浅析宜昌市城区PM_(2.5)污染特征及防治对策研究

依据2013年白龙岗站点自动监测数据,对PM2.5污染特征及手工采集的PM2.5膜中水溶性阴离子进行分析,并结合实际提出相应的防治对策。结果表明,PM2.5作为首要污染物,其分布具有季节性特征,冬季最高,夏季最低;灰霾日PM2.5、PM10、SO2和NO2具有相同的变化趋势;NO-3/SO2-4的比值表明宜昌市呈现工业污染和机动车尾气污染的复合污染特征。     

悬浮填料生物反应器处理低浓度氨氮的动力学特性分析

城市污水经一级强化处理后,NH3-N浓度为10~15mg/L,CODCr为40~60mg/L。试验利用悬浮填料床对一级强化处理出水中的氨氮进行深度处理,分析了悬浮填料表面负荷和硝化速率与水力停留时间的关系,并模拟分析了硝化速率与氨氮浓度的关系。结果表明,悬浮填料床内混合液氨氮浓度为0.5~2.5mg/L时,硝化反应符合半级反应动力学,半级反应速率常数k1/2为0.48(g/m)0.5/d;混合液氨氮浓度>2.1mg/L时,硝化反应遵循零级反应动力学,rmax为0.71g/(m2.d)。动力学理论计算值与实际运行结果基本吻合,说明动力学模型对悬浮填料床的硝化性能具有良好的预测和指导意义。     

14C-生物碱在模拟水环境中暴露行为的研究

本文采用同位素示踪技术和室内模拟微生境研究了“C-盐酸脱廷胡索碱在好氧、厌氧水环境中的行为;对水、绿藻、溞及底泥中的残留量进行了分析:并用TLC分离出了水体及底泥中的转化产物,结果表明,该生物碱进入水环境后向底泥相转移是其主要迁移途径,最终在底泥上的残留量占85％以上,光及底泥微生物对该生物碱的转化起了一定作用。     

Do we understand trends in atmospheric sulfur species?

Anomalies appear to exist in our understanding of atmospheric sulfur compounds, specifically as evidenced in the time trends of the different chemical forms of these compounds. Trends determined at a number of locations by several different groups seem to indicate that, responding to emission reductions across North America, the concentration of SO2 in the atmosphere is declining more rapidly than that of aerosol SO4(2-). A number of possible reasons for this discrepancy are examined, but it is not possible to provide a definitive answer at this stage. The intent is to stimulate debate, because shortcomings in our understanding of the processes involved could have profound implications for the credibility of abatement strategies and policies for both acid deposition and fine particulate matter (PM).     

Economic analysis of best management practices to reduce watershed phosphorus losses

In phosphorus-limited freshwater systems, small increases in phosphorus (P) concentrations can lead to eutrophication. To reduce P inputs to these systems, various environmental and agricultural agencies provide producers with incentives to implement best management practices (BMPs). In this study, we examine both the water quality and economic consequences of systematically protecting saturated, runoff-generating areas from active agriculture with selected BMPs. We also examine the joint water quality/economic impacts of these BMPs-specifically BMPs focusing on barnyards and buffer areas. Using the Variable Source Loading Function model (a modified Generalized Watershed Loading Function model) and net present value analysis (NPV), the results indicate that converting runoff-prone agricultural land to buffers and installing barnyard BMPs are both highly effective in decreasing dissolved P loss from a single-farm watershed, but are also costly for the producer. On average, including barnyard BMPs decreases the nutrient loading by about 5.5% compared with only implementing buffers. The annualized NPV for installing both buffers on only the wettest areas of the landscape and implementing barnyard BMPs becomes positive only if the BMPs lifetime exceeds 15 yr. The spatial location of the BMPs in relation to runoff producing areas, the time frame over which the BMPs are implemented, and the marginal costs of increasing buffer size were found to be the most critical considerations for water quality and profitability. The framework presented here incorporates estimations of nutrient loading reductions in the economic analysis, and is applicable to farms facing BMP adoption decisions.     

Evaluation of physico-chemical and structural properties of biochar produced from pyrolysis of urban biowaste

Journal of Material Cycles and Waste Management - Understanding proper utilization and evaluation of biowaste materials in any metropolitan city across the world is crucial with respect to...