Area Waste Authorities (Autorità d’Ambito) established in the form of publicly held companies, as forms of aggregation between local authorities for the management of waste collection and disposal services, cannot be classified as public administrations for the purposes of the rules prohibiting recourse to contractual arbitration (arbitrato irrituale), where they carry out an activity which, although of public interest, is not characterised by the exercise of authoritative and discretionary powers proper to public functions, being conducted according to criteria of cost-effectiveness and using instruments of private law in contractual relations; consequently, an arbitration clause providing for contractual arbitration (arbitrato irrituale) inserted in a procurement contract entered into by such bodies is valid and effective, thereby removing jurisdiction over the relevant dispute from the ordinary courts.