北京市居民PET饮料瓶的消费及回收行为研究

2010年,中国成为世界上PET饮料瓶使用量最大的国家,但中国目前缺乏正规、完整的废PET饮料瓶回收系统,导致了严重的社会与环境问题.因此,采用街头访问的方式,对北京市PET饮料瓶的回收情况展开调研.结果显示,消费后的废PET饮料瓶,44％被消费者存放在家里以卖钱,56％被消费者直接扔进垃圾桶.通过拾荒者、流动回收人员等回收者的回收行为,北京几乎所有的废PET饮料瓶都得到了回收,其中90％是由非正规的回收者回收的.回收后的废PET饮料瓶绝大部分都被小型的、非正规的、没有环境污染防治设施的小工厂使用.     

废聚酯瓶的回收和再生利用

概述了我国废聚酯(PET)瓶的回收现状,总结了化学法和物理法回收废PET瓶的方法,介绍了欧美国家研究开发的废PET瓶再生利用新技术,分析了我国废PET瓶再生利用存在的问题。建议政府职能部门充分发挥自己的作用,通过制定相关的政策和法规,鼓励企业用循环经济的思维来开展废PET瓶的再生利用工作。     

简讯

国内首台饮料瓶智能回收机亮相地铁十号线记者从北京市发改委获悉,中国首例将物联网技术与再生资源回收体系创新结合的饮料瓶智能回收机2012年12月将亮相北京地铁。智能回收机的出现,让废旧饮料瓶从回收源头就进入安全环保的处理渠道,让废饮料瓶这一"城市矿产"得到最大限     

回收系统联成网络饮料瓶罐变废为宝

在挪威的超级市场的进口处装有一种特别的机器,走进超市的人都会把带来的废饮料瓶、罐塞进机器上方的圆孔.不一会,机器就会吐出一张抵扣券,印出这批饮料瓶、罐的价值.抵扣券立即生效,你再买东西的时候就可以扣回.这台机器就是世界上颇有名气的Tomra回收系统,在北欧、美国和日本已有相当的使用规模.     

骨料特征对GRC耐久性影响

为了研究骨料特征对GRC耐久性的影响,以废混凝土再生骨料、废砖再生骨料分别取代GRC中的天然砂,分别采用自然老化和50℃加速老化的方法,研究不同性能特征的骨料对GRC长期性能的影响。结果表明:废混凝土再生骨料、废砖再生骨料表面粗糙、多孔的特征,可减少体系中Ca(OH)_2的含量、减小Ca(OH)_2的结晶尺寸;废砖再生骨料还具有火山灰效应,可消耗体系中Ca(OH)_2,因而其对GRC的耐久性改善作用较废混凝土骨料更显著;两种骨料具有的特征不但可提高GRC基体的抗折强度,还可减轻玻璃纤维被腐蚀的程度,有利于GRC耐久性的改善。     

用废聚对苯二甲酸乙二醇酯制备对苯型不饱和聚酯树脂

用废聚对苯二甲酸乙二醇酯(PET)制备对苯型不饱和聚酯树脂。考察了醇解时间对醇解产物、聚合温度对反应产物的影响。该方法的主要工艺参数为：废PET：PG(摩尔比)等于1：1．5,废PET：MA(摩尔比)等于1：1,醇解温度190～200℃,醇解时间3．5～4h,聚合温度190～210℃,聚合反应时间1．5～2h。试验所得对苯型不饱和聚酯树脂产品的性能符合企业通用型不饱和聚酯树脂的标准。     

废混凝土骨料、废砖粉透水混凝土配比试验

为了提高对建筑垃圾的利用率,实验利用废混凝土和废砖粉制备透水混凝土,研究水灰比、废砖粉和减水剂掺量对透水混凝土性能的影响,结果显示:胶骨比和废砖粉掺量一定时,水灰比越大,抗压强度越高,孔隙率越低;提高废砖粉掺量会使抗压强度降低,连通孔隙率提高;在水灰比一定时,提高减水剂加入量,会使抗压强度增加,连通孔隙率降低。     

我国废纺织原料及制品禁止进口措施实施成效分析

基于联合国商品贸易数据库,2015—2019年中国废纺织原料及制品进口额和进口量数据,对比分析2017年被列入我国《禁止进口固体废物目录》的14种废纺织原料及制品,禁止进口限制措施实施成效.结果显示,除其他动物细毛的落毛(HS 510310)仍有少量进口外,其余废纺织原料及制品进口均得到有效的限制,这有助于提高国内废纺...     

