Thermo-chemical pre-treatment to solubilize and improve anaerobic biodegradability of press mud

► The best pretreatment conditions (100 °C, Ca(OH)2) on press mud were determined. ► COD solubilization and VFAs production were relationship to pretreatment severity. ► Both COD solubilization and methane yield were increased for pretreated press mud. ► Higher solubilization did not mean a biodegradability increase.