Supercritical water oxidation of tannery sludge: Stabilization of chromium and destruction of organics.

Highlights: [•] We report simultaneous destruction of organics and recovery of chromium in tannery sludge by SCWO. [•] Destruction of COD increases with higher temperature and oxidant, with maximum value 96.5%. [•] Recovery efficiency of Cr from sludge to ash reaches more than 98% under all conditions. [•] Recovered chromium in solid ash is in amorphous structure under temperature 500°C. [•] Leaching toxicity of heavy metals like Cr is greatly reduced through stabilization. [ABSTRACT FROM AUTHOR]