基于生态足迹的大学食堂餐具生态影响分析

以生态足迹为定量分析方法,以广州大学食堂为例,分析计算了一次性餐具和公用餐具对生态环境的影响,并比较分析了各种型号的餐具生态足迹.分析了一次性餐具和公用餐具生产过程中的原料消耗及能耗.广州大学食堂所用的餐具主要为塑料制餐具、不锈钢餐具、木制和竹制筷子.消耗的资源主要为钢铁、乙烯、木材和竹材等,可归于化石能源地足迹和林地足迹.调查了公用餐具洗涤过程中的资源消耗,主要为洗涤过程中的水电消耗以及废水处理能耗,可归于化石能源地足迹和可耕地足迹.最后结合学校食堂餐具的使用方案,计算了一次性餐具和公用餐具(以1a为限)的生态足迹.研究表明,公用餐具组合的足迹为3.7236×10-3gm2(全球平方米,记为gm2),使用竹筷的一次性餐具组合足迹为2.2085×10-2 gm2,使用木筷一次性餐具组合足迹为9.3781×10-2gm2.公用餐具足迹是一次性餐具的3.97%～16.8%.此外,由于竹筷的足迹是木筷23.55%,因此使用竹筷能大大降低一次性餐具对生态的影响.     

北京市消耗食物生态足迹距离

以北京市消耗食物生态足迹的距离为研究核心。结果表明2008年至2012年,北京的生态足迹距离、人均生态足迹和生态足迹总里程总体呈现逐年增长趋势:生态足迹距离增大到676.75 km,增长19.3%;人均生态足迹距离增加到18.42万km,增长54%;生态足迹总里程增加了1倍强,达到56亿t km。北京市的食物生态足迹距离不断扩大,并涵盖了全国大部分地区,北京城市化的生态成本上升。所消耗各类食物的生态足迹距离从大到小分别为水果类、蔬菜或粮油类、肉蛋类和水产类。蔬菜类和水果类的生态足迹距离存在明显的季节波动,且冬春季节远高于夏秋季节。从转移生态承载力来源地的视角,直线距离越远、占据市场份额越大的地区,对北京市消耗食物生态足迹距离的贡献率越高。     

生态足迹研究——辽宁省生态足迹计算与分析

可持续发展的定量测度研究是当前国际上关于生态经济研究的前沿问题之一。生态足迹分析法是近年来发展的用于定量研究和判断一个国家或地区的可持续发展状况的新方法。应用生态足迹的方法 ,以辽宁省 2 0 0 0年 ,2 0 0 1年 ,2 0 0 2年统计资料为依据 ,对其 1999～ 2 0 0 1年 3a的生态足迹进行了实证计算和研究 ,从纵向比较并分析了辽宁省生态足迹的变化规律及其原因。研究结果表明 :辽宁省生态赤字呈逐年增加的趋势 ,1999年人均生态赤字为 2 .2 90 hm2 ,2 0 0 0年为 2 .36 8hm2 ,2 0 0 1年为 2 .4 74hm2 ,其主要影响因素是由于资源过度消耗 ,人口增长以及耕地减少等。通过生态足迹的研究 ,提出了辽宁省在振兴东北老工业基地 ,进行可持续发展过程中应采取的对策措施     

大连市生态足迹与水足迹

生态足迹模型已广泛应用于可持续发展和生态承载力评估中。本文以大连市统计资料为依据,计算了大连市的人均生态足迹和人均生态承载力,用来分析大连市生态可持续发展情况;同时基于生态足迹理论,运用水足迹模型,计算了大连市2001年的水足迹。结果表明：从1991-2004年,大连市人均生态足迹整体呈上升趋势,多年人均生态足迹均在2．250hm^2·人^-1以上;2004年为3．965hm^2·人^-1,是1991年（2．250hm^2·人^-1）的1．76倍,2000-2004年大连市存在不同程度的生态赤字现象;2001年人均水足迹为748．270m^2·人^-1,低于北方人均水足迹水平,属于水资源短缺型城市。     

