Effects of thermally dried and composted sewage sludges on the fertility of residual soils from limestone quarries

► Sewage sludge improved the physicochemical and biological properties of residual soils. ► The sludge effect differed with the pre and post treatments of the sludges. ► The effect decreased the most in endpoints associated with labile organic matter. ► The exudates and plant residues contributed to residual soil enzyme activities. ► β-Glucosidase activity was found partly associated with stabilized organic matter.