建立再生资源回收体系产业链条促进回收体系产业化发展

介绍了北京市海淀区再生资源回收体系产业化发展的经验。作为建设主体企业,海淀区物资回收公司合理规划、布局回收网点,疏通物流运输渠道,建设专业化分拣中心,开展厂商直挂业务,有效推进海淀区再生资源回收体系建设。     

固定化酶制备方法研究进展

对固定化酶的主要制备方法进行了系统的阐述,根据作者本人的试验经验对目前应用的研究得较多的方法作了详细的说明,对所阐述的各种固定化酶的制备方法的优缺点进行了比较。     

环境权架构的路径探析--兼论后现代主义对环境权研究的影响

环境权的研究遭遇着理论和实践的双重困境.若想摆脱困境,必须重新审视创设一项权利的相关基本理论,从而选择一条明晰的路径,有的放矢地架构权利内容.环境权创设的目的是保护自然环境的生态功能;环境要素生态功能的特征、市场和政府在环境保护方面的失灵以及环境法学的独立自足性论证了创设环境权的必要性;而将环境权定位于一项法律权利,并充分考虑其与现有权利的兼容性之后,提出了较为务实的架构环境权的制度取向.     

借助两个市场开发两种资源积极发展中国再生有色金属产业

在我国的工业化进程中,有色金属作为国民经济建设中不可或缺的基础材料,担当着十分重要的角色. 近年来,我国有色金属的年产量逐年递增,已成为位居世界第二的有色金属生产和消费大国. 虽然我国目前正处在产业结构大调整时期,但有色金属的年产量却始终以较高的速度增长,十分引人注目的是,在我国有色金属生产总量构成中,以各种各样的工业和民用废弃物为原料生产的再生有色金属的年增长速度始终比以原矿为原料的传统有色金属的年增长速度要快得多,这是个不争的事实.     

废旧电脑的综合处理与处置

随着社会文明的高速发展,越来越多的高科技新兴产品进入人们的生活,带给人们更多的方便和享受的同时,也使城市生活垃圾结构发生了很大的改变,废电池、废电冰箱、废电脑等家用电器及其废物的另类生活垃圾成为今天新的环境问题.从环境管理和绿色处理的角度,综合概述了国内外废旧电脑处理的现状,结合国外的发展经验从绿色处理的角度对废旧电脑的处理与处置方法提出了一些建议.     

促进循环经济发展的税收对策

循环经济是一种全新的经济模式,它关注的是资源减量、循环及再利用的问题.通过对国外为实现循环型经济所采取的税收政策的比较,指出了我国目前在该领域采取的措施所存在的问题.根据我国的实际情况,提出了促进循环经济发展的税收对策.     

论环保产业的法律保护

市场对环保产业的发展所起的作用是有限的,政府必须通过法律调控的方式引导环保产业的发展,当前的重点是建立有利于其发展的经济刺激法律制度.     

处理废水的膜工艺

美国公司开发了从工业废水中分离贵重组分的膜工艺,利用新型的可以把水分子分解成氢离子和氢氧离子的两极膜。盐溶液的水在表面上流过,通过外部带电的膜层向分离腔自由扩散,在分离腔内,水分解成氢离子和氢氧离子。在膜的间隙内,在电势的影响下,氧离子通过膜的一个外表层,而负的氢氧离子通过另一个外表层,因此,在两极的对面相反电荷的离子浓度增加。同时,沿两极膜两面分布的两个普通的单极离子交换膜,相反电荷的离于通过氢     

循环经济导向的废旧物资回收体系创新--基于我国社会经济发展进入加速转型期的基本判断

发展循环经济的基本原则之一是促进废旧物资的再生利用,因此废旧物资回收体系的建设是循环经济能否健康发展的重要环节.但是,目前废旧物资回收体系存在着种种不适应循环经济发展内在要求的制度性问题,这在很大程度上影响了循环经济的健康发展.在上述制度性问题分析的基础上,基于目前社会经济发展转型的基本判断,提出若干循环经济导向的废旧物资回收体系的制度创新的对策.     

