Trace chemical partitioning in construction and demolition debris fines: process and market implications

Construction and demolition debris (CDD) fines, a residue generated from mechanized CDD recycling, can often be beneficially reused. Concentrations of chemicals of potential concern in CDD fines should be evaluated prior to being reintroduced into the environment to assess risk and make informed decisions about appropriate reuse opportunities. The distribution of trace chemicals in CDD fines as a function of particle size was measured to evaluate if concentrations in the bulk material can be reduced by removing certain particle size ranges through screening. Chemicals of potential concern, including arsenic, lead, sulfate and polycyclic aromatic hydrocarbons (PAH), were characterized in four different size fractions (19–4.8 mm, 4.8–0.84 mm, 0.84–0.3 mm, < 0.3 mm) of CDD fine samples collected from 12 US CDD recycling facilities throughout the US. Results revealed that aluminum, arsenic and chromium concentrations were distributed evenly throughout all four size fractions. As for the remaining chemicals, most samples had lower concentrations in the 19–4.8 mm size range. In some samples and for certain chemicals, removal of the finer size fractions reduced overall concentrations in CDD fines, suggesting that additional processing may be worth further investigation.     

Urban solid waste management in Chongqing: challenges and opportunities

The dual influences of the resource supply and protection in ecological environments will pose a significant challenge to China's sustainable development. Solid waste management offers opportunities to improve profits by conserving resources and improving environmental performance. This paper examines municipal solid waste (MSW) management in urban Chongqing, the nation's fourth largest municipality after Beijing, Shanghai and Tianjin. In this paper, we will provide information on the quantity and composition of MSW, as well as give an overview of different methods for collection, transport, treatment and disposal of MSW. At present the daily amount of MSW generated per person is about 1.08 kg; food waste accounts for about 59% of total MSW. MSW in Chongqing has a higher moisture content (64.1%) and a lower LHV (3728 kJ/kg) than other cities in Asia, which is an obstruction for incineration. Landfills are the main method of disposal in Chongqing, but pollution caused by simple landfills and lack of backup MSW disposal capacity are becoming major problems in the main districts of Chongqing. In this paper, the challenges being faced and opportunities to MSW in Chongqing are analyzed and some suggestions are given for improving the MSW system in the future.     

双效混凝-兼性水解-SBR组合工艺处理印染废水的工程应用

针对印染废水色度大,有机物含量高,可生化性差,而且水量和水质变化大,水质成分复杂的特点,采用双效混凝兼性水解SBR组合工艺处理印染废水。运行结果表明,该工艺对CODCr、BOD5、SS、色度等均有很好的去除效果,出水水质满足纺织印染行业水污染物排放二级标准(GB428792)。     

浅谈房地产开发项目环境影响评价

房地产开发项目在推动城市经济和社会发展的同时,施工期和运营期产生的废水、废气、噪声及固废对城市及周围的环境造成不利的影响。因此,必须抓好房地产开发项目的环境影响评价工作。本文根据房地产开发项目的特点,阐述了房地产开发项目环境影响评价的内容及重点,还简单论述了绿色房地产评价的相关内容及建议。     

The effects of grassland degradation on plant diversity,primary productivity,and soil fertility in the alpine region of Asia’s headwaters

A 3-year survey was conducted to explore the relationships among plant composition, productivity, and soil fertility characterizing four different degradation stages of an alpine meadow in the source region of the Yangtze and Yellow Rivers, China. Results showed that plant species diversity, productivity, and soil fertility of the top 30-cm soil layer significantly declined with degradation stages of alpine meadow over the study period. The productivity of forbs significantly increased with degradation stages, and the soil potassium stock was not affected by grassland degradation. The vegetation composition gradually shifted from perennial graminoids (grasses and sedges) to annual forbs along the degradation gradient. The abrupt change of response in plant diversity, plant productivity, and soil nutrients was demonstrated after heavy grassland degradation. Moreover, degradation can indicate plant species diversity and productivity through changing soil fertility. However, the clear relationships are difficult to establish. In conclusion, degradation influenced ecosystem function and services, such as plant species diversity, productivity, and soil carbon and nitrogen stocks. Additionally, both plant species diversity and soil nutrients were important predictors in different degradation stages of alpine meadows. To this end, heavy degradation grade was shown to cause shift of plant community in alpine meadow, which provided an important basis for sustaining ecosystem function, manipulating the vegetation composition of the area and restoring the degraded alpine grassland.     

涉刑环境监测中有待解决的若干技术问题及对策建议

指出了涉刑环境监测工作中,司法鉴定机构的资质及监测数据认可、环保标准与规范、固体废物监测等方面存在的问题。提出,涉刑监测单位应尽快获取司法鉴定机构资质;国家层面应给出涉刑监测数据认可的指导性意见;加快环境标准制修订工作,增强标准的适用性和可操作性;修订《危险废物鉴别技术规范》（HJ/T 298-2007）和相应系列鉴别标准。     

气相色谱-串联质谱法测定土壤中十氯酮

研究了提取溶剂效率、净化方式等因素对十氯酮测定的影响,对比了加速溶剂提取、微波萃取及超声波等提取方式,考察了不同电子轰击能量、碰撞能量下特征离子对的响应。建立了加速溶剂萃取,H2SO4净化分离,气相色谱法-三重四极杆质谱法测定土壤中十氯酮的分析方法。取5.0 g土壤干样,内标法定量,线性相关系数为0.999 7,加标回收率为91.7%~121%,相对标准偏差为3.4%(n=6),检出限为0.1 ng/kg。     

食品生产企业周边空气中的异味监测

简述了食品生产企业产生的异味无机物、有机物的种类,指出其异味主要来源于食品加工、原料贮存以及废物处理等环节,分析了异味物质的产生机理。介绍了空气中异味物质的监测方法包括,嗅辨法、气相色谱-质谱联用法、傅里叶红外光谱法以及气相色谱/气相色谱-质谱与嗅闻联用法等,及其适用性,以及测定结果的评价方法。     

城市固体废物优化管理模型及管理成本影响因素研究

采用不确定性多目标动态优化模型,以优化环境和经济为目标,对中国佛山市固体废物管理进行规划.结果表明,该模型能大幅度降低固体废物管理与处理成本,节省财政支出.研究得出影响固体废物总处理费用的3个重要影响因素为产生量、回收量、处理容量.针对以上3个因素深入分析比较,提出了广义和狭义的综合处理技术,这是经济、环保、可行的技术策略:首先,将广义综合处理应用到实际中,采用分类回收、压缩收集、优化模型对废物进行合理配置,尽量降低经济成本和环境影响;其次,从狭义角度出发,采用多种技术组合,达到处理率高、资源化程度高、环境影响小的目的.     

制革厂铬鞣废水中铬的回收处理研究

针对制革厂铬鞣废水含铬(Cr3 )量高、成分复杂、沉淀后铬泥纯度低的问题,本实验采用优化后的直接加碱沉淀法、絮凝后再加碱沉淀法和新型的硅铁电极法来回收铬鞣废水中的铬.3种方法所得铬泥的纯度分别在36%、65%和80%以上,比原铬泥纯度(27.7%)最多提高了近2倍.