废纸酶法脱墨的应用研究进展

制浆造纸工业面临着原料短缺、污染严重和能源紧张等问题 ,脱墨废纸浆作为一种二次纤维用于造纸生产 ,不但可以减轻环境污染 ,节约能源 ,更可以部分解决我国森林资源贫乏、纸浆紧缺的问题。脱墨浆生产成本低、节电节水 ,排污负荷远低于其他浆种 ,1ｔ脱墨浆可替代 2 7ｍ3 木材[1] 。近十年来回收纤维的利用有显著发展 ,在欧洲就有人把废纸原料市场称为“新的造纸森林”[2 ] 。废纸化浆后并不能直接用于抄造新纸。一是张纸的植物纤维在干燥、贮存过程中会发生角质化现象 ,从而对纤维乃至纸浆性能产生很大的影响 ,使回收纤维在许多性能方面不…     

生态足迹方法:可持续性定量研究的新方法——以张掖地区1995年的生态足迹计算为例

生态足迹是一种定量测量人类对自然利用程度的新方法。通过跟踪区域的能源和资源消费,将它们转化为提供这种物质流所必须的各种生物生产型土地类型的面积,并同区域能提供的生物生产型土地面积进行比较,能定量判断一个区域的发展是否处于生态承载能力的范围内,介绍了生态足迹的概念及生态足迹计算模型,分析总结了生态足迹模型的优缺点等,在此基础上,对张掖地区1995年生态足迹进行了实证计算和分析,结果表明1995年张掖地区人均生态字为0．34hm^2.     

基于环境污染账户核算的生态足迹模型优化——以珠江三角洲城市群为例

针对传统的生态足迹分析模型在账户设置中忽略对环境污染核算的缺陷,本文提出了涵盖污染账户的生态足迹模型,将污染物进行合理转化进而纳入核算账户,在生态足迹核算中增加了污染足迹的计算,在生态承载力核算中增加了环境承载力的计算,并通过2005年珠江三角洲城市群的生态足迹对优化的生态足迹模型进行了验证.结果表明,通过优化模型计算得出的2005年珠江三角洲城市群的生态足迹结果与该区的实际发展特征和空间结构具有较高的吻合度.说明优化的模型在内涵上为环境污染在生态足迹模型中进行了较准确的定位,使结果能更全面地反映人类活动对生态环境的影响,在核算的完整性和客观性上均优于传统的生态足迹核算体系.     

中国单位畜牧产品生态足迹分析

中国畜牧业生产以农户散养为主要生产方式,一方面,它的工业化程度远低于发达国家,另一方面,又比其他发展中国家生产得更为精细.因此在计算单位畜牧产品生态足迹这一畜牧业生态影响评价中的重要参数时,必须考虑到我国牲畜口粮的特点.分析了我国牲畜口粮的成分,据此确定猪肉、禽肉和禽蛋足迹主要来自饲料中粮食,而牛肉、羊肉和牛奶足迹则来自草料和饲料中粮食.基于我国单位畜牧产品耗粮量和草地平均产肉产奶量,计算各种单位畜牧产品的生态足迹.结果表明,1kg禽肉足迹为7.6687gm2(全球平方m2,记作gm2)、禽蛋足迹为8.0106gm2、猪肉足迹为9.7859gm2或11.7326gm2、牛肉足迹为139.704gm2、羊肉足迹为232.0662gm2和牛奶足迹为37.2368 gm2.将计算结果与世界自然基金会(World Wildlife Fund,简称WWF)的结果进行了对比分析,并从料肉比、役畜、牲畜食草量和居民饮食结构等几个方面分析了二者之间差异的原因.     

生态足迹深度和广度:构建三维模型的新指标

追踪自然资本存量消耗与流量占用是当前可持续发展研究的核心议题.系统阐述了国际上新近提出的生态足迹三维模型的概念与计算方法,重点对足迹深度和足迹广度两个指标进行了探讨,总结了模型的主要优势,并通过引入资本流量占用率和存量流量利用比两个新指标对模型作进一步完善,在此基础上实证分析了1961-2006年的中国生态足迹.结果表明,中国自 1978年步人生态赤字时代以来,足迹深度增长了近2倍,足迹广度减少了11.84％,因自然资本流量不足导致资本存量大幅肖耗已成为社会发展常态.到2006年时,中国需要2.9倍的国土才能持续支撑其资源消费量.研究表明,三维模型分别从时空两方面表征了人类对资本存量的消耗(足迹深度)和对流量的占用(足迹广度),增强了生态足迹在不同区域、不同时期之间的可比性,并在一定程度上克服了经典模型的评估缺陷.最后指出了三维模型今后发展的主要方向.     

