Biodegradation of Slow-Release Fertilizers (Methyleneureas) in Soil

The biodegradation of urea and condensation products thereof (ureaforms or methyleneureas), their nitrification, and their influence on the respiratory rate of soil was studied over periods of up to 100 days. The total methyleneurea content of the soil was determined after its acidic extraction, using a convenient colorimetric assay, and an HPLC protocol was established to analyze for specific components of methyleneureas. Urea, unfractionated methyleneureas, and hot-water soluble methyleneureas were rapidly metabolized to ammonium, which accumulated to high concentrations and was consequently oxidized to nitrate; an accumulation of nitrite was observed during urea but not during methyleneurea degradation. Hot water-insoluble methyleneureas were degraded much more slowly, and ammonium formed from these compounds was oxidized to nitrate without being released in significant amounts. These results suggest that the use of methyleneureas of optimized composition with regard to their water solubility may help to resolve problems such as the toxicity of ammonia to plant growth as well as nitrogen loss by leaching of nitrate, denitrification and volatilization.     

中国废纸回收利用行业发展路径及政策探讨

2012和2013年的废纸市场让很多企业一筹莫展,全球经济不振,国内需求不足,产能过剩,直接影响了造纸行业的生产和销售,作为原料供应商的废纸回收利用行业,必然受到连带影响,整个产业进入低迷阶段.除了外部经济环境的影响,行业内部应该如何调整,产业政策又该怎样引导行业健康发展,将是未来需要持续探讨的课题.     

Treatment-oriented characterization of dry scrubber residue from municipal solid waste incineration

 Dry scrubber residue from municipal solid waste incineration (MSWI) was characterized to identify critical inorganic pollutants and to suggest a conceptual treatment method. The key methods used were thermal analysis, including thermogravimetry (TG) and differential thermal analysis (DTA), pH_stat titration, qualitative X-ray diffraction (XRD), scanning electron microscopy (SEM), chemical equilibrium calculations, and statistics such as error propagation, principal component analysis (PCA), and empirical modeling based on factorial designs. Based on EU directives, the major inorganic pollutants Cd, Cr, Pb, and Zn were found. In addition, the pH was too high. With dry scrubber residue stabilization in mind, the impact of carbonation and hydration was assessed and judged to be encouraging. In particular, chemical equilibrium calculations showed that carbonation has considerable potential to lower the pH and the availability of Pb, Zn, and Cr. The impact of carbonation on the mobility of Cd was found to be small. During carbonation, a metal-trapping calcium aluminosilicate hydrate (C–A–S–H) phase is also formed. Both processes together have the potential to lead to a robust, reliable, and reasonable stabilization method for dry scrubber residue. However, to control these processes, the decisive factors need to be identified and their effects need to be quantified. Ca, Cl, Na, and K might be abundant components which would be mobile even after stabilization. Received: September 11, 2001 / Accepted: December 6, 2001     

The Effect of Sediment Source Changes on Pollen Records in Lake Sediments

A major focus of palynological research has been to assess the various pathways by which pollen is delivered to sedimentary archives. In open lake systems, the contribution of streamborne pollen to lake sediments is thought to be highly significant. Despite this, little research has attempted to identify changes in the pollen record that might be attributed to changing sediment pathways rather than to changes in vegetation. This research aims to partially redress this gap by examining a dated pollen sequence from Kyre Pool, Worcestershire, England. The results presented in this paper suggest that some changes in sediment source, as determined by a fingerprinting approach, can influence the pollen record reconstructed from a lake sediment profile.     

协同创新视角下资环专业研究生科技创新能力提升途径

资源循环科学与工程专业硕士毕业生存在规模小、科技创新能力不足、能力施展受限等问题,无法满足产业对高层次人才的需求。究其原因有:(1)新兴专业,其研究生导师队伍建设不健全,人才培养质量参差不齐;(2)交叉专业,其科技创新能力培养方向尚需融合凝练;(3)综合专业,其现有科研平台还不足以支撑学科发展,科技创新能力培养模式还没有完全形成。因此,本学科研究生培养单位应树立协同创新理念,坚持行业需求导向,充分挖掘办学特色和优势,凝练培养方向、完善以科技创新能力培养核心的研究生培养方案;加强师资队伍建设,建立健全科研平台;支持鼓励科技创新实践活动,做好学科前沿追踪;加强校校交流互动,提升硕士点认可度。     

