倒置A2/O与常规A2/O工艺除磷效果对比

通过对西安市某污水处理厂倒置A2/O工艺的沿程监测和工艺解析,分析明确了该工艺生物除磷效果差的影响因素。研究表明,缺氧池反硝化不完全,厌氧池高浓度硝酸盐是抑制聚磷菌释磷的重要因素。当厌氧池内硝酸盐浓度大于4 mg/L时会明显抑制生物除磷效果。硝酸盐的浓度在1~4 mg/L时,随着硝酸盐浓度的升高,释磷效果显著降低。为避免硝酸盐对聚磷菌的影响,需将厌氧池硝酸盐浓度控制在1 mg/L以下。硝酸盐对聚磷菌释磷的影响原因是生物脱氮除磷对碳源的竞争,以乙酸钠和原污水为碳源分析硝氮盐对释磷效果的影响。结果表明,易于生物降解的优质碳源更有利于聚磷菌在厌氧环境下释磷,倒置A2/O的前置式缺氧池首先将大量优质碳源用于反硝化,而造成后续厌氧池聚磷菌释磷效果差。针对这一研究结果,对该污水厂提出将倒置A2/O调整为常规A2/O的改造方案,改造后厌氧池硝酸盐浓度由3.57 mg/L降低至0.89 mg/L,聚磷菌释磷量提高1.8倍,系统除磷效果增强,出水总磷降低至0.66 mg/L,与倒置A2/O相比降低0.21 mg/L。     

pH对污水好氧处理过程N2O产生的影响

采用能够同时监测气态和溶解态N2O功能的污水好氧处理过程模拟装置,研究了不同pH条件下氨氧化细菌(AOB)好氧反硝化途径N2O的产生特点、污染物转化过程、胞内聚合物聚羟基脂肪酸酯(PHA)含量的变化以及它们之间的内在联系。结果表明,pH在6.5~8.0范围内,N2O产生量随pH的升高而减小。pH较低时,氧化亚氮还原酶活性受到抑制,导致好氧反硝化过程中产生的N2O大量积累并逸散;随着pH得升高,氧化亚氮还原酶活性增强,N2O产生量随之减少。     

城市污泥过热蒸汽与热风干燥特性

为研究城市污泥过热蒸汽和热风干燥特性,研制了一套常压内循环式干燥实验装置。以4 mm和10 mm污泥薄层为研究对象,在160~280℃温度下进行过热蒸汽和热风干燥特性实验。实验结果表明,随着温度升高过热蒸汽与热风干燥时间越来越接近,当温度达到280℃时,过热蒸汽干燥与热风干燥时间大致相同;过热蒸汽干燥初期存在凝结过程,4 mm和10 mm污泥在160~280℃下凝结量范围为3.39~1.07 g和9.71~3.62 g,凝结现象的出现导致干燥速率出现负值,但随着温度升高凝结过程对整个干燥时间影响愈来愈轻。从干燥结束后污泥的表观形态可以观察到过热蒸汽干燥的污泥表面裂纹密集、质地疏松,没有发生燃烧炭化的现象,能够避免污泥干燥时可能发生燃烧和爆炸的危险。     

单甲脒农药对鱼脑胆碱酯酶活性的影响

金鱼,鲤鱼在实验室驯化４－７ｄ,其脑胆碱酯酶活力在显著水平为Ｐ≤０．０５时,不同组的金鱼,鲤鱼无显著差异。离体实验条件下,单甲脒农药对金鱼,鲤鱼的半抑制浓度分别为１２５．９ｍｇ．ｌ＾－１和２５．７ｍｇ．ｌ＾－１。ＤＭＡ农药对鲤鱼的作用大于对金鱼的作用。     

Evaluation of rural habitat environment in under-developed areas of Western China: a case study of Northern Shaanxi

Environment, Development and Sustainability - Rural areas in Northwest China have always been the main concentration of poverty-stricken people in China. In 1986, China listed 665 poor counties...     

