Intercomparison of Leaching Tests for Stabilized Waste

The emphasis on treatment of waste by solidification/stabilization has led to the need for leaching tests to assess the environmetal benefits of such treatment processes. In this paper the intercomparison of leaching tests for stabilized waste. In this study Municipal Solid Waste Incinerator fly ash was used. The sample preparation, the testing for homogeneity of sample batches and the verification of the repeatability of leaching in one laboratory using the tank leaching test used as common method to be carried out by all participants is described. The influence of prolonged hardening of the cement-based stabilization product is discussed as well as influences of forced air and carbondioxide exposure on the release. An explanation of the observations and the implications for testing are given. The repeatability and reproducibility standard deviation of analysing a Standard Leachate for Na proved to be resp. 2.5 and 5.3 % (mean value: 56.85 mg/1). The repeatability and reproducibility standard deviation of the effective diffusion coefficient of Na obtained form the tank leaching test (expressed as pDc= -log Dc) proved to be resp. 0.071 and 0.095 (in pDc units) at a mean value of 11.46 (N=16).