A Baumol–Oates approach to solid waste taxation

A national Baumol–Oates tax on waste in Denmark helped achieve a reduction of 26% in net solid waste from 1987 to 1998. The tax, which is levied per ton of waste, was particularly effective as regards the heavier waste streams such as construction waste and garden waste. When it comes to industrial and commercial waste, there are indications that the waste tax is not sufficiently significant to induce changes in behavior, and that except for very waste-intensive enterprises, companies do not seem to be very price sensitive. For household waste, the impact of the tax can be improved where tariffs for garbage collection are weight based, rather than per unit. However, the waste sector is an area in which the price signals are modified and filtered by institutionalized practices in municipal administration, and in which true-cost pricing is not easy to achieve. Hence, the rational choice assumption of environmental economics needs to be supplemented by an institutional dimension to interpret responses to environmental taxes correctly. Received: July 13, 2001 / Accepted: October 2, 2001     

Aerobic Biodegradation of Polymers in Solid-State Conditions: A Review of Environmental and Physicochemical Parameter Settings in Laboratory Simulations

During the last few years, biodegradable polymers have been developed to replace petrochemical polymers. Until now, research devoted to these polymers essentially focused on their biodegradability. There is now a need to bear out their nontoxicity. To verify this, the biodegradation must be carried out in accelerated laboratory tests which allow the metabolites and residues to be recovered. To reproduce the natural conditions (compost, field) as closely as possible, degradation experiments must be run on solid-state substrates. We review studies of aerobic degradation in solid-state substrates. This article focuses in particular on the environmental, physical, and chemical parameters (such as substrate nature, moisture, temperature, C/N ratio, and pH) that influence biodegradation kinetics. This study also aims at finding the solid substrate most adapted to residues and metabolite recovery. The most significant parameters would appear to be the substrate type, moisture content, and temperature. Inert substrates such as vermiculite are well suited to residue extraction. This review also opens the field to new research aimed at optimizing conditions for aerobic solid-state biodegradation and at recovering the metabolites and residues of this degradation process.     

电石法聚氯乙烯生产行业的汞污染防治

结合我国电石法聚氯乙烯生产行业的发展现状,提出了采用低汞触媒替代高汞触媒以降低汞消耗、开发高效除汞器以提高脱汞效率、深度解吸废盐酸以解决汞转移问题、深度处理含汞废水以实现综合利用、优化工艺控制以降低汞触媒消耗、改善防护措施以减轻汞扩散等汞污染防治工作的要点。     

Geotechnical properties of municipal solid waste at different phases of biodegradation

This paper presents the results of laboratory investigation conducted to determine the variation of geotechnical properties of synthetic municipal solid waste (MSW) at different phases of degradation. Synthetic MSW samples were prepared based on the composition of MSW generated in the United States and were degraded in bioreactors with leachate recirculation. Degradation of the synthetic MSW was quantified based on the gas composition and organic content, and the samples exhumed from the bioreactor cells at different phases of degradation were tested for the geotechnical properties. Hydraulic conductivity, compressibility and shear strength of initial and degraded synthetic MSW were all determined at constant initial moisture content of 50% on wet weight basis. Hydraulic conductivity of synthetic MSW was reduced by two orders of magnitude due to degradation. Compression ratio was reduced from 0.34 for initial fresh waste to 0.15 for the mostly degraded waste. Direct shear tests showed that the fresh and degraded synthetic MSW exhibited continuous strength gain with increase in horizontal deformation, with the cohesion increased from 1 kPa for fresh MSW to 16–40 kPa for degraded MSW and the friction angle decreased from 35° for fresh MSW to 28° for degraded MSW. During the triaxial tests under CU condition, the total strength parameters, cohesion and friction angle, were found to vary from 21 to 57 kPa and 1° to 9°, respectively, while the effective strength parameters, cohesion and friction angle varied from 18 to 56 kPa and from 1° to 11°, respectively. Similar to direct shear test results, as the waste degrades an increase in cohesion and slight decrease in friction angle was observed. Decreased friction angle and increased cohesion with increased degradation is believed to be due to the highly cohesive nature of the synthetic MSW. Variation of synthetic MSW properties from this study also suggests that significant changes in geotechnical properties of MSW can occur due to enhanced degradation induced by leachate recirculation.     

