系统动力学模型在城市发展规划环评中的应用——以山西省临汾市为例

鉴于作为评价对象的城市社会经济环境复合系统具有多目标、多要素、动态关联等突出的系统动力学特征,选择和应用系统动力学方法开展城市发展规划环评在理论上具有可行性和技术优势.作为典型资源型城市的山西省临汾市正面临转变发展方式和加快环境治理的紧迫要求,本文依托该市转型发展规划环评工作,在全面识别和剖析城市发展要素、现状问题及其成因基础上,以经济发展、产业结构、节能减排和环境改善为重点研究了规划要素间的动态反馈关系,以此构建城市转型发展规划环评SD模型,并对4个规划替代方案进行模拟和评价.结果显示,在环境目标刚性约束下所有替代方案均不能实现人均GDP翻番的较高经济增长目标,其中以较强环境约束为特征的"方案III"具有最好的环境与经济综合效果.据此评价建议临汾市应在确保实现环境改善目标的前提下主动放缓工业增长速度,同时加快以"煤焦铁电"为代表的主导产业结构调整并继续加大节能减排力度,全面提高城市可持续发展能力.     

书讯

<正>张殿印、王海涛主编的《袋式除尘器管理指南—安装、运行与维护》,由机械工业出版社于2013年11月出版,全国新华书店和机械工业出版社官网发行。该书是专门介绍袋式除尘器安装、运行与维护的管理技术书。全书约75万字,共分为8章,分别介绍袋式除尘器的分类、性能、选择,袋式除尘器安装准备、安装流程,安装方法与验收,袋式除尘器调整试验、运行操作、维护保养、故障排除和袋式除尘系统运行管理。本书内容全面,资     

不同基质的人工湿地去除猪场沼液中磷的性能

以猪场沼液为研究对象,通过静态吸附试验研究沸石、硅藻土、煤渣、铁粉、石英砂5种基质对磷的等温吸附特征,并采用一级和二级动力学模型分析吸附动力学过程。根据试验结果,构建了4种人工湿地单元研究人工湿地对猪场沼液处理效果及对高浓度沼液的抗冲击能力。结果表明,5种基质对总磷的吸附更符合非线性Langmuir方程。准二级动力学方程更能描述各种基质对总磷的动力学吸附过程。沸石对磷的最大饱和吸附量1.868 mg/g,对磷去除率最高,可达到96.01%。沸石-垂直流人工湿地在构建的4种人工湿地单元中具有最强抗冲击能力。     

新型有机废液焚烧炉炉内燃烧过程的数值模拟

为了实现化工有机废液的减量无害化处理,提出了一种新型废液焚烧炉。以某20 t/h废液焚烧炉为研究对象,利用fluent软件对新型有机废液焚烧炉炉内燃烧过程进行了数值模拟,分析了炉内温度场分布、速度场、水分浓度场分布。结果表明:炉内一二层燃烧器分级布置的四角切圆燃烧方式能很好的组织废液的干燥及燃烧,焚烧炉设计合理。研究结果可为改进废液焚烧炉的设计提供参考。     

600 MW机组加装增压风机旁路系统的探索

应环保政策要求,火电厂烟气旁路系统必须在2014年底前取消,如何解决取消烟气旁路后锅炉的安全运行问题呢?漳山电厂提出加装增压风机旁路系统的方案,并通过检测风烟系统阻力,进行可行性研究。该方案实施后,完全达到预期效果,当增压风机故障时,烟气经旁路烟道进入吸收塔,保障了锅炉正常运行,实现了增压风机在线检修。     

丽泽金融商务区道路交通噪声模拟与噪声污染防治措施的合理选用探析

通过对丽泽金融商务区交通噪声分布量进行模拟,指出丽泽路是商务区噪声超标的路段,并从噪声源、传播途径、接收点三个环节各自采用的隔声降噪措施及其效果进行模拟和评估,提出合理的隔声降噪合理措施的相关建议。     

Biostability in distribution systems in one city in southern China：Characteristics, modeling and control strategy

