Combustion of horse manure for heat production

The main objectives of this paper have been to evaluate the use of horse manure and wood-shavings as a fuel for heat production and to provide sets of data on the chemical composition, ash characteristics and ash forming elements of the fuel. Another objective has been to investigate the possibility to use the ash as fertiliser by analysing the heavy metal and nutrient contents. The results showed that the fuel is well suited for combustion for heat production causing low emissions of products of incomplete combustion. The emissions of NO_x were however high due to the high content of fuel bound nitrogen. Emissions of CO and NO_x were typically in the range of 30–150 mg/Nm³ and 280–350 mg/Nm³ at 10 vol% O₂, respectively. The analysis of the ash showed on sufficiently low concentration of heavy metals to allow recycling.     

Leaf construction cost in <Emphasis Type="Italic">Avicennia germinans</Emphasis> as affected by salinity under field conditions

This study assessed the effects of salinity and drought upon leaf construction (CC) and maintenance (MC) costs in Avicennia germinans growing under contrasting soil salinities in the field. Additionally, an analysis of leaf chemical composition was carried out to determine the underlying reasons for possible variation in CC. With the increase of external salinity, leaf osmotic potential (_s) declined and a significant negative correlation was found between both variables. Changes in average CC were about 15 % when _s changed by 85 %. Despite this, leaf ash-free heat of combustion per unit of leaf dry mass remained relatively constant at 21.3 ± 0.9 kJ g^–1 in all conditions. The estimated maximum and minimum CC for the synthesis of protein present in leaves increased significantly with total leaf CC. Conversely, the estimated CC for lipid synthesis shows a tendency to decrease with total leaf CC. Under conditions of high salinity, ash content increased by 78 % compared to that of leaves collected at low salinity. It is concluded that undergoing changes in proteins and lipids (expensive) and ash (cheap) explain the changes in CC under contrasting salinities. Additionally, the average MC remained almost constant at moderate salinity and declined by 6 % under hyper-saline conditions. Thus, differences in CC and MC with salinity are explained in part by changes in the chemical composition of different compound fractions.     

Comparative LCAs for Curbside Recycling Versus Either Landfilling or Incineration with Energy Recovery (12 pp)

