Effect of different types of elemental sulfur on bioleaching of heavy metals from contaminated sediments

The application of two different types of elemental sulfur (S0) was studied to evaluate the efficiency on bioleaching of heavy metals from contaminated sediments. Bioleaching tests were performed in suspension and in the solid-bed with a heavy metal contaminated sediment using commercial sulfur powder (technical sulfur) or a microbially produced sulfur waste (biological sulfur) as substrate for the indigenous sulfur-oxidizing bacteria and thus as acid source. Generally, using biological sulfur during suspension leaching yielded in considerably better results than technical sulfur. The equilibrium in acidification, sulfur oxidation and metal solubilization was reached already after 10-14 d of leaching depending upon the amount of sulfur added. The metal removal after 28 d of leaching was higher when biological sulfur was used. The biological sulfur added was oxidized with high rate, and no residual S0 was detectable in the sediment samples after leaching. The observed effects are attributable to the hydrophilic properties of the biologically produced sulfur particles resulting in an increased bioavailability for the Acidithiobacilli. In column experiments only poor effects on the kinetics of the leaching parameters were observed replacing technical sulfur by biological sulfur, and the overall metal removal was almost the same for both types of S0. Therefore, under the conditions of solid-bed leaching the rate of sulfur oxidation and metal solubilization is more strongly affected by transport phenomena than by microbial conversion processes attributed to different physicochemical properties of the sulfur sources. The results indicate that the application of biological sulfur provides a suitable means for improving the efficiency of suspension leaching treatments by shortening the leaching time. Solid-bed leaching treatments may benefit from the reuse of biological sulfur by reducing the costs for material and operating.     

Mobility of pharmaceuticals carbamazepine, diclofenac, ibuprofen, and propyphenazone in miscible-displacement experiments

Many pharmaceuticals pass the unsaturated zone before reaching an aquifer. Therefore, laboratory sand column transport experiments were conducted to study the transport behavior of carbamazepine, diclofenac, ibuprofen, and propyphenazone under unsaturated conditions. The test water was artificial sewage effluent to simulate the infiltration of reused wastewater. The test water was spiked with the pharmaceutically active compounds and the tracer LiCl. Afterwards it was passed through laboratory sand columns, one experiment for each pharmaceutical. The physical and chemical parameters were recorded and general ions measured. Pharmaceuticals were measured using solid phase extraction, derivatization, and detection with GC-MS. The column experiments indicate a significant elimination of ibuprofen (54%), propyphenazone (55%), and diclofenac (35%), whereas carbamazepine was not eliminated. Retardation factors varied between 1.84 for carbamazepine, 2.51 for propyphenazone, 3.00 for ibuprofen, and 4.80 for diclofenac. These results show that mobility and elimination of diclofenac, ibuprofen, and propyphenazone is about in the same range as for experiments under saturated conditions whereas carbamazepine had a significantly lower sorption and elimination under unsaturated conditions.     

Screening of short- and medium-chain chlorinated paraffins in selected riverine sediments and sludge from the Czech Republic

Wide distribution of chlorinated paraffins in the environment has already been demonstrated in several studies; however, information about their levels in the Central Europe is still very limited. First study focused on the SCCP contamination of the Czech aquatic environment have been performed recently, and its results motivated the authors to analyze sediments from a wide set of the Czech rivers in order to obtain more detailed information. Thirty-six sediment samples from eleven rivers and five drainage vents neighboring the chemical factories were analyzed; special attention was paid to the industrial areas. For the first time in the Czech Republic, medium-chain in addition to short-chain chlorinated paraffins were analyzed using GC-ECNI-MS. Chlorinated paraffins were detected in sediment samples on the concentration levels up to 347 ngg(-1) for short-chain chlorinated paraffins, and 5575 ngg(-1) for medium-chain chlorinated paraffins. Average chlorination degree of SCCPs was 65%.     

