Sulfur recirculation for increased electricity production in Waste-to-Energy plants

Sulfur recirculation is a new technology for reducing boiler corrosion and dioxin formation. It was demonstrated in full-scale tests at a Waste to Energy plant in Göteborg (Sweden) during nearly two months of operation. Sulfur was recirculated as sulfuric acid from the flue gas cleaning back to the boiler, thus creating a sulfur loop.The new technology was evaluated by extensive measurement campaigns during operation under normal conditions (reference case) and operation with sulfur recirculation. The chlorine content of both fly ash and boiler ash decreased and the sulfur content increased during the sulfur recirculation tests. The deposit growth and the particle concentration decreased with sulfur recirculation and the dioxin concentration (I-TEQ) of the flue gas was reduced by approximately 25%. Sulfuric acid dew point measurements showed that the sulfuric acid dosage did not lead to elevated SO₃ concentrations, which may otherwise induce low temperature corrosion.In the sulfur recirculation corrosion probe exposures, the corrosion rate decreased for all tested materials (16Mo3, Sanicro 28 and Inconel 625) and material temperatures (450 °C and 525 °C) compared to the reference exposure. The corrosion rates were reduced by 60–90%. Sulfur recirculation prevented the formation of transition metal chlorides at the metal/oxide interface, formation of chromate and reduced the presence of zinc in the corrosion products. Furthermore, measured corrosion rates at 525 °C with sulfur recirculation in operation were similar or lower compared to those measured at 450 °C material temperature in reference conditions, which corresponds to normal operation at normal steam temperatures. This implies that sulfur recirculation allows for higher steam data and electricity production without increasing corrosion.     

Substance-related environmental monitoring strategies regarding soil, groundwater and surface water — an overview

Substance-related monitoring is an essential tool within environmental risk assessment processes. The soundness of policy decisions including risk management measures is often directly related to the reliability of the environmental monitoring programs. In addition, monitoring programs are required for identifying new and less-investigated pollutants of concern in different environmental media. Scientifically sound and feasible monitoring concepts strongly depend on the aim of the study. The proper definition of questions to be answered is thus of pivotal importance. Decisions on sample handling, storage and the analysis of the samples are important steps for the elaboration of problem-oriented monitoring strategies. The same applies to the selection of the sampling sites as being representative for scenarios to be investigated. These steps may become critical to handle for larger international monitoring programs and thus trigger the quality of their results. This study based on the work of an IUPAC (International Union of Pure and Applied Chemistry) task group addresses different kinds and approaches of substance-related monitoring of different compartments of soil, groundwater and surface water, and discusses their advantages and limitations. Further important aspects are the monitoring across policies and the monitoring data management using information systems.     

The Sampling and Electron Microscopy of Asbestos Aerosol in Ambient Air By Means of Nuclepore Filters

Despite the fact that adverse health effects of asbestos have been known since shortly after the turn of the century,¹ there has been little progress in techniques for determining the mineral in the airborne state. This absence of sampling and analysis methods appears to derive from two main sources: (1) In the environments of the asbestos using industries, asbestos concentrations tend to be high relative to other particulate species, and especially compared with other fibrous species, making estimation of concentration by microscopy relatively easy. (2) The term "asbestos" describes a crystal habit, not a chemical compound; therefore there is no unique chemical property of asbestos that can be used as the basis for its measurement. Interestingly, there appears to be no basis for distinguishing the health effects of one type of asbestos over another;² the physiological response seems more dependent on crystal habit than on composition.     

Estimates of Ground Level TSP,S02 and HCI for a Municipal Waste Incinerator to be Located at Tynes Bay—Bermuda

The computer model Industrial Source Complex Short Term (ISCST) was used to study the stack emissions from a refuse Incinerator proposed for the island of Bermuda. The model predicts that the highest ground level pollutant concentrations will occur near Prospect, 800 m to 1000 m due south of the stack. We installed a portable laboratory and instruments at Prospect to begin making air quality baseline measurements. By comparing the model’s estimates of the incinerator contribution to the background levels measured at the site we predict that stack emissions will not cause an Increase In TSP or SO₂. The incinerator will be a significant source of HCI to Bermuda air with ambient levels approaching air quality guidelines.     

Air Emission Inventories in North America: A Critical Assessment

Abstract

Although emission inventories are the foundation of air quality management and have supported substantial improvements in North American air quality, they have a number of shortcomings that can potentially lead to ineffective air quality management strategies. Major reductions in the largest emissions sources have made accurate inventories of previously minor sources much more important to the understanding and improvement of local air quality. Changes in manufacturing processes, industry types, vehicle technologies, and metropolitan infrastructure are occurring at an increasingly rapid pace, emphasizing the importance of inventories that reflect current conditions. New technologies for measuring source emissions and ambient pollutant concentrations, both at the point of emissions and from remote platforms, are providing novel approaches to collecting data for inventory developers. Advances in information technologies are allowing data to be shared more quickly, more easily, and processed and compared in novel ways that can speed the development of emission inventories. Approaches to improving quantitative measures of inventory uncertainty allow air quality management decisions to take into account the uncertainties associated with emissions estimates, providing more accurate projections of how well alternative strategies may work. This paper discusses applications of these technologies and techniques to improve the accuracy, timeliness, and completeness of emission inventories across North America and outlines a series of eight recommendations aimed at inventory developers and air quality management decision-makers to improve emission inventories and enable them to support effective air quality management decisions for the foreseeable future.     

