试论绿色食品农业基地的建设

建立绿色食品农业基地是一项综合性的系统工程。自１９９０年以来,我国已陆续建立了一批粮食、蔬菜、水果、茶叶及其加工产品的绿色食品基地。据统计,我国绿色食品的实际生产已达到年增长１３０％的速度,只是规模依然很小,基地依旧匮乏。为满足绿色食品生产的需要,确保绿色食品的质量和信誉,加快建设绿色食品农业基地已是当务之急。１绿色食品与绿色食品农业基地绿色食品系指经专门机构认定,许可使用绿色食品标志的无污染的安全、优质、营养食品。绿色食品分Ａ级和ＡＡ级两类。绿色食品农业基地是指中国绿色食品发展中心根据特定的标…     

电磁辐射防护的基本技术和进展

电磁辐射污染问题经过几十年的争论,虽然在非致热效应的影响问题上尚未达到统一的认识,但人们对电磁辐射污染的存在和其严重性已清楚认识和日益重视。目前,对于电磁辐射污染危害的报道已屡见不鲜,而对其防护的基本技术和进展的报道却不多见,我们拟对此作一报道,以飨读者。王广播、电视发射台的电磁辐射防护广播、电视发射台的电磁辐射防护首先应该在项目建设前,以《电磁辐射防护规定》（GB8702－88）为标准,进行电磁辐射环境影响评价,实行预防性卫生监督,提出预防性防护措施,包括防护带要求。如果业已建成的发射台对周围区域造…     

加强规划，重建家园——浅谈洪灾后的恢复重建规划

１９９８年,我国长江、松花江流域均经历了１００年罕见的特大洪灾。据初步统计,受灾面积达２１２万ｋｍ２,倒塌房屋４９７万多间,直接经济损失达１６６６亿元。为确保灾区恢复重建工作能做到生产与生活统筹,治标和治本结合,当前利益与长远利益兼顾,避免工作的盲...     

论综合性自然资源立法

综合性自然资源立法是完善我国自然资源法制的最佳方案选择。本文以正确处理自然资源开发、利用、保护和节约之间的关系为基本内容,提出了以实现自然资源的优化配置和可持续利用为目标的综合性自然资源立法的基本原则,并对综合性自然资源立法进行了具体的框架结构设计。     

高温环境下气藏型储气库泥岩盖层密封性评价

为探究高温作用对泥岩盖层密封性的影响,从理论上剖析储气库盖层产生热应力的3种形式,在室内试验的基础上,分析泥岩在高温环境下力学损伤程度和盖层物性封闭评价指标随温度变化特征.结果表明:高温环境下泥岩整体结构性能降低,400℃左右是泥岩在周期热应力作用下损伤的阈值温度;高温作用会显著改变泥岩盖层物性封闭特征,400℃左右是...     

ISO14000国际环境管理标准的认证策略

在分析ISO14000想要达到的目的以及ISO14000系列标准基本构成的基础上,对组织是否要申请ISO14000认证,以及什么时候申请ISO14001认证的策略作一讨论。     

Investigation of basic properties of fly ash from urban waste incinerators in China

Basic properties of fly ash samples from different urban waste combustion facilities in China were analyzed using as X-ray fluorescence （XRF）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）. The leaching toxicity procedure and some factors influencing heavy metals distribution in fly ash were further investigated. Experimental results indicate that the fly ash structures are complex and its properties are variable. The results of XRF and SEM revealed that the major elements （〉10000 mg/kg, listed in decreasing order of abundance） in fly ash are O, Ca, Cl, Si, S, K, Na, Al, Fe and Zn. These elements account for 93% to 97%, and the content of Cl ranges from 6.93% to 29.18 %, while that of SiO2 does from 4.48% to 24.84%. The minor elements （1000 to 10000 mg/kg） include Cr, Cu and Pb. Primary heavy metals in fly ash include Zn, Pb, Cr, Cu etc. According to standard leaching test, heavy metal leaching levels vary from 0 to 163.10 mg/L （Pb） and from 0.049 to 164.90 mg/L （Zn）, mostly exceeding the Chinese Identification Standard for hazardous wastes. Morphology of fly ash is irregular, with both amorphous structures and polycrystalline aggregates. Further research showed that heavy metals were volatilized at a high furnace temperature, condensed when cooling down during the post-furnace system and captured at air pollution control systems. Generally, heavy metals are mainly present in the forms of aerosol particulates or tiny particulates enriched on surfaces of fly ash particles. The properties of fly ash are greatly influenced by the treatment capacities of incinerators or the variation of waste retention time in chamber. Fly ash from combustors of larger capacities generally has higher contents of volatile component and higher leaching toxicity, while those of smaller capacities often produce fly ash containing higher levels of nonvolatile components and has lower toxicity. The content of heavy metals and leaching toxicity maybe have no convincing correlation, and high alkali content of CaO greatly contribute to leaching toxicity of heavy metal and acid neutralization capacity against acid rain.     

Approach of technical decision-making by element flow analysis and Monte-Carlo simulation of municipal solid waste stream

This paper deals with the procedure and methodology which can be used to select the optimal treatment and disposal technology of municipal solid waste （MSW）, and to provide practical and effective technical support to policy-making, on the basis of study on solid waste management status and development trend in China and abroad. Focusing on various treatment and disposal technologies and processes of MSW, this study established a Monte-Carlo mathematical model of cost minimization for MSW handling subjected to environmental constraints. A new method of element stream （such as C, H, O, N, S） analysis in combination with economic stream analysis of MSW was developed. By following the streams of different treatment processes consisting of various techniques from generation, separation, transfer, transport, treatment, recycling and disposal of the wastes, the element constitution as well as its economic distribution in terms of possibility functions was identified. Every technique step was evaluated economically. The Mont-Carlo method was then conducted for model calibration. Sensitivity analysis was also carried out to identify the most sensitive factors. Model calibration indicated that landfill with power generation of landfill gas was economically the optimal technology at the present stage under the condition of more than 58% of C, H, O, N, S going to landfill. Whether or not to generate electricity was the most sensitive factor. If landfilling cost increases, MSW separation treatment was recommended by screening first followed with incinerating partially and composting partially with residue landfilling. The possibility of incineration model selection as the optimal technology was affected by the city scale. For big cities and metropolitans with large MSW generation, possibility for constructing large-scale incineration facilities increases, whereas, for middle and small cities, the effectiveness of incinerating waste decreases.