The Application of Chemical Leasing Business Models in Mexico

- DOI: http://dx.doi.org/10.1065/espr2006.02.294 Background, Aim and Scope. To better address the requirements of the changing multilateral order, the United Nations Industrial Development Organization (UNIDO) Cleaner Production Programme, in 2004, developed the new Sustainable Industrial Resource Management (SIRM) approach. This approach is in accordance with the principles decided at the United Nations Conference on Environment and Development (UNCED) in Rio de Janeiro, Brazil in 1992. Unlike the traditional approaches to environmental management, the SIRM concept captures the idea of achieving sustainable industrial development through the implementation of circular material and energy flows in the entire production chain and reduction of the amount of material and energy used with greater efficiency solutions. The SIRM approach seeks to develop new models to encourage a shift from selling products to supplying services, modifying, in this manner, the supplier/user relationship and resulting in a win-win situation for the economy and the environment. Chemical Leasing represents such a new service-oriented business model and is currently being promoted by UNIDO′s Cleaner Production Programme. Main Features. One of the potential approaches to address the problems related to ineffective use and over-consumption of chemicals is the development and implementation of Chemical Leasing business models. These provide concrete solutions to the effective management of chemicals and on the ways negative releases to the environment can be reduced. The Chemical Leasing approach is a strategy that addresses the obligations of the changing international chemicals policy by focusing on a more service-oriented strategy. Mexico is one of the countries that were selected for the implementation of UNIDO's demonstration project to promote Chemical Leasing models in the country. The target sector of this project is the chemical industry, which is expected to shift their traditional business concept towards a more service and value-added approach. This is being achieved through the development of company specific business models that implement the above-indicated Chemical Leasing concept with the support from the Mexican National Cleaner Production Centre (NCPC). Results and Conclusions. The implementation of Chemical Leasing in Mexico has proven to be an efficient instrument in enhancing sustainable chemical management and significantly reducing emissions in Mexico. Several companies from the chemical industrial sector implement or agreed to implement chemical leasing business models. Based on the positive findings of the project, several Mexican companies started to negotiate contents of possible Chemical Leasing contracts with suitable business partners. The project further aimed at disseminating information on Chemical Leasing. It successfully attracted globally operating companies in the chemicals sector to explore possibilities to implement Chemical Leasing business models in Mexico. At the international level, the results of the UNIDO project were presented on 20TH September 2005 during a side event of the Strategic Approach to International Chemicals Management (SAICM) Preparation Conference in Vienna. Recommendations and Outlook. To facilitate the promotion and application of Chemical Leasing project at international level, UNIDO is currently developing a number of tools to standardize Chemical Leasing projects. These include, among others, Chemical leasing contract models; Chemical Leasing data base to find partners for chemical leasing; and guidelines to implement Chemical Leasing projects and work programmes.     

Modeling organic carbon dynamics and cadmium fate in long-term sludge-amended soil

A model is described that may help to resolve uncertainty and controversy over the long-term consequences of sludge applications to arable land, especially with regard to the effects of sludge adsorption characteristics on trace metal solubility and bioavailability (e.g., the sludge "time bomb" or sludge "protection" hypotheses). Mass balances of organic and inorganic material derived from sludge and crop residues are simulated. Each pool has a potentially different adsorption affinity for trace metals, and this leads to changes in the adsorption capacity of sludge-amended soil that influence leaching and crop uptake. Model simulations were compared with measured changes in organic carbon and ethylenediaminetetraacetic acid (EDTA)-extractable cadmium contents in a clay loam soil following 41 years of sludge applications. The model adequately reproduced the data, although discrepancies in the vertical distribution of Cd were attributed to the effects of macropore transport and root-uptake driven recirculation. A Monte Carlo sensitivity analysis demonstrated that the most important parameters affecting leaching and crop uptake were the Cd loading and parameters controlling adsorption, especially the partition coefficient for sludge-derived inorganic material and the exponent regulating the effect of pH on sorption. Scenario simulations show that no general conclusions can be drawn with respect to the validity of the sludge "time bomb" and sludge "protection" hypotheses. Either may occur, or neither, depending on three key system parameters: the ratio of sludge adsorption capacity to the initial adsorption capacity of the soil, the proportion of the sludge adsorption capacity contributed by the inorganic fraction, and the sludge Cd loading.     

