Determination of lindane leachability in soil-biosolid systems and its bioavailability in wheat plants

The leachability of lindane from different biosolid amended soils was determined and compared to its bioavailability. Sand, soil, and a mixture of soil-sand (1:1 w/w) were spiked with lindane, blended with different amounts of biosolids, and subjected to a leaching process with water that lasted for 1-28 d. This procedure is in accordance with ISO/TS 21268-1: 2007. After these batch tests, lindane was extracted from the leachates using three different solvent-free microextraction techniques, including solid phase microextraction (SPME), stir-bar sorptive extraction (SBSE), and silicone rod extraction (SRE). The amount of lindane was determined with thermal desorption and gas chromatography coupled to mass spectrometry (GC-MS). The efficiencies of the three microextraction techniques were statistically different, and the efficiency could be related to the amount of polydimethylsiloxane (PDMS) in each extraction device. However, all of the techniques provide data that shows that the leachability of lindane is dependent on the amount of organic matter contained in the matrix.The results of the lindane leachability assay were compared to the bioavailability of lindane, which was determined by measuring the amount of lindane that accumulated in the roots of wheat plants grown in similar soil-biosolid systems.It was confirmed that the amount of organic matter in the matrix is a determining factor for lindane immobilization. The presence of biosolids decreases the mobility of lindane in all of the systems under study. Similarly, increasing biosolid concentrations in the soil significantly decreased the bioavailability of lindane and, consequently, plant absorption.The good correlation (R² = 0.997) between the leachability of lindane from the matrix and plant absorption of lindane indicates that the proposed biomimetic methodology can predict the bioavailability of lindane in a time period as short as 7 d.The results of this work confirm that amending contaminated soils with biosolids is beneficial for immobilizing lindane and helps prevent the percolation of lindane through the soil profile and into groundwater.     

Improved Ventilation of Open Top Greenhouses

Plant injury caused by air pollutants is a well recognized effect causing economic losses totalling millions of dollars. Farm crops, forest species, and ornamentals are all affected depending upon kind of plant and degree of exposure. Benedict¹ estimated the minimum annual agricultural losses in the U. S. to be $132 million in 1969-1971. Millecan² estimated California crop losses caused by air pollutants to be at least $25 million in 1972. Recent studies by Brewer³ in which conventional greenhouses were placed in the field over cotton gave results showing yields were reduced by 10-30% in the San Joaquin valley where significant levels of photochemical smog occur. However, these estimates of losses represent little more than educated guesses because the procedures available for obtaining the information are so imprecise.     

Towards the selection of a produced water enrichment for biological gas hydrate inhibitors

Economic concerns associated with the recovery of non-conventional hydrocarbon reserves include unexpected ice as well as ice-like gas hydrate formation. Antifreeze proteins (AFPs) inhibit ice growth, and experiments with fish, plant, and insect AFPs have shown promise of effective gas hydrate inhibition in lab-scale experiments. If produced on an industrial scale, AFPs could provide a more environmentally friendly alternative to kinetic inhibitors, but a large-scale production of these AFPs is not currently feasible. We believe that these difficulties could be surmounted by the production of microbial AFPs, but to date, only a few such proteins have been identified and purified, and none of these are associated with hydrocarbon reserves. Here, we have used ice-affinity and freeze-thaw stress to select microbes derived from oil and gas formation water, or produced water, as a source of anaerobic microbial communities. Ice-affinity successfully incorporated anaerobic bacteria under aerobic conditions, and the mixed culture had ice-associating properties. Under these conditions, ice-affinity selection does not result in cultivatable isolates, but similar, cultivable microbes were obtained following freeze-thaw selection under anaerobic conditions. Since these mixed cultures inhibited the growth of ice crystals, they also have the potential to inhibit hydrate growth. Overall, freeze-thaw selection provides a promising first step towards the isolation of microbes capable of the inhibition of ice and gas hydrate growth, for possible application for energy exploration and recovery at high-latitudes and in-deep, cold waters.     

