Biodegradable Polymer Composites as Coating Materials for Granular Fertilizers

The composites consisting of poly(vinyl alcohol), horn meal, rapeseed cake, glycerol and phosphogypsum were proposed for the encapsulation of mineral fertilizers. Poly(vinyl alcohol) was used as a binder. The other components making ca. 70% of the mass of the composites were waste materials or by-products. They contain phosphorus, nitrogen, calcium, potassium and sulphur, which are useful nutrients for plants. The effect of the amount of glycerol and of the composition of the mixture of the fillers on the mechanical, sorption properties, water vapour permeability, solubility in water, dimensional stability of the composite films was studied. The addition of phosphogypsum and increase of the concentration of glycerol in the composites lead to the decrease of the tensile strength, water vapour permeability and to the increase of elongation at break and of the solubility of the composite films in water. The composites prepared were used for encapsulation of fertilizers. It was established that encapsulation resulted in the increase of the time of release of the fertilizers. In addition, encapsulation improved mechanical properties of the fertilizers. The fertilizer granules were coated with composite films and tested in the cultivation of tomato sprouts. They showed considerable positive effect on the development of the roots of the plants.     

味精行业废水资源化利用研究现状及展望

味精废水产生量大,平均生产1t100％味精,会产生10～12 t味精废水,废水中含有大量的有机物,处理费用较高,味精行业负担较重,直接排放会造成资源的浪费,同时也会造成水体污染,所以实现味精废水资源化利用是缓解味精行业经济压力的有效途径.根据目前中国味精废水资源化利用研究现状,从废物资源化利用角度进行了归纳和总结.并以味精行业为主导,通过横向延伸产业链、纵向耦合共生,提出建立味精废水资源化网络的方法.     

Life Cycle Assessment of the MBT plant in Ano Liossia, Athens, Greece

The aim of this paper is the application of Life Cycle Assessment to the operation of the MBT facility of Ano Liossia in the region of Attica in Greece. The region of Attica is home to almost half the population of Greece and the management of its waste is a major issue. In order to explicitly analyze the operation of the MBT plant, five scenarios were generated. Actual operation data of the MBT plant for the year 2008 were provided by the region of Attica and the LCA modeling was performed via the SimaPro 5.1 software while impact assessment was performed utilizing the Eco-indicator’99 method.The results of our analysis indicate that even the current operation of the MBT plant is preferable to landfilling. Among the scenarios of MBT operation, the one with complete utilization of the MBT outputs, i.e. compost, RDF, ferrous and non-ferrous metals, is the one that generates the most environmental gains. Our analysis indicates that the exploitation of RDF via incineration is the key factor towards improving the environmental performance of the MBT plant. Our findings provide a quantitative understanding of the MBT plant. Interpretation of results showed that proper operation of the modern waste management systems can lead to substantial reduction of environmental impacts and savings of resources.     

Model of technological alternatives of production of sodium chromate (VI) with the use of chromic wastes

This article presents a mathematical model which describes the sodium chromate (VI) production process with the use of chromic waste as a substitution of natural raw materials. This model is a function of selected process parameters common for all of the examined alternatives and based on equations of material balance. Optimization of the elaborated technological alternatives of the production process with use of recycling of chromic waste has been evaluated by determining the extreme value of the quality indicator WJ. This indicator defines the quantity of waste created in the process. Optimization results enabled the selection of the optimal technological solution from all of the alternatives possible for use in industrial practice. Negative values of the indicator prove that there is the possibility of introducing to the process a larger quantity of waste than the one obtained in the process and transported to the storage heaps.     

Seismic analysis for translational failure of landfills with retaining walls

In the seismic impact zone, seismic force can be a major triggering mechanism for translational failures of landfills. The scope of this paper is to develop a three-part wedge method for seismic analysis of translational failures of landfills with retaining walls. The approximate solution of the factor of safety can be calculated. Unlike previous conventional limit equilibrium methods, the new method is capable of revealing the effects of both the solid waste shear strength and the retaining wall on the translational failures of landfills during earthquake. Parameter studies of the developed method show that the factor of safety decreases with the increase of the seismic coefficient, while it increases quickly with the increase of the minimum friction angle beneath waste mass for various horizontal seismic coefficients. Increasing the minimum friction angle beneath the waste mass appears to be more effective than any other parameters for increasing the factor of safety under the considered condition. Thus, selecting liner materials with higher friction angle will considerably reduce the potential for translational failures of landfills during earthquake. The factor of safety gradually increases with the increase of the height of retaining wall for various horizontal seismic coefficients. A higher retaining wall is beneficial to the seismic stability of the landfill. Simply ignoring the retaining wall will lead to serious underestimation of the factor of safety. Besides, the approximate solution of the yield acceleration coefficient of the landfill is also presented based on the calculated method.     

