北京和上海居民旧衣物回收再利用体系建设初探

北京和上海在迈向国际化大都市进程中,随着人口的迅速增长,生活垃圾产生量与日俱增,垃圾减量从源头做起。旧衣物作为可回收、可再利用资源,现有的垃圾分类标准和回收箱的设置,不利于旧衣物的回收和再利用。目前,北京和上海在政府的支持和推动下,设专项开展旧衣物回收试点工作,已取得良好的效果。未来,如何使北京和上海旧衣物回收再利用成为一种常态,仍需政府的支持和全社会的共同参与。     

Effective rates of heavy metal release from alkaline wastes--quantified by column outflow experiments and inverse simulations

Column outflow experiments operated at steady state flow conditions do not allow the identification of rate limited release processes. This requires an alternative experimental methodology. In this study, the aim was to apply such a methodology in order to identify and quantify effective release rates of heavy metals from granular wastes. Column experiments were conducted with demolition waste and municipal waste incineration (MSWI) bottom ash using different flow velocities and multiple flow interruptions. The effluent was analyzed for heavy metals, DOC, electrical conductivity and pH. The breakthrough-curves were inversely modeled with a numerical code based on the advection–dispersion equation with first order mass-transfer and nonlinear interaction terms. Chromium, Copper, Nickel and Arsenic are usually released under non-equilibrium conditions. DOC might play a role as carrier for those trace metals. By inverse simulations, generally good model fits are derived. Although some parameters are correlated and some model deficiencies can be revealed, we are able to deduce physically reasonable release-mass-transfer time scales. Applying forward simulations, the parameter space with equifinal parameter sets was delineated. The results demonstrate that the presented experimental design is capable of identifying and quantifying non-equilibrium conditions. They show also that the possibility of rate limited release must not be neglected in release and transport studies involving inorganic contaminants.     

Assessment of the Health Impacts of Particulates from the Redevelopment of Kings Cross

The Kings Cross/St. Pancras area has been a rail transport hub from Central London to the Midlands and North Eastern England since the middle of the nineteenth century and dust from the Kings Cross railway lands was even described by Charles Dickens.¹ The Channel Tunnel high speed Rail Link (CTRL) is being constructed between 2001 and 2007 to connect continental Europe to Central London. The CTRL and associated development will help regenerate an area that is surrounded by deprived high density housing estates. London Borough of Camden has set up an extensive particulate monitoring programme to determine if there are any health impacts on local residents from emissions from the demolition and construction work. This article assesses the results from particulate measurements in 2003–2004 and compares this to baseline conditions before the redevelopment work began. The evidence suggests that although 2003 had higher than average pollution levels in the UK as a whole, even higher levels of particulates in the size range PM₁₀–PM_2.5 (defined as PM_coarse) were measured in Kings Cross. Due to the size of these particulates, they tend to be released from construction works rather than transport or secondary particulate sources. Concentrations in 2004 were lower than 2003, but this was primarily due to meteorological conditions. The paper also looks at the health of the local population and discusses whether these elevated levels are creating a problem and legally constitute a statutory nuisance. The Council continues to work with the contractors to try and ensure best practical means to minimise dust emissions and their effect on local residents. ¹Our Mutual Friend     

苏中地区生态小城镇建设模式初探

以江苏沿江开发和环境优美乡镇规划为依托,提出苏中地区生态小城镇的建设模式,包括沿长江和大运河小城镇主导发展生态工业和生态农业,形成可持续生态型小城镇,并着重探讨发展措施,进而设计苏中地区生态型小城镇评价指标体系。     

经济开发区生态规划与建设研究的几个问题

生态规划和生态建设是协调经济发展和生态环境关系,创造人与环境相和谐的人工化环境的重要调控对策.本文研究了沈阳开发区生态规划与建设中的理论、方法,着重探讨了开发区经济、环境协调发展的途径.其主要是:①选择理想的协调发展优化方案.②发展集中供热和低能耗的高技术产业.③节约水资源,提高水循环利用率.④在生态学原理指导下进行生态管理.     

