因子分析及其在河网水质综合评价中的应用研究

对因子分析方法在天然水体水质评价中的应用进行研究,证明在数据较为缺乏的情况下,使用因子分析方法可以损失较少信息,减少评价指标,针对主因子进行分析,使水质评价结果更为合理和有效。同时,利用因子的得分值还可以将不同地区进行比较分析。应用因子分析对河网地区典型河流的水质状况进行分析,发现了增长潜力较大的主要因子,并对该地区的水质状况做出了符合实际的总体评价,表明因子分析在水质评价中具有重要应用价值。     

Resistance to metal contamination by historically-stressed populations of Ceriodaphnia pulchella: environmental influence versus genetic determination

Field populations of daphnids historically-stressed by metal contamination may show increased resistance to those contaminants. This study was undertaken aiming to confirm/infirm three main hypotheses: (1) field populations living in historically-impacted environments are more tolerant to metal stress than populations from reference sites; (2) resistance differences are genetically-determined, i.e., differences persist after controlling for environmental and maternal effects, by acclimating cloned lineages to similar conditions; and (3) resistance to stress in field populations living in historically-impacted environments is due to the disappearance of sensitive individuals rather than the appearance of highly resistant ones, i.e., the shift in the central tendency of resistance is linked to a decrease in the range of population resistance and not to an increased upper limit of the population resistance. Three populations of the cladoceran Ceriodaphnia pulchella Sars in Southern Portugal were sampled; one of which has been historically-stressed by acid mine drainage (AMD) from an abandoned cupric-pyrite mine and two from reference sites within the same watershed. To assess if resistance differences were genetically-determined, the three populations were acclimated for at least five generations under the same controlled conditions. Assays with AMD contaminated water samples were performed with both non-acclimated and acclimated individuals from all studied populations. Reproduction results in sub-lethal assays revealed significant differences between the reference and stressed populations. Significant differences in resistance to lethal levels of toxicity were observed for both non-acclimated and acclimated populations, individuals from population I being more resistant than those from reference populations. The existence of genetically-determined sensitivity differences was attested by the presence of significant differences in resistance to lethal levels of toxicity in acclimated individuals from reference and stressed populations. Results from cumulative mortality assays revealed that sensitive individuals were most probably present in the original population, but no conclusion could be draw about the presence of extreme resistant individuals in the historically-stressed population. Finally, it was shown that responses among populations converged from high to low levels of contamination.     

An improved model for analyzing the performance of photocatalytic oxidation reactors in removing volatile organic compounds and its application

An improved photocatalytic oxidation (PCO) reactor model was developed to analyze the removal of volatile organic compounds (VOCs) in indoor air. One new parameter, the average total removing factor Kt, together with the other two parameters, the number of mass transfer units NTUm and the fractional conversion epsilon, are found to be the main parameters influencing the photooxidation performance of PCO reactors. Three new parameters, the ideal reaction number of mass transfer units, NTUm,ir; the ideal reaction fractional conversion, epsilonir; and the reaction effectiveness, eta, also are defined. These concepts are helpful to the structural design and optimization for PCO reactors. The application of the model in designing a plate-type PCO reactor is demonstrated. This study shows that the present model is an effective tool for designing PCO reactors and for evaluating VOC removal performance of available PCO reactors.     

Shifted power-law relationship between NO2 concentration and the distance from a highway: A new dispersion model based on the wind profile model

In this paper, a shifted power-law model, based on the wind profile model, had been supposed to simulate concentration gradient of nitrogen dioxide (NO₂) with distance from a highway. Field experiments were performed for NO₂ gradients from a highway in Shanghai by using passive samplers. The shifted power-law model was fitted well with experimental results of field experiments both in this study and in the literature. The results not only verified the validity of shifted power-law relationship between NO₂ concentration and the distance from a highway, but also partially demonstrated that there were some significant similarities between wind profile and air pollutants concentration profile near highway. With known concentration of chosen reference point and appropriate value of the parameter k, the model could be practically applied for predicting the NO₂ distributions near a highway. The methods of determining the parameter k were also discussed for further detailed studies.     

高效堆肥菌种的筛选及在城市污泥堆肥上的应用

分离筛选出了4株猪粪堆肥菌种,初步的分类鉴定表明它们均属于芽孢杆菌属.利用这些菌种制成混合菌剂,并进行城市污泥堆肥对比试验,结果显示,接菌处理在各项堆肥指标上明显优于未接菌的空白处理,自制菌与酵素菌在堆肥过程中具有非常相似的发酵能力,均能加快堆肥的升温速度,提高堆肥的最高温度,加快物料含水率的下降.说明自制菌不但可以应用于猪粪的堆肥发酵,在城市污泥高温堆肥方面也有很好的应用潜力.     

活性炭颗粒填充三维电极电化学烟气脱硫的研究

基于三维电极电化学技术较高的反应效率和不产生废弃物等优点,将这一先进的反应器运用到烟气脱硫领域.用活性炭作为工作电极,在通电状况下,将模拟烟气通入反应器发生反应.通过一系列试验,分析了填充床厚度、槽电压、进气流量、通电时间对脱硫率的影响,并且探讨了该反应的反应原理.     

Performance of bioferric-submerged membrane bioreactor for dyeing wastewater treatment

Adding iron salt or iron hydroxide to sludgemixed liquor in an aeration tank of a conventional activated sludge processes (bioferric process) can simultaneously improve the sludge’s filterability and enhance the system’s treatment capacity. In view of this, Fe(OH)₃ was added to a submerged membrane bioreactor (SMBR) to enhance the removal efficiency and to mitigate membrane fouling. Bioferric process and SMBR were combined to create a novel process called Bioferric-SMBR. A side-by-side comparison study of Bioferric-SMBR and common SMBR dealing with dyeing wastewater was carried out. Bioferric-SMBR showed potential superiority, which could enhance removal efficiency, reduce membrane fouling and improve sludge characteristic. When volumetric loading rate was 25% higher than that of common SMBR, the removal efficiencies of Bioferric-SMBR on COD, dye, and NH₄ ⁺-N were 1.0%, 9.5%, and 5.2% higher than that of common SMBR, respectively. The trans-membrane pressure of Bioferric-SMBR was only 36% of that in common SMBR while its membrane flux was 25% higher than that of common SMBR. The stable running period in Bioferric-SMBR was 2.5 times of that in common SMBR when there was no surplus sludge discharged. The mixed liquor suspended solids concentration of Bioferric-SMBR was higher than that of common SMBR with more diversified kinds of microorganisms such as protozoans and metazoans. The mean particle diameter and specific oxygen uptake rate of Bioferric-SMBR were 3.10 and 1.23 times the common SMBR, respectively.     

中学环境教育的重要性及其实施

介绍了环境教育理念,环境教育的重要性和中学开展环境教育的意义,提出了中学环境教育的目标和原则,探讨了中学环境教育方法与模式。     

新世纪的清洁能源--燃料电池

介绍了一种高效，环境良好的发电方式-燃料电池发电技术，阐述了燃料电池的发电原理及其开发现状，对其发展前景作了展望。     

Restructuring water industry in China: towards sustainable urbanization

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