Life cycle assessment of the selective catalytic reduction process for power plants

The overall reduction of the environmental impact by the use of selective catalytic reduction (SCR) of nitrogen oxide emissions in power plants was determined by strict application of ISO 14040 and ISO/DIS 14041. Special emphasis was placed on the implementation of the total product life cycle (PLC) of ammonium molybdate as a key input material. The environmental impact was generated by application of the life cycle assessment (LCA) concept of “ecoscarcity” and integrated in the life cycle inventory analysis (LCI) of SCR systems. The LCI was used to generate the life cycle impact assessment (LC1A) by use of different quantitative valuation methods. Under consideration of the overall LCIA results and the environmental protection costs of the SCR variants, the Ecological Effectiveness of the SCR alternatives was determined. The results enable plausible conclusions with regard to the ecological advantages of the use of deNOx catalysts in the SCR used in hard-coal fired power plants.     

Life cycle inventories for the production of sodium silicates

Soluble alkali silicate glasses, liquids and powders are an important class of primary synthetic chemicals and are produced in large quantities both in Europe and world-wide. They are utilised in a broad range of application fields, both industrial and domestic, including detergents, chemical feedstocks, paper manufacture, civil engineering and adhesives. In order to establish viable figures for the consumption of raw materials, water and energy and the emissions to air and water and solid waste generation, the production routes for five typical commercial sodium silicate products were traced back to the extraction of the relevant raw materials from the earth. Life Cycle Inventories for these products were compiled by EMPA St. Gallen / Switzerland on behalf of CEES, a Sector Group of CEFIC, using the data input based on the production of 1995 from 12 West European silicate producers covering about 93% of the total alkaline silicate production in Western Europe.     

Estimating tree and stand sapwood area in spatially heterogeneous southeastern Australian forests

Aims Natural and anthropogenic changes in forests can have important influences on transpiration and water production. Understanding the effects of increasing disturbances, due for example to climate change and forest harvesting, requires detailed information on how forest density and structural attributes relate to transpiration. Mean annual transpiration of eucalypt forest communities is often strongly correlated with total cross-sectional sapwood area. Our aim was to test an efficient method for estimating sapwood area at 1.3 m height (SA 1.3) in a large number of trees to understand the spatial heterogeneity of tree and stand sapwood area within and between forest communities, and develop allometric relationships that predict SA 1.3 with forest inventory data. We also apply tree competition models to determine the degree to which the relationship between SA 1.3 and tree basal area at 1.3 m height (BA 1.3) is influenced by competition.Methods We visited 25 recently harvested southeastern Australian forest sites consisting of 1379 trees and 5 Eucalyptus species to evaluate a new efficient data collection method for estimating SA 1.3 with tree taper and stump dimensions data using mixed effects models. The locations of 784 stumps within one 5-ha site were accurately mapped using an unmanned aerial vehicle (UAV), and four distance-dependent tree competition models were applied across the site to explain within-stand variation in the ratio of SA 1.3 to BA 1.3. Data from 24 additional sites, consisting of ten 15 m radial plots per site, were used to analyse within-site variation in R Ha (the ratio of stand sapwood area SA Ha to stand basal area BA Ha). The radial plots were merged within each site to evaluate between-site variations in R Ha across the landscape. For predicting SA Ha with forest inventory data, we computed the relationship between SA Ha and a new index of total stem perimeter per hectare, defined as ? B A H a N T, where N T is tree stocking density.Important findings Our 1379 measured stems represent the most comprehensive measure of sapwood area, surpassing the 757 measured stems in native eucalypt forests published in literature. The species-specific R Ha varied considerably across sites and therefore extrapolating SA Ha with spatially distributed BA Ha maps and a generalized R Ha would introduce local uncertainty. We found that the species-specific stem perimeter index was more effective at capturing variability in SA Ha across the landscape using forest composition, structure and density data (R 2 : 0.72–0.77). The strong correlation between tree SA 1.3 and BA 1.3 improved slightly using tree competition models (R 2 increased from 0.86 to 0.88). Relating SA Ha to routinely measured forest inventory attributes within permanent plots and Light Detection and Ranging (LiDAR) data may provide opportunities to map forest water use in time and space across large areas disturbed by wildfire and logging.     

