微生物燃料电池对苯酚的降解及其产电性能

构建了单室空气阴极微生物燃料电池(MFC),研究了苯酚含量对以苯酚和葡萄糖为底物的MFC产电性能及苯酚去除率的影响。实验结果表明:当CODB(苯酚贡献的COD)为0时,MFC的运行周期为36 h,最大输出电压为560 m V,最大功率密度为489 m W/m2;CODB为1 000 mg/L时,MFC的运行周期为54 h,最大输出电压为436 m V,最大功率密度为98 m W/m2;当CODB为200 mg/L时,MFC的COD去除率、苯酚去除率和库伦效率(CE)均达到最大,分别为89.7%、99.9%和7.2%,同时,MFC的阳极生物膜产生的氧化峰电流最高,表明在葡萄糖-苯酚双底物对微生物的协同作用下,MFC的阳极生物膜氧化性最强;随着CODB的增大,COD去除率、苯酚去除率和CE均逐渐减小,说明苯酚的抑制作用导致微生物活性降低。     

Green pre-concentration techniques during pesticide analysis in food samples

The ever-increasing demand for determining pesticides at low concentration levels in different food matrices requires a preliminary step of pre-concentration which is considered a crucial stage. Recently, the parameter of “greenness” during sample pre-concentration of pesticides in food matrices is as important as selectivity in order to avoid using harmful organic solvents during sample preparation. Developing new green pre-concentration techniques is one of the key subjects. Thus, to reduce the impact on the environment during trace analysis of pesticides in food matrices, new developments in pre-concentration have gone in three separate directions: the search for more environmentally friendly solvents, miniaturization and development of solvent-free pre-concentration techniques. Eco-friendly solvents such as supercritical fluids, ionic liquids and natural deep eutectic solvents have been developed for use as extraction solvents during pre-concentration of pesticides in food matrices. Also, miniaturized pre-concentration techniques such as QuEChERS, dispersive liquid–liquid micro-extraction and hollow-fiber liquid-phase micro-extraction have been used during trace analysis of pesticides in food samples as well as solvent-free techniques such as solid-phase micro-extraction and stir bar sorptive extraction. All these developments which are aimed at ensuring that pesticide pre-concentration in different food matrices is green are critically reviewed in this paper.     

From Multifunctionality to Multiple Ecosystem Services? A Conceptual Framework for Multifunctionality in Green Infrastructure Planning for Urban Areas

Green infrastructure (GI) and ecosystem services (ES) are promoted as concepts that have potential to improve environmental planning in urban areas based on a more holistic understanding of the complex interrelations and dynamics of social–ecological systems. However, the scientific discourses around both concepts still lack application-oriented frameworks that consider such a holistic perspective and are suitable to mainstream GI and ES in planning practice. This literature review explores how multifunctionality as one important principle of GI planning can be operationalized by approaches developed and tested in ES research. Specifically, approaches developed in ES research can help to assess the integrity of GI networks, balance ES supply and demand, and consider trade-offs. A conceptual framework for the assessment of multifunctionality from a social–ecological perspective is proposed that can inform the design of planning processes and support stronger exchange between GI and ES research.     

Assessing the ecosystem service of air pollutant removal by urban trees in Guangzhou (China)

In Chinese cities, air pollution has become a serious and aggravating environmental problem undermining the sustainability of urban ecosystems and the quality of urban life. Besides technical solutions to abate air pollution, urban vegetation is increasingly recognized as an alternative ameliorative method by removing some pollutants mainly through dry deposition process. This paper assesses the capability and monetary value of this ecosystem service in Guangzhou city in South China. The results indicated an annual removal of SO(2), NO(2) and total suspended particulates at about 312.03Mg, and the benefits were valued at RMB90.19 thousand (US$1.00=RMB8.26). More removal was realized by recreational land use due to a higher tree cover. Higher concentration of pollutants in the dry winter months induced more removal. The lower cost of pollution abatement in China generated a relatively subdued monetary value of this environmental benefit in comparison with developed countries. Younger districts with more extensive urban trees stripped more pollutants from the air, and this capacity was anticipated to increase further as their trees gradually reach final dimensions and establish a greater tree cover. Tree cover and pollutant concentration constitute the main factors in pollutant removal by urban trees. The efficiency of atmospheric cleansing by trees in congested Chinese cities could be improved by planting more trees other than shrubs or grass, diversifying species composition and biomass structure, and providing sound green space management. The implications for greenery design were discussed with a view to maximizing this ecosystem service in Chinese cities and other developing metropolises.     

