Projects / Programmes
Influence of geotechnical fills from recycled materials on groundwater
| Code |
Science |
Field |
Subfield |
| 1.08.00 |
Natural sciences and mathematics |
Control and care of the environment |
|
| Code |
Science |
Field |
| P000 |
Natural sciences and mathematics |
|
| Code |
Science |
Field |
| 1.05 |
Natural Sciences |
Earth and related Environmental sciences |
recycled waste materials, geotechnical composite, monitoring, leachate, circular economy.
Researchers (21)
Organisations (4)
Abstract
Industry produces large quantities of residues (waste materials and by-products), which are potentially suitable for beneficial use, for example as recycled materials in geotechnical applications as a substitute for natural raw materials. The prerequisite for the beneficial use of residues is their environmental acceptability and their technical adequacy. However, compared to natural raw materials, recycled materials can have a higher content of potential toxic contaminants, which can be inorganic or organic. This may present a limiting factor for the use of such materials, due to the potential release of the contaminants when the material comes into contact with water.
In the case of the production of geotechnical composites based on recycled materials, it is possible to produce chemical inert materials in which potentially toxic contaminants are effectively immobilized. Such composites can especially be used as geotechnical fill. However, one of the main concerns about the use of such new composites still refers to insufficient knowledge about their environmental properties, so that the leaching behaviour of such composites needs to be investigated thoroughly.
One of main objectives of the study is to investigate the storage and transport of contaminants which can be potentially released from three selected new composites (based on the use of recycled industrial and combustion residues, as well as of recycled sludge) that are produced and placed by TERMIT and HARSCO, and used as geotechnical fills. Investigated composites have different leaching potentials. Since the release of potentially toxic substances is difficult to monitor (the transport processes are still insufficiently explained), this research presents a challenge from both the scientific point of view, and the development perspective. Nowadays, there is also an increasing demand for development of sensitive, reliable, and cost and time effective monitoring tools for the detection of anthropogenic contaminants in subsoil and groundwater. This gap is aimed to be fulfilled within proposed project.
Three types of composites based on various recycled materials will be installed in the pilot testing laboratory (i.e. this will be located in the area owned by TERMIT). The materials which are relatively abundant, relatively difficult to recycle, and some of them involve components which are difficult to immobilize will be chosen. Part of the composites will be installed in the form of compacted layers and part in the form of non-compacted layers. In the latter case, less favourable conditions related to the higher permeability of the composite to infiltrating water (resulting in higher leaching potential) will be simulated. Leachates will be collected by means of lysimeters in order to study potential emissions of released contaminants. Passive samplers will also be used to determine the contaminants in the subsoil and groundwater.
The proposed project has following goals:
· To determine the presence of potential contaminants in leachates released from selected composites.
· To determine the impact of hydrogeological conditions on leachate emissions.
· To improve the existing methods for performing monitoring of the contaminants which are released from geotechnical fills, and of their migration into the environment.
· To prepare recommendations for the selection and use of the optimal combination of methods and for data analysis and interpretation.
· To improve the existing method for the integration of leachate emissions which affect groundwater quality into LCA.
· To find new business opportunities for circular economy and improve industrial symbiosis.
· To develop self-assessment tools for stakeholders, in the sense that they will be able to evaluate sustainability of the procedures related with beneficial use of recycled materials.
· To establish broad social acceptance in the field of beneficial use of recyc
Significance for science
The significances for the development of science are as follows:
1) Development of innovative procedure for effective, simple, economic and timely viable environmental monitoring of installed composites in geotechnical fills and their potential influences on soil and groundwater.
2) New knowledge in the field of leaching of potential toxic elements (PTE) from construction products made of recycled waste into geological basis and development of new models of mobilization of pollutants in different subsoils.
3) Validation of laboratory leaching models, taking into account actual data from field monitoring.
4) Development of new models for evaluation of environmental impact in the LCA based on real laboratory and field data, especially in ecotoxicity, acidification and eutrophication impact categories.
Emissions of PTE released from construction products (made of recycled materials) used for geotechnical purposes in rehabilitation of mining areas are still poorly studied. Within the project, we will develop and critically evaluate the effectiveness of the new proposed methods for validating the environmental performance of products made from recycled materials. A combination of results obtained from laboratory leaching tests and field monitoring will be taken into account. New soon to be standardized environmental models (currently in the phase of public debate) will be calibrated with field data. The project will also have a direct impact on the improvement of LCA tools with new models that will connect the actual measured values of PTE released to subsoil and groundwater.
The project is explicitly interdisciplinary and deals with the Slovenian and world-wide recognized urgent and actual topic related to the use of recycled materials in civil engineering and linked environmental problems. It is expected that it will have a synergetic effect in the fields of environment, geology and the construction industry. One of the main goals of the project is to properly evaluate the available recycling alternatives, which can lead to a significant improvement of environmental sustainability in the construction sector. As stated in paper of Blankendaal et al. (2013), the impact of reducing primary material consumption can be very significant, since activities of construction industry consume about 40% of materials entering the global economy and generate around 50% of the global output of greenhouse gasses.
Reference:
Blankendaal, T., Schuur, P., Voordijk, H., 2013. Reducing the environmental impact of concrete and asphalt: a scenario approach. Journal of Cleaner Production 66, 27-36.
Significance for the country
The project is directly responding to the problem of poor social acceptability of new circular business models (CEBM), where secondary resources are used. This is connected with distrust among stakeholders, who consider such business models as waste management and don't recognize it as secondary raw materials production, which is one of the main domains of circular economy strategy.
TERMIT CEBM, in which different waste materials are recycled into construction products, for the rehabilitation of active mining areas, is one of the most advanced models of industrial symbiosis in Slovenia. It involves stakeholders from different industries as well as construction and mining sector and increases their competitiveness, taking into account lower prices of wastes treatment and production at considerably decreased environmental impacts.
The direct impacts of the project on TERMIT and its value/supply chain are as follows:
1) Better communication with different stakeholders (especially decision makers and the local community) based on the results of analyzes performed in the project. This will contribute to so-called "social licensing" where the local community recognizes numerous benefits (new jobs, better community) and its importance for them.
2) Involving more actors into the value / supply chain (more recycling, more products from secondary raw materials) due to increased recognition of the model.
3) Improved material, environmental and economic efficiency of processes by using new hybrid tools (e.g. identifying and eliminating hot spots).
A better recognition of TERMIT CEBM will have a direct impact on the development of sustainable Slovenian construction sector. Construction legislation already allows and encourages the use of secondary raw materials (SRM), but in practice this is still poorly implemented due to distrust in new products, high initial testing costs and controls compared to conventional products. Better recognition of TERMIT CEBM will have positive effect on development of similar business models, especially among SMEs that are main operators in construction sector. We expect the project will also influence on the development of various incentives for the use of SRM in construction (e.g. green public procurement), which will make the use of SRM in the construction industry an obligation!
By introducing new ways of verifying the environmental impacts of construction products made from SRM, the project will directly affect environmental and legislative procedures, such as, for example, introducing "end-of-waste" criteria and simplifying / synchronizing procedures in the field of waste transition into a product from the point of environmental, construction and mining legislations.
Most important scientific results
Interim report
Most important socioeconomically and culturally relevant results
Interim report