Experimental investigation of wood combustion in a fixed bed with hot air

Waste combustion on a grate with energy recovery is an important pillar of municipal solid waste (MSW) management in the Netherlands. In MSW incinerators fresh waste stacked on a grate enters the combustion chamber, heats up by radiation from the flame above the layer and ignition occurs. Typically, the reaction zone starts at the top of the waste layer and propagates downwards, producing heat for drying and devolatilization of the fresh waste below it until the ignition front reaches the grate. The control of this process is mainly based on empiricism.MSW is a highly inhomogeneous fuel with continuous fluctuating moisture content, heating value and chemical composition. The resulting process fluctuations may cause process control difficulties, fouling and corrosion issues, extra maintenance, and unplanned stops. In the new concept the fuel layer is ignited by means of preheated air (T > 220 °C) from below without any external ignition source. As a result a combustion front will be formed close to the grate and will propagate upwards. That is why this approach is denoted by upward combustion.Experimental research has been carried out in a batch reactor with height of 4.55 m, an inner diameter of 200 mm and a fuel layer height up to 1 m. Due to a high quality two-layer insulation adiabatic conditions can be assumed. The primary air can be preheated up to 350 °C, and the secondary air is distributed via nozzles above the waste layer. During the experiments, temperatures along the height of the reactor, gas composition and total weight decrease are continuously monitored. The influence of the primary air speed, fuel moisture and inert content on the combustion characteristics (ignition rate, combustion rate, ignition front speed and temperature of the reaction zone) is evaluated.The upward combustion concept decouples the drying, devolatilization and burnout phase. In this way the moisture and inert content of the waste have almost no influence on the combustion process. In this paper an experimental comparison between conventional and reversed combustion is presented.     

Hochwasser 2002

In August 2002, highly contaminated areas in the region of Bitterfeld, e.g. the floodplain of the creek Spittelwasser, as well as the adjacent regions of Jeßnitz and Raguhn, were submerged by the river Mulde. An input of mobilized contaminated sediments in residential areas was the matter of concern. The objective of the present study was to estimate the pollutants load on the basis of chemical and biological data and identify the sources of pollutants. Deposited sludge and flood water samples were assessed on the basis of biological and chemical analyses and in comparison with administrative reference values. The pollution of the investigated sites was rather heterogeneous. At several sites, tolerance limits of the German Klärschlammverordnung or the Bundesbodenschutzverordnung were clearly exceeded, e.g. for Pb, As and HCH. Organic extracts exhibited significant effects in several biotests. This may be relevant with respect to direct particle uptake via ingestion or respiration. Pollution patterns for heavy metals as well as for organic pollutants differed significantly from the pattern found in the Spittelwasser flood plain before the inundation, which is in contrast to the initial hypothesis of a possible transport of contaminated Spittelwasser sediments into residential areas. Interestingly, a correlation of chemical load and the overall biological effect could be shown. From the viewpoint of the precautionary principle, the identification of the compounds exerting toxic effects and of the respective pollutant sources would be desirable.     

From Management to Negotiation: Technical and Institutional Innovations for Integrated Water Resource Management in the Upper Comoé River Basin, Burkina Faso

This study focuses on the potential role of technical and institutional innovations for improving water management in a multi-user context in Burkina Faso. We focus on a system centered on three reservoirs that capture the waters of the Upper Comoé River Basin and servicing a diversity of users, including a sugar manufacturing company, a urban water supply utility, a farmer cooperative, and other downstream users. Due to variable and declining rainfall and expanding users’ needs, drastic fluctuations in water supply and demand occur during each dry season. A decision support tool was developed through participatory research to enable users to assess the impact of alternative release and diversion schedules on deficits faced by each user. The tool is meant to be applied in the context of consultative planning by a local user committee that has been created by a new national integrated water management policy. We contend that both solid science and good governance are instrumental in realizing efficient and equitable water management and adaptation to climate variability and change. But, while modeling tools and negotiation platforms may assist users in managing climate risk, they also introduce additional uncertainties into the deliberative process. It is therefore imperative to understand how these technological and institutional innovations frame water use issues and decisions to ensure that such framing is consistent with the goals of integrated water resource management.