Wet Oxidation of Process Waters from the Hydrothermal Carbonization of Sewage Sludge

Abstract

Abstract Combing hydrothermal carbonization (HTC) of sewage sludge with wet oxidation of the resulting process waters (PWs) is a favorable economic process leading to a wastewater that is better amenable to biological treatments. Five PWs from HTC of sewage sludge and straw were oxidized with molecular oxygen. A good removal of chemical oxygen demand and dissolved organic carbon was shown. The oxidized waters proved good substrates for a subsequent anaerobic digestion. However, the oxidized PWs were identified as more toxic in germination tests with cress ( Lepidium sativum L.) compared to the untreated PWs.