青海省生态功能区划与建设研究——以互助土族自治县为例

以青海省互助土族自治县为典型研究案例,根据互助县自然条件、地貌类型、资源状况、生态区位、主导生态系统服务功能以及社会经济发展等情况,按照地域连片、主导功能相对一致的原则,对全县进行生态功能区划,在此基础上再进行全县主体功能区划,在研究区域范围4个生态功能区及4个主体功能区合理划分的基础上,提出了促进区域生态建设的对策和建议。研究结果可为构建互助县国土生态安全格局,保护生态环境、促进当地社会经济发展以及生态文明建设提供参考和安全保障。     

疏浚底泥的资源化利用

各种各样的疏浚工程产生的疏浚底泥量日益增加,以往的底泥堆放,吹填和抛海等常规处置方式对环境造成了潜在的不利影响.因而,疏浚底泥资源化越来越为人们所重视.本文总结了疏浚底泥资源化的途径,对土地利用、制造填方材料和建筑材料等资源化利用进行了讨论,并对疏浚底泥的资源化利用提出一些建议.     

城市辖区生态示范区建设规划中若干问题探讨

以国家生态示范区建设试点区——乌鲁木齐市沙依巴克区生态示范区为例,针对城市行政辖区作为复合生态系统相对独立性太弱的特点,对在规划中需特别注意的政府职责层次、示范区区域界定及建设区模式选择等问题进行了探讨,并根据该区生态示范区规划编制工作中的实际情况,提出了解决这些问题的基本思路。     

Heavy equipment and truck-related deaths on excavation work sites

PROBLEM: Contact with objects and equipment is the third leading cause of death in construction. This study examines heavy equipment- and truck-related deaths in the excavation work industry in construction. METHODS: The Bureau of Labor Statistics Census of Fatal Occupational Injuries identified 253 heavy equipment related deaths on construction sites in the Excavation Work industry for the years 1992-2002. RESULTS: Heavy equipment operators and construction laborers made up 63% of the heavy equipment- and truck-related deaths. Backhoes and trucks were involved in half the deaths. Rollovers were the main cause of death of heavy equipment operators. For workers on foot and maintenance workers, being struck by heavy equipment or trucks (especially while backing up for workers on foot), and being struck by equipment loads or parts were the major causes of death. DISCUSSION: Ensuring adequate rollover protective structures for heavy equipment, requiring fastening of seat belts, adoption of a lock-out/tagout standard, establishing restricted access zones around heavy equipment, and requiring spotters for workers who must be near heavy equipment or trucks would reduce the risk of heavy equipment- and truck-related deaths in construction. IMPACT ON INDUSTRY: Safety of heavy equipment operators in particular is a major concern in excavation that needs to be addressed.     

Mass,energy and material balances of SRF production process. Part 2: SRF produced from construction and demolition waste

In this work, the fraction of construction and demolition waste (C&D waste) complicated and economically not feasible to sort out for recycling purposes is used to produce solid recovered fuel (SRF) through mechanical treatment (MT). The paper presents the mass, energy and material balances of this SRF production process. All the process streams (input and output) produced in MT waste sorting plant to produce SRF from C&D waste are sampled and treated according to CEN standard methods for SRF. Proximate and ultimate analysis of these streams is performed and their composition is determined. Based on this analysis and composition of process streams their mass, energy and material balances are established for SRF production process. By mass balance means the overall mass flow of input waste material stream in the various output streams and material balances mean the mass flow of components of input waste material stream (such as paper and cardboard, wood, plastic (soft), plastic (hard), textile and rubber) in the various output streams of SRF production process. The results from mass balance of SRF production process showed that of the total input C&D waste material to MT waste sorting plant, 44% was recovered in the form of SRF, 5% as ferrous metal, 1% as non-ferrous metal, and 28% was sorted out as fine fraction, 18% as reject material and 4% as heavy fraction. The energy balance of this SRF production process showed that of the total input energy content of C&D waste material to MT waste sorting plant, 74% was recovered in the form of SRF, 16% belonged to the reject material and rest 10% belonged to the streams of fine fraction and heavy fraction. From the material balances of this process, mass fractions of plastic (soft), paper and cardboard, wood and plastic (hard) recovered in the SRF stream were 84%, 82%, 72% and 68% respectively of their input masses to MT plant. A high mass fraction of plastic (PVC) and rubber material was found in the reject material stream. Streams of heavy fraction and fine fraction mainly contained non-combustible material (such as stone/rock, sand particles and gypsum material).