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241.
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Manfred Fehr 《Environment, Development and Sustainability》2009,11(2):319-328
As biodegradable material represents approximately 70% of household waste in Brazil, any strategy to divert appreciable waste
quantities from landfills of necessity has to include valorization and recycling of this material. A societal change of attitude
is required to perceive this challenge. Experiments in an urban apartment building are described that produced this change
of attitude with a success factor of 80%. Divided waste collection was implemented that separated at the source biodegradable
from inert material. Correct collection, handling and display procedures were established. Composting of biodegradable material
was carried out under the rooftop of the building as an alternative to using it as animal feed. Half of the inert material
entered the reverse logistics chain and was also diverted from the landfill. Waste related material flow through the building
is completely quantified, food intake and waste production are related, diversion of both biodegradable and inert waste components
from the landfill is measured and the composting process is described. The landfill diversion stands at 61%, mass reduction
through the composting process is 80% and matured compost is returned to residents for use in flower cages. The system has
been operational for two years and stands out as a precedent in successful decentralized household waste management supported
by material flow analysis.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
243.
Permeation of Cu(II) from its aqueous solution through a supported liquid membrane (SLM) containing di(2-ethylhexyl)phosphoric acid (D2EHPA) carrier dissolved in coconut oil has been studied. The effects of Cu(II), pH (in feed), H2SO4 (stripping) and D2EHPA (in membrane) concentrations have been investigated. The stability of the D2EHPA-coconutoil has also been evaluated. High Cu(II) concentration in the feed leads to an increase in flux from 4.1 × 10-9 to 8.9 × 10-9 mol/(m2·s) within the Cu(II) concentration range 7.8×10-4-78.6×10-4 mol/L at pH of 4.0 in the feed and 12.4 × 10-4 mol/L D2EHPA in the membrane phase. Increase in H2SO4 concentration in strip solution leads to an increase in copper ions flux up to 0.25 mol/L H2SO4, providing a maximum flux of 7.4 × 10-9 mol/(m2·s). The optimum conditions for Cu(II) transport are, pH of feed 4.0, 0.25 mol/L H2SO4 in strip phase and 12.4 × 10-4 mol/L D2EHPA (membrane) in 0.5 (m pore size polytetrafluoroethylene (PTFE) membrane. It has been observed that Cu(II) flux across the membrane tends to increase with the concentration of copper ions. Application of the method developed to copper plating bath rinse solutions has been found to be successful in the recovery of Cu(II). rane. It 相似文献
244.
Crosslinkable poly(4-methyl-2-pentyne) (PMP) membranes were cast from carbon tetrachloride solutions containing PMP and either 4,4′-diazidobenzophenone or 4,4′-(hexafluoroisopropylidene)diphenyl azide. The composite membranes were transparent and homogeneous and were crosslinked by UV irradiation at room temperature or thermal treatment at 180 °C. Low levels of the bis(aryl azide) (1–4.5 wt%) were effective in rendering the membranes insoluble in cyclohexane and carbon tetrachloride, both are good solvents for PMP, thus PMP can easily be converted to mechanically stable membranes with permeabilities and selectivities comparable or higher than those of the well-known poly(dimethylsiloxane) (PDMS). The permeabilities of O2, N2, H2, CH4 and CO2 were measured. Compared to pure PMP, the crosslinked membranes containing bis(aryl azide) had lower permeabilities and higher selectivities, consistent with a reduction in free volume. 相似文献
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印染废水处理的磁混凝-高梯度磁分离协同作用 总被引:8,自引:3,他引:5
混凝过程作为工业废水的预处理技术普遍受到重视,在混凝过程中降低污泥产生量并提高污泥分离速度是该技术发展的方向,基于上述目标,通过将磁粉引入絮体使之磁化并在自行研制的高梯度磁分离装置中实现磁混凝与磁分离的协同作用.以高浊度的印染废水作为试验废水,以色度、COD及SS作为考核指标,重点考察了磁混凝反应及磁分离的影响因素.当印染废水的色度约为900倍、COD约为595 mg/L、SS约为500 mg/L时,在pH=8.5、FeSO4500 mg/L、PAM3.5 mg/L、磁粉400 mg/L的适宜磁混凝反应条件下,相应指标去除率比传统混凝法分别高出17.3%、21.7%及24.2%,此时絮团沉降速度增大了64.3%,污泥体积减少了61%,污泥压缩比为0.39.在电流强度8 A、流速2.5 L/min和介质填充率1%的操作条件下,该磁性絮体流经高梯度磁分离装置时的水力表面负荷达到61.0 m3/m2·h,处理出水达到国家二级排放标准. 相似文献
247.
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249.
空中交通管制进近程序间隔安全性评估模型 总被引:1,自引:0,他引:1
空中交通的飞行冲突问题日益严重,笔者认为对空中飞行碰撞风险问题研究非常必要,旨在建立进近程序间隔评估模型。通过对影响进近间隔因素的分析确定了各因素对进近间隔的影响程度。应用假设平移法证明了导航台(VOR/NDB)顶空盲区内飞机报告过台位置偏离顶空盲区中心的距离与该距离下报告的飞机数量服从正态分布。应用概率等数学方法计算求得各因素决定的间隔,由各因素间的相互关系确定了模型间隔如何满足各因素确定的间隔。建立了进近间隔评估模型并对模型进行了验证和推广。 相似文献
250.