Effect of ozonation on activated sludge solubilization and mineralization

New strategies for sludge stabilization and mineralization need to be devel oped since the use of sludge in agriculture is debatable and sludge inciner ation cannot be a systematic solution. Minimization of sludge production sh ould be preferred. In this work, the effect of ozone on activated sludge so lubilization and mineralization during batch experiments is assessed by est ablishing carbon and ozone mass balances. After extended ozonation of the s ludge, more than 90% of the particulate carbon is modified. Depending on th e experimental conditions, from 15 to 50% is found in a soluble form and fr om 35% to 95% was mineralized. The VSS / SS ratio decreases from 86% to les s than 50% illustrating the sludge mineralization. The initial rate of ozon e consumption by the sludge is very high (estimated value: 30 mgO(3) / g VS S.min) and corresponds to high rates of carbon solubilization and mineraliz ation. More than 50% of the carbon obtained after ozonation is found to be readily biodegradable using a short-term BOD procedure.