修复达标土壤回填对地下水环境影响的层次化评估方法应用研究

以含1,2-二氯乙烷等10种有机物污染土壤异位修复后回填为例,采用层次化方法评估将按原厂址健康风险评价确定的修复目标进行达标修复后的土壤回填对回填区地下水下游700 m处饮用水井水质的影响.第一层次预测结果显示8种污染物在回填土层淋溶液中的浓度将超过评价标准,可能对目标水井水质造成污染.考虑回填区非饱和带土壤的吸附截留进行第二层次评价的结果显示,到达回填区地下水水面处浓度依然超过评价标准的污染物降低至6种,不能排除对目标水井的水质影响.进一步考虑地下水混合稀释进行第三层次评估的结果显示,经地下水混合稀释后,超过评价标准的污染物降低至4种.最后,考虑饱和带吸附截留作用进行第四层次评估的结果显示,目标水井中超过评估标准的污染物仅1种.由此可见,随着评估层次的不断深入,虽然所需开展的工作及获取的场地参数增加,但是污染物预测浓度更接近目标预测点的浓度,需调整修复目标的污染物数量逐渐减少,污染防治成本将逐渐降低.     

层次化健康风险评估方法在苯污染场地的应用及效益评估

以北京某大型苯污染场地为例,详细介绍了如何开展层次化健康风险评估.同时,结合场地污染调查结果,比较了不同层次风险评价确定的土壤苯修复目标、修复量及修复成本的差异.结果表明,在1×10-6可接受致癌风险水平下,该场地第二层次风险评价确定的0～1.5 m深度范围内土壤苯修复目标为0.26 mg·kg-1、1.5～10 m范围内土壤苯修复目标为0.15mg·kg-1,相应的土壤修复量约为292 759 m3,修复成本约2.06亿元.但是,基于该场地苯污染区域土壤气中苯浓度进行的第三层次风险评价确定的0～1.5 m深度范围内土壤苯修复目标为2.6 mg·kg-1、1.5～10 m范围内土壤苯修复目标为1.5mg·kg-1,相应的土壤修复量约为153 222 m3,减少139 537 m3,修复成本为1.49亿元,减少了5 700万元,修复成本的降低远多于因开展第三层次风险评价所付出的约10万元的成本.因此,对于类似大型VOCs污染场地,开采第三层次健康风险评价能够节省大量修复成本、带来巨大的经济效益.     

优化城镇污水处理厂运行管理的探讨

结合城镇污水处理厂运行管理经验,探讨通过优化工艺控制、科学合理的生产调度、强化设备管理、加强安全管理和成本管理控制等措施,来实现优化城镇污水处理厂的运行管理;从而有利于污水处理厂实现安全生产、稳定达标、高效运行。通过优化和强化城镇污水处理厂运行管理,不仅有利于充分发挥污水处理厂污水治理的环境效益,在国家节能减排工作中发挥更大的作用;同时有利于污水处理厂进一步降低运行成本、开源节流,实现污水处理厂的可持续发展。     

基于排队论的城市垃圾箱最佳间距研究

针对城市垃圾箱最佳间距的研究不够精细的现状,本文通过建立排队论模型得到了可供不同城市参考的城市垃圾箱最佳间距参数表。通过对部分城市街道的垃圾箱摆放间距情况进行实地调查,运用层次分析法将影响垃圾箱间距分布的多重因素转化为单因素;建立了基于指数分布的教学模型,利用排队论分析单因素状态下的垃圾箱间距分布,得到了求解城市垃圾箱最佳间距的一般方法。     

Artificial neural network model for identifying taxi gross emitter from remote sensing data of vehicle emission

Vehicle emission has been the major source of air pollution in urban areas in the past two decades. This article proposes an artificial neural network model for identifying the taxi gross emitters based on the remote sensing data. After carrying out the field test in Guangzhou and analyzing various factors from the emission data, the artificial neural network modeling was proved to be an advisable method of identifying the gross emitters. On the basis of the principal component analysis and the selection of algorithm and architecture, the Back-Propagation neural network model with 8-17-1 architecture was established as the optimal approach for this purpose. It gave a percentage of hits of 93%. Our previous research result and the result from aggression analysis were compared, and they provided respectively the percentage of hits of 81.63% and 75%. This comparison demonstrates the potentiality and validity of the proposed method in the identification of taxi gross emitters.     

Towards a capability approach of sustainability

Despite having a strong influence on development policies, theories of sustainability have not paid much attention to the capability approach (CA) thus far. Against this backdrop, the present paper argues for the CA’s usefulness of sustainability. In order to avoid just an additional contribution to the already confusing theoretical situation as well as to rely our exploration of the CA’s aptness for a conception of sustainability on a transparent and comparable basis, we will first identify six adequacy conditions for concepts of sustainability. We will then work out a categorial framework for conceptions of sustainability. Finally we will demonstrate how the CA is a promising candidate for filling in the demands of this framework and what further research will be needed.     

