals are valid in Austria. The study investigated the occurrence of these compounds in municipal wastewater treatment plant (WWTP) effluents. In a first screening of 15 WWTPs relevant substances were identified, which subsequently were monitored in 9 WWTPs over 1 year (every 2 months). Out of 77 substances or groups of substances (including more than 90 substances) 13 were identified as potentially relevant in respect to water pollution and subjected to the monitoring, whereas most other compounds were detected in concentrations far below the respective EQS for surface waters and therefore not further considered. The preselected 13 compounds for monitoring were cadmium (Cd), nickel (Ni), copper (Cu), selenium (Se), zinc (Zn), diuron, polybrominated diphenyl ethers (PBDEs), di(ethyl-hydroxyl)phthalate (DEHP), tributyltin compounds (TBT), nonylphenoles (NP), adsorbable organic halogens (AOX) and the complexing agents ethylenediaminetetraacetic acid (EDTA) as well as nitrilotriacetic acid (NTA). In the effluents of WWTPs the concentrations of the priority substances Cd, NP, TBT and diuron frequently exceeded the respective EQS, whereas the concentrations for DEHP and Ni were below the respective EQS. The effluent concentrations for AOX, EDTA, NTA, Cu, Se and Zn frequently are in the range or above the Austrian EQS for surface waters. Besides diuron and EDTA all compounds are removed at least partially during wastewater treatment and for most substances the removal via the excess sludge is the major removal pathway. For the 13 compounds which were monitored in WWTP effluents population equivalent specific discharges were calculated. Since for many compounds no or only few information is available, these population equivalent specific discharges can be used to assess emissions from municipal WWTPs to surface waters as well as to make a first assessment of the impact of a discharge on surface waters chemical status. Comparing discharges and river pollution on a load basis, the influence of diffuse sources becomes obvious and therefore should also be taken into consideration in river management.     

短程硝化过程中NO-2-N高效富集的工艺条件实验研究

针对厌氧氨氧化工艺需要提供充足的亚硝酸盐氮为电子受体的问题,利用培养基对SBR中具有一定短程硝化功能的污泥进行富集培养,得到氨氧化菌和亚硝酸盐氧化菌的数量之比为104︰1,并研究了工艺条件对短程硝化的影响,结果表明,适合氨氧化菌生长的最佳温度为30℃、pH为7.5、nHCO^-₃/nNH⁺₄-N值为1。以适合氨氧化菌生长的最佳环境条件优化SBR,在进水氨氮浓度为250 mg/L时,氨氮的转化率达到90％以上,亚硝酸盐氮积累率维持在85％以上,反应器中氨氧化菌与亚硝酸盐氧化菌的数量之比为10³∶1,亚硝酸盐的高效积累为厌氧氨氧化工艺处理高氨废水的过程提供了稳定的电子受体。     

磷酸铵镁沉淀法预处理垃圾渗滤液

探讨了用磷酸铵镁沉淀法预处理垃圾渗滤液时,沉淀剂种类、pH值、物质摩尔配比和反应时间等因素对氨氮去除效果的影响。得出了处理氨氮浓度为2 677.34 mg/L的垃圾渗滤液时,在兼顾所用镁盐量尽量低和处理出水氨氮或磷酸盐的残留量都比较低的较佳实验条件为:沉淀剂种类为:MgSO4.7H2O和Na2HPO4.12H2O,反应时间为20 min,pH=9.5,n(Mg)∶n(P)∶n(N)=1.3∶1.15∶1.0。在较佳实验条件下,垃圾渗滤液的NH3-N去除率为97.05%,处理出水PO34--P含量为8.35 mg/L,NH3-N含量为75.86 mg/L。对所得沉淀物进行了成分分析和X-衍射光谱、扫描电镜表征,表明大部分沉淀物为磷酸铵镁物质。