固定式燃气内燃机排放特性与大气环境影响研究

燃气内燃机冷热电联供机组由于其特性在城市楼宇型建筑中得到一定的运用,虽然它发电效率高,在建筑规模较小时,其经济性能也优于燃气轮机发电机组,但是其NOx的排放水平较高,噪声较大,因此有必要对其排放特性及污染控制进行研究和探讨.以某城区燃气内燃机冷热电联供项目为例,采用AERMOD烟羽扩散模式首次模拟了该燃气内燃机NOx等污染物排放对周边建筑物不同楼层的影响.结果表明,对近距离高于排气筒高度一定范围内的楼层,NOx的排放影响较大.     

江苏省太湖流域农村生活污水处理现状及对策研究

基于对江苏省太湖流域农村生活污水处理设施的全面调研,统计分析了江苏省太湖流域农村生活污水处理设施现状,包括建设数量、建设规模、处理工艺、运维模式、经费来源等,探讨了江苏省太湖流域农村生活污水处理设施存在的问题并提出建议。结果表明：目前江苏省太湖流域农村生活污水处理设施以中小规模(<100 t/d)为主,主要采用生物生态耦合处理技术,出水一般执行(GB 18918-2002)《城镇污水处理厂污染物排放标准》中的一级B标准,以属地管理的运维模式为主。应加快制订符合江苏省太湖流域的农村生活污水处理设施建设标准,并形成责任主体明确、监管制度完善、资金投入有保障的长效稳定运行体制。     

江苏太湖流域畜禽养殖及农业氮磷污染防治示范区构建技术研究

畜禽养殖废弃物及农业氮磷流失造成的环境面源污染已经成为太湖流域湖泊和水体污染的主要来源之一.通过现场勘查、文献查阅、实地调研等方法,对以太仓为代表的江苏太湖流域畜禽养殖及农业氮磷流失造成的农村生态环境污染问题进行了分析,研究提出了污染防治示范区构建的指导思想、基本原则、技术路径、技术及模式创新点,用五大发展新理念指导污染防治示范区构建,创新畜禽养殖废弃物及农业氮磷污染防治的产业化模式、区域分散畜禽粪便收集服务的社会化体系、覆盖农业氮磷污染防治全程的可控化技术体系.     

Gamma irradiation-induced decomposition of sulfamethoxazole in aqueous solution: the influence of additives,biological inhibitory,and degradation mechanisms

Sulfamethoxazole (SMX) was decomposed by using gamma irradiation in the presence of different additives such as NO₃ ⁻, NO₂ ⁻, Cr(VI), 2-propanol, and tert-butanol. The results demonstrated that NO₃ ⁻, NO₂ ⁻, 2-propanol, and tert-butanol inhibited SMX radiolytic removal. However, there existed a synergetic effect for radiolytic removal of the mixture containing SMX and Cr(VI). At an absorbed dose of 150 Gy, the removal percentages of SMX and Cr(VI) in the mixture were 73.5 and 84.6%, respectively, which was higher than the removal percentages of 70.6 and 4.1% for the single component of SMX and Cr(VI). This provides us an insight into treating the combined pollution in micro-polluted water. The SMX radiolytic removal followed a pseudo first-order reaction kinetic model, and the rate constant ratios of ·OH, e_aq ⁻, and H· towards SMX radiolysis were 10.4:1:2.9. In addition, 24-h bio-inhibitory to the macroalgae of SMX solution during gamma irradiation reached the maximum of 0.85 at an adsorbed dose of 100 Gy, then gradually decreased with the increasing adsorbed dose. Based on LC-MS analysis and quantum chemical calculation, the degradation intermediates were determined and concluded that SMX radiolytic removal was mainly via ·OH radical attack and direct decomposition of SMX molecule by gamma ray.