Characterization of municipal solid waste from the main landfills of Havana city

The city of Havana, the political, administrative and cultural centre of Cuba, is also the centre of many of the economic activities of the nation: industries, services, scientific research and tourism. All of these activities contribute to the generation of municipal solid waste (MSW), which also impact other Cuban cities. Inadequate handling of waste and the lack of appropriate and efficient solutions for its final disposal and treatment increase the risk and possibility of contamination. The main difficulty in the development of a system of management of MSW lies in the lack of knowledge of the chemical composition of the waste that is generated in the country as a whole, and especially in Havana, where solid waste management decisions are made. The present study characterizes MSW in Havana city during 2004. The Calle 100, Guanabacoa and Ocho Vías landfills were selected for physical-chemical characterization of MSW, as they are the three biggest landfills in the city. A total of 16 indicators were measured, and weather conditions were recorded. As a result, the necessary information regarding the physical-chemical composition of the MSW became available for the first time in Cuba. The information is essential for making decisions regarding the management of waste and constitutes a valuable contribution to the Study on Integrated Management Plan of MSW in Havana.     

Effects of Mine Drainage on Breakdown of Aspen Litter in Mountain Streams

Rates of aspen litter breakdown were measured at 40 sites in streams of the Rocky Mountains of Colorado, U.S.A. The sites encompassed a range of effects of mine drainage, from pristine (no effects) to highly stressed. The pH, concentrations of dissolved zinc, and deposition rates of metal oxides (the three main stresses from mine drainage) were measured in each stream. Rates of litter breakdown were estimated from changes in mass of aspen leaves in litterbags. The biological communities associated with litter breakdown also were evaluated by measuring the biomass of shredding invertebrates in litterbags and the rate of microbial respiration on litter. Of the stresses from mine drainage, concentration of zinc and deposition rate of metal oxides were most closely related (negatively) to rate of litter breakdown. Biomass of shredding invertebrates was also negatively related to concentration of dissolved zinc and deposition of metal oxides. Microbial respiration was negatively related to deposition rate of metal oxides and positively related to concentration of nutrients. Both shredder biomass and microbial respiration were positively related to litter breakdown rate and, together, accounted for 79% of its variation. Recovery of litter breakdown in streams affected by mine drainage requires remediation that limits both dissolved and deposited metals.     

建筑可持续发展视角下供应链协调与社会责任共担机理研究方案架构

基于建筑全生命周期这个主线,建筑可持续发展视角下供应链协调与社会责任共担机理研究,以绿色建筑供应链运行效率为导向,以既有建筑节能改造效率为切入点,以产业链过程中各主体行为规律为基础,采用“总-分-合”的基本研究思路模式,聚焦了“主导企业驱动下绿色建筑供应链协调机理与策略、既有建筑节能改造主体社会责任共担机理、建筑废弃物再生利用产业链主体社会责任共担机理”等三部分核心内容,初步形成建筑可持续发展视角下供应链协调与社会责任共担机理的理论体系。本成果采用“总-分-合”的思路模式,基于循环经济理念和主体行为策略视角,遵循研究的学理逻辑,以研究生学位论文为基础,开展“主导企业驱动下绿色建筑供应链协调机理与策略、既有建筑节能改造主体社会责任共担机理、建筑废弃物再生利用产业链主体社会责任共担机理”3个子课题研究,从系统整体概况实施全面研究规划着手,构架了总括、绿色建筑供应链协调机理、既有建筑节能改造主体社会责任共担、建筑废弃物再生利用社会责任共担、总结等五大模块及上中下三大篇共12章的系统体系。     

Mercury removal from aqueous solutions by zinc cementation

The main purpose of this research is to study the addition effect of the surfactant and other operating factors on the treatment of wastewater containing mercury ions in aqueous solution by cementation with sacrificing metal, zinc. The removal of mercury ions from aqueous solutions by cementation of zinc powder was found to be a function of solution pH and temperature, amount of zinc, concentration of mercury ion, contact time and the addition of several organic surfactants. Cementation of mercury was shown to be a feasible process to achieve a very high degree of mercury removal over a broad operational range within a fairly reasonable contact time. The reaction rate is approximately first order with respect to the concentration of mercury ion in aqueous solution. Among the surfactants used in this study, only the presence of SDS, an anionic surfactant, slightly enhanced the cementation rate of mercury. The presence of CTAB and Triton-X100 retarded the cementation of mercury by zinc.     

