Little is known about the degradation kinetics of sewage sludge, sanitized with Ca(OH)2, in soil. Thus, this work aimed to monitor
the degradation of limed sludge, under field conditions, when applied on soil surface or incorporated into the soil. The limed sludge
was applied in dystrophic Inceptisol at a dose of 500 kg ha-1 yr-1 of total nitrogen. The mineralization process in the soil was
monitored for 131 days. Samples of organic material were collected for analysis of total and easily oxidizable organic carbon; total,
ammonium, nitric and organic nitrogen; volatile solids; and water contents. The undigested secondary sewage sludge generated in
wastewater aerobic treatment mineralizes faster when limed and incorporated, compared to being arranged on soil surface. The
estimated annual mineralization fraction of the limed sludge was 100% and greater than 95%, when incorporated or arranged on
soil surface, respectively. Such values are higher than those established in the Brazilian environmental legislation for undigested
sewage sludge disposal on soil.