广西北部湾地区生态足迹动态分析

生态足迹方法为定量计算地区可持续性发展提供了一种简单易行的方法。论文将在传统生态足迹方法的基础上结合目前国外最新生态足迹动态分析方法对广西北部湾地区从1998年到2005年的生态足迹进行了计算。结果表明:结合万元GDP占用生态足迹、生态足迹多样性指数和经济系统发展能力指数等指标的生态足迹动态分析方法,加强了传统生态足迹方法对地区可持续发展状况的反应。1998～2005年期间,广西北部湾地区,土地生产效率不断提高,经济发展能力在逐步增强,但是人均生态足迹呈逐年增加趋势,出现生态赤字,处于不可持续发展状态,仅林地资源与建筑用地资源还有少量人均盈余。     

用纸浆代棉花合成CMC

羧甲基纤维素(CMC)系天然纤维素的衍生物。它是由天然纤维素分子上引入强极性羧甲基钠而得到的。我们采用纸浆为原料替代棉花生产CMC,测试了其性能,并讨论了反应温度、反应时间和碱用量对粘度的影响。结果表明:此法简化了工艺,原料来源广泛,产品性能优良,成本低,能满足使用要求。     

新型杀菌剂在造纸生产流程中的中试研究

造纸白水中的可溶性有机物以及造纸系统的pH值、温度等环境条件都极其有利于微生物生长。当白水中的微生物含量大于10~8CFU/mL,造纸系统就会产生腐浆,进而引起断纸、洞眼等问题。因此造纸系统要使用杀菌剂抑制微生物生长。本研究采用两种新型杀菌剂分别进行了实验室和中试抑菌试验,结果表明在两种杀菌剂协同作用下,造纸系统没有明显的腐浆产生。     

Levanases for control of slime in paper manufacture

Formation of slime deposits is a major problem facing paper industries. The slime may be biological or nonbiological. Biological deposits that are composed of varied microflora along with fibers, fillers and dirt are the most troublesome. Slime producing microbes secrete extracellular polysaccharides that gum up the process machinery. The specific nature of slime and its formation depend on the mill environment. Correspondingly, countermeasures vary with the type of slime deposit. Conventional slime control methods generally employ combinations of biocides. This leads to effluent toxicity, as well as high processing and treatment costs. Therefore, alternative control measures are in demand. Once such measure is the use of enzymes (levanases) that dissolve the slime to some degree and improve biocide penetration into the slime layer. As a result, the amount of biocide required is reduced, process economics improve and effluent treatment is simplified.     

Lignin: Genetic Engineering and Impact on Pulping

Lignin is a major component of wood, the most widely used raw material for the production of pulp and paper. Although the biochemistry and molecular biology underpinning lignin production are better understood than they are for the other wood components, recent work has prompted a number of re-evaluations of the lignin biosynthetic pathway. Some of the work on which these revisions have been based involved the investigation of transgenic plants with modified lignin biosynthesis. In addition to their value in elucidating the lignin biosynthetic pathway, such transgenic plants are also being produced with the aim of improving plant raw materials for pulp and paper production. This review describes how genetic engineering has yielded new insights into how the lignin biosynthetic pathway operates and demonstrates that lignin can be improved to facilitate pulping. The current technologies used to produce paper are presented in this review, followed by a discussion of the impact of lignin modification on pulp production. Fine-tuned modification of lignin content, composition, or both is now achievable and could have important economic and environmental benefits.     