     

Phytostabilization potential of evening primrose (Oenothera glazioviana) for copper-contaminated sites

A field investigation, field experiment, and hydroponic experiment were conducted to evaluate feasibility of using Oenothera glazioviana for phytostabilization of copper-contaminated soil. In semiarid mine tailings in Tongling, Anhui, China, O. glazioviana, a copper excluder, was a dominant species in the community, with a low bioaccumulation factor, the lowest copper translocation factor, and the lowest copper content in seed (8 mg kg^?1). When O. glazioviana was planted in copper-polluted farmland soil in Nanjing, Jiangsu, China, its growth and development improved and the level of γ-linolenic acid in seeds reached 17.1 %, compared with 8.73 % in mine tailings. A hydroponic study showed that O. glazioviana had high tolerance to copper, low upward transportation capacity of copper, and a high γ-linolenic acid content. Therefore, it has great potential for the phytostabilization of copper-contaminated soils and a high commercial value without risk to human health.     

Project feasibility study: the key to successful implementation of sustainable and socially responsible construction management practice

This paper introduces a new approach for conducting project feasibility study by embracing the principles of sustainable development. Construction projects, in particular, infrastructures have major influence on the attainment of sustainable development, thus project sustainability needs to be considered. This becomes a pressing issue particularly in those developing countries or regions, such as China where a huge amount of construction works are currently performed and remain to happen in the future. Previous study has addressed little on the relevance of project feasibility study to project sustainability performance. The importance of incorporating sustainable development principles in conducting project feasibility study is not effectively understood by project stakeholders. This paper addresses major challenges of undertaking project feasibility study in line with sustainable construction practice with reference to the Chinese construction industry. A case study approach is the major research method in this study. The research team collected 87 feasibility study reports from various projects. Attributes are used for measuring project performance, including 18 economic performance attributes, nine social performance attributes, and eight environmental performance attributes. Research results show that economic performance is given the most concern in the current practice of project feasibility study, whilst less attention is given to the social and environmental performance. The study reveals the insufficiency of examining the performance of implementing a construction project from the perspective of sustainable development. The results also suggest the need for shifting the traditional approach of project feasibility study to a new approach that embraces the principles of sustainable development.     

Comparative study on indoor air quality in Japan and China: Characteristics of residential indoor and outdoor VOCs

We conducted a comparative study on the indoor air quality for Japan and China to investigate aromatic volatile organic compounds (VOCs) in indoor microenvironments (living room, bedroom, and kitchen) and outdoors in summer and winter during 2006–2007. Samples were taken from Shizuoka in Japan and Hangzhou in China, which are urban cities with similar latitudes. Throughout the samplings, the indoor and outdoor concentrations of many of the targeted VOCs (benzene, toluene, ethylbenzene, xylenes, and trimethylbenzenes) in China were significantly higher than those in Japan. The indoor concentrations of VOCs in Japan were somewhat consistent with those outdoors, whereas those in China tended to be higher than those outdoors. Here, we investigated the differences in VOC concentrations between Japan and China. Compositional analysis of indoor and outdoor VOCs showed bilateral differences; the contribution of benzene in China was remarkably higher than that in Japan. Significant correlations (p < 0.05) for benzene were observed among the concentrations in indoor microenvironments and between the outdoors and living rooms or kitchens in Japan. In China, however, significant correlations were observed only between living rooms and bedrooms. These findings suggest differences in strengths of indoor VOC emissions between Japan and China. The source characterizations were also investigated using principal component analysis/absolute principal component scores. It was found that outdoor sources including vehicle emission and industrial sources, and human activity could be significant sources of indoor VOC pollution in Japan and China respectively. In addition, the lifetime cancer risks estimated from unit risks and geometric mean indoor concentrations of carcinogenic VOCs were 2.3 × 10^?5 in Japan and 21 × 10^?5 in China, indicating that the exposure risks in China were approximately 10 times higher than those in Japan.     

