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Kayleigh Brown Avik J. Ghoshdastidar Jillian Hanmore James Frazee Anthony Z. Tong 《Waste management (New York, N.Y.)》2013,33(11):2188-2194
Compost leachate forms during the composting process of organic material. It is rich in oxidizable organics, ammonia and metals, which pose a risk to the environment if released without proper treatment. An innovative method based on the membrane bioreactor (MBR) technology was developed to treat compost leachate over 39 days. Water quality parameters, such as pH, dissolved oxygen, ammonia, nitrate, nitrite and chemical oxygen demand (COD) were measured daily. Concentrations of caffeine and metals were measured over the course of the experiment using gas chromatography – mass spectrometry (GC/MS) and inductively coupled plasma – mass spectrometry (ICP–MS) respectively. A decrease of more than 99% was achieved for a COD of 116 g/L in the initial leachate. Ammonia was decreased from 2720 mg/L to 0.046 mg/L, while the nitrate concentration in the effluent rose to 710 mg/L. The bacteria in the MBR system adjusted to the presence of the leachate, and increased 4 orders of magnitude. Heavy metals were removed by at least 82.7% except copper. These successful results demonstrated the membrane bioreactor technology is feasible, efficient method for the treatment of compost leachate. 相似文献
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Abstract Ground level ozone pollution has become a significant air pollution problem in Beijing. Because of the complex way in which ozone is formed, it is difficult for policy makers to identify optimal control options on a cost-effective basis. This paper identifies and assesses a range of options for addressing this problem. We apply the Ambient Least Cost Model and compare the economic costs of control options, then recommend the most effective sequence to realize pollution control at the lowest cost. The study finds that installing of Stage II gasoline vapor recovery system at Beijing’s 1446 gasoline stations would be the most cost-effective option. Overall, options to reduce ozone pollution by cutting vehicular emissions are much more cost-effective than options to “clean up” coal-fired power plants. 相似文献
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The concept of school-based disaster risk reduction (DRR) education has increasingly become popular as greater emphasis is placed on the role of schools in reducing risks and building the resilience of the education system. This paper discusses the variations in the implementation of DRR education among primary schools in different areas including urban, rural, mountainous, plain and coastal areas in Da Nang City, Central Vietnam. For rural schools, similarities in the implementation of DRR education are observed and schools in both rural plain and rural mountainous areas stress the provision of disaster-related training. In addition, improvement of school buildings and external relationship is important for the resilience of urban schools. Specifically, for schools in urban coastal areas, school location and structure are significant, while for schools in the urban plain lands, enhancement of collaboration with their community has the most potential to contribute to the resilience of a school. From that, this research proposes that leadership and prioritization are key factors in helping schools to manage internal and external resources to efficiently overcome challenges and effectively promote DRR education towards the enhancement of schools’ resilience. 相似文献
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为解决铁路综合客运枢纽客流疏解预警忽略旅客心理感知与焦虑问题,基于状态焦虑问卷,定量描述旅客焦虑状态,通过引入心理测量学中积极率划分客流疏解等级阈值,确定枢纽客流疏解预警等级,构建以旅客感知疏解时间为预警指标的回归预测模型。研究结果表明:模型可定量预测枢纽站各种交通接驳方式客流的感知疏解时间,准确描述枢纽站预警等级,研究结果可为管理人员选择相应疏解措施提供依据。 相似文献
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Yindong Tong Xuejun Wang James J. Elser 《Frontiers of Environmental Science & Engineering》2022,16(11):149
Eutrophication is the most widespread water quality issue globally. To date, most efforts to control eutrophication have focused on reductions of external nutrient inputs, yet importance of nutrient stoichiometry and subsequent shift in plankton composition in aquatic ecosystem has been largely neglected. To address eutrophication, improved sanitation is one of the United Nations Sustainable Development Goals, spurring the constructions of wastewater treatment facilities that have improved water quality in many lakes and rivers. However, control measures are often targeted at and effective in removing a single nutrient from sewage and thus are less effective in removing the others, resulting in the changes of nutrient stoichiometry. In general, more effective phosphorus removal relative to nitrogen has occurred in wastewater treatment leading to substantial increases in N/P ratios in effluent relative to the influent. Unfortunately, high N/P ratios in receiving waters can impose negative influences on ecosystems. Thus, long-term strategies for domestic wastewater management should not merely focus on the total reduction of nutrient discharge but also consider their stoichiometric balances in receiving waters. 相似文献