Background This article describes two projects conducted recently by Sound Resource Management (SRMG) – one for the San Luis Obispo County Integrated Waste Management Authority (SLO IWMA) and the other for the Washington State Department of Ecology (WA Ecology). For both projects we used life cycle assessment (LCA) techniques to evaluate the environmental burdens associated with collection and management of municipal solid waste. Both projects compared environmental burdens from curbside collection for recycling, processing, and market shipment of recyclable materials picked up from households and/or businesses against environmental burdens from curbside collection and disposal of mixed solid waste. Method logy. The SLO IWMA project compared curbside recycling for households and businesses against curbside collection of mixed refuse for deposition in a landfill where landfill gas is collected and used for energy generation. The WA Ecology project compared residential curbside recycling in three regions of Washington State against the collection and deposition of those same materials in landfills where landfill gas is collected and flared. In the fourth Washington region (the urban east encompassing Spokane) the WA Ecology project compared curbside recycling against collection and deposition in a wasteto- energy (WTE) combustion facility used to generate electricity for sale on the regional energy grid. During the time period covered by the SLO study, households and businesses used either one or two containers, depending on the collection company, to separate and set out materials for recycling in San Luis Obispo County. During the time of the WA study households used either two or three containers for the residential curbside recycling programs surveyed for that study. Typically participants in collection programs requiring separation of materials into more than one container used one of the containers to separate at least glass bottles and jars from other recyclable materials. For the WA Ecology project SRMG used life cycle inventory (LCI) techniques to estimate atmospheric emissions of ten pollutants, waterborne emissions of seventeen pollutants, and emissions of industrial solid waste, as well as total energy consumption, associated with curbside recycling and disposal methods for managing municipal solid waste. Emissions estimates came from the Decision Support Tool (DST) developed for assessing the cost and environmental burdens of integrated solid waste management strategies by North Carolina State University (NCSU) in conjunction with Research Triangle Institute (RTI) and the US Environmental Protection Agency (US EPA)1. RTI used the DST to estimate environmental emissions during the life cycle of products. RTI provided those estimates to SRMG for analysis in the WA Ecology project2. For the SLO IWMA project SRMG also used LCI techniques and data from the Municipal Solid Waste Life- Cycle Database (Database), prepared by RTI with the support of US EPA during DST model development, to estimate environmental emissions from solid waste management practices3. Once we developed the LCI data for each project, SRMG then prepared a life cycle environmental impacts assessment of the environmental burdens associated with these emissions using the Environmental Problems approach discussed in the methodology section of this article. Finally, for the WA study we also developed estimates of the economic costs of certain environmental impacts in order to assess whether recycling was cost effective from a societal point of view. Conclusions Recycling of newspaper, cardboard, mixed paper, glass bottles and jars, aluminum cans, tin-plated steel cans, plastic bottles, and other conventionally recoverable materials found in household and business municipal solid wastes consumes less energy and imposes lower environmental burdens than disposal of solid waste materials via landfilling or incineration, even after accounting for energy that may be recovered from waste materials at either type disposal facility. This result holds for a variety of environmental impacts, including global warming, acidification, eutrophication, disability adjusted life year (DALY) losses from emission of criteria air pollutants, human toxicity and ecological toxicity. The basic reason for this conclusion is that energy conservation and pollution prevention engendered by using recycled rather than virgin materials as feedstocks for manufacturing new products tends to be an order of magnitude greater than the additional energy and environmental burdens imposed by curbside collection trucks, recycled material processing facilities, and transportation of processed recyclables to end-use markets. Furthermore, the energy grid offsets and associated reductions in environmental burdens yielded by generation of energy from landfill gas or from waste combustion are substantially smaller then the upstream energy and pollution offsets attained by manufacturing products with processed recyclables, even after accounting for energy usage and pollutant emissions during collection, processing and transportation to end-use markets for recycled materials. The analysis that leads to this conclusion included a direct comparison of the collection for recycling versus collection for disposal of the same quantity and composition of materials handled through existing curbside recycling programs in Washington State. This comparison provides a better approximation to marginal energy usage and environmental burdens of recycling versus disposal for recyclable materials in solid waste than does a comparison of the energy and environmental impacts of recycling versus management methods for handling typical mixed refuse, where that refuse includes organics and non-recyclables in addition to whatever recyclable materials may remain in the garbage. Finally, the analysis also suggests that, under reasonable assumptions regarding the economic cost of impacts from pollutant emissions, the societal benefits of recycling outweigh its costs.     

兴安落叶松人工林腐殖质阴燃燃烧温度变化特征

森林地下火是发生在腐殖质层的一种缓慢、无焰、低温、持久的阴燃燃烧,整个燃烧过程都是靠自身所释放的热量所维持。所以地下火发生时产生的温度是研究其火行为特征的重要指标,更是森林地下火监测和扑救过程中的重要依据。以大兴安岭地区5种地类下人工种植的兴安落叶松林为研究对象,以室内控制点烧实验为基础,研究不同地类和腐殖质粒径阴燃燃烧的温度变化特征。结果表明：不同粒径的腐殖质阴燃燃烧最高温度之间不存在显著差异（P>0.05）,而不同地类和二者的交互作用对阴燃燃烧最高温度的影响则存在显著差异（P<0.05）;4种腐殖质粒径下不同地类之间的阴燃燃烧最高温度都存在显著差异（P<0.05）。任意一种腐殖质粒径下塔头甸子的阴燃燃烧温度都是最高的,最高可达897.53℃,其次是水湿地,有坡山地、无坡山地、农用地的腐殖质阴燃燃烧温度较低。不同地类的腐殖质燃烧地表温度较高,最高温度可达618.83℃;随着燃烧时间的增加,腐殖质燃烧的地表温度随之降低,二者之间关系可以用y=a×x^b方程拟合,并且拟合程度高（R²>0.9,P<0.01）。相关研究成果可以为该地区森林地下火监测扑救提供科学有效的理论依据。     