Effects of a pulp and paper mill on the ecology of the La Trobe River,Victoria, Australia

Four riverine animal communities were measured to assess the impact of extensively treated wastewater from a pulp and paper mill on the lower La Trobe River in Victoria, Australia. Benthic macroinvertebrates in channel and bankside habitats were sampled using a new air-lift corer. Population density was expressed in relation to substrate volume. Other communities measured at five sites upstream and downstream of the mill's wastewater outfall were the zooplankton, and the animals associated with submerged littoral vegetation. Ten environmental variables were also measured during the two sampling periods.A total of 50 benthic macro-invertebrate taxa were dominated by Oligochaeta, Chironomidae and Bivalvia. Benthic communities upstream and downstream of the outfall were very similar. Benthic samples showed large unexplained variation between stations and seasons, despite the similarity of stations and the stratified sampling design, but within-sample variation was small. There was some evidence that benthic faunal patchiness was associated with patterns of stream-bed scouring and deposition in periods of high flow. Littoral samples collected 28 taxa, dominated by Decapoda and Hemiptera. The benthic and littoral communities were quite distinct, with only three species common to both.Only two of the biological and environmental variables responded to wastewater from the mill: total dissolved solids rose by 20–25% over upstream levels; and zooplankton density increased by 2–3 orders of magnitude. It was concluded that wastewater treatment had successfully avoided the major environmental problems often associated with pulp and paper mills.     

Trichoderma Xylanases,Their Properties and Application

Abstract

Trichoderma spp. are known to produce enzymes with high xylanolytic activity. Different xylanases and various components of their xylanolytic system have been identified and purified. Some of the xylanases have been characterized extensively with respect to their physicochemical, hydrolytic, and molecular properties. Cellulase-free xylanase preparations have been tested successfully in industrial applications such as the prebleaching of kraft pulps in the pulp and paper industry. Future work on understanding the functional significance of xylanase multiplicity, the mechanisms of xylanase prebleaching, and the structural conformation of xylanases could lead to improved or alternative applications of Trichoderma xylanases.     

Putative anaerobic activity in aerated composts

It has been suggested that anaerobic microenvironments develop in aerobic composts, regardless of the aeration system used, and that anaerobic activity is responsible for odor generation and nitrogen losses. This study was designed to measure levels of microorganisms capable of anaerobic growth in two aerated composts: municipal solid waste, a relatively nutrient-rich compost, and pulp and paper-mill solid waste, which is relatively nutrient-poor. Anaerobic microorganisms were isolated from both composts at mesophilic and thermophilic temperatures. The majority of the anaerobic mesophiles were facultative anaerobes, whereas facultative, anaerobic thermophiles varied from 0 to 100%. Serially-diluted samples were spot-plated onto various media to preserve microbial consortia. Levels of aerobic and anaerobic exoenzyme production on spot-plates were similar on cell-wall, starch, and casein media. Although microbial levels on spread plates indicate that aerobes are present in much higher numbers than anaerobes (in 47 of 56 subsamples, 90% of the population were aerobes), microbial growth levels and exoenzyme production on spot-plates indicate that anaerobes may be responsible for a large portion (greater than or equal to 72%) of the metabolic activity in anaerobic microenvironments of aerobic composts.     

Organosolv pulping of wheat straw by use of phenol

A central composite design was used to investigate the influence of the cooking conditions (time, temperature and phenol concentration) for wheat straw with phenol-water mixtures on the properties of the pulp obtained (yield and holocellulose, -cellulose, lignin and ethanol-benzene extractable contents) and the pH of the resulting wastewater. A second-order polynomial model consisting of three independent process variables was found to accurately describe the organosolv pulping of wheat straw. The equations derived predict the yield, the holocellulose, -cellulose, lignin and ethanol-benzene extractable contents of the pulp, and the pH of the wastewater with multiple-R, R² and adjusted-R² high values. The process variables must be set at low variables in order to ensure a high yield and pH. Conversely, if high holocellulose and -cellulose contents, and low lignin and ethanol-benzene extractable contents are desired, then a high temperature (200°C), long cooking time (120 min), and intermediate phenol concentration (65%) must be used.     