人水和谐理念下城市河涌整治的环境社会学思考

导致城市河涌污染和不健康的因素众多,不仅具有生态学的根源,而且还具有社会学的根源。河涌整治已经成为许多城市环境治理的重点。文章依据环境社会学的理论和人水和谐的理念,分析当前河涌整治的模式及优缺点,重点探讨政府、企业、市民、传媒等利益相关者在城市水环境污染与治理中的角色、作用以及相互之间的互动与整合,为城市河涌综合整治建立长效社会机制提供依据。     

Preparation of hapten-specific monoclonal antibody for cadmium and its ELISA application to aqueous samples

High-affinity and specific monoclonal antibodies against cadmium-ethylene diamine tetraacetic acid (EDTA) complex have been produced using the hybridoma technique. A hapten was synthesized and characterized by Fourier Transform Infrared Spectroscopy (FT-IR) and UV-Vis. Competitive enzyme-linked immunosorbent assay (ELISA) for quantitative detection of cadmium in aqueous sample was developed. The monoclonal antibody with high level of binding affinity for Cd-IEDTA-BSA and high specificity for soluble Cd-EDTA complex showed less than 0.99% cross-reactivity with other 11 metals. The limit of detection was 0.10 μg·L⁻¹, and the effective linear range was 10⁻¹–10³ μg·L⁻¹. The intra- and inter-assay coefficient variations were 1.5%–6.3% and 3.2%–7.4%, respectively. The spike recovery in different water samples were between 98.5% and 110.3%. The detection limit of this assay was well below the allowable concentration of cadmium (3 μg·L⁻¹), and the working range was wider than that of other methods which showed the range of 2.19–86.38 and 0–10³ μg·L⁻¹. The competitive ELISA established in this paper was sensitive and accurate in the screening of cadmium in aqueous samples. The results will lay a solid foundation for construction of an immunoassay kit for cadmium.     

多目标优化方法在城市污水厂汇水区污染源总量控制规划中的应用

在城市污水处理厂汇水区实行污染源总量控制,应该避免与城市污水处理厂重复治理.针对这个问题,提出难降解有机物控制的多目标准则指标,建立了多目标优化模型.     

Distribution,transfer, and health risks of polycyclic aromatic hydrocarbons (PAHs) in soil-wheat systems of Henan Province,a typical agriculture province of China

In order to investigate the distribution, transfer, and human health risks of polycyclic aromatic hydrocarbons (PAHs) in the soil-wheat systems, soil samples from 20 farmlands and corresponding wheat tissues were collected from selected regions of Henan Province in June 2013 and were analyzed to estimate the concentration of PAHs. The total concentrations of 15 PAHs (∑₁₅ PAHs) in soils from Henan Province varied from 6.91 to 72.4 ng/g. Moreover, two-ring to three-ring PAHs (1.59–29.1 ng/g) were the major species in soils, occupying 56.2% of total PAHs. Principal component analysis (PCA)-multiple linear regression (MLR) revealed that fossil fuel burning dominated the input of PAHs in agricultural soils of Henan Province. The range of ∑₁₅ PAHs concentrations in wheat tissues was 13.9–50.9 ng/g, which decreased along the root-straw-grain. Positive correlation among PAHs of soil and wheat tissues showed that PAHs in wheat mainly came from soil and then migrated along root-straw-grain. Moreover, PAHs were accumulated highest in root and lowest in grain. Two-ring to three-ring PAHs were easier to transfer from soil to wheat than five-ring to six-ring PAHs. Consumption of wheat grain created potential risk of cancer in Henan Province.

     

化工制药工艺残渣燃烧过程固氯研究

采用管式固定床反应器对化工制药工艺残渣的燃烧分解进行了实验研究,进一步通过加入氧化钙/碳酸钙来防止燃烧过程残渣中氯的释放.实验结果表明,残渣在燃烧时氯主要以氯化氢形式排出,加入固氯剂后能有效地抑制氯化氢的生成,且固氯效果随着钙化物投加量的增加而明显提高.当氧化钙/残渣比(质量比)达到0.8时,固氯率可达97%以上;当碳酸钙/残渣比(质量比)提高到2.0时,固氯率为76%.与此对应的Ca/Cl摩尔比分别为30和40.继续增加钙投加量,固氯效果基本不变.同时发现添加一定量的木屑在助燃的同时有助于提高固氯效果.