Laboratory Evaluation of Crushed Glass–Dredged Material Blends

A comprehensive laboratory evaluation of blending 9.5?mm (3/8?in.) minus curbside-collected crushed glass (CG) with dredged material (DM) was conducted to evaluate their potential for beneficial use as fill materials for urban applications. Tests were performed on 100% CG (USCS classification SP) and 100% DM (OH) specimens and 20/80, 40/60, 50/50, 60/40, and 80/20 CG–DM blends (dry weight percent CG content reported first). The addition of 20% CG resulted in a 10–20 point (33–67%) reduction in wopt while increasing the dry density by approximately 1–3?kN/m3 for standard and modified levels of compaction, respectively. Simultaneously, the compressibility of the DM was reduced by approximately 50% and the hydraulic conductivity was reduced by ? order of magnitude. The addition of 20% CG significantly decreased the moisture content and significantly improved the workability of the 100% DM, where workability refers to the ease of handling, transport, placement, and compaction of the CG–DM blends (compared to 100% DM). CIū triaxial strength testing indicated effective friction angles of 34 and 37° for 100% DM and CG compacted to a minimum of 95% relative compaction by ASTM D1557, respectively. A peak effective friction angle of 39° occurred for the 60/40 and 80/20 CG–DM blends which were also 1 and 3 orders of magnitude more permeable than 100% DM, respectively. Related increases in cv resulted in decreased times required for consolidation. The range of properties obtainable by the CG–DM blends offers a versatility that allows for the design of fills that can be potentially optimized to meet multiple design parameters (e.g. strength, settlement, drainage, or higher CG or DM content).     

中小铸造企业面对材料价格持续暴涨的发展方向

介绍了中小铸造企业通过降低生产成本、提高生产率、完善生产工艺、资源循环利用等手段，来应对材料价格的持续上涨。     

钛白废酸回收装置国产化实践

南通三圣开发了拥有自主知识产权的“钛白废酸资源化回收利用的工艺技术及装置”,并通过了江苏省科技厅科技成果鉴定。从工艺技术革新、装置水平．经济效益及能耗分析、防腐材料及设备的开发、国产化装置的实施和优越性比较等几个方面证实了该装置的技术含量已世界先进水平．充分论证了钛白废酸的综合治理、回收利用是切实可行的。     

面向机电产品回收的选择性拆卸技术

合理选择拆卸方法是提高废旧机电产品回收率的重要保证。研究和构建了机电产品面向回收的选择性拆卸模型,提出了绿色制造系统的优选方法,同时通过废旧产品选择性拆卸的递归算法,以BD-148冰柜产品作为实例研究,最终获得最经济的回收方案。     

福建传统民居对南方地区城乡建设中节能减排措施的启发

在当前城乡建设中,要坚持科学发展观,紧紧抓住节能减排这一工作重心,节约能源,提高资源利用率。本文通过对福建传统民居绿色环保型建筑的分析,这些传统民居的建筑选址、结构布局以及“天人合一”的环境观和”聚族而居”的生活模式对城乡建设中节能减排有重要的启示作用和借鉴意义。     

关于余浆的回收利用

近年来随着我国设计单位、施工企业对管桩产品认识的加深,管桩的市场得到了很大的开发,但随之产生的余浆污染,也着实让管桩行业为难,如何处理余浆已成了各个生产厂家急需解决的问题。本文是通过把余浆作为一种掺合料着手,通过对其成份的分析,经过大量的试验及实践验证,成功的把余浆用于管桩再生产过程中,既变废为宝,降低了生产成本,又为企业增加效益开辟了新路子。     