废粘土砖粉潜在活性探究

通过将磨细的废砖粉取代水泥制作胶砂试件,并测其抗折、抗压强度值来研究废砖粉的潜在活性,并在此基础上,进一步研究了石灰对废砖粉活性的激发作用.结果表明：磨细的废砖粉具有潜在活性,且粒径越小,活性越大;在一定掺量时,石灰可进一步激发废砖粉的活性.     

日以化学方法回收 PET瓶

日本旭化成工业公司开始着手用化学方法回收 PET聚酯瓶. 该公司于 1971年就曾在 Nobeoka的聚酯工厂安装了化学回收设备,重复利用工厂产生的废纱. 为适应市场的需要,该公司最近又改进了设备,从收集起来的 PET瓶中回收 EG(乙二酯 )和 DMT(对苯二甲酸二甲酯 ). 因为质量和市场上出售的普通单体很相似,所以回收的材料可以用来作制造皮革所需的聚酯和超细微纤维. (赵永春 )     

Distribution of Cd,Ck, Pb and Zn in Soil and Vegetation Compartments in Stands of Five Boreal Tree Species in N.E. Sweden

Concentrations and total quantity of cadmium (Cd), cupper (Cu),lead (Pb) and zink (Zn) were determined in biomass and soil compartments in a replicated tree species experiment with 27-yr-old stands growing on former farmland in N.E. Sweden. Sequentialextractions of soil samples were performed in order to estimate the exchangeable and an organically bound fraction of each element. The tree species included were Picea abies (L.)H. Karst., Pinus sylvestris L., Pinus contorta Dougl., Larix sibirica Ledeb., and Betula pendula Roth.Tree species influenced the rate of removal of Cu, Pb and Zn incase of stemwood harvesting, and of Cd, Cu and Zn in the case ofwhole-tree harvesting. B. pendula and P. abies had higher quantities and average concentrations of Zn in the biomass. For all species, >50% of the Zn in the stems was found in the bark. P. abies and L. sibirica had higher quantities of Cu in the biomass than the other species.P. abies and P. contorta had high quantities of Cd inthe biomass in relation to the other species. Branches and stembark contained high concentrations of Cd and Pb in relation to foliage and stemwood. Dead branches had especially high concentrations of Pb. The high accumulation rate of Zn in thebiomass of B. pendula was related to a low exchangeable amount of Zn in the A horizon. In the superficial centimeters ofthe A horizon, a depletion similar to that found for Zn was detected for Cu, whereas for Cd and Pb, no correlations were found between quantities of elements in the trees and element pools in the soil.     

Starch-plastic materials—Preparation,physical properties,and biodegradability (a review of recent USDA research)

Recent starch-plastic research at the National Center for Agricultural Utilization Research is reviewed and related worldwide efforts are noted. Properties of starch that influence its formulation and performance in plastics are discussed. Methods are given for preparation of starch-poly(methyl acrylate) graft copolymer, starch-poly(ethylene-co-acrylic acid), and starch-poly(ethylene-co-acrylic acid)-polyethylene plastics. Their physical properties are discussed, as is degradability by enzymes or amylolytic organisms from soil, ponds, and streams.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Application of Cellulose Microfibrils in Polymer Nanocomposites

Cellulose microfibrils obtained by the acid hydrolysis of cellulose fibers were added at low concentrations (2–10% w/w) to polymer gels and films as reinforcing agents. Significant changes in mechanical properties, especially maximum load and tensile strength, were obtained for fibrils derived from several cellulosic sources, including cotton, softwood, and bacterial cellulose. For extruded starch plastics, the addition of cotton-derived microfibrils at 10.3% (w/w) concentration increased Young’s modulus by 5-fold relative to a control sample with no cellulose reinforcement. Preliminary data suggests that shear alignment significantly improves tensile strength. Addition of microfibrils does not always change mechanical properties in a predictable direction. Whereas tensile strength and modulus were shown to increase during addition of microfibrils to an extruded starch thermoplastic and a cast latex film, these parameters decreased when microfibrils were added to a starch–pectin blend, implying that complex interactions are involved in the application of these reinforcing agents.     