Life-cycle cost-benefit analysis of extensive vegetated roof systems

The built environment has been a significant cause of environmental degradation in the previously undeveloped landscape. As public and private interest in restoring the environmental integrity of urban areas continues to increase, new construction practices are being developed that explicitly value beneficial environmental characteristics. The use of vegetation on a rooftop--commonly called a green roof--as an alternative to traditional roofing materials is an increasingly utilized example of such practices. The vegetation and growing media perform a number of functions that improve environmental performance, including: absorption of rainfall, reduction of roof temperatures, improvement in ambient air quality, and provision of urban habitat. A better accounting of the green roof's total costs and benefits to society and to the private sector will aid in the design of policy instruments and educational materials that affect individual decisions about green roof construction. This study uses data collected from an experimental green roof plot to develop a benefit cost analysis (BCA) for the life cycle of extensive (thin layer) green roof systems in an urban watershed. The results from this analysis are compared with a traditional roofing scenario. The net present value (NPV) of this type of green roof currently ranges from 10% to 14% more expensive than its conventional counterpart. A reduction of 20% in green roof construction cost would make the social NPV of the practice less than traditional roof NPV. Considering the positive social benefits and relatively novel nature of the practice, incentives encouraging the use of this practice in highly urbanized watersheds are strongly recommended.     

北京清洁取暖政策实施效果及成本收益量化分析

我国北方农村地区居民普遍采用的散煤分户取暖是当地污染物排放和温室气体排放的重要来源。为加大散煤治理、推进清洁取暖,北京率先推行了清洁取暖政策。本研究基于北京市约4000户农村家庭的入户调查数据,对清洁取暖政策的实施效果进行系统性分析,并对"煤改电""煤改气"和"清洁燃煤替代"三种主要清洁取暖措施的成本和收益进行量化与对比分析。结果显示,"煤改电""煤改气"和"清洁燃煤替代"均增加了居民的取暖成本,但也普遍改善了居民取暖的主观感受;政策实施减少污染物排放所带来的环境和人体健康方面的收益均大于实施成本,增进了社会福利。其中,"煤改气"户均收益最高,而"清洁燃煤替代"户均成本最低。最后,本文在研究结果的基础上,对取暖政策的推行提出相应的政策建议。     

绿色GDP核算--以海南省2004年度为例

绿色GDP核算体系的一个重要组成部分就是环境经济核算,主要核算国民经济活动对环境的影响,包括环境污染和生态破坏两个方面.从实物量与价值量两个层面对海南省环境污染进行核算,从而得到2004年海南省经环境污染调整的绿色GDP值为760.88亿元,绿色GDP指数为98.9%.     

以电代煤的经济与环境效益分析

我国《能源发展战略行动计划(2014—2020年)》指出,加快构建清洁、高效、安全、可持续的现代能源体系,重点实施"绿色低碳"等四种能源发展战略,因此"以电代煤"将成为我国未来能源战略中的一项重要选择。本文运用技术经济分析法和排放系数法,计算了八大主要用能部门以电代煤的经济成本和环境价值。计算结果表明:各部门用电设备的初始投资和电力消费等经济成本是燃煤设备的初始投资及燃煤消费等经济成本的1.8~2.8倍,但是,以用电设备替代燃煤设备的环境价值非常可观。在考虑了环境外部性成本后,居民生活行业,商业,非金属矿物制品业,石油加工、炼焦和核燃料加工业,化学原料和化学制品制造业,以及非高耗能工业六个部门进行"以电代煤"在目前的情况下具有经济可行性,而有色金属冶炼和压延工业,以及黑色金属冶炼和压延工业"以电代煤"暂时不具有经济可行性。最后,提出了相关政策建议。     

生态退耕前后张家口市耕地变化及影响因素识别

耕地变化与相关土地政策密切相关,为揭示生态退耕政策实施前后,耕地变化特征及其影响因素的差异性,该研究以北方农牧交错区——张家口市为例,分析了生态退耕前后（1989—2000年和2000—2015年）耕地变化特征。在此基础上,应用多项Logistic回归模型研究了耕地变化的影响因素。研究结果表明：1）耕地面积由1989年的1 090 031.02 hm²减少到2015年的924 647.32 hm²,持续减少了15.17%,特别是生态退耕后,耕地减少速度加快;但耕地仍然集中分布在张北县、康保县、沽源县。2）生态退耕前后,耕地转出与转入并存。与生态退耕前相比,生态退耕后耕地转换变化总面积增加121 695.72 hm²,其中转出面积增加占88.72%;耕地主要转换去向由草地（17 063.59 hm²）、建设用地（9 007.00 hm²）、林地（8 932.72 hm²）和园地（5 981.19 hm²）,变为林地（51 902.41 hm²）、园地（40 311.23 hm²）、草地（32 292.66 hm²）和建设用地（23 152.11 hm²）。3）生态退耕前后,耕地转换变化的影响因素不同。退耕前,海拔和坡度分别是耕地转为园地、林地和转为草地、建设用地的主导因素;退耕后,耕地转化的影响因素多样化,海拔仍是耕地向园地转换的主导影响因素,人均GDP变化和到最近道路距离分别成为耕地转为林地、草地和转为建设用地的首要因素。基本农田保护区和自然保护区对耕地转为园地、林地和草地也起着重要作用。研究结果能为张家口市耕地保护、生态环境保护及经济社会协调发展提供科学依据。     

垃圾填埋场填埋气发电工程设计

简要介绍生活垃圾填埋场填埋气发电工程设计,对采用燃气发电机组综合利用填埋气进行探讨,并分析沼气利用对填埋场节能和碳减排的作用。