北方常见农作物根际土壤中铅、锌的形态转化及其植物有效性

采用盆栽试验结合形态分析技术研究了北方地区常见农作物对污染土壤中铅(Pb)、锌(Zn)的形态转化及其植物有效性的影响。土壤Pb、Zn形态分析结果显示,与非根际土壤相比,多数作物根际可交换态、碳酸盐结合态、有机质结合态Pb比例降低,而铁锰氧化物结合态、残渣态Pb则显著增加;Zn则表现为可交换态比例略呈降低趋势,碳酸盐结合态、铁锰氧化物结合态与有机质结合态升高,残渣态Zn则大幅下降。这提示,作物根际土壤Pb存在由松结合态向紧结合态转化的现象,从而植物有效性降低;而根际土壤Zn的形态变化则与Pb相反,即由紧结合态向松结合态转化,相应地提高了Zn的植物有效性。     

生物-微电解组合工艺处理染料废水研究

采用上流式污泥床过滤器（upflow blanket filter，UBF）＋曝气生物滤池（biological aerated filter，BAF）＋微电解的组合工艺，对盐度接近2％、色度和COD分别约为8000倍和600．5mg／L的染料废水进行处理。经过连续120d的稳定运行后，组合系统处理效果良好，脱色率和COD去除率分别达到99％和75％以上。UBF和微电解单元均可以大幅度提高废水的可生化性，有利于进一步的生物处理。UV—Vis扫描和GC—MS分析表明，该组合工艺能破坏染料的发色基团和共轭双键，并能高效降解原水中的酚类、氯代有机物和复杂的杂环类化合物。实验结果表明，UBF＋BAF＋微电解的组合工艺是处理染料废水的一种有效方法。     

非稳态条件下人工湿地水流规律及其对水力停留时间的影响

由于降水的随机性,处理农业或城市径流的人工湿地通常在进水水量波动的非稳态条件下工作.为研究在非稳态条件下人工湿地的水流规律,在基于时间轴的多点示踪剂试验的基础上,利用RTD(水力停留时间分布)探讨了单峰和双峰两种水力冲击非稳态条件下水平潜流人工湿地中的水流规律.结果表明,非稳态过程的水量变化对不同时刻流入人工湿地的液体的RTD影响明显.用基于出水流量的非线性无量纲时间变量(φ)对原始RTD进行归一化处理,所得的RTD浓度曲线[C'(φ)]在整个非稳态过程中相对稳定,具有相似的倾斜度、峰值时间(单峰冲击下为0.83~1.00,双峰冲击下为0.87~1.08)、重心位置(单峰冲击下为1.08~1.25,双峰冲击下为1.05~1.25)及相关统计学参数,表现出一种独立于流量变化之外的相对稳定的特征水流规律.与稳态基流量下的t_mean(平均停留时间)相比,水力冲击使人工湿地t_mean呈冲击前持续缩短、冲击后又快速回升的趋势(单峰、双峰冲击下最大值与最小值相差分别约为30和32 h);而t_mean'(归一化平均停留时间)在非稳态过程中却相对稳定(单峰、双峰冲击下最大值与最小值相差分别约为0.15和0.20),适合作为非稳态下表征人工湿地水流规律和停留时间的特征参数.研究显示,归一化RTD易于模拟,可用其描述非稳态下人工湿地的水流规律以及水流规律对污染物接触反应时间的影响.      

生物源挥发性有机化合物排放及其在空气质量模式的应用研究

综述了近30年来国内外关于生物源挥发性有机化合物（ BVOCs ）排放及其应用的研究进展,包括BVOCs排放的化学组成、影响排放的主要环境因素和排放模式的建立及其应用等。重点探讨BVOCs排放在空气质量模拟应用中的重要性,提出一些值得注意的关键点。最后从BVOCs排放模式机理、基础数据和大气化学输送模式对BVOCs排放处理等方向进行了展望。     

天津市挥发性有机物排放控制标准与污染源在线监控技术研究

大气中的VOCs和NOx在发生光化学反应后不易沉降,易造成大气能见度差等现象.“十二五”期间中国重点区域和重点行业开展了挥发性有机物(VOCs)污染防治工作,依据环境管理的需求,天津市开展了挥发性有机物排放控制标准制定与污染源在线监控技术研发,建立VOCs综合控制指标和苯系物单项控制指标,覆盖全部工业VOCs排放行业,推行VOCs在线监测与无组织泄漏检测,研发监测数据具有代表性和可比性、低成本、安全性高且易推广的VOCs污染源在线监测系统.     