四氮唑废水处理工艺设计

高浓度、高盐分的四氮唑生产废水通过三效蒸发浓缩,馏出液经铁炭氧微电解和混凝预处理,再采用水解酸化一接触氧化一反应二沉主体组合工艺进行处理。研究了该工艺所需构筑物和设备的设计与选型。该工艺在正常运行条件下,处理后出水pH6～9,COD 302mg／L,BOD5 108mg／L,SS30mg／L,色度36倍,水质达到GB8978--1996（污水综合排放标准》三级标准。     

Bioassessment of silvicultural impacts in streams and wetlands of the Eastern United States

Bioassessment is a useful tool to determine the impact of logging practices on the biological integrity of streams and wetlands. Measuring biota directly has an intuitive appeal for impact assessment, and biota can be superior indicators to physical or chemical characteristics because they can reflect cumulative impacts over time. Logging can affect stream and wetland biota by increasing sedimentation rates, altering hydrologic, thermal, and chemical regimes, and changing the base of food webs. Biotic impacts of logging on streams compared to wetlands probably differ, and in this paper we review some of those differences. In streams, invertebrates, fishes, amphibians, algae, and macrophytes have been used as indicators of logging impacts. In wetlands, bioassessment is just beginning to be used, and plants and birds are the most promising indicator taxa. Various best management practices (BMPs) have been developed to reduce the impacts of logging on stream and wetland biota, and we review quantitative studies that have evaluated the efficacy of some of these techniques in streams and wetlands in the eastern United States. Remarkably few studies that address the overall efficacy of BMPs in limiting biotic changes in streams and wetlands after BMP implementation have been published in scientific journals, although some work exists in reports or is unpublished. We review these works, and compile conclusions about BMP efficacy for biota from this body of research.     

Characterization of air emissions and residual ash from open burning of electronic wastes during simulated rudimentary recycling operations

Air emissions and residual ash samples were collected and analyzed during experiments of open, uncontrolled combustion of electronic waste (e-waste), simulating practices associated with rudimentary e-waste recycling operations. Circuit boards and insulated wires were handled separately to simulate processes associated with metal recovery. The average emissions of polychlorinated dibenzodioxins and dibenzofurans (PCDD/PCDFs) were 92 ng toxic equivalency (TEQ)/kg [n = 2, relative standard deviation (RSD) = 98%] and 11 900 ng TEQ/kg (n = 3, RSD = 50%) of the initial mass of the circuit boards and insulated wire, respectively. The value for the insulated wire is about 100 times higher than that for backyard barrel burning of domestic waste. The emission concentrations of polybrominated dibenzodioxins and dibenzofurans (PBDD/PBDFs) from the combustion of circuit boards were 100 times higher than for their polychlorinated counterparts. Particulate matter (PM) sampling of the fly ash emissions indicated PM emission factors of approximately 15 and 17 g/kg of the initial mass for the circuit boards and insulated wire, respectively. Fly ash samples from both types of e-waste contained considerable amounts of several metallic elements and halogens; lead concentrations were more than 200 times the United States regulatory limits for municipal waste combustors and 20 times those for secondary lead smelters. Leaching tests of the residual bottom ash showed that lead concentrations exceeded U.S. Environmental Protection Agency landfill limits, designating this ash as a hazardous waste.     

Does Soil Acidification Affect Spruce Needle Chemical Composition and Tree Growth?

In 1994, a large survey of soil chemistry was undertaken in thecounty of Värmland in central Sweden (Lundström et al., 1998).The southern part of the county was affected by soilacidification whereas there were no such indications in thenorthern part. To investigate the influence of soil chemistryon the trees at the specific sites, the survey was continued byan analysis of needle chemistry (Norway spruce) which wasundertaken at 150 of the 180 sites, and of tree growth at 65 ofthe 180 sites. Growth was expressed as a ratio between expectedgrowth, estimated with a national, empirical growth model, andthe growth observed in the field. In statistical analyses,using rank correlation, PCA and PLS, there were only weakindications of an influence of soil chemistry on needlechemistry and on tree growth. A moderate correlation betweennitrogen and sulphur in needles was found, which wasinterpreted as an effect of deposition and of processes in thetree canopy. No obvious regional pattern of the growth ratiowas found, in contrast to the clear pattern of soilacidification. The statistical analysis could not with anycertainty point out any of the soil chemistry variables asespecially important for the tree growth ratio.     