再生资源研究与可持续发展战略

(续前) 三、可持续发展战略的核心思想 人类社会的发展，科学技术的进步，不仅只表现为物质文化生活水平的提高，更表现为人们理性思维水平的提高和自觉行为的增强。特别是在现代化信息社会条件下，任何事业的成功，任何事物的发展，没有理论思维指导下的科学预见行为的存在，是很难取得较为理想的预期成果的。这也是作为一个现代民族，现代人类实践活动的一个重要标志。正如恩格斯指出的：“一个民族要想站在科学的最高峰，就一刻也不能没有理论的思维”。 随着人类社会的进步和发展，人们的社会行为及思维方式，已由被动适应生存型向主动斗争生存型转化，由实践经验型向理论思维型转化，由盲目探索型向科学预见型转化，由自发社会行为型转向自觉社会行为型转化。这是人类自身进化发展不可逆转的历史进程。“可持续发展战略”的提出，就是充分体现人类在与地球环境自然资源长期相互作用和影响过程后的一种行为方式的科学选择。只有实施可持续发展战略，才能保证人类社会行为的合理性，从而保证人类社会的稳定持续发展，最终达到人与自然界，以及人与人之间的真正和谐与统一发展。     

Determination of the Thermal Efficiency of Pre-boilover Burning of a Slick of Oil on Water

The burning rate of a slick of oil on a water bed is calculated by a simple expression derived from a one-dimensional heat conduction equation. Heat feedback from the flame to the surface is assumed to be a constant fraction of the total energy released by the combustion reaction. The constant fraction (χ) is named the burning efficiency and represents an important tool in assessing the potential of in situ burning as a counter-measure to an oil-spill. The total heat release, as a function of the pool diameter, is obtained from an existing correlation. It is assumed that radiative heat is absorbed close to the fuel surface, that conduction is the dominant mode of heat transfer in the liquid phase and that the fuel boiling temperature remains constant. By matching the characteristic thermal penetration length scale for the fuel/water system and an equivalent single layer system, a combined thermal diffusivity can be calculated and used to obtain an analytical solution for the burning rate. Theoretical expressions were correlated with crude oil and heating oil, for a number of pool diameters and initial fuel layer thickness. Experiments were also conducted with emulsified and weathered crude oil. The simple analytical expression describes well the effects of pool diameter and initial fuel layer thickness permitting a better observation of the effects of weathering, emulsification and net heat feedback to the fuel surface. Experiments showed that only a small fraction of the heat released by the flame is retained by the fuel layer and water bed (of the order of 1%). The effect of weathering on the burning rate decreases with the weathering period and that emulsification results in a linear decrease of the burning rate with water content.     

Review of the kinetics of alkaline degradation of cellulose in view of its relevance for safety assessment of radioactive waste repositories

The degradation of cellulose (a substantial component of low- and intermediate-level radioactive waste) under alkaline conditions occurs via two main processes: a peeling-off reaction and a basecatalyzed cleavage of glycosidic bonds (hydrolysis). Both processes show pseudo-first-order kinetics. At ambient temperature, the peeling-off process is the dominant degradation mechanism, resulting in the formation of mainly isosaccharinic acid. The degradation depends strongly on the degree of polymerization (DP) and on the number of reducing end groups present in cellulose. Beyond pH 12.5, the OH^- concentration has only a minor effect on the degradation rate. It was estimated that under repository conditions (alkaline environment, pH 13.3-12.5) about 10% of the cellulosic materials (average DP = 1000-2000) will degrade in the first stage (up to 10⁵ years) by the peeling-off reaction and will cause an ingrowth of isosaccharinic acid in the interstitial cement pore water. In the second stage (10⁵-10⁶ years), alkaline hydrolysis will control the further degradation of the cellulose. The potential role of microorganisms in the degradation of cellulose under alkaline conditions could not be evaluated. Proper assessment of the effect of cellulose degradation on the mobilization of radionuclides basically requires knowing the concentration of isosaccharinic acid in the pore water. This concentration, however, depends on several factors such as the stability of ISA under alkaline conditions, sorption of ISA on cement, formation of sparingly soluble ISA-salts, etc. A discussion of all the relevant processes involved, however, is far beyond the scope of the presented overview.     