Verbleib von spurenschadstoffen bei der methylesterherstellung aus altspeisefett im technikumsmaßstab

Aims and Scope

In Germany, 120,000 tons per year of waste edible fats are collected from the catering and the food industry Until recently, these fats have widely been used as a nutritional additive for poultry and other animals fodder. Due to the BSE crisis and some affairs based on dioxins in feeding stuff, waste fats are now barely used as fodder. Currently, these fats substitute fresh vegetable oils in the chemical industry and are used as raw material for the production of biodiesel. Therefore, alternative fields of application are required. In this context, the Deutsche Bundesstiftung Umwelt (DBU) is sponsoring a joint research project which deals with the production and testing of cooling lubricants based on monoesters made from waste edible fats.

Methods

In a first step, characteristics and quality of wasteedible fats of different origins were chemically analysed and monitored. The investigations covered the following fat specific parameters: total contamination, sulphate ash, water content, peroxide number, iodine value, kinematical viscosity, neutralisation number (free fatty acids) and fatty acid spectra. In the next step, a process development/optimisation was carried out for the production of methylesters based on the raw material waste fat, leading to the construction of a pilot plant. To investigate the fate of trace pollutants during the production process of waste-fat methylester, samples were systematically contaminated with polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and the elements Al, Cd, Cr, Cu, Ni, P, Pb, Sn, and Zn. These contaminated fat samples were transesterified in laboratory scale. The primary and by-products were analysed subsequently.

Results

Valuable hints on the design of the technical process of fatty adid methylester production based on waste edible fats were gained by regarding the fat specific parameters. For example, filtration and dewatering of the waste fats proved necessary. The saturated fatty acids, most wanted for the production of cooling lubricants due to their high oxidation stability, were present in the range of 11,3% to 31,6%. Due to the low content of free fatty acids, a base catalysed process occurred more suitable for the transesterification of the waste edible fats. Trace analytical investigations concerning inorganic and organic pollutants proved a low basic contamination of the waste edible fats. Experiments with systematic contamination of the fats indicated an accumulation of the heavy metals in the glycerol phase during the transesterification process, whereas the organic pollutants were detected in the methylester fraction by amounts of 80% to 95%.

Outlook

In a next step, the further processing of the methylesters to monoesters with alcohols of the chain length C2 to C8 will be presented. Associated results of chemical-analytical investigations on the process and the application of the cooling lubricants will also be given.     

Global-scale vs. regional-scale scenario assumptions: implications for estimating future water withdrawals in the Elbe River basin

In this paper, we explore how scenarios of future water withdrawals in a river basin are influenced by scale-dependent quantifications of the driving forces for two global-scale storylines. Either global-scale information or region-specific information is used to do the quantifications. In addition, we analyze the impact of including or not some restricted regional-scale information in the employed water use model. To develop scenarios of water withdrawals in the German part of the Elbe River basin, we applied the modules for domestic, thermoelectric power and manufacturing water use of the global water model WaterGAP, using scale-dependent driving forces scenarios and other scale-dependent model input. In the global-scale quantitative interpretations of the storylines of the IPCC SRES scenarios A1 and B2, all major driving forces of water withdrawals in the basin—population, thermoelectric power production and industrial gross domestic product—show vigorous increases between 2000 and 2025, while from the regional perspective, smaller increases but mostly decreases appear to be plausible. These discrepancies are partly due to the fact that for the global-scale interpretations only the historic developments until 1990 were taken into account, and not until 2000 as in the regional case. The resulting scenarios of sectoral water withdrawals in 2025 differ strongly between the two scale-dependent interpretations of the storylines, with the global one leading to much higher absolute water withdrawals and much lower withdrawal decreases between 2000 and 2025. Therefore, for regional assessments of water withdrawals, we recommend to embed the scenario analysis in global-scale storylines by performing regional-scale quantifications of the global qualitative driving forces scenarios, based on a limited amount of region-specific information.