Greenhouse gas emissions from dairy open lot and manure stockpile in northern China: A case study

The open lots and manure stockpiles of dairy farm are major sources of greenhouse gas (GHG) emissions in typical dairy cow housing and manure management system in China. GHG (CO₂, CH₄ and N₂O) emissions from the ground level of brick-paved open lots and uncovered manure stockpiles were estimated according to the field measurements of a typical dairy farm in Beijing by closed chambers in four consecutive seasons. Location variation and manure removal strategy impacts were assessed on GHG emissions from the open lots. Estimated CO₂, CH₄ and N₂O emissions from the ground level of the open lots were 137.5±64.7 kg hd^-1 yr^-1, 0.45±0.21 kg hd^-1 yr^-1 and 0.13±0.08 kg hd^-1 yr^-1, respectively. There were remarkable location variations of GHG emissions from different zones (cubicle zone vs. aisle zone) of the open lot. However, the emissions from the whole open lot were less affected by the locations. After manure removal, lower CH₄ but higher N₂O emitted from the open lot. Estimated CO₂, CH₄ and N₂O emissions from stockpile with a stacking height of 55±12 cm were 858.9±375.8 kg hd^-1 yr^-1, 8.5±5.4 kg hd^-1 yr^-1 and 2.3±1.1 kg hd^-1 yr^-1, respectively. In situ storage duration, which estimated by manure volatile solid contents (VS), would affect GHG emissions from stockpiles. Much higher N₂O was emitted from stockpiles in summer due to longer manure storage.

Implications: This study deals with greenhouse gas (GHG) emissions from open lots and stockpiles. It’s an increasing area of concern in some livestock producing countries. The Intergovernmental Panel on Climate Change (IPCC) methodology is commonly used for estimation of national GHG emission inventories. There is a shortage of on-farm information to evaluate the accuracy of these equations and default emission factors. This work provides valuable information for improving accounting practices within China or for similar manure management practice in other countries.     

磁絮凝法处理规模化猪场废水的实验研究

实验通过磁絮凝法处理猪场废水,确定适宜的磁种和絮凝剂、助凝剂的投加量,以及搅拌条件。结果表明,对于CODCr为3 232 mg/L、浊度435 NTU的猪场废水样,PAC加入量为0.75 g/L,磁种用量为1.5 g/L,PAM加入量为16 mg/L,搅拌速度300 r/min为最佳工艺条件。     

A DFT study on the carbamates formation through the absorption of CO2 by AMP

DFT calculations in gas and aqueous solution phases have been performed to study the mechanism of carbamate formation by the absorption of CO₂ in 2-amino-2-methyl-1-propanol (AMP). The results reveal the importance of considering the effect of water as solvent for the reaction to proceed. Furthermore water molecules play an important role as a basic reactant leading to stable intermediates formation. These results point at a single-step, third order reaction as the most probable mechanism for the formation of carbamate by the absorption process.     

基于尖点突变的人群拥挤模型研究

近年来的统计分析表明,人群拥挤踩踏事故逐步上升为大型公共聚集场所的主要人为事故灾害类型之一。为了防止这类事故带来的危害,需要从理论高度开展对人群拥挤踩踏事故的承载体人群的运行系统的研究。国内外关于人群拥挤事故的研究方法很多,但至今还未找到较为完善、科学和经济的方法。因此提出将尖点突变理论引入到人群拥挤模型中,建立人群拥挤的尖点突变模型。实证分析表明,用突变模型得出的结论与数据拟合得出的结果大体一致,这说明突变理论应用于此领域是可行的。