路面径流的大肠菌群污染及其雨水花园处理

调查了上海市区路面径流中大肠菌群的污染状况,分析了径流中大肠菌群含量的主要影响因素,采用雨水花园模拟柱,考察雨水花园对城市路面径流中大肠菌群的去除效果。结果表明,上海市区地面道路径流中总大肠菌群、粪大肠菌群的均值分别为2.28×106、9.48×105 cfu/100 mL,污染较严重,径流中大肠菌群含量与气温呈正相关;雨水花园对径流中大肠菌群具有良好的去除效果,不同模拟柱平均去除率范围在92.4%~99.5%。填料深度和水力停留时间是影响雨水花园对大肠菌群去除效果的主要因素。长期运行后,填料中没有大肠菌群的积累,雨水花园对大肠菌群的去除效果可保持长期稳定。     

响应面法优化甘蔗渣-污泥复合活性炭的制备工艺

为了提高污泥活性炭的吸附性能以提升其实际应用价值,提出在污泥中掺杂甘蔗渣制备复合活性炭,并采用Plackett-Burman联用响应面法对影响复合活性炭碘值的条件进行筛选优化。通过Plackett-Burman实验筛选出热解温度、热解时间和甘蔗渣与污泥干重比为主要影响因素,对这3个因素进行Box-Behnken实验,经响应面优化得到影响碘值的二次响应曲面模型,模型显示热解温度与热解时间、热解温度与干重比的交互作用显著,并确定了最佳制备条件:热解温度550℃、热解时间30 min和干重比50%,此时复合活性炭碘值为814 mg/g,优于未优化条件下制备的复合活性炭。通过比表面积、孔结构和碘值的测定以及元素和扫描电镜分析得出,甘蔗渣的掺杂提高了复合活性炭的比表面积、微孔体积、碘值及含碳量。研究结果表明,甘蔗渣掺杂和制备条件优化是提高污泥活性炭吸附性能的有效手段。     

Adsorption of multi-heavy metals Zn and Cu onto surficial sediments: modeling and adsorption capacity analysis

Improved multiple regression adsorption models (IMRAMs) was developed to estimate the adsorption capacity of the components [Fe oxides (Fe), Mn oxides (Mn), organic materials (OMs), residuals] in surficial sediments for multi-heavy metal Zn and Cu. IMRAM is an improved version over MRAM, which introduces a computer program in the model developing process. As MRAM, Zn(Cu) IMRAM, and Cu(Zn) IMRAM again confirmed that there is significant interaction effects that control the adsorption of compounded Zn and Cu, which was neglected by additional adsorption model. The verification experiment shows that the relative deviation of the IMRAMs is less than 13 %. It is revealed by the IMRAMs that Mn, which has the greatest adsorption capability for compounded Zn and Cu (54.889 and 161.180 mg/l, respectively), follows by interference adsorption capacity of Fe/Mn (?1.072 and ?24.591 mg/l respectively). Zn and Cu influence each other through different mechanisms. When Zn is the adsorbate, compounded Cu mainly affects the adsorption capacities of Fe/Mn and Fe/Mn/OMs; while when Cu is the adsorbate, compounded Zn mainly exerts its effect on Mn, Fe/Mn, and Mn/OMs. It also shows that the compounded Zn or Cu weakened the interference adsorption of Fe/Mn, and meanwhile, strengthened the interference adsorption of Mn/OMs.     

The fate and risk of selected pharmaceutical and personal care products in wastewater treatment plants and a pilot-scale multistage constructed wetland system

The removal of 12 pharmaceuticals and personal care products (PPCPs) in two full-scale wastewater treatment plants (WWTPs) and a tertiary treatment system was studied. The ecological risks of effluents from both secondary and tertiary treatment systems as well as excess sludge were evaluated. Primary treatment and ultraviolet light disinfection showed limited ability to remove most selected PPCPs. The combination of an anaerobic process and triple-oxidation ditches can eliminate DEET better than the anaerobic/anoxic/oxic process. Adsorption to sludge played a key role in the removal of triclocarban. Multistage constructed wetlands as a tertiary treatment efficiently removed caffeine and ibuprofen from wastewater and could decrease the risk of partial selected PPCPs. Selected PPCPs residues in excess sludge generally produced higher risks to the ecological environment than effluents from WWTPs.     

Impact assessment of human diet changes with rapid urbanization on regional nitrogen and phosphorus flows—a case study of the megacity Shanghai

Regional material flows are strongly influenced by human diets. To diagnose and prevent environmental problems that threaten urban sustainability, the impact of human diet changes with rapid urbanization on the regional nitrogen (N) and phosphorus (P) flows were quantitatively evaluated. A survey of day-to-day activities was conducted of 450 individuals surveyed (adults over 18 years old) in three representative areas (the central district, the new district, and the suburban/rural areas) of Shanghai, a megacity which has attracted worldwide attention. The lifestyle (eating habits, domestic sanitation, drainage facilities, etc.) pattern was determined and the potential N and P loads from human diets on the environment were calculated. The daily potential nitrogen and phosphorus loads from human diets was 19.36 g-N, 1.80 g-P in the central district, 16.48 g-N, 1.52 g-P in the new district, and 13.04 g-N, 1.20 g-P in the suburban/rural areas of Shanghai. Respondents in all three areas, especially those in the suburban/rural areas reported a preference for increasing the intake of animal-derived as well as processed foods, which means that the potential N and P load from human diets to the environment will increase further. In addition, most respondents consider industrial wastewater discharge as the main cause of eutrophication of waterbodies, though in recent years water pollution caused by domestic wastewater has increased rapidly, but this has received much less attention. Environment-friendly eating habits and improvements in the environmental awareness will be required.     