Study of Aging Characteristics of Ternary Blends of Polyethylenes—II

Six film samples of low-density polypropylene (LDPE)/linear LDPE (LLDPE)/high-density polypropylene (HDPE) with varying ratios of LDPE (20–45 ... wt%) and LLDPE (25–50 wt%) having a fixed amount of HDPE at 30 wt% were prepared by blown film extrusion technique. The samples were aged at four different temperatures, 55°, 70°, 85°, and 100°C, for four different time periods in the interval of between 150 hours and up to 600 hours. The change in the structure of various constituents and the formation of various oxygenated (peroxy and hydroperoxy) and unsaturated groups during thermo-oxidative degradation was discussed by infrared spectroscopy. The visiosity-average molecular weight was found to have decreased slowly in the initial aging hours and temperatures, whereas it decreased by 10% with its previous value tensile strength that is, 100°C when aged for 600 hours. The tensile strength of the sample first increased by 67% at 55°C and 89% at 70°C up to 450 hours, whereas the values increased by 52.5% at 85°C and 33.9% at 100°C when aged for 150 hours and then decreased. The percentage elongation at break increased by 2.7% at 55°C and 10.7% at 70°C for 150 and 300 hours of aging, respectively, whereas the percentage decreased when aged at 85°C and 100°C for up to 600 hours of aging. The values of gel content (percent) increased and initial degradation temperature decreased with aging time and temperature.     

富拉尔基发电总厂200MW机组除尘器改造

对富拉尔基发电总厂5号炉的设计条件进行了分析，针对燃用低硫煤，飞灰比电阻高，场地较小，除尘效率要求高的情况，在电除尘器的设计上采取有效措施，达到了排放要求。     

Calculation of carbon balances for evaluation of the biodegradability of polymers

Establishing carbon balances has been proven to be an applicable and powerful tool in testing biodegradability of polymers. In controlled degradation tests at a 4-L scale with the model polymer poly(-hydroxybutyrate) (PHB), it was shown that the degree of degradation could not be determined with satisfactory accuracy from CO₂ release alone. Instead, the course of degradation was characterized by means of establishing carbon balances for the degradation of PHB withAcidovorax facilis and a mixed culture derived from compost. Different analytical methods for determining the different carbon fractions were adapted to the particular test conditions and compared. Quantitative determination of biomass and residual polymer were the main problems in establishing carbon balances. Amounts of biomass derived from protein measurements depend strongly on assumptions of the protein content of the biomass. Selective oxidation of biomass with hypochlorite was used as alternative, but here problems arose from insoluble metabolic products. Determination of soluble components with the method of chemical oxygen demand (COD) also includes empirical assumptions but seems acceptable if the dissolved carbon fraction is in the range of some 10% total carbon. Results confirm both analytical assays and theoretical approaches, in ending up at values very close to 100%, within an acceptable standard deviation range under test conditions comparable to standard test practice.Paper presented at the Bio/Environmentally Degradable Polymer Society—Third National Meeting, June 6–8, 1994, Boston, Massachusetts.     

Effects of temperature on the release of nutrient elements of solid organic materials under conditions of oversaturation

