Institutes: ISTITUTO PER LO STUDIO DEGLI ECOSISTEMI Description: The stabilization-humification process of biological sludge is efficient and enables

closure of the purifying cycle inside the depuration plant using a natural process which is also ecologically and economically sustainable. A species of infesting swamp cane, Phragmites australis, was placed in the gravel beds previously used for sludge drainage. While the plant grows, it absorbs and favours the transpiration of water contained in the sludge, thus allowing the sludge to dry out. At the same time, aerobic microorganisms which use the oxygen transferred by the plants, carry out the biodegradation and stabilization of the sludge, thus reducing its volume by about 80%. Such a sludge is ready to be used as amendment. Use: The stabilised and humified product can mainly be used as: i) organic amendment in agriculture, and ii) mixed with other inorganic residues, can be considered as a soil-like material (technogenic soil) for agronomic and environmental uses Advantage: The process has the following advantages: Economic: permitting to save money in the sludge management and disposal due to the reduction of about 80% of its initial volume. Ecologic: closure of the sludge treatment cycle at the wastewater treatment plant