Leaching eXpert System - LeachXS

A new environmental impact assessment tool

LeachXS, is a database/expert decision support system for characterisation and environmental impact assessment based on estimated contaminant release as derived from leaching tests.  Applicable materials for assessment include:

Soils and Contaminated Soil                Sludge                                                 Compost                                 Sediments

Municipal Wastes                               Industrial and Hazardous Wastes          Mining Wastes                         Preserved Wood

Treated Wastes                                 Stabilised Waste                                 Construction Materials              Cement Mortars and Concrete

The materials leaching database contains results of laboratory leaching tests, various lysimeter test results and field data from more than 600 materials and wastes. In a few cases, interrelated laboratory, lysimeter and field scale data are available.

Leaching tests are interpreted in an expert system to provide estimates of the short and long term release of constituents of interest. This makes the database/expert system a unique tool to study the release behaviour of different materials when used, recycled or landfilled.

A regulatory database allows comparison of test data against criteria for specific utilisation or disposal conditions. Constituents included comprise virtually all inorganic constituents, a selection of organic components and will be suitable for radionuclides. At present, the database system covers leaching/extraction test data, field data and composition data.

Geochemical speciation and chemical reaction/transport modelling capabilities are integrated into the system by using the modelling environment ORCHESTRA. The geochemical modelling includes mineral solubility (extended MINTEQ database), sorption on Fe-oxide (Dzombak & Morel), Al-oxide, dissolved organic carbon (DOC) and particulate organic carbon (POM) interaction according to NICA -DONNAN. Graphical and tabular output is generated in MS Excel.

LeachXS will facilitate compliance with environmental regulations for recycling, waste management, contaminated soil and sediment assessment, fertiliser use and construction product use. It also will facilitate the selection and development of appropriate treatment processes and engineering designs to minimise waterborne environmental impacts.