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211.
高负荷人工土层地下渗滤系统处理生活污水中试工程的研究 总被引:3,自引:0,他引:3
对传统的地下渗滤系统进行改进,采用多层过渡结构的人工土层来增大对颗粒有机物的接触氧化表面积,同时设置曝气装置保证好氧过程的氧气供应,可以大大提高污水地下处理系统的水力负荷.以中国南方典型的红壤土、河沙和砾石为填充材料,处理广州地化所小区的生活污水,水力负荷达40 cm/d,远大于类似系统.试验结果表明,改进后的系统能创造良好的好氧/厌氧环境,对污染物去除效果良好,COD、BOD5、TN、NH 4-N、TP和SS去除率分别达到了76.7%~89.1%、83.3%~92.5%、50.3%~66.1%、65.2%~79.6%、75.4%~90.1%和77.0%~91.3%,出水主要污染物达到了《污水综合排放标准》(GB 8978-1996)一级排放标准或二级排放标准. 相似文献
212.
213.
铁屑去除酸法地浸采铀地下水中硝酸盐的试验研究 总被引:1,自引:0,他引:1
在酸法地浸采铀过程中,硝酸及硝酸盐的广泛使用使硝酸盐在地下不断累积并扩散到地下水中,这给矿区地下水造成了一定程度的污染.本试验以铁屑为还原剂,对该地下水中NO3--N的去除进行了批试验和动态试验研究.试验结果表明,铁屑可有效去除地下水中的NO3--N,其去除率随pH值的降低而逐渐升高;溶液中共存的Ca2 、Mg2 对NO3--N的去除影响不大,而SO42-、HCO3-的存在可明显降低NO3--N去除率;铁屑最佳投加量为120 g/L,铁炭最佳体积比为1∶1;二级柱可以明显提高柱子的稳定运行时间,在55 h内NO3--N去除率可保持在93%以上,去除效果较好. 相似文献
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216.
TOPSIS法在职业危害综合控制方案决策中的应用 总被引:1,自引:1,他引:0
职业危害控制方案决策属于多属性决策,应用Topsis法对职业危害控制方案进行决策,可以满足不同工艺、不同作业条件、不同经济、技术水平企业选择适宜的职业危害控制方案的需求,以达到有效控制职业危害的目的。Topsis法用于企业职业危害控制方案进行决策具有较好的准确性、实用性,是一种较易于操作、客观的综合决策方法。 相似文献
217.
This paper introduces an integrated water management model at the industrial park level. It suggests four approaches to water
management: first, direct water reuse among users; second, water reuse among users by blending with freshwater; third, water
reuse between users and a wastewater treatment plant; and fourth, groundwater recharge by reclaimed wastewater or other feasible
applications in order to optimize the overall water efficiency. The model results in a comprehensive management methodology
for optimizing water resources within an industrial park, seeking potential water reuse among industries, and incorporating
the size and cost of reclaimed wastewater delivery systems. A case study is employed to test the model’s feasibility. An economic
analysis of the optimized water use network is also carried out, showing the potential water and cost savings. 相似文献
218.
This article measures the changes in energy use, blue water footprint, and greenhouse gas (GHG) emissions associated with shifting from current US food consumption patterns to three dietary scenarios, which are based, in part, on the 2010 USDA Dietary Guidelines (US Department of Agriculture and US Department of Health and Human Services in Dietary Guidelines for Americans, 2010, 7th edn, US Government Printing Office, Washington, 2010). Amidst the current overweight and obesity epidemic in the USA, the Dietary Guidelines provide food and beverage recommendations that are intended to help individuals achieve and maintain healthy weight. The three dietary scenarios we examine include (1) reducing Caloric intake levels to achieve “normal” weight without shifting food mix, (2) switching current food mix to USDA recommended food patterns, without reducing Caloric intake, and (3) reducing Caloric intake levels and shifting current food mix to USDA recommended food patterns, which support healthy weight. This study finds that shifting from the current US diet to dietary Scenario 1 decreases energy use, blue water footprint, and GHG emissions by around 9 %, while shifting to dietary Scenario 2 increases energy use by 43 %, blue water footprint by 16 %, and GHG emissions by 11 %. Shifting to dietary Scenario 3, which accounts for both reduced Caloric intake and a shift to the USDA recommended food mix, increases energy use by 38 %, blue water footprint by 10 %, and GHG emissions by 6 %. These perhaps counterintuitive results are primarily due to USDA recommendations for greater Caloric intake of fruits, vegetables, dairy, and fish/seafood, which have relatively high resource use and emissions per Calorie. 相似文献
219.
Measures for vehicle exhaust emissions aimed at reducing either air pollution or global warming could have counterproductive effects on one another. Increasing diesel passenger vehicles, which generally have lower CO2 emissions than gasoline counterparts, leads to increasing particulate matter (PM) emissions, while gasoline has lower PM emissions than diesel. It is said that stringent limits on PM emission factors discourages improved CO2 emission factors. Without including both effects in a risk evaluation, one cannot evaluate whether the total risk is reduced or not. Hence, we evaluated representative exhaust emission measures based on risk evaluation for both air pollution and global warming. Considering consumer choice between diesel and gasoline passenger vehicles and emissions standards adopted in Japan from 1995 to 2005, we built five cases for vehicle policy evaluation. For each case, we estimated disability-adjusted life years (DALY) as an index of human health risk caused by lung cancer linked to inhalation exposure of elemental carbon in PM as well as due to global warming linked to CO2. The results of our risk evaluation reveal that the case adopting the 2005 new long-term Japanese emission standard reduces the human health risk caused by lung cancer due to air pollution by 0.6 × 103 DALY, but would increase the risk due to global warming by 31.9 × 103 DALY compared with the case of adopting EURO 4, for the same conditions of passenger vehicle choice from 1995. These results suggest that the characteristics of Japanese emissions standards are mainly designed to reduce air pollution. 相似文献
220.
To achieve a safe and reliable drinking water supply, water producers need to manage a large range of risks regarding both water quality and quantity. A risk management approach where risks are systematically identified and handled in a preventive manner is promoted by the World Health Organization and supported by researchers and drinking water experts worldwide. Risk assessment is an important part of such a management approach, and a variety of tools for risk assessment are described in the literature. There is, however, little knowledge of how drinking water risk assessment is performed in practice, including which tools that are actually used. This study investigates the use of risk assessment tools, and the approach to risk management, on a local level in the Swedish water sector. It is based on interviews with key persons from a targeted selection of water producers. We find that the application of tools as well as the approach to risk assessment and management differs considerably between the water producers. The tools most frequently used are mainly the ones promoted or required by Swedish national organizations. Although many of the water producers have done some kind of risk assessment, most have not implemented a risk management approach. Furthermore, their knowledge of the concepts of risk and risk management is often limited. The largest challenge identified is to prioritize risk assessment, so that it is actually performed and then used as a basis for managing risk in a systematic way. 相似文献