变频器故障波形预处理方法研究

电力电子设备在电力系统中的运用越来越广泛,其故障后对电力系统的运行影响也越来越大,从运行设备中提取波形用于诊断其相关故障的诊断方法的研究正在深入开展。由于现场采集波形的数据往往过于庞杂,不利于切中关键的故障特征,在研究用现场录波进行故障诊断前,首先要研究如何对实际采集的波形数据进行简化的方法。本文通过编制C＋＋程序,对故障录波简化过程进行了研究,并通过故障波形不同简化效果的对比说明了提高数据处理效率与减少波形特征损失的结合点的选取。     

输变电工程电磁场引起公众风险感受调查分析

为了解和掌握输变电工程运行产生电磁场引起公众风险感受的心理状态,以制定出合理的策略来缓解和降低这种恐慌情绪,采用社会心理学的调查研究方法,在开展对公众定性访谈的基础上,归纳总结获取的信息、设计问卷,以实现对更大范围的公众进行风险感受相关信息的调查与统计。数据分析表明,公众对电磁场原理及相关信息的不了解,是使得这一风险事件具有群体性特征,进而导致其蔓延和激化的主要原因,建议在制定宣传策略的同时,加强对输变电工程相关信息公平、公正、公开的管理,以营造和谐与信任的沟通氛围。     

Effects of Duststorms on the Air Pollution in Beijing

The objective of this study was to investigate the air pollutionin Beijing before, during, and after duststorms occur. There aretwo different phenomena of air pollution in Beijing during a duststorm; one being related to the concentration of particulatematter and the second related to gaseous chemical pollutant concentrations. In this study, the concentrations of the chemicalpollutants, such as SO₂, NO_x and CO, were high prior to the occurrence of the duststorms. At the beginning of the two duststorms studied, the air quality related to these chemicalconstituents was improved due to a strong wind blowing away the chemical pollutants, which caused a decrease in the concentrations of SO₂, CO and NO_x. During the duststorm, the concentration of particulate matter, quantified by PM₁₀, wasobserved to increase and the atmospheric visibility decreased.     

多措并举构筑火力发电企业安全防御机制

针对当前火力发电企业安全管理中普遍存在的问题,以黔北发电总厂为例,提出以发电企业落实文化为基础,采取多种措施,构筑火力发电企业安全防御机制,为火力发电企业安全管理提供了可供借鉴的经验。     

Landfill reduction experience in The Netherlands

Modern waste legislation aims at resource efficiency and landfill reduction. This paper analyses more than 20 years of landfill reduction in the Netherlands. The combination of landfill regulations, landfill tax and landfill bans resulted in the desired landfill reduction, but also had negative effects. A fierce competition developed over the remaining waste to be landfilled. In 2013 the Dutch landfill industry generated €40 million of annual revenue, had €58 million annual costs and therefore incurred an annual loss of €18 million. It is not an attractive option to prematurely end business. There is a risk that Dutch landfill operators will not be able to fulfil the financial obligations for closure and aftercare. Contrary to the polluter pays principle the burden may end up with society. EU regulations prohibiting export of waste for disposal are in place. Strong differentials in landfill tax rate between nations have nevertheless resulted in transboundary shipment of waste and in non-compliance with the self-sufficiency and proximity principles. During the transformation from a disposal society to a recycling society, it is important to carefully plan required capacity and to guide the reorganisation of the landfill sector. At some point, it is no longer profitable to provide landfill services. It may be necessary for public organisations or the state to take responsibility for the continued operation of a ‘safety net’ in waste management. Regulations have created a financial incentive to pass on the burden of monitoring and controlling the impact of waste to future generations. To prevent this, it is necessary to revise regulations on aftercare and create incentives to actively stabilise landfills.     

Emission of Volatiles from Polymers — A New Approach for Understanding Polymer Degradation

Emission of low molar mass compounds from different polymeric materials was determined and the results from the volatile analysis were applied to predict the degree of degradation and long-term properties, to determine degradation rates and mechanisms, to differentiate between biotic and abiotic degradation and for quality control work. Solid-phase microextraction and solid-phase extraction together with GC-MS were applied to identify and quantify the low molar mass compounds. Volatiles were released and monitored at early stages of degradation before any matrix changes were observed by e.g. SEC, DSC and tensile testing. The analysis of volatiles can thus also be applied to detect small differences between polymeric materials and their susceptibility to degradation. The formation of certain degradation products correlated with the changes taking place in the polymer matrix, these indicator products could, thus, be analysed to rapidly predict the degree of degradation in the polymer matrix and further to predict the long-term properties and remaining lifetime of the product.     

Increasing biogas production from sewage sludge anaerobic co-digestion process by adding crude glycerol from biodiesel industry

In an effort to convert waste streams to energy in a green process, glycerol from biodiesel manufacturing has been used to increase the gas production and methane content of biogas within a mesophilic anaerobic co-digestion process using primary sewage sludge. Glycerol was systematically added to the primary digester from 0% to 60% of the organic loading rate (OLR). The optimum glycerol loading range was from 25% to 60% OLR. This resulted in an 82–280% improvement in specific gas production. Following the feeding schedule described, the digesters remained balanced and healthy until inhibition was achieved at 70% glycerol OLR. This suggests that high glycerol loadings are possible if slow additions are upheld in order to allow the bacterial community to adjust properly. Waste water treatment plant operators with anaerobic digesters can use the data to increase loadings and boost biogas production to enhance energy conversion. This process provides a safe, environmentally friendly method to convert a typical waste stream to an energy stream of biogas.     