内蒙古大兴安岭森林可燃物燃烧释放PM2.5中水溶性离子排放特性

研究森林可燃物燃烧释放的细颗粒物(PM_2.5)的排放因子对于揭示森林火灾对大气和生态系统的影响至关重要,而水溶性离子是细颗粒物的重要化学成分,对颗粒物的形成具有重要意义。利用自主设计的生物质燃烧系统,模拟内蒙古大兴安岭5种典型乔木(蒙古栎、白桦、兴安落叶松、黑桦、山杨)的3种组成部分(树干、树枝、树皮)及其地表死可燃物(凋落物层、半腐殖质层、腐殖质层)以及3种典型灌木(平榛、二色胡枝子、兴安杜鹃)树枝燃烧,采用ISC1100离子色谱分析仪测定2种燃烧状态(阴燃和明燃)下PM_2.5中水溶性离子(Na⁺、NH₄⁺、K⁺、Mg²⁺、Ca²⁺、F^-、Cl^-、NO₃^-、NO₂^-、SO₄^2-)的排放因子。结果表明:乔木所有组成部分及其地表死可燃物和灌木树枝燃烧所排放PM_2.5中检测到的水溶性离子,阴燃以K⁺、Cl^-和Na⁺为主要组分,明燃以K⁺、Cl^-和SO₄^2-为主要组分。不同燃烧状态下相同乔木树种及其地表死可燃物和相同灌木排放PM_2.5中检测到的水溶性离子总量均存在显著差异。灌木树枝在阴燃期间PM_2.5中水溶性无机离子的排放因子比明燃更高。乔木释放的PM_2.5中阳离子与阴离子的比率为1.26,地表死可燃物为1.12,灌木为2.0,表明颗粒物呈碱性。内蒙古大兴安岭的森林大火不会通过释放水溶性离子导致生态系统的酸化。     

Distribution patterns of Cd,Cu, Mn,Pb and Zn in wood fly ash emitted from domestic boilers

Abstract

Wood fuels being a renewable source of primary energy have been considered environmentally friendly. However, wood combustion in domestic boilers is a source of air pollution. The lack of a dust collection device is the reason why flue gases emit a significant load of particulate pollutants into the air, including heavy metals. The aim of this research was to assess the environmental hazard caused by both emissions of heavy metals during wood combustion in domestic boilers and their chemical forms present in fly ash.

From the various wood fuels burnt in domestic boilers, the fly ash selected for this study came from the combustion of briquettes of softwood from non-polluted areas, and from burning hardwood fuel from trees exposed to pollutants from heavy traffic. The wood fuels satisfy the quality demands determined in the EN 14961 Solid Biofuels - Fuel quality assurances. However, the concentrations of Cd, Cu, Pb and Zn in the fly ash are considerably higher than the appropriate limit values determined for soil improvers. Sequential extraction shows that Cd and Zn are associated mainly with the water leaching and carbonate fractions, regarded as mobile and bioavailable, and pose the potentially greatest hazard to the environment and human health. Cu, Mn and Pb associated with less mobile fractions may not pose a direct air quality hazard but, due to their high concentrations, medium-term and long-term effects on soils and surface and subsurface waters should be considered.     

Integrated generation of solid fuel and biogas from green cut material from landscape conservation and private households

Green cut material is a potential source of renewable energy which is not fully exploited through conventional energy recovery systems. A new energy conversion process, the integrated generation of solid fuel and biogas from biomass (IFBB), which includes mechanical separation after hydro-thermal conditioning, was investigated. Ash softening temperature and lower heating value of the solid fuel were increased through the IFFB process in comparison to the untreated raw material. The net energy yield of IFBB at 40 °C conditioning temperature ranged between 1.96 and 2.85 kWh kg(-1) dry matter (DM) and for the direct combustion between 1.75 and 2.65 kWh kg(-1) DM. Conversion efficiencies for the IFBB system were 0.42-0.68 and for direct combustion 0.42-0.63. The IFBB system produces storable energy from material which is nowadays not used for energy conversion.     

