Environmental behaviour of a construction made of a mixture of hydraulic binders and air pollution control residues from municipal solid waste incineration Part 2. Simulation tests and validation of the source term modelling

The reuse of waste materials requires the development of assessment methods for the long-term release of pollutants (source term) from wastes (or materials containing wastes) in contact with water. These methods depend on the scenario conditions: characteristics of the materials (especially physical structure and composition), contact with water… The scenario studied here is a water storage reservoir for fire extinguishing. The reservoir construction is made of a mixture of hydraulic binders and air pollution control (APC) residues from municipal solid waste incinerator (MSWI). The modelling of the source term is performed in five steps ranging from the physico-chemical characterisation of the material to the validation of the proposed model by means of field simulation devices. This paper follows a first publication on source term modelling using laboratory tests which therefore concerns the comparison of the results obtained with the previously established model. The first laboratory scale simulation test aims at taking into account the role of the leachate carbonation in the leaching behaviour of the studied material. The results obtained show that air carbonation of the leachate does not fundamentally change mass transfer mechanisms of easily soluble species (especially for alkaline metals). For these species, the use of the apparent diffusional model (model proposed in the previous paper) is, therefore, at first, a satisfactory solution for the prediction of long term leaching behaviour. The field scale test enables us to validate and calibrate the release model determined on a laboratory scale basis.