The effects of temperature on the release of chemical components of six solid organic materials under conditions of oversaturation were investigated in this paper. The six materials were peat moss (PM), weathered coals (WC), charred rice husks (CRH), sawdust (Sd), turfgrass clippings (TC), and chicken manure (CM). Significant differences were observed in the available nitrogen and phosphorus content of the aqueous extracts of organic materials at different temperatures. The available nitrogen content in aqueous extracts of PM and WC at 25 °C was higher than that registered at 15 °C and 35 °C. Available nitrogen content in the aqueous extracts of CRH, Sd, TC, and WC at 35 °C was higher than at 15 °C and 25 °C. The available phosphorus content in the aqueous extracts of organic materials at 35 °C was higher than that available at 15 °C and 25 °C, with the exception of Sd. In addition, the release of available phosphorus in the aqueous solution of organic materials at different temperatures varied constantly for 108 h. The release of potassium (K⁺) and sodium (Na⁺) ions in the aqueous extracts of organic materials was basically steady over time, with the exception of CM. High temperature (35 °C) may significantly hasten the release of K⁺ from organic substrates (except for WC) with low temperatures significantly inhibiting release of K⁺ in Sd and CRH. High temperatures (35 °C) might significantly facilitate the release of Na⁺ in CM and TC. However, no significant differences were manifested in the release of Na⁺ from organic substrates at different temperatures, with the exception of CM and TC. Moreover, no significant differences were observed in the release of calcium, magnesium and iron ions with time, nor were there any significant differences in the contents of iron ions in the aqueous extracts of organic materials at different temperatures. The results indicate that multiple mediums should be pretreated in water for a week before being used for planting. They should be used when all mineral elements of organic materials are steady and ignoring the effect of organic mediums.     

Selection of adsorbents for treatment of leachate: batch studies of simultaneous adsorption of heavy metals

The simultaneous adsorption of copper (Cu), cadmium (Cd), nickel (Ni), and lead (Pb) ions from spiked deionized water and spiked leachate onto natural materials (peat A and B), by-product or waste materials (carbon-containing ash, paper pellets, pine bark, and semi-coke), and synthetic materials (based on urea-formaldehyde resins, called blue and red adsorbents) or mixtures thereof was investigated. The adsorbents that gave the highest metal removal efficiencies were peat A, a mixture of peat B and carbon-containing ash, and a mixture of peat A and blue. At an initial concentration of 5 mg/l for each metal, the removal of each species of metal ion from spiked water and spiked leachate solutions was very good (>90%) and good (>75%), respectively. When the initial concentration of each metal in the solutions was twenty times higher (100 mg/l), there was a noticeable decrease in the removal efficiency of Cu²⁺, Cd²⁺, and Ni²⁺, but not of Pb²⁺. Langmuir monolayer adsorption capacities, q_m, on peat A were found to be 0.57, 0.37, and 0.36 mmol/g for Pb²⁺, Cd²⁺, and Ni²⁺, respectively. The order of metal adsorption capacity on peat A was the same in the case of competitive multimetal adsorption conditions as it was for single-element adsorption, namely Pb²⁺ > Cd²⁺ ≥ Ni²⁺. The results show that peat alone (an inexpensive adsorbent) is a good adsorbent for heavy metal ions.     

袋式除尘器气流分布数值计算研究

采用结构化/非结构化混合网格技术、多孔介质模型及k-ε两方程湍流模型,对某袋式除尘器及进出口管道内的气体流场进行了数值计算.计算结果表明,合理布置导流板后,袋式除尘器两箱体流量偏差为1.8％;除尘器下游滤袋单元处理气量偏大,中游滤袋单元处理气量较小,最大流量与最小流量偏差为22.3％;靠近除尘器进口处灰斗内存在气流回流特性,易造成粉尘的二次附着现象.     

Effect of Degree of Substitution of Octenyl Succinate Starch on Enzymatic Degradation

Octenyl succinate starch of degree of substitution (ds) 0.03, 0.07, and 0.11 was synthesized in an aqueous medium. These compounds were then tested for the susceptibility to enzymatic degradation. The multiple-enzyme regime of -amylase, amyloglucosidase, and pullulanase was chosen for the evaluation. This combination of enzymes had been proven to degrade 99.5% of unmodified starch to glucose and hence was chosen for this study. It was found that even small amounts of subsituent caused a considerable decrease in the extent of degradation. The net extent of degradation decreased with increasing ds. Surprisingly, the amount of glucose from all three substituted substrates was quite similar, suggesting the effect small amounts of subtituent had on the enzymatic activity.     

Effect of depth of landfill on the characteristics of soil-like material of aged waste: a case study of Bhalswa dumpsite,India

Journal of Material Cycles and Waste Management - This study characterizes the municipal solid waste (MSW) accumulated for more than 25 years at Bhalswa dumpsite, Delhi, India. 50...