Establishing Life Cycle Inventories of Chemicals Based on Differing Data Availability (9 pp)

Goal, Scope and Background In contrast to inventory data of energy and transport processes, public inventory data of chemicals are rather scarce. Chemicals are important to consider in LCA, because they are used in the production of many, if not all, products. Moreover, they may cause considerable environmental impacts. For these reasons, it was one goal of the new ecoinvent database to provide LCI data on chemicals. In this paper, the methods and procedures used for establishing LCIs of chemicals in ecoinvent are presented.Methods Three different approaches are suggested for situations of differing data availability. First, in the case of good data availability, the general quality guidelines of ecoinvent can be followed. Second, a procedure is proposed for the translation of aggregated inventory data (cumulative LCI results) from industry into the ecoinvent format. This approach was used, if adequate unit process data was not available. Third, a procedure is put forward for estimating inventory data using stoichiometric equations from technical literature as a main information source. This latter method was used if no other information was available. The application of each of the three procedures is illustrated with the help of a case study.Results and Conclusion When sufficient information is available to follow the general guidelines of ecoinvent, the resulting dataset is characterized by a high degree of detail, and it is thus of high quality. For chemicals, however, the application of the standard procedure is possible in only a few cases. When using industrial data, the main drawback is the fact that those data are often available only as aggregated data, thus being out of tune with the quality guidelines of ecoinvent and its main aim, the harmonization of LCI data. As a third approach, the use of the stoichiometric reaction equation is used for the compilation of LCI datasets of chemicals. This approach represents an alternative to neglecting chemicals completely, but it contains a high risk to not consider important aspects of the life cycle of the respective substance.Outlook Further work in the area of chemicals should focus on an improvement of datasets, so far established by either of the two estimation procedures (APME method; estimation based on technical literature) described. Besides the improvement of already established inventories, the compilation of further harmonized inventories of specific types of chemicals (e.g. solvents) or of chemicals for new industrial sectors (e.g. electronics industry) are in discussion.     

Carbon sequestration in arid-land forest

Rising atmospheric CO₂ concentrations may lead to increased water availability because the water use efficiency of photosynthesis (WUE) increases with CO₂ in most plant species. This should allow the extension of afforestation activities into drier regions. Using eddy flux, physiological and inventory measurements we provide the first quantitative information on such potential from a 35‐year old afforestation system of Aleppo pine (Pinus halepensis Mill.) at the edge of the Negev desert. This 2800 ha arid‐land forest contains 6.5 ± 1.2 kg C m^?2, and continues to accumulate 0.13–0.24 kg C m^?2 yr^?1. The CO₂ uptake is highest during the winter, out of phase with most northern hemispheric forest activity. This seasonal offset offers low latitude forests ～10 ppm higher CO₂ concentrations than that available to higher latitude forests during the productive season, in addition to the 30% increase in mean atmospheric CO₂ concentrations since the 1850s. Expanding afforestation efforts into drier regions may be significant for C sequestration and associated benefits (restoration of degraded land, reducing runoff, erosion and soil compaction, improving wildlife) because of the large spatial scale of the regions potentially involved (ca. 2 × 10⁹ ha of global shrub‐land and C4 grassland). Quantitative information on forest activities under dry conditions may also become relevant to regions predicted to undergo increasing aridity.     

绿化植物的生活型对边坡植被物种多样性及护坡性能的影响

为了探讨绿化植物生活型构成对边坡植被物种多样性及护坡性能的影响, 揭示生活型构成-群落特征-物种多样性-生态系统功能间的内在联系, 借助三物种组装实验, 分别构建以草本、灌木或乔木为主体的草本型(HHX_i)、灌木型(SSX_i)、乔木型(AAX_i)或草-灌-乔混合型(HSA)配置模式的实验小区, 对实验区内边坡植被的群落特征、护坡性能进行持续4年的生态监测。结果表明: (1)边坡植被的物种丰富度与绿化植物生活型构成有关, AAX_i的物种丰富度总体高于其他模式, 呈AAX_i > SSX_i > HSA > HHX_i趋势。(2)不同配置模式边坡植被的群落盖度不一样, 年际间差异显著: 建坪初期(2010-2011年), HHX_i的群落盖度远高于其他模式, HSA次之, AAX_i最低; 2012-2013年间, HSA的群落盖度最高, HHX_i次之, AAX_i最低。(3)边坡植被的Shannon-Wiener指数、Pielou指数与绿化植物生活型构成有关, 其变化规律与群落盖度类似: 建坪初期, HHX_i的多样性水平远高于其他模式, 呈HHX_i > HSA > SSX_i > AAX_i趋势; 之后, 呈HSA > HHX_i > SSX_i > AAX_i趋势。(4)边坡植被的护坡性能与群落内的物种多样性密切相关: 多样性水平越高, 护坡性能越强。可见, 在生态护坡过程中, 绿化植物生活型构成对提高边坡植被物种多样性、改善护坡性能至关重要。     