Fractionation of technical p-nonylphenol with preparative capillary gas chromatography

A fractionation procedure for technical p-nonylphenol using preparative capillary gas chromatography (pcGC) was developed and evaluated for its potential applicability in effect-directed analysis (EDA). The instrument is composed of (1) a preparative unit equipped with a cold injection system (CIS), two preparative fraction collectors (PFCs) with six fraction traps each, and a flame ionization detector (FID) and (2) an analytical unit sharing the same GC oven and equipped with another CIS and mass spectrometric detection (MSD) for isomer identification. The pcGC methodology used in this study is characterized by a high reproducibility of retention times and peak areas. This provides the fractionation of nonylphenol isomers into 11 fractions containing 77-552microg of isomers collected after 600 single injections. This yield is sufficient to allow subsequent biotesting in the E-screen assay.     

Leaf extracellular ascorbate in relation to O(3) tolerance of two soybean cultivars

Soybean [Glycine max (L.) Merr.] cultivars Essex and Forrest that exhibit differences in ozone (O(3)) sensitivity were used in greenhouse experiments to investigate the role of leaf extracellular antioxidants in O(3) injury responses. Charcoal-filtered air and elevated O(3) conditions were used to assess genetic, leaf age, and O(3) effects. In both cultivars, the extracellular ascorbate pool consisted of 80-98% dehydroascorbic acid, the oxidized form of ascorbic acid (AA) that is not an antioxidant. For all combinations of genotype and O(3) treatments, extracellular AA levels were low (1-30nmolg(-1) FW) and represented 3-30% of the total antioxidant capacity. Total extracellular antioxidant capacity was twofold greater in Essex compared with Forrest, consistent with greater O(3) tolerance of Essex. The results suggest that extracellular antioxidant metabolites in addition to ascorbate contribute to detoxification of O(3) in soybean leaves and possibly affect plant sensitivity to O(3) injury.     

Seasonal differences and within-canopy variations of antioxidants in mature spruce (Picea abies) trees under elevated ozone in a free-air exposure system

The effect of free-air ozone fumigation and crown position on antioxidants were determined in old-growth spruce (Picea abies) trees in the seasonal course of two consecutive years (2003 and 2004). Levels of total ascorbate and its redox state in the apoplastic washing fluid (AWF) were increased under double ambient ozone concentrations (2xO3), whilst ascorbate concentrations in needle extracts were unchanged. Concentrations of apoplastic and symplastic ascorbate were significantly higher in 2003 compared to 2004 indicating a combined effect of the drought conditions in 2003 with enhanced ozone exposure. Elevated ozone had only weak effects on total glutathione levels in needle extracts, phloem exudates and xylem saps. Total and oxidised glutathione concentrations were higher in 2004 compared to 2003 and seemed to be more affected by enhanced ozone influx in the more humid year 2004 compared to the combined effect of elevated ozone and drought in 2003 as observed for ascorbate.     

Arzneimittelwirkstoffe in der Umwelt

During the last decade, the impact of chemical pollution and environmental chemistry has focused almost exclusively on the conventional ‘priority’ pollutants which are regulated in different environmental laws. This spectrum of chemicals, however, is only one piece in the larger puzzle of ‘holistic’ risk assessment. The pharmacentical drugs are a diverse group of bioactive chemicals receiving comparatively little attention as potential environmental pollutants. The aim of the literature review is to describe the most important exposition scenarios for human and veterinary pharmacenticals in different environmental compartments (soil, surface, waste water, ground water, table water, etc.)     

Nitrate in tile drainage of the semiarid Palouse Basin

Topographically heterogeneous agricultural landscapes can complicate and accelerate agrochemical contamination of streams due to rapid transport of water and chemicals to poorly drained lower-landscape positions and shallow ground water. In the semiarid Palouse region, large parts of these landscapes have been tile drained to enhance crop yield. From 2000-2004 we monitored the discharge of a tile drain (TD) and a nearby profile of soil water for nitrate concentration ([NO(3)]), electrical conductivity level (EC), and water content to develop a conceptual framework describing soil nitrate occurrence and loss via subsurface pathways. Tile-drain baseflow [NO(3)] was consistently 4 mg N L(-1) and baseflow EC was 200 to 300 microS cm(-1). Each year sudden synoptic increases in TD discharge and [NO(3)] occurred in early winter following approximately 150 mm of fall precipitation, which saturated the soil and mobilized high-[NO(3)] soil water throughout the profile. The greatest TD [NO(3)] (20-30 mg N L(-1)) occurred approximately contemporaneous with greatest TD discharges. The EC decrease each year (to approximately 100 microS cm(-1)) during high discharge, a dilution effect, lagged approximately 1 mo behind the first appearance of high [NO(3)] and was consistent with advective transport of low-EC water from the shallow profile under saturated conditions. Water-budget considerations and temporal [NO(3)] patterns suggest that these processes deliver water to the TD from both lower- and upper-slope positions, the latter via lateral flow during the high-flow season. Management practices that reduce the fall reservoir of soil nitrate might be effective in reducing N loading to streams and shallow ground water in this region.