长泥龄膜生物反应器中活性污泥的膜污染研究

长泥龄膜生物反应器(MBR)内污泥性质与普通活性污泥有显著差异。利用一污泥停留时间长达300 d的膜生物反应器研究了污泥浓度、过膜压力和错流速率对长泥龄活性污泥膜污染特性的影响。研究结果表明,使用0.2 μm微滤膜错流过滤时,浓差极化阻力R_cp和滤饼层阻力R_c是膜污染的主要影响因素,各占总的膜阻力R_t的23%～63%和31%～73%。与之相比,膜内部阻力R_if和膜固有的阻力R_m只占总的膜阻力Rt的0.7%～2.4%和1.2%～6.4%,几乎可以忽略不计。随着污泥浓度,过膜压力的增大和错流速率的减小,膜污染逐渐加剧。因此,降低过膜压力,提高流速,可以有效减缓膜污染,减少清洗频率,延长膜组件的使用寿命,从而节约操作成本,推广应用。     

CO_2倍增和气候变化对北京山区栓皮栎林NPP影响研究

应用生物地球化学过程模型BIOME-BGC估算了1977—1992年北京妙峰山栓皮栎（Quercus variabilis）林的净第一性生产力（NPP）,并分析气候对NPP年际变化的影响以及未来气候变化情景下对NPP的影响。结果表明：1977—1992年15年间栓皮栎的NPP（以C计）平均值为340.17g·m-2·a-1,NPP（以C计）变化在143.56～431.56g·m-2·a-1之间,并无明显的整体变化趋势,但表现出明显的年际变化,年际变动率达18%。在这段时间内降水量成为控制栓皮栎林NPP年际变化的主要气候因子。通过设置18种不同未来气候方案进行栓皮栎林NPP模拟表明,CO2浓度加倍会降低栓皮栎林的NPP但降低幅度较小。在CO2浓度不变的情况下,温度升高2.0℃和降水的协同增加以及单个因子的增加都有利于NPP的积累,但协同增加不如单个因子的增加对NPP的积累效应明显;在CO2和气候同时改变的情况下,CO2浓度加倍、温度升高2.0℃和降水的协同增加有利于NPP的积累且协同增加比单个因子的增加对NPP的积累效应明显,但各因子之间交互作用较弱。     

永定河(北京段)河流生态系统服务价值评估

借鉴《千年生态系统评估》中对生态系统服务的划分（供给、调节、文化与支持四项服务）,建立生态服务价值评价指标体系,开展永定河（北京段）供水、调蓄洪水、气候调节、休闲娱乐、生物多样性等功能的调查研究,明确永定河（北京段）生态系统主要功能与服务.研究结果如下：永定河（北京段）生态服务总价值432.82亿元.其中供给功能价值为...     

Particulate matter assessment of a wetland in Beijing

To increase the knowledge on the particulate matter of a wetland in Beijing, an experimental study on the concentration and composition of PM₁₀ and PM_2.5 was implemented in Beijing Olympic Forest Park from 2013 to 2014. This study analyzed the meteorological factors and deposition fluxes at different heights and in different periods in the wetlands. The results showed that the mean mass concentrations of PM₁₀ and PM_2.5 were the highest at 06:00–09:00 and the lowest at 15:00–18:00. And the annual concentration of PM₁₀ and PM_2.5 in the wetland followed the order of dry period (winter) > normal water period (spring and autumn) > wet period (summer), with the concentration in the dry period significantly higher than that in the normal water and wet periods. The chemical composition of PM_2.5 in the wetlands included NH₄⁺, K⁺, Na⁺, Mg^2 +, SO₄^2 −, NO₃⁻, and Cl⁻, which respectively accounted for 12.7%, 1.0%, 0.8%, 0.7%, 46.6%, 33.2%, and 5.1% of the average annual composition. The concentration of PM₁₀ and PM_2.5 in the wetlands had a significant positive correlation with relative humidity, a negative correlation with wind speed, and an insignificant negative correlation with temperature and radiation. The daily average dry deposition amount of PM₁₀ in the different periods followed the order of dry period > normal water period > wet period, and the daily average dry deposition amount of PM_2.5 in the different periods was dry period > wet period > normal water period.     

基于氧猝灭的有机改性溶胶-凝胶微生物传感器测定BOD的研究

通过有机改性溶胶凝胶PVA包埋方法固定微生物菌株，以氧光化学传感器作为二次传感，制备了响应良好的光化学BOD微生物传感器．在此基础上，考察了微生物传感膜的活化浓度、温度、pH、无机盐及部分金属离子对传感器响应的影响．并对传感器的重现性、储存稳定性和线性范围进行了考察，实验结果表明BOD含量在0—100mg/L浓度范围内与传感器的荧光值成线性关系，传感膜的响应活性保持较好，具有较长的使用寿命和良好的稳定性．     

Acute toxicity assessment of explosive-contaminated soil extracting solution by luminescent bacteria assays