Carbon footprint of food - approaches from national input-output statistics and a LCA of a food portion

The aim of the study, on which this paper is based, was to provide guidance to consumers to make environmentally responsible choices in their food consumption, to assist food supply chain stakeholders to identify the key areas for environmental improvements, and to provide policy makers with a tool for monitoring the potential impacts on climate change resulting from developments within the food sector. At the macro level, the EIO-LCA model was developed specifically for the Finnish food chain; at the micro level, LCAs were performed on 30 lunch portions. The contribution of the Finnish food chain to climate change was 14%, which comprised 40% CO₂ emissions, 25% CH₄ emissions, and 34% N₂O emissions. The share of impacts from domestic agricultural processes was the highest, at 69%. The impact of a single lunch portion ranged between 0.65 and 3.80 kg of equivalent CO₂. According to the EIO-LCA model, the average impact was 7.7 kg CO₂ eq/person daily. The consumer phase accounted for between 8 and 47% of the climate change impacts for homemade portions. In ready-to-eat portions industry and retail phases were emphasized, representing 25-38% of climate change impacts. We present an approach to steer the Finnish food sector onto an environmentally sustainable path; practical tools for consumers and farmers will especially need to be developed further.     

天津市夏季蜂窝状溶蚀器涂层溶液浓度确定的实验研究

于2013年7月1日～8月31日,在天津市南开大学理化楼楼顶,采用蜂窝状溶蚀器进行了溶蚀器涂层溶液最适浓度的探究实验.结果表明,在天津夏季,蜂窝状溶蚀器的碳酸钠涂层溶液最适浓度为3%,柠檬酸涂层溶液最适浓度为6%.含有溶蚀器系统的颗粒物采样法与传统采样法对比发现,含蜂窝状溶蚀器的采样系统所得到的PM2.5样品浓度有86%低于传统方法所得到的PM2.5样品浓度,其原因主要为1酸/碱性气体被去除,使其无法与富集在采样膜上的颗粒物发生反应,也无法吸附到颗粒物上;2溶蚀器系统采样过程中,部分颗粒物被捕集到溶蚀器上;3酸/碱性气体被去除,导致气-粒平衡被打破,部分颗粒物组分向气态转化.     

TiO2/膨润土复合材料对Hg2+的吸附性能研究

利用纳米TiO_2对膨润土进行复合改性,制备TiO_2/膨润土复合材料.采用电镜扫描、X-射线衍射表征改性前后膨润土的结构和形貌.通过室内模拟实验,以膨润土为对照,研究不同添加量、pH、吸附时间及初始Hg~(2+)浓度等条件下,TiO_2/膨润土复合材料对Hg~(2+)的吸附特性与性能,同时通过正交试验,探究TiO_2/膨润土复合材料吸附Hg~(2+)的最优条件.结果表明,改性后的膨润土颗粒明显变小,且颗粒疏松多空孔,层间距增大.相比于膨润土,TiO_2/膨润土复合材料吸附性能得到极大提高.TiO_2/膨润土复合材料对Hg~(2+)的吸附率均随着添加量、pH、吸附时间的增大而增大,添加量为1.5 g·L~(-1)、pH为7.0、吸附时间为120 min时,吸附率达98.0%以上.但TiO_2/膨润土复合材料对Hg~(2+)的吸附率随着初始Hg~(2+)浓度的增大而减小.通过4种动力学模型拟合发现,吸附过程符合假二级动力学方程,吸附以化学吸附为主.吸附等温线更符合Langmuir等温方程,属于典型的单分子层吸附,最大吸附量为20.66 mg·g-1.吸附Hg~(2+)的最优实验条件:添加量为2.0 g·L~(-1),pH为8.0,初始Hg~(2+)浓度为45 mg·L~(-1),吸附时间为16 h,此时吸附率99.9%,平衡浓度为0.034 mg·L~(-1).     

基于智能优化算法的河流水质模型参数的优化简

为探索河流水质模型参数新的求解方法，根据有限的实测数据，分别应用免疫进化优化算法和免疫进化优选的捕食搜索算法，对河流水质模型计算公式中的多参数进行优化。将优化得到的计算公式用于国内外若干河流的河段中DO浓度值的拟合，并与实测结果进行了比较。结果表明，将免疫进化优化算法或免疫进化优选的捕食搜索算法优化得到的水质模型参数精度不仅较高，而且相对稳定，从而为河流水质模型参数的优化提供了一种新方法。