This study investigated the bacterial regrowth in drinking water distribution systems receiving finished water from an advanced drinking water treatment plant in one city in southem China. Thirteen nodes in two water supply zones with different aged pipelines were selected to monitor water temperature, dissolved oxygen （DO）, chloramine residual, assimilable organic carbon （AOC）, and heterotrophic plate counts （HPC）. Regression and principal component analyses indicated that HPC had a strong correlation with chloramine residual. Based on Chick-Watson＇s Law and the Monod equation, biostability curves under different conditions were developed to achieve the goal of HPC 100 CFU/mL. The biostability curves could interpret the scenario under various AOC concentrations and predict the required chloramine residual concentration under the condition of high AOC level. The simulation was also carded out to predict the scenario with a stricter HPC goal （≤50 CFU/mL） and determine the required chloramine residual. The biological regrowth control strategy was assessed using biostability curve analysis. The results indicated that maintaining high chloramine residual concentration was the most practical way to achieve the goal of HPC ≤ 100 CFU/mL. Biostability curves could be a very useful tool for biostability control in distribution systems. This work could provide some new insights towards biostability control in real distribution systems.     

Review on water leakage control in distribution networks and the associated environmental benefits

Water supply is the primary element of an urban system. Due to rapid urbanization and water scarcity, maintaining a stable and safe water supply has become a challenge to many cities, whereas a large amount of water is lost from the pipes of distribution systems. Water leakage is not only a waste of water resources, but also incurs great socio-economic costs. This article presents a comprehensive review on the potential water leakage control approaches and specifically discusses the benefits of each to environmental conservation. It is concluded that water leakage could be further reduced by improving leakage detection capability through a combination of predictive modeling and monitoring instruments, optimizing pipe maintenance strategy, and developing an instant pressure regulation system. The environment could benefit from these actions because of water savings and the reduction of energy consumption as well as greenhouse gas emissions.     

Primary neuronal-astrocytic co-culture platform for neurotoxicity assessment of di-(2-ethylhexyl) phthalate

Plastics such as polyvinyl chlorides （PVC） are widely used in many indoor constructed environments; however, their unbound chemicals, such as di-（2-ethylhexyl） phthalates （DEHP）, can leach into the surrounding environment. This study focused on DEHP＇s effect on the central nervous system by determining the precise DEHP content in mice brain tissue after exposure to the chemical, to evaluate the specific exposure range. Primary neuronal-astrocyte co-culture systems were used as in vitro models for chemical hazard identification of DEHP. Oxidative stress was hypothesized as a probable mechanism involved, and therefore the total reactive oxygen species （ROS） concentration was determined as a biomarker of oxidative stress. In addition, NeuriteTracer, a neurite tracing plugin with ImageJ, was used to develop an assay for neurotoxicity to provide quantitative measurements of neurological parameters, such as neuronal number, neuron count and neurite length, all of which could indicate neurotoxic effects. The results showed that with 1 nmol/L DEHP exposure, there was a significant increase in ROS concentrations, indicating that the neuronal-astrocyte cultures were injured due to exposure to DEHP. In response, astrocyte proliferation （gliosis） was initiated, serving as a mechanism to maintain a homeostatic environment for neurons and protect neurons from toxic chemicals. There is a need to assess the cumulative effects of DEHP in animals to evaluate the possible uotake and effects on the human neuronal system from exoosure to DEHP in the indoor environment.     

Experimental study on filtration and continuous regeneration of a particulate filter system for heavy-duty diesel engines

This study investigated the filtration and continuous regeneration of a particulate filter system on an engine test bench, consisting of a diesel oxidation catalyst（DOC） and a catalyzed diesel particulate filter（CDPF）. Both the DOC and the CDPF led to a high conversion of NO to NO2 for continuous regeneration. The filtration efficiency on solid particle number（SPN） was close to100%. The post-CDPF particles were mainly in accumulation mode. The downstream SPN was sensitively influenced by the variation of the soot loading. This phenomenon provides a method for determining the balance point temperature by measuring the trend of SPN concentration.