微波辐照修复氯丹污染土壤的影响因素

采用微波辐照技术修复氯丹污染土壤,以氯丹的挥发率和分解率为主要评价指标,研究了微波辐照条件对土壤修复效果的影响。实验结果表明:氯丹的挥发率随微波辐照功率的增大而增大,而氯丹的分解率则无明显变化;当活性炭与土壤质量比为9∶120时,氯丹的去除效果最好,去除率达89%;氯丹的挥发性能在前20min内随微波辐照时间的延长而增强,而氯丹的分解性能则刚好相反;当土壤含水率为15%时,氯丹的挥发率最高,为2.5%,而氯丹分解率最小,为16.8%;在酸性偏中性范围内氯丹的去除效果较差,随土壤p H的不断增大,氯丹的挥发率明显升高,且氯丹的分解率也增大。     

Mathematical modeling of biomass fuels formation process

The increasing demand for thermal and electric energy in many branches of industry and municipal management accounts for a drastic diminishing of natural resources (fossil fuels). Meanwhile, in numerous technical processes, a huge mass of wastes is produced. A segregated and converted combustible fraction of the wastes, with relatively high calorific value, may be used as a component of formed fuels. The utilization of the formed fuel components from segregated groups of waste in associated processes of co-combustion with conventional fuels causes significant savings resulting from partial replacement of fossil fuels, and reduction of environmental pollution resulting directly from the limitation of waste migration to the environment (soil, atmospheric air, surface and underground water). The realization of technological processes with the utilization of formed fuel in associated thermal systems should be qualified by technical criteria, which means that elementary processes as well as factors of sustainable development, from a global viewpoint, must not be disturbed. The utilization of post-process waste should be preceded by detailed technical, ecological and economic analyses. In order to optimize the mixing process of fuel components, a mathematical model of the forming process was created. The model is defined as a group of data structures which uniquely identify a real process and conversion of this data in algorithms based on a problem of linear programming. The paper also presents the optimization of parameters in the process of forming fuels using a modified simplex algorithm with a polynomial worktime. This model is a datum-point in the numerical modeling of real processes, allowing a precise determination of the optimal elementary composition of formed fuels components, with assumed constraints and decision variables of the task.     

废弃电器电子产品绿色回收工艺及集中处理案例研究

从废弃电器电子产品资源化的潜在价值、产业政策、环保政策等方面，分析了废弃电器电子产品回收及资源化基地建设的必要性。重点论述了大宗废弃电器电子产品的资源化方法及工艺，同时说明了这些技术及工艺应用的优缺点、产污环节及其控制方式。以佛山市废弃电器电子产品绿色回收拆解及资源循环利用示范基地为例，分析了废旧家电集中处理的可行性和优越性，同时介绍了该基地的建设情况、经济效益和环境效益。该基地的实施为其他城市同类废物回收提供了一个借鉴模板。     

Conservation Policies for Protected Areas (Wetlands) in Greece: A Survey of Local Residents' Attitude

This study was carried out in 32 communities neighbouring four Ramsar wetlands in Northern Greece. In particular, it concerns the study of local residents' attitude regarding the ways of management and exploitation of the wetlands and their sociological features, using the opinion poll method (1600 questionnaires were distributed). The aim of this investigation is the evaluation of findings for planning of effective management and conservation policy of wetlands, incorporating the opinions of local residents. Further protection of the wetlands, awareness of local residents of the value of wetlands, tourism or agriculture development (in some cases), as well as more governmental support, became obvious results from this research.     

Feedstock recycling of waste polymers by thermal cracking in molten metal: thermodynamic analysis

Waste plastics contribute to serious environmental and social problems, such as the loss of natural resources, environmental pollution, and depletion of landfill space, but they also create demands on the environmentally-oriented part of the society. Feedstock recycling of scrap polymers by thermal and chemical methods is well known and environmentally accepted. The paper presents the results of thermodynamic analysis of the conversion of polyolefins in a fuel-like mixture of hydrocarbons using thermal cracking in a new type of tubular reactor with molten metal. Evaluation of the efficiency of the process was based on exergy calculations. Calculated exergy efficiency was ca. 79.5 %. It means that feedstock recycling of waste is better from an energetic and environmental point of view than other processes, particularly incineration.     