E-waste: An assessment of global production and environmental impacts

E-waste comprises discarded electronic appliances, of which computers and mobile telephones are disproportionately abundant because of their short lifespan. The current global production of E-waste is estimated to be 20-25 million tonnes per year, with most E-waste being produced in Europe, the United States and Australasia. China, Eastern Europe and Latin America will become major E-waste producers in the next ten years. Miniaturisation and the development of more efficient cloud computing networks, where computing services are delivered over the internet from remote locations, may offset the increase in E-waste production from global economic growth and the development of pervasive new technologies. E-waste contains valuable metals (Cu, platinum group) as well as potential environmental contaminants, especially Pb, Sb, Hg, Cd, Ni, polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs). Burning E-waste may generate dioxins, furans, polycyclic aromatic hydrocarbons (PAHs), polyhalogenated aromatic hydrocarbons (PHAHs), and hydrogen chloride. The chemical composition of E-waste changes with the development of new technologies and pressure from environmental organisations on electronics companies to find alternatives to environmentally damaging materials. Most E-waste is disposed in landfills. Effective reprocessing technology, which recovers the valuable materials with minimal environmental impact, is expensive. Consequently, although illegal under the Basel Convention, rich countries export an unknown quantity of E-waste to poor countries, where recycling techniques include burning and dissolution in strong acids with few measures to protect human health and the environment. Such reprocessing initially results in extreme localised contamination followed by migration of the contaminants into receiving waters and food chains. E-waste workers suffer negative health effects through skin contact and inhalation, while the wider community are exposed to the contaminants through smoke, dust, drinking water and food. There is evidence that E-waste associated contaminants may be present in some agricultural or manufactured products for export.     

Life Cycle Assessment of urban wastewater reuse with ozonation as tertiary treatment: A focus on toxicity-related impacts

Life Cycle Assessment has been used to compare different scenarios involving wastewater reuse, with special focus on toxicity-related impact categories. The study is based on bench-scale experiments applying ozone and ozone in combination with hydrogen peroxide to a wastewater effluent from a Spanish sewage treatment plant. Two alternative characterisation models have been used to account for toxicity of chemical substances, namely USES-LCA and EDIP97. Four alternative scenarios have been assessed: wastewater discharge plus desalination supply, wastewater reuse without tertiary treatment, wastewater reuse after applying a tertiary treatment consisting on ozonation, and wastewater reuse after applying ozonation in combination with hydrogen peroxide. The results highlight the importance of including wastewater pollutants in LCA of wastewater systems assessing toxicity, since the contribution of wastewater pollutants to the overall toxicity scores in this case study can be above 90%. Key pollutants here are not only heavy metals and other priority pollutants, but also non-regulated pollutants such as pharmaceuticals and personal care products. Wastewater reuse after applying any of the tertiary treatments considered appears as the best choice from an ecotoxicity perspective. As for human toxicity, differences between scenarios are smaller, and taking into account the experimental and modelling uncertainty, the benefits of tertiary treatment are not so clear. From a global warming potential perspective, tertiary treatments involve a potential 85% reduction of greenhouse gas emissions when compared with desalination.     

Accelerated carbonation for treatment of MSWI bottom ash

Leaching of heavy metals from MSWI bottom ash exceeds some of the Flemish limit values for recycling the material as granular construction application. In particular, leaching of Cu, Zn and Pb often exceeds the limit value, with Cu being the most critical. In order to recycle bottom ash, treatment is therefore required. The bottom ash studied was divided on-site into four fractions using a large-scale wet sieving installation: a sludge fraction (Ø 0–0.1 mm), a sand fraction (Ø 0.1–2 mm) and two gravel fractions (Ø 2–6 and 6–50 mm). The two gravel fractions complied with the limit values after 3 months of natural ageing. The sand and sludge fraction did not reach the limit value for Cu. Four weeks of accelerated carbonation resulted in an important decrease of Cu leaching from these two fractions, although the limit value is still exceeded. In view of applying carbonation as one of the treatment methods in an integrated industrial application, two tests were additionally performed. The use of stack gas as carbonating medium was verified by setting up an accelerated carbonation experiment at the incineration plant. Also, the depth of carbonation was measured in a 10 cm thick sample of the sand fraction after different periods of treatment. After 3 months of natural ageing only the upper 4 cm underwent a significant carbonation, while after one week of accelerated carbonation the total sample was carbonated. A model was developed to predict these experimental results.