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ECN publication
Developments in evaluating environmental impact from utilizationof bulk inert wastes using laboratory leaching tests and field verification : international symposium on bulk "inert" wastes: an opportunity for use, September 1995, Leeds
Published by: Publication date:
ECN 1995
ECN report number: Document type:
ECN-RX--95-056 Other
Number of pages: Full text:
34 Download PDF  

In recent years leaching tests for construction materials and wastes havebeen developed with emphasis on using them as prediction tools for release in the long term rather than on using them as arbitrary pass/fail tests. In the first stages of development, the mechanisms of release and release controlling parameters have been assessed. For each of these aspects leaching tests have been selected, developed and in part standardized. Not all relevant aspects of leaching are covered yet. The reducing properties of materials, for example, are still not taken into account properly. The need for more elaborate tests is increasing as the policy to reuse waste materials in construction is expanding. As a consequence, the desire to improve material quality is increasing as well. For this purpose more detailed knowledge on the chemical speciation of contaminants is needed, as a treatment of waste carried out to reduce a few contaminants with too high leach rates may lead to an undesired increase in the release of other contaminants, which were previously not a problem. Tests focussed on two main aspects of leaching can be identified: release as a function of time, and release as a function of main leaching controlling parameters such as pH, redox and complexation. The relation between these tests and the data interpretation associated with them is discussed. Another distinction in the use of tests is related to the level of understanding needed. In CEN TC 292 tests have been distinguished in: characterization tests, compliance tests, and on-site verification tests. An important aspect of the new development of tests with release prediction capabilities is the verification of such predictions in the field. Some first examples of the relation between predictions of release from laboratory test data and field observations will be presented: release from MSWI bottom ash monofills, and release from road-base application of coal fly ash and MSWI bottom ash. Finally, recent developments in EC DG12 Standard, Measurements and Testing Programme and CEN TC 292 Characterization of Wastes are addressed. 11 figs., 2 tabs., 50 refs.

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