Evaluation of a Decision Support System for the useful application of hazardous wastes with means of immobilisation-techniques

In the Netherlands, dumping of hazardous wastes on a landfill is discouraged. On the other hand, the Building Material Decree set standards to building materials in order to protect surface-, groundwater and soil from the leaching of hazardous components. Moreover, the government intends to minimise the use of primary materials. Therefore, new applications of hazardous wastes are needed. The most promising is Stabilisation/Solidification, sometimes called immobilisation. Immobilisation-techniques are defined as changing the physical and chemical state of hazardous wastes in order to reduce the leaching of hazardous components. Despite financial incentives, few applications of immobilised wastes are known. Therefore, a Decision Support System (DSS) is necessary to calculate the impact of the immobilised waste on the environment. A DSS is developed and evaluated for a case with contaminated soil and residues from inorganic industry. The first criterion of the DSS is called long term behaviour and aims at minimising the release of hazardous compounds in relation to external influences and material properties. The second criterion, environmental load focuses at consumption of (non)renewable natural resources. The third criterion is financial consequences, which calculates the overall costs and incomes during the life cycle with respect to all stakeholders.