大兴安岭小尺度草甸火燃烧效率研究

燃烧效率是进行生物质燃烧温室气体释放量计算的关键因子,以大兴安岭典型草甸区为研究区域,通过样地调查和采样,应用GIS和地统计学的方法对燃烧格局和燃烧效率进行计算。结果表明:研究区域内草甸可燃物的平均载量为37.3t/hm²,草本层、枯落物层和腐殖层载量平均所占比例分别为18.50%,28.95%和52.55%。样地的块金系数分别在80.84%-97.88%之间变化,过火迹地的燃烧深度具有弱的空间相关性。研究区域内平均燃烧效率为64.51%,根据不同的火烧强度,研究区域的燃烧效率在44.35%-90.6%之间变化。     

微藻固定燃烧烟气中CO2 的研究进展

空气中CO2浓度升高导致的气候变暖问题已经成为全球性的环境、科学、政治、经济问题。近年来,对可用于直接固定工业废气尤其是燃烧烟气中CO2的捕捉和封存 (CCS) 技术进行了广泛的研究。在这些技术中,微藻生物固定CO2是一种具有大规模应用前景和经济上可行的CCS技术。以下从藻种的筛选、烟气条件对微藻固定CO2的影响、高效光生物反应器的开发和微藻产物的利用等方面对微藻生物固定烟气中CO2的现状和发展以及作者所在实验室在这一领域的研究情况进行了分析和总结,最后对其技术前景进行了展望,以期对微藻固定燃烧烟气中CO     

Assessment of Lead Ecotoxicity in Water using the Amphibian Larvae (<Emphasis Type="BoldItalic">Xenopus laevis</Emphasis>) and Preliminary Study of its Immobilization in Meat and Bone Meal Combustion Residues

Lead (Pb) is a major chemical pollutant of the environment. It has been associated with human activities for the last 6000 years. Quite rightly, it remains a public health concern today. The present investigation evaluates the toxic potential of Pb in larvae of the toad Xenopus laevis after 12 days exposure in lab conditions. Acute toxicity, genotoxicity and Pb bioaccumulation were analyzed. The genotoxic effects were analyzed in the circulating blood from the levels of micronucleus induction according to the French standard micronucleus assay (AFNOR 2000 Association française de normalization. Norme NFT 90-325. Qualité de l’Eau. Evaluation de la génotoxicité au moyen de larves d’amphibien (Xenopus laevis, Pleurodeles waltl)). Lead bioaccumulation was analyzed in the liver of larvae at the end of exposure. Moreover, the toxic potential of lead, in aquatic media, was investigated in the presence of meat and bone meal combustion residues (MBMCR) known to be rich in phosphates and a potential immobiliser of lead. Previously, acute toxicity and genotoxicity of MBMCR alone were evaluated using Xenopus larvae. The results obtained in the present study demonstrated: (i) that lead is acutely toxic and genotoxic to amphibian larvae from 1 mg Pb/l and its bioaccumulation is significant in the liver of larvae from the lowest concentration of exposure (1 μg Pb/l), (ii) MBMCR were not acutely toxic nor genotoxic in Xenopus larvae, (iii) lead in presence of MBMCR induced inhibition or reduction of the toxic and genotoxic potential of lead in water at concentrations that do not exceed the capacity of MBMCR of Pb-binding (iv) Pb accumulation in larvae exposed to lead with MBMCR in water was lower than Pb-accumulation in larvae exposed to lead alone except at the concentration of 0.01 mg Pb/l suggesting complex mechanisms of MBMCR interaction in organisms. The results confirm the high toxicity and genotoxicity of lead in the aquatic compartment and suggest the potential utility of MBMCR for use in remediation.