Leaching behaviour of different scrap materials at recovery and recycling companies: Full-, pilot- and lab-scale investigation

Scrap material recovery and recycling companies are confronted with waste water that has a highly fluctuating flow rate and composition. Common pollutants, such as COD, nutrients and suspended solids, potentially toxic metals, polyaromatic hydrocarbons and poly chlorinated biphenyls can exceed the discharge limits. An analysis of the leaching behaviour of different scrap materials and scrap yard sweepings was performed at full-scale, pilot-scale and lab-scale in order to find possible preventive solutions for this waste water problem. The results of these leaching tests (with concentrations that frequently exceeded the Flemish discharge limits) showed the importance of regular sweeping campaigns at the company, leak proof or covered storage of specific scrap materials and oil/water separation on particular leachates. The particulate versus dissolved fraction was also studied for the pollutants. For example, up to 98% of the polyaromatic hydrocarbons, poly chlorinated biphenyls and some metals were in the particulate form. This confirms the (potential) applicability of sedimentation and filtration techniques for the treatment of the majority of the leachates, and as such the rainwater run-off as a whole.     

Optimization of bio-drying of kitchen waste: inoculation,initial moisture content and bulking agents

Journal of Material Cycles and Waste Management - Bio-drying has been proved to be a promising method for treatment of MSW (municipal solid waste) and sewage sludge due to its high energy...     

Medical waste management in China: A case study of Nanjing

Medical waste management is of great importance due to its infectious and hazardous nature that can cause undesirable effects on humans and the environment. The objective of this study was to analyze and evaluate the present status of medical waste management in the light of medical waste control regulations in Nanjing. A comprehensive inspection survey was conducted for 15 hospitals, 3 disposal companies and 200 patients. Field visits and a questionnaire survey method were implemented to collect information regarding different medical waste management aspects, including medical waste generation, segregation and collection, storage, training and education, transportation, disposal, and public awareness.The results indicated that the medical waste generation rate ranges from 0.5 to 0.8 kg/bed day with a weighted average of 0.68 kg/bed day. The segregated collection of various types of medical waste has been conducted in 73% of the hospitals, but 20% of the hospitals still use unqualified staff for medical waste collection, and 93.3% of the hospitals have temporary storage areas. Additionally, 93.3% of the hospitals have provided training for staff; however, only 20% of the hospitals have ongoing training and education. It was found that the centralized disposal system has been constructed based on incineration technology, and the disposal cost of medical waste is about 580 US$/ton. The results also suggested that there is not sufficient public understanding of medical waste management, and 77% of respondents think medical waste management is an important factor in selecting hospital services.The problematic areas of medical waste management in Nanjing are addressed by proposing some recommendations that will ensure that potential health and environmental risks of medical waste are minimized.     

Performance of Streptomyces pactum–assisted phytoextraction of Cd and Pb: in view of soil properties,element bioavailability,and phytoextraction indices

Environmental Science and Pollution Research - Microbe-assisted phytoremediation provides an eco-friendly and cost-effective approach to reclaim Cd- and Pb-contaminated soils. In this work,...     

Famine relief,public order,and revolts: interaction between government and refugees as a result of drought/flood during 1790–1911 in the North China Plain

Regional Environmental Change - As a direct result of climate change and extreme weather events, refugee migration has attracted worldwide concern. In this study, we select the North China Plain...     

Phosphorus removal from wastewater by waste concrete: influence of P concentration and temperature on the product

Environmental Science and Pollution Research - This study investigated the feature of phosphorus uptake by low-cost waste concrete. Adsorption isotherms, metal dissolution, influence of P...     

土壤温度上升与森林衰退

土壤温度上升可能会引起土壤产生过量的ＨＮＯ３，而过量的ＨＮＯ３在酸性土壤中将导致Ａｌ（３＋）浓度的升高和盐基阳离子的流失，使养分失调，细根坏死。土壤温度上升还可能会改变土壤有机质动力学、土壤水文学和土壤物理学，从而改变森林生境特征，影响森林的正常生长。     

分子碰撞与惯性分离原理在油烟净化中的应用

应用分子碰撞和惯性分离原理,对油烟烟气进行分离是一种新的油烟净化方法.阐述了该方法的净化过程、基本原理和装置的最佳条件.研究结果表明：该方法是一种新型、高效、实用的油烟净化方法,提出了进一步完善该方法的研究内容.     

嘉陵江流域坡耕地“生态农业旅游”垂直景观模式

从治理水土流失角度出发，提出了坡耕地“生态农业旅游”技术与示范。其垂直生态景观模式按坡度和等高线布置：在坡度大于25°的山坡顶形成水保林木区，坡上15°～25°的陡坡种植桃树，坡中5°～15°的斜坡种植枇杷，坡下小于5°的缓坡地带种植特种水果、瓜类及蔬菜，坡底形成“稻—鱼”和“藕—鱼”特色水域区。道路系统设计为环山而下的水泥主路、观景石板干路、埂边地界小路三级，道路两侧实施还林还草。“农家乐”型旅游接待自然分布在试验区内，同时在坡上建立旅游“一条街”、坡底试验旅游产业化经营。果园内实施多熟作物覆盖、间种套种。垂直生态景观产生了独特而丰富的景观效果，并具有较好的生态功能、经济功能和社会功能。     

Where,why, and to what extent have rangelands in the Karoo,South Africa,desertified

We used simple questionnaire surveys to obtain rough categorical information on the status of semiarid and arid rangelands in the Karoo, South Africa. We sent questionnaires to extension officers of the Department of Agricultural Development, asking them to rank the condition of the rangeland in their extension districts (usually about 500 farms) on a three- or five-point scale. The questionnaire also sought information on the possible reasons for changes in the condition of the rangelands; vegetation types most at risk on mismanaged rangelands; and changes in the status of plants, birds, and mammals. Extension officers rated 35% of the semiarid rangelands in southwestern South Africa (the Karoo and southern Kalahari Desert) as being in poor condition. There was some congruency between the perceived condition of the agricultural extension district and the percentage that the stocking rate had decreased. Rangeland condition in more arid areas tends to be poor. Stocking rates have decreased disproportionately more in arid areas than in the more mesic areas of southwestern South Africa. Grasses were rated as the most threatened group of plants, and succulents the least threatened group. Overgrazing in the past was considered to be the most important cause of present-day rangeland condition, followed by present overstocking of rangelands. Antelope were considered more threatened by rangeland management than mammalian carnivores. Avian raptors and bustards, gamebirds, and tortoises were all perceived to be threatened by rangeland mismanagement.