Objectives

The presence of toxic Heavy Metals and Metalloids (HMM) in the environment greatly affects the quality of water and chain-food. The aim of the project is to develop a number of bioprocesses, based on the activity of sulfate- and metal-reducing bacteria (SMRB), to prevent HMM pollution in water bodies by assessing and minimizing HMM pollution originating from contaminated sites. More precisely, the proposal objectives are (1) to obtain improved biological tools (bacteria and enzymes), and (2) to develop new, cost-effective and reliable technological alternatives for removing HMM from ground waters and soils.

Project technical diagram/flow sheet:

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Scientific/technical approach

In order to achieve the above-mentioned project objectives, the technical work program consists of the following four main tasks:

1. Improved biological tools for metal and sulphate reduction. This work will include the selection of sulphate- and metal-reducing bacterial stains (SMRB), and the improvement of the cytochrome efficiency.

2. Monitoring of biological processes. New biocaptors with whole cells or enzymes (cytochromes) will be built and used to monitor bioavailable metal content, and new methods will be developed to analyze the bacterial communities.

3. Development of methods for the treatment of HMM pollutants in ground waters and soils. Direct and indirect reduction of the HMM with the SMRB will be exploited at laboratory scale in order to propose specific remedial strategies for each particular and actual contamination problem. The direct reduction of HMM by SMRB will be applied to ground waters using bioreactors (pump and treat) and also to soils after excavation, pulping or heaping, and inoculation (on site leaching). The indirect reduction of HMM by sulphate-reducing bacteria will be applied to ground waters using bioreactors (pump and treat). In situ active barriers will be used for soil pore waters.

4. Technical feasibility and economic assessment of the treatment of HMM in ground waters and soils. Modeling and simulation of the retained processes will follow setting up in-situ and on site pilot operations.

The above tasks and related objectives are fully complementary. The important and successive milestones are: a) procuring improved biological tools, b) acquiring process operating parameters, and c) getting technical and economic data.

The expected results will be a) tools for monitoring bioavailable HMM content, and b) technically and economically evaluated bioprocesses for HMM treatment.

The project objectives fit well into cluster 1 (Liquid processing and recovery) of TRAWMAR network and also into cluster 1 (Mining technologies) of EUROTHEN network. In both networks there are projects concerning effluent treatment and soil decontamination.