A Delphi Approach to Understanding Varying Expert Viewpoints in Sustainability Communication: The Case of Water Footprints of Bio‐Based Fiber Resources

In recent years, the concepts of accounting for water use and assessing its impact, also known as the water footprint (WF), have evolved. The cultivation of wood and cotton are two important bio‐based fiber resources that can use, consume, and pollute huge amounts of water. The purpose of this study is to identify the methodological options on an inventory level asociated with a WF assessment for bio‐based fiber resources. Using a three‐step Argument Delphi approach with international experts, important, but controversial, aspects of water footprinting are elaborated. During the different rounds of the Delphi procedure, the interlacement of the crucial topics became apparent, including the net green water or the total volume of green water, trade‐offs between water use and land‐use impacts, allocation of the green WF on ecosystem services, and nomination of a reference situation (e.g., potential natural vegetation). Further, this study evaluates whether the experts allowed generalizations about these methodological options. Finally, the agreement of experts on some generalized statements showed that such statements can be used legitimately as long as knowledge of the inventory methods and knowledge of production characteristics are carefully combined.     

Determining spatio-temporal distribution of bee forage species of Al-Baha region based on ground inventorying supported with GIS applications and Remote Sensed Satellite Image analysis

In arid zones, the shortage of bee forage is critical and usually compels beekeepers to move their colonies in search of better forages. Identifying and mapping the spatiotemporal distribution of the bee forages over given area is important for better management of bee colonies. In this study honey bee plants in the target areas were inventoried following, ground inventory work supported with GIS applications. The study was conducted on 85 large plots of 50 × 50 m each. At each plot, data on species name, height, base diameter, crown height, crown diameter has been taken for each plant with their respective geographical positions. The data were stored, and processed using Trimble GPS supported with ArcGIS10 software program. The data were used to estimate the relative frequency, density, abundance and species diversity, species important value index and apicultural value of the species. In addition, Remotely Sensed Satellite Image of the area was obtained and processed using Hopfield Artificial Neural Network techniques. During the study, 182 species from 49 plant families were identified as bee forages of the target area. From the total number of species; shrubs, herbs and trees were accounting for 61%, 27.67%, and 11.53% respectively. Of which Ziziphus spina-christi, Acacia tortilis, Acacia origina, Acacia asak, Lavandula dentata, and Hypoestes forskaolii were the major nectar source plants of the area in their degree of importance. The average vegetation cover values of the study areas were low (<30%) with low Shannon’s species diversity indices (H′) of 0.5–1.52 for different sites. Based on the eco-climatological factors and the variations in their flowering period, these major bee forage species were found to form eight distinct spatiotemporal categories which allow beekeepers to migrate their colonies to exploit the resources at different seasons and place. The Remote Sensed Satellite Image analysis confirmed the spatial distribution of the bee forage resources as determined by the ground inventory work. An integrated approach, combining the ground inventory work with GIS and satellite image processing techniques could be an important tool for characterizing and mapping the available bee forage resources leading to their efficient and sustainable utilization.     

First record of the genus Wilkinsonellus (Hymenoptera,Braconidae, Microgastrinae) from Fiji with description of three new species

Wilkinsonellus Mason is a relatively small Pantropical genus of braconid parasitoid wasps within the subfamily Microgastrinae. Most of the currently described species are from the Palaeotropics; however, previous records were absent from Fiji. Here, the first three Wilkinsonellus species from Fiji are described: Wilkinsonellus corpustriacolor sp. n., Wilkinsonellus fijienis sp. n. and Wilkinsonellus nescalpura sp. n. The material was collected by Malaise traps set up in a quite variety of ecosystems (wet zone, dry zone and coastal forests) throughout the archipelago. With these records, Fiji represents the easternmost known distribution of the genus in the Indo-Pacific Region. A key to all of the currently known Wilkinsonellus species is included to facilitate species identification.