Enantioselectivity in toxicity and degradation of dichlorprop-methyl in algal cultures

Enantioselectivity in the toxicity and degradation of the herbicide dichlorprop-methyl (2,4-DCPPM) in algal cultures was studied. Enantioselectivity was clearly observed in the toxicity of racemic 2,4-DCPPM and its two enantiomers. R-2,4-DCPPM showed low toxicity to Chlorella pyrenoidosa and Chlorella vulgaris, but higher toxicity to Scenedesmus obliquus. The observed toxicity was ranked: R-2,4-DCPPM > S-2,4-DCPPM ? Rac-2,4-DCPPM; the toxicity of R-2,4-DCPPM was about 8-fold higher than that of Rac-2,4-DCPPM. Additionally, 2,4-DCPPM was quickly degraded, in the initial 12 h, and different algae cultures had different enantioselectivity for the 2,4-DCPPM enantiomers. There was no significant enantioselectivity for 2,4-DCPPM in Chlorella vulgaris in the initial 7 h. However, racemic 2,4-DCPPM was degraded by Scenedesmus obliquus quickly, in the initial 4 h, much quicker, in fact, than the S- or R-enantiomers (racemate > R- > S-), indicating that the herbicide 2,4-DCPPM was absorbed enantioselectively by Scenedesmus obliquus. The rapid formation of 2,4-DCPP suggested that 2,4-DCPPM adsorbed by algal cells was catalytically hydrolyzed to the free acid, a toxic metabolite. The production rates of 2,4-DCPP were as follows: Scenedesmus obliquus > Chlorella pyrenoidosa > Chlorella vulgaris, consistent with the degradability of 2,4-DCPPM. Scenedesmus obliquus had quick, but different, degradative and uptake abilities for R-, S-, and Rac-2,4-DCPPM. The R- and S- enantiomers were not hydrolyzed in the first 12 h, while both enantiomers were hydrolyzed slowly after that. These results indicate that some physical and chemical properties of compounds are of importance in determining their enantioselective toxicity and degradation. The ester and its metabolite likely played an important role in enantioselective toxicity to the three algae.     

Insight into fluorescence properties of 14 selected toxic single-ring aromatic compounds in water: Experimental and DFT study

• The fluorescence peak location of 14 compounds interpreted at protein-like region. • The p-electron system inside aromatic ring contributes to the fluorophore region. • Functional group variation effects the emission spectra. • Decrease in quantum yield and increase in DE is due to atomic weight F>Cl>Br>I. • Theoretically results are in line with experimental ones. Various single-ring aromatic compounds in water sources are of great concern due to its hazardous impact on the environment and human health. The fluorescence excitation-emission matrix (EEMs) spectrophotometry is a useful method to identify organic pollutants in water. This study provides a detailed insight into the fluorescence properties of the 14 selected toxic single-ring aromatic compounds by experimental and theoretical analysis. The theoretical analysis were done with Time-Dependent Density Functional Theory (TD-DFT) and B3LYP/6-31G (d,p) basis set, whereas, Polarizable Continuum Model (PCM) was used to consider water as solvent. The selected compounds displayed their own specific excitation-emission (Ex/Em) wavelengths region, at Ex<280 nm and Em<340 nm, respectively. Whereas the theoretical Ex/Em was observed as, Ex at 240 nm–260 nm and Em at 255 nm–300 nm. Aniline as a strong aromatic base has longer Em (340 nm) than alkyl, carbonyl, and halogens substituted benzenes. The lone pair of electrons at amide substituent serves as a p-electron contributor into the aromatic ring, hence increasing the stability and transition energy, which results in longer emission and low quantum yield for the aniline. The fluorescence of halogenated benzenes illustrates an increase in the HOMO-LUMO energy gap and a decrease in quantum yield associated with atomic size (F>Cl>Br>I). In this study the theoretical results are in line with experimental ones. The understanding of fluorescence and photophysical properties are of great importance in the identification of these compounds in the water.