Anaerobic treatment of sludge from a nitrification-denitrification landfill leachate plant

The viability of anaerobic digestion of sludge from a MSW landfill leachate treatment plant, with COD values ranging between 15,000 and 19,400mg O(2)dm(-3), in an upflow anaerobic sludge blanket reactor was studied. The reactor employed had a useful capacity of 9l, operating at mesophilic temperature. Start-up of the reactor was carried out in different steps, beginning with diluted sludge and progressively increasing the amount of sludge fed into the reactor. The study was carried out over a period of 7 months. Different amounts of methanol were added to the feed, ranging between 6.75 and 1cm(3)dm(-3) of feed in order to favour the growth of methanogenic flora. The achieved biodegradation of the sludge using an upflow anaerobic sludge blanket Reactor was very high for an HRT of 9 days, obtaining decreases in COD of 84-87% by the end of the process. Purging of the digested sludge represented approximately 16% of the volume of the treated sludge.     

Role of aluminous component of fly ash on the durability of Portland cement-fly ash pastes in marine environment

The durability, of mixtures of two kinds of Spanish fly ashes from coal combustion (ASTM class F) with 0, 15 and 35% replacement of Portland cement by fly ash, in a simulated marine environment (Na(2)SO(4)+NaCl solution of equivalent concentration to that of sea water: 0.03 and 0.45 M for sulphate and chloride, respectively), has been studied for a period of 90 days. The resistance of the different mixtures to the attack was evaluated by means of the Koch-Steinegger test. The results showed that all the mixtures were resistant, in spite of the great amount of Al(2)O(3) content of the fly ash. The diffusion of SO(4)(2-), Na+ and Cl- ions through the pore solution activated the pozzolanic reactivity of the fly ashes causing the corresponding microstructure changes, which were characterized by X-ray diffraction (XRD), mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). As a result, the flexural strength of the mixtures increased, principally for the fly ash of a lower particle size and 35% of addition.     

Study of the effect of political measures on the citizen participation rate in recycling and on the environmental load reduction

Obtaining the cooperation of citizens to participate in separate waste collection is essential to create a recycling-oriented society. In this research, the degree of change in the citizen participation rate, which occurs when the contents of political measures such as the raising of awareness, provision of information, and the conditions of collection services were changed, was estimated together with the effect on the reduction in environmental load. A questionnaire survey was conducted, targeted at residents of Itabashi Ward, while logistic regression analyses were also conducted to create predictive models for recycling behavior, and sensitivity analyses of the models were carried out to estimate the increase in citizen participation rate achievable through the implementation of various political measures. It was found that the effect of "thorough perception of information" was the largest, followed by "minimization of evaluation of trouble" and "thorough perception of efficacy of measures." The effect of the improvement in the citizen participation rate on the reduction in environmental load was also evaluated quantitatively by life cycle inventory analyses. It was indicated that "maximization of perception of information" had the greatest effect. However, the reduction effect with "paper packs" and "PET bottles" was relatively small compared with that of "bottles/cans."     

闽、浙两省变电所外空间工频电磁污染分布研究

以闽、浙两省110 kV以上等级变电所的电磁场监测结果为基础,着重研究了各电压等级变电所边界处及边界外的空间工频电磁场场强分布规律,分析和探讨了变电所外空间电磁污染的现状,为进一步开展变电所的电磁环境影响研究提出了建设性意见.     

双掺粉煤灰再生骨料对混凝土强度影响研究

通过试验研究再生骨料混凝土中粉煤灰和再生骨料对混凝土强度的影响。采用粉煤灰替代部分水泥、再生骨料替代部分天然粗骨料的方法,通过正交试验测定混凝土立方体抗压强度的方法,来研究粉煤灰对再生骨料混凝土强度的影响。试验得出:当再生骨料掺量为20%~30%时,粉煤灰的最佳掺量为20%左右;当再生骨料掺量高于40%、粉煤灰掺量高于20%时,其混凝土拌合物搅拌时间不小于240 s,且当粉煤灰在20%~30%时,可获得较理想的混凝土抗压强度;当粉煤灰的掺入量分布在20%~30%、再生骨料的最佳掺量为50%时,可获得较理想的混凝土抗压强度。由此得出,合理的再生骨料、粉煤灰掺量对混凝土的抗压强度影响并不明显且有提高的趋势,对降低混凝土成本,提高建筑垃圾的再生利用,有一定的经济效益和社会效益。     

生物法处理印染废水的研究进展

介绍了生物法在印染废水处理中的应用,主要从印染废水的水质、新旧排放标准的对比、生物法的改进及强化(包括微生物研究、生物固定化技术的开发、工艺流程的改进)、生物法研究领域的新探索(包括生物法与其他处理方法的联用、产电微生物的应用)等方面分析和总结了生物法研究的现状和存在的问题,对未来生物法发展的方向进行了初步探讨,认为生物法的深度研究及生物法与其他方法的联用探索格外重要。