Solubility and Potential Mobility of Heavy Metals in Two Contaminated Urban Soils from Stockholm,Sweden

The solubility and potential mobility of heavy metals (Cd, Cu,Hg, Pb and Zn) in two urban soils were studied by sequential andleaching extractions (rainwater). Compared to rural (arable) soils on similar parent material, the urban soils were highlycontaminated with Hg and Pb and to a lesser extent also with Cd,Cu and Zn. Metal concentrations in rainwater leachates were related to sequential extractions and metal levels reported fromStockholm groundwater. Cadmium and Zn in the soils were mainly recovered in easily extractable fractions, whereas Cu and Pb were complex bound. Concentrations of Pb in the residual fractionwere between two- and eightfold those in arable soils, indicatingthat the sequential extraction scheme did not reflect the solidphases affected by anthropogenic inputs. Cadmium and Zn conc. inthe rainwater leachates were within the range detected in Stockholm groundwater, while Cu and Pb conc. were higher, whichsuggests that Cu and Pb released from the surface soil were immobilised in deeper soil layers. In a soil highly contaminatedwith Hg, the Hg conc. in the leachate was above the median concentration, but still 50 times lower than the max concentration found in groundwater, indicating the possibilityof other sources. In conclusion, it proved difficult to quantitatively predict the mobility of metals in soils by sequential extractions.     

Biodegradation of Injection Molded Starch-Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) Blends in a Natural Compost Environment

Injection molded specimens were prepared by blending poly (hydroxybutyrate-co-valerate) (PHBV) with cornstarch. Blended formulations incorporated 30% or 50% starch in the presence or absence of poly-(ethylene oxide) (PEO), which enhances the adherence of starch granules to PHBV. These formulations were evaluated for their biodegradability in natural compost by measuring changes in physical and chemical properties over a period of 125 days. The degradation of plastic material, as evidenced by weight loss and deterioration in tensile properties, correlated with the amount of starch present in the blends (neat PHBV < 30% starch < 50% starch). Incorporation of PEO into starch-PHBV blends had little or no effect on the rate of weight loss. Starch in blends degraded faster than PHBV and it accelerated PHBV degradation. Also, PHBV did not retard starch degradation. After 125 days of exposure to compost, neat PHBV lost 7% of its weight (0.056% weight loss/day), while the PHBV component of a 50% starch blend lost 41% of its weight (0.328% weight loss/day). PHB and PHV moieties within the copolymer degraded at similar rates, regardless of the presence of starch, as determined by ¹H-NMR spectroscopy. GPC analyses revealed that, while the number average molecular weight (Mn) of PHBV in all exposed samples decreased, there was no significant difference in this decrease between neat PHBV as opposed to PHBV blended with starch. SEM showed homogeneously distributed starch granules embedded in a PHBV matrix, typical of a filler material. Starch granules were rapidly depleted during exposure to compost, increasing the surface area of the PHBV matrix.     

Historical Weathering Based on Chemical Analyses of Two Spodosols in Southern Sweden

Chemical weathering losses were calculated for two conifer stands in relation to ongoing studies on liming effects and ash amendments on chemical status, soil solution chemistry and soil genesis. Weathering losses were based on elemental depletion trends in soil profiles since deglaciation and exposure to the weathering environment. Gradients in total geochemical composition were assumed to reflect alteration over time. Study sites were Horröd and Hasslöv in southern Sweden. Both Horröd and Hasslöv sites are located on sandy loamy Weichselian till at an altitude of 85 and 190 m a.s.l., respectively. Aliquots from volume determined samples from a number of soil levels were fused with lithium metaborate, dissolved in HNO₃, and analysed by ICP – AES. Results indicated highest cumulative weathering losses at Hasslöv. The weathering losses for the elements are in the following order:Si > Al > K > Na > Ca > MgTotal annual losses for Ca+Mg+K+Na, expressed in mmol_c m^-2 yr^-1, amounted to c. 28 and 58 at Horröd and Hasslöv, respectively. Variations between study sites could not be explained by differences in bulk density, geochemistry or mineralogy. The accumulated weathering losses since deglaciation were larger in the uppermost 15 cm than in deeper B horizons for most elements studied.