再生资源回收体系建设巡礼——走进武汉

2008年3月武汉市被商务部列为全国再生资源回收体系建设26个试点城市之一；2008年又被国务院批准成为“两型社会”改革试验区。党和国家对再生资源回收利用工作的高度关注为武汉市再生资源回收行业的规范管理和加速发展提供了前所未有的机遇和动力。为贯彻落实《武汉市再生资源回收利用体系建设实施方案》，促进武汉市循环经济发展和“两型社会”建设，武汉市结合自身的具体情况，在再生资源回收体系建设方面开展了以下工作。     

石家庄市农村再生资源回收体系建设的现状、存在问题及对策

石家庄市是再生资源回收体系建设试点城市，再生资源回收利用事业扎实推进，成绩显著，但石家庄市广大农村地区再生资源回收利用网络建设事业发展缓滞。分析了石家庄市农村再生资源回收体系建设的现状和存在的问题，对如何有效地推进农村再生资源回收利用事业发展，更好地促进农村生态文明和社会主义新农村建设提出建议和对策。     

武汉市东西湖区再生资源循环利用体系调查与分析

通过对武汉市东西湖区再生资源循环利用体系进行实地调查,描述了其再生资源回收网络现状及资源循环利用体系运作模式现状,并进行分析,结合现阶段小区内垃圾源头分类的趋势,提出新的再生资源模式,即资源回收与小区管理相结合的再生资源循环系统,并对其实行企业化管理,促使再生资源循环利用体系更能适应社会发展的需求,进一步提高城区再生资源产业化水平。     

鹤壁资源利用项目国家备选

全国再生资源回收体系建设试点工作现场会于2008年11月27日在天津市召开。会议内容，一是总结和交流再生资源回收体系建设试点城市试点工作的经验和取得的成效；二是研究加快推进再生资源回收体系建设的政策措施；三是实地考察天津市再生资源回收网络。商务部副部长姜增伟到会讲话，副市长任学锋致辞。商贸服务管理司邸建凯司长主持会议，门晓伟副司长作会议总结。国家有关部委、省级和试点城市商务主管部门的处长以及龙头企业的负责人共百人参加了会议。     

建设有中国特色的再生资源回收利用体系

分析了我国再生资源回收利用工作的现状，借鉴发达国家的先进经验，提出建设我国再生资源回收利用体系的基本框架，以及发展我国再生资源产业的政策建议。指出建设具有中国特色的再生资源回收利用体系是推动再生资源产业成为新的经济增长点的前提和保障。     

深入贯彻落实科学发展观 加快推进再生资源回收体系建设——访商务部副部长姜增伟

由传统经济向循环经济转变,既是国情的需要,也是维护国家经济安全的需要.再生资源的回收利用是循环经济发展过程中一个必不可少的环节,从某种意义上说,没有再生资源回收体系的建立,就没有循环经济体系的发展.因此,如何认识理解再生资源回收体系建设,如何促进再生资源行业的发展,对于发展循环经济具有特殊意义.     

成都市再生资源回收体系建设完成验收

近日，根据《市商务局、市财政局关于印发〈成都市2011年度再生资源回收体系建设及运营项目支持资金实施意见〉的通知》精神，成都市商务局组织有关部门和专家成立验收组，完成了对成都市一、二圈层区（县）再生资源回收体系运营综合考评、三圈层县（市）再生资源市场投运、再生资源回收利用基地建设、中心城区再生资源回收企业与网络服务平台协作运营试点共4个再生资源回收体系建设及运营项目的验收工作。项目验收全部合格。这些项目的开展促进了成都市再生资源回收体系建设和运营工作向标准化、连锁化、信息化、规模化发展，推动了再生资源回收电子商务化发展。     

天津市深入推进再生资源回收体系建设

根据《商务部关于加快再生资源回收体系建设的指导意见》、《商务部办公厅关于组织开展再生资源回收体系建设试点工作的通知》精神，天津市围绕加快与发展循环经济相适应的再生资源回收体系建设，以社区回收网络、初级分拣加工中心、专业集散加工中心建设为重点，深入推进再生资源回收体系试点项目建设。经过近年来的不懈努力，取得了阶段性成果。     

再生资源回收体系建设巡礼——走进福州

2006年2月25日，商务部在石家庄召开了再生资源回收体系建设工作会议，制定了再生资源回收体系建设试点工作方案，确定了再生资源回收体系建设第一批试点单位。此后，各地积极推进再生资源回收体系建设工作，取得了很大的进展，积累了一些经验。本刊特开设“再生资源回收体系建设巡礼”专栏，旨在宣传各地回收体系建设取得的成绩，介绍各地的经验以及存在的问题，促进交流和相互学习，争取全社会对回收体系建设工作的理解和支持。     

青州市商务局关于加快再生资源回收体系建设规范流动收购人员管理的意见

为进一步规范再生资源流动收购人员的收购行为,净化城市环境,提升城市形象,维护社会治安,根据国务院《关于建立完整的先进的废旧商品回收体系的意见》和《再生资源回收管理办法》,以及青州市人民政府《关于加快再生资源回收体系建设的意见》、《青州市再生资源回收行业发展规划》,特制订以下管理意见：     

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.     

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.     

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。     

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.     

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.     

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.     

Kinetics of Hydrolytic Degradation of PLA

The chemical recycling of poly(lactic acid) (PLA) to its monomer is crucial to reduce both the consumption of renewable resources for the monomer synthesis and the environmental impact related to its production and disposal. In particular, the production of lactic acid from PLA wastes, rather than from virgin raw materials, it is also possible to achieve considerable primary energy savings. The focus of this work is to analyse deeply the PLA hydrolytic decomposition by means of a kinetic model based on two reactions mechanism. To this end, new experimental data have been gathered in order to investigate a wider temperature range (from 140 to 180 °C) and to extend the water/PLA ratio up to 50 % of PLA by weight. The reported results clearly highlight that more than 95 % of PLA is hydrolyzed to water-soluble lactic acid within 120 min, when it is hydrolyzed within 160–180 °C. Furthermore, the kinetic constant is highly influenced by reaction temperature. The proposed “two reactions” kinetic mechanism complies satisfactorily with the experimental data under analysis.