Quantitative assessments of municipal waste management systems: Using different indicators to compare and rank programs in New York State

The primary objective of waste management technologies and policies in the United States is to reduce the harmful environmental impacts of waste, particularly those relating to energy consumption and climate change. Performance indicators are frequently used to evaluate the environmental quality of municipal waste systems, as well as to compare and rank programs relative to each other in terms of environmental performance. However, there currently is no consensus on the best indicator for performing these environmental evaluations. The purpose of this study is to examine the common performance indicators used to assess the environmental benefits of municipal waste systems to determine if there is agreement between them regarding which system performs best environmentally. Focus is placed on how indicator selection influences comparisons between municipal waste management programs and subsequent system rankings. The waste systems of ten municipalities in the state of New York, USA, were evaluated using each common performance indicator and Spearman correlations were calculated to see if there was a significant association between system rank orderings. Analyses showed that rank orders of waste systems differ substantially when different indicators are used. Therefore, comparative system assessments based on indicators should be considered carefully, especially those intended to gauge environmental quality. Insight was also gained into specific factors which may lead to one system achieving higher rankings than another. However, despite the insufficiencies of indicators for comparative quality assessments, they do provide important information for waste managers and they can assist in evaluating internal programmatic performance and progress. To enhance these types of assessments, a framework for scoring indicators based on criteria that evaluate their utility and value for system evaluations was developed. This framework was used to construct an improved model for waste system performance assessments.     

A Cumulative Energy Demand indicator (CED), life cycle based,for industrial waste management decision making

Life cycle thinking is a good approach to be used for environmental decision-support, although the complexity of the Life Cycle Assessment (LCA) studies sometimes prevents their wide use. The purpose of this paper is to show how LCA methodology can be simplified to be more useful for certain applications.In order to improve waste management in Catalonia (Spain), a Cumulative Energy Demand indicator (LCA-based) has been used to obtain four mathematical models to help the government in the decision of preventing or allowing a specific waste from going out of the borders. The conceptual equations and all the subsequent developments and assumptions made to obtain the simplified models are presented.One of the four models is discussed in detail, presenting the final simplified equation to be subsequently used by the government in decision making.The resulting model has been found to be scientifically robust, simple to implement and, above all, fulfilling its purpose: the limitation of waste transport out of Catalonia unless the waste recovery operations are significantly better and justify this transport.     

Development of a database of landfills and dump sites in Asian countries

This article briefly summarizes the limited landfill/dump information available for developing Asian countries, and introduces a database that aims to close the information gap through collecting and sharing data. Developing nations usually try to adapt the systems and technologies of developed countries. However, this approach may not be appropriate because of differences in socioeconomic, cultural, and political backgrounds. Many waste management projects fail after operations are transferred to local authorities owing to a lack of funds to cover the high operational expenses. Some successful projects have been adapted to local conditions, although the information on these successes is not often available for others. Nevertheless, only a few developing countries even have a national inventory of their dumps/landfills, and decision-makers have little awareness of the dumps and their impacts. The database introduced here will gather landfill/dump information from each country and organize it in a comparable format, and it will then be published on the Internet.     

Biodiesel production from vegetable oil and waste animal fats in a pilot plant

In this study, corn oil as vegetable oil, chicken fat and fleshing oil as animal fats were used to produce methyl ester in a biodiesel pilot plant. The FFA level of the corn oil was below 1% while those of animal fats were too high to produce biodiesel via base catalyst. Therefore, it was needed to perform pretreatment reaction for the animal fats. For this aim, sulfuric acid was used as catalyst and methanol was used as alcohol in the pretreatment reactions. After reducing the FFA level of the animal fats to less than 1%, the transesterification reaction was completed with alkaline catalyst. Due to low FFA content of corn oil, it was directly subjected to transesterification. Potassium hydroxide was used as catalyst and methanol was used as alcohol for transesterification reactions. The fuel properties of methyl esters produced in the biodiesel pilot plant were characterized and compared to EN 14214 and ASTM D6751 biodiesel standards. According to the results, ester yield values of animal fat methyl esters were slightly lower than that of the corn oil methyl ester (COME). The production cost of COME was higher than those of animal fat methyl esters due to being high cost biodiesel feedstock. The fuel properties of produced methyl esters were close to each other. Especially, the sulfur content and cold flow properties of the COME were lower than those of animal fat methyl esters. The measured fuel properties of all produced methyl esters met ASTM D6751 (S500) biodiesel fuel standards.