Assessment of the water quality produced from mechanical thermal expression processing of three Latrobe Valley lignites

Mechanical Thermal Expression (MTE) is a developing non-evaporative brown coal (lignite) dewatering technology. This study assesses the physical and chemical properties of MTE product water expressed from three Latrobe Valley lignites. MTE product water was found to be acidic, contain concentrations of dissolved organic and inorganic components of up to 5.3 g/L and was found to contain suspended colloidal coal particles of up to 1.7 g/L. The concentration of contaminants in the product water was found to be related to different coal types. The selection of coals for future MTE processing will have significant implications for the quality of water produced. Many investigated water parameters are in breach of selected water use guidelines and remediation of the water from this process is required prior to reuse or disposal.