CRITICAL EVALUATION OF METHODS FOR HAZARD CLASSIFICATION OF WASTE ECOTOXIC PROPERTIES

摘要

A new regulation for waste classification, harmonizing the waste and chemicals legislation, applies from 1st of June 2015. Assessment of ecotoxic hazard (HP14), however, still lacks criteria and guidance for waste classification. This paper provides an improved understanding of two alternative HP14 classification frameworks: (i) summation methods for mixtures, (ii) leaching tests. The two frameworks were evaluated by geochemical speciation modeling of an ash from incinerated waste. Our results indicates that classification based on summation methods overestimate the hazard. Important parameters that are governing the availability of toxic elements e.g. transformation from one species to another and complexation on organic or inorganic sorbents, are not accounted for in the summation method. This study demonstrates that a mechanistically modelling approach is a powerful tool for the evaluation of different leaching test strategies. The Liquid/Solid-ratio (L/S) and pH are shown to be critical for classification. A testing strategy based on standardized waste leaching tests at L/S 10 and the own pH of the waste will underestimate the hazard associated with the presence of toxic compounds (Cu and Zn) while simultaneously falsely overestimate the hazard of non-toxic compounds (Ca and K). The results suggests that classification should be based on leaching tests at L/S higher than 1000 and at a fixed range of pH 5.5-8.5 to avoid erroneous results. Further studies are needed to define a practical and functional testing strategy for hazardous waste classification.