木质素降解菌Bax的筛选及特性研究

为了高效降解造纸污水中木质素类化合物,采用苯胺兰和鞣酸平板法从腐木分离、筛选得到一株具有高降解木质素活性的丝状真菌,经鉴定为绿色木霉,命名为Bax.最适碳源为葡萄糖和蔗糖,最适氮源为蛋白胨和尿紊,最适酸碱度为pH 5.0,最适温度为30℃.通过对木质素氧化酶系分析,主要起作用的是漆酶和木质素酶,为造纸污水的处理奠定了基础.     

Life cycle assessment of printing and writing paper produced in Portugal

Goal, Scope and Background The environmental sustainability is one of the current priorities of the Portuguese pulp and paper industry. Life Cycle Assessment (LCA) was the methodology chosen to evaluate the sustainability of the printing and writing paper production activity. This paper grade represents about 60% of the total production of paper in Portugal and its production is expected to increase in the near future. The main goal of this study was to assess the potential environmental impacts associated with the entire life cycle of the printing and writing paper produced in Portugal from Eucalyptus globulus pulp and consumed in Germany, in order to identify the processes with the largest environmental impacts. Another goal of this study was to evaluate the effect on the potential environmental impacts of changing the market where the Portuguese printing and writing paper is consumed: German market vs. Portuguese market. Methods The main stages considered in this study were: forestry, pulp production, paper production, paper distribution, and paper final disposal. Transports and production of chemicals, fuels and energy in the grid were also included in these stages. Whenever possible and feasible, average or typical data from industry were collected. The remaining data were obtained from the literature and specialised databases. A quantitative impact assessment was performed for five impact categories: global warming over 100 years, acidification, eutrophication, non-renewable resource depletion and photochemical oxidant formation. Results In the German market scenario, the paper production stage was a remarkable hot spot for air emissions (non-renewable CO₂, NO_x and SO₂) and for non-renewable energy consumption, and, consequently, for the impact categories that consider these parameters: global warming, acidification and non-renewable resource depletion. These important environmental impacts are due to the energy requirements in the printing and writing paper production process, which are fulfilled by on-site fuel oil burning and consumption of electricity from the national grid, which is mostly based on the use of fossil fuels. The pulp production stage was identified as the largest contributor to water emissions (COD and AOX) and to eutrophication. Considering that energy consumed by the pulp production processes comes from renewable fuels, this stage was also the most contributing to renewable energy consumption. Discussion The paper distribution stage showed an important contribution to NO_x emissions, which, however, did not result in a major contribution to acidification or eutrophication. The final disposal stage was the main contributor to the photochemical oxidant formation potential due to CH₄ emissions from wastepaper landfilling. On the other hand, paper consumption in Portugal was environmentally more favourable than in Germany for the parameters/impact categories where the paper distribution stage has a significant contribution (non-renewable CO₂, NO_x, non-renewable energy consumption, acidification, eutrophication and non-renewable resource depletion) due to shorter distances needed to deliver paper to the consumers. For the remaining parameters/impact categories, the increase observed in the final disposal stage in the Portuguese market was preponderant, and resulted from the existence of significant differences in the final disposal alternatives in the analysed markets (recycling dominates in Germany, whereas landfilling dominates in Portugal). Conclusions The pulp and paper production stages were found to be of significance for almost all of the inventory parameters as well as for the impact assessment categories. The paper distribution and the final disposal stages were only of importance for some of the inventory parameters and some of the impact categories. The forestry stage played a minor role in the environmental impacts generated during the paper life cycle. The consumption of paper in Portugal led to a decrease in the environmental burdens of the paper distribution stage, but to an increase in the environmental burdens of the final disposal stage, when compared with the consumption of paper in Germany. Recommendations and Perspectives This study provides useful information that can assist the pulp and paper industry in the planning of future investments leading to an increase in its sustainability. The results of inventory analysis and impact assessment show the processes that play an important role in each impact category, which allow the industry to improve its environmental performance, making changes not only in the production process itself, but also in the treatment of flue gases and liquid effluents. Besides that concern regarding pollution prevention, other issues with relevance to the context of sustainability, such as the energy consumption, can also be dealt with.