Rapid and efficient removal of Ni2+ from aqueous solution by the one-pot synthesized EDTA-modified magnetic nanoparticles

A facile one-pot process has been proposed to prepare the novel ethylenediaminetetraacetic acid (EDTA)-modified magnetite nanoparticles (EDTA-MNPs). The bared Fe₃O₄ magnetite nanoparticles and EDTA-MNPs were characterized using FTIR spectroscopy, TEM, VSM, and X-ray diffraction. The application of the modified magnetite nanoparticles for metal ion uptake was studied using Ni²⁺ as a model. The adsorption was fast and the equilibrium was established within 5 min, and the adsorption kinetics of Ni²⁺ onto EDTA-MNPs followed the pseudo second-order chemisorption mechanism. Maximum adsorption capacity for Ni²⁺ reached as high as 41.3 mg/g at pH 6. The successive adsorption–desorption studies indicated that the EDTA-MNPs kept the adsorption and desorption efficiencies constant over ten cycles. Importantly, EDTA-MNPs were able to remove nearly 100 % of Ni²⁺ from real water.     

Effects of water-emulsified fuel on a diesel engine generator’s thermal efficiency and exhaust

Water-emulsified diesel has proven itself as a technically sufficient improvement fuel to improve diesel engine fuel combustion emissions and engine performance. However, it has seldom been used in light-duty diesel engines. Therefore, this paper focuses on an investigation into the thermal efficiency and pollution emission analysis of a light-duty diesel engine generator fueled with different water content emulsified diesel fuels (WD, including WD-0, WD-5, WD-10, and WD-15). In this study, nitric oxide, carbon monoxide, hydrocarbons, and carbon dioxide were analyzed by a vehicle emission gas analyzer, and the particle size and number concentration were measured by an electrical low-pressure impactor. In addition, engine loading and fuel consumption were also measured to calculate the thermal efficiency. Measurement results suggested that water-emulsified diesel was useful to improve the thermal efficiency and the exhaust emission of a diesel engine. Obviously, the thermal efficiency was increased about 1.2 to 19.9%. In addition, water-emulsified diesel leads to a significant reduction of nitric oxide emission (less by about 18.3 to 45.4%). However, the particle number concentration emission might be increased if the loading of the generator becomes lower than or equal to 1800 W. In addition, exhaust particle size distributions were shifted toward larger particles at high loading. The consequence of this research proposed that the water-emulsified diesel was useful to improve the engine performance and some of exhaust emissions, especially the NO emission reduction.

Implications:The accumulated test results provide a good basis to resolve the corresponding pollutants emitted from a light-duty diesel engine generator. By measuring and analyzing transforms of exhaust pollutant from this engine generator, the effects of water-emulsified diesel fuel and loading on emission characteristics might be more clear. Understanding reduction of pollutant emissions during the use of water-emulsified diesel helps improve the effectiveness of the testing program. The analyzed consequences provide useful information to the government for setting policies to curb pollutant emissions from a light-duty diesel engine generator more effectively.     

Planning of methane emission control from hoggery using an inexact two-stage optimization model

This study aims to develop an inexact two-stage optimization model to gather manure distributed over the southwest Taiwan and convert it into bioenergy. In the method, local optimization of each hauling zone is performed first using a gray mixed-integer programming model. Then, the hauling zones are prioritized by its performance on four gray scenarios. Although the biogas yield and the manure generation rate are ambiguous, one can easily evaluate his opportunity and risk by gray interval, which is a group of values within the lower and upper bounds. The analyses reveal that the biogas yield dominates the profit in this project, and it leads to the failure of the project when the biogas yield is below the level of 0.2 m³ kg^?1. With the goal of reducing 45% of methane emissions from pig farms, seven hauling zones are required to be developed. The farmers living in these zones from the project get carbon credits ranging from 478 to 3269 ton CO_2eq per year, and the investors own the carbon credits in the range of 3264–11820 ton CO_2eq per year. Through the carbon trading, both the investors and pig farmers are able to make profits by trading their carbon credits.

Implications:Biogas recovered from hoggery can be used as a bioenergy source and mitigate the atmospheric greenhouse effect and global warming. This research develops an inexact two-stage optimization model to evaluate the potential of gathering manure for biogas and converting it into bioenergy. The analyses reveal that the biogas yield dominates the profit in this project, and it leads to the failure of the project when the biogas yield is below the level of 0.2 m³ kg^?1. This study has provided a useful reference for the management of biogas production and carbon trading from hoggery for bioenergy.     

CO2分压及盐效应对碳酸盐沉积物地区地下水硬度升高的影响

为研究我国北方城市地区地下水硬度升高的机理,我们除进行现场调查和室内模拟试验研究外,还根据有关化学原理对调查中所得的典型资料进行了理论计算.下列计算有助于说明盐污染物和可生物降解的有机污染物对碳酸盐沉积物地区下水硬度升高的影响.     

固体微粒的扩散与行星边界层风速廓线

文章利用大气边界层风速廓线的理论和实验研究结果,重新推导了高斯扩散沉积模式中烟轴高度、地面反射系数及输送因子表达式,从而导出了能描述风速随高度变化的新的高斯扩散沉积模式。 文章还利用数值计算的结果讨论了风速廓线对地面相对浓度的影响。