Explosive-contaminated soil is harmful to people’s health and the local ecosystem. The acute toxicity of its extracting solution was tested by bacterial luminescence assay using three kinds of luminescent bacteria to characterize the toxicity of the soil. An orthogonal test L ₁₆ (4⁵) was designed to optimize the soil extracting conditions. The optimum extracting conditions were obtained when the ultrasonic extraction time, ultrasonic extraction temperature, and the extraction repeat times were 6 h, 40 °C, and three, respectively. Fourier transform infrared spectroscopy (FTIR) results showed that the main components of the contaminated soil’s extracting solution were 2,4-dinitrotoluene-3-sulfonate (2,4-DNT-3-SO₃ ⁻); 2,4-dinitrotoluene-5-sulfonate (2,4-DNT-5-SO₃ ⁻); and 2,6-dinitrotoluene (2,6-DNT). Compared with Photobacterium phosphoreum and Vibrio fischeri, Vibrio qinghaiensis sp. Nov. is more suitable for assessing the soil extracting solution’s acute toxicity. Soil washing can remove most of the contaminants toxic to luminescent bacterium Vibrio qinghaiensis sp. Nov., suggesting that it may be a potential effective remediation method for explosive-contaminated soil.

     

沸石与生物沸石薄层覆盖技术削减富营养化景观水体氮比较研究

以扬州古运河河水和表层沉积物为研究对象,实验室静态模拟实验比较研究了沸石与生物沸石（即附着高效异养硝化菌和好氧反硝化菌的沸石）薄层覆盖削减富营养化景观水体氮效果,考察了生物沸石薄层覆盖削减氮可行性,探讨了生物沸石薄层覆盖削减氮的机理和影响因素。实验结果表明,当实验历时21d时,2kg／m^2（2mm厚）的沸石和生物沸石覆盖对上覆水体TN的削减率分别为36．92％和60．41％,生物沸石比沸石对TN削减率提高了23．48％,高效菌的生物脱氮作用明显;21d后生物沸石覆盖对TN的削减率维持在60％～75％,但生物沸石相对于沸石削减氮的效果有降低趋势。实验后期碳源不足是影响高效菌生物脱氮的主要影响因素。可见,生物沸石薄层覆盖削减富营养化景观水体氮是可行的,但需要进一步研究强化高效反硝化细菌适应能力方法。     

Health risk assessment of heavy metals (Cr, Ni, Cu, Zn, Cd, Pb) in circumjacent soil of a factory for recycling waste electrical and electronic equipment

The aim of the study was to determine the potential environmental contamination in a typical factory for recycling waste electrical and electronic equipment in Shanghai. Heavy metals (Cr, Ni, Cu, Zn, Cd, Pb) in the soil around the factory have been evaluated in this paper. Compared with the background value, the concentrations of six metals detected in all the samples were higher, which showed that toxic metals were released into soil around the factory. Compared with the Environmental Quality Standards for Soils, China grade III, all the six metals are under soil guidelines. The non-cancer risk in different directions from the factory was in the order of: the north > the west > the south > the east. For inhalation and ingestion, the non-cancer risk in the soil west of the factory was biggest. Nevertheless, the non-cancer risk in the soil north of the factory was the biggest for dermal contact. The trend of cancer risk was the west > the south > the north > the east. The non-cancer risk and the carcinogenic risk for Cr, Ni, and Cd were all below the limiting value. This study might provide a reference for the risk assessment involved in electronic waste management and recycling activities.     

Quantitative Identification of Disturbance Thresholds in Support of Aquatic Resource Management

The identification of disturbance thresholds is important for many aspects of aquatic resource management, including the establishment of regulatory criteria and the identification of stream reference conditions. A number of quantitative or model-based approaches can be used to identify disturbance thresholds, including nonparametric deviance reduction (NDR), piecewise regression (PR), Bayesian changepoint (BCP), quantile piecewise constant (QPC), and quantile piecewise linear (QPL) approaches. These methods differ in their assumptions regarding the nature of the disturbance-response variable relationship, which can make selecting among the approaches difficult for those unfamiliar with the methods. We first provide an overview of each of the aforementioned approaches for identifying disturbance thresholds, including the types of data for which the approaches are intended. We then compare threshold estimates from each of these approaches to evaluate their robustness using both simulated and empirical datasets. We found that most of the approaches were accurate in estimating thresholds for datasets with drastic changes in responses variable at the disturbance threshold. Conversely, only the PR and QPL approaches performed well for datasets with conditional mean or upper boundary changes in response variables at the disturbance threshold. The most robust threshold identification approach appeared to be the QPL approach; this method provided relatively accurate threshold estimates for most of the evaluated datasets. Because accuracy of disturbance threshold estimates can be affected by a number of factors, we recommend that several steps be followed when attempting to identify disturbance thresholds. These steps include plotting and visually inspecting the disturbance-response data, hypothesizing what mechanisms likely generate the observed pattern in the disturbance-response data, and plotting the estimated threshold in relation to the disturbance-response data to ensure the appropriateness of the threshold estimate.