Combustible waste is normally received at the plant by means of specially equipped and authorised vehicles. The possibility of managing the logistics via rail is also under evaluation, since the services at the Industrial Consortium of Isernia Venafro, where the plant is located, in principle allow this solution to be adopted. The incoming material is identified and recorded in accordance with the statutory procedures and subjected to a preliminary examination in order to verify it is conforming to the specifications according to internal management and control procedures based on the ISO 14001 and EMAS standards. If it is found to be suitable and conforming to the predefined chemical, physical and merceological properties, after being weighed on a weighbridge, the product is unloaded in a specifically dedicated storage facility. The storage facility consists of a 2,200 m2 reinforced concrete structure, fully enclosed and equipped with an air extraction system which provides an hourly renewal appropriate to the volume of the facility, thereby ensuring the best environmental conditions. Also the primary combustion air is taken directly from inside the storage facility, so that no odours or volatile substances are dispersed into the surrounding environment. The RDF is stored solely inside e storage facility: biomasses not housed in the facility are placed under cover to protect them from atmospheric precipitation.

The boiler is the unit in which the thermal energy generated by combustion is used to convert water into superheated steam, at high pressure and temperature, which is used to operate a steam turbine coupled to a power generator. The Pozzilli plant boiler, with a thermal power of 47 MWt, consists of a Martin grid on which the fuel is burnt: the high temperature gaseous fraction of combustion, or fumes, first follows an ascending path in the combustion chamber consisting of continuous walls of pipes set side by side and connected by membranes containing water being converted into steam. The temperature of the fumes in the hottest part is never less than 1,100gradiC, and is in any case guaranteed to remain at a temperature of more than 1,100gradiC for at least two seconds, in accordance with current standards: this helps to prevent the formation of noxious gases such as dioxins and furans. Subsequently, the fumes pass through another four vertical heat exchanging zones in which, by progressively giving up their heat, they allow the steam to be brought to the temperature and pressure levels required for injection into the turbine; at the same time, the water is preheated and sent to the boiler in a closed cycle. The solid residues of the combustion consist of the ashes collected on the grid and some lighter weight residues borne by the fumes, together with the unburnt particles collected along the circuit in the boiler until a final filtering stage in a special filter system.

This consists of a steam turbine alternator condenser unit. The triple spillback, multistage steam turbine transforms the energy of the high pressure/temperature steam into mechanical energy; in practice, it is a motor coupled to a three phase power generator. The steam that drove the turbine is discharged into a water cooled heat exchanger, the condenser, where it returns to the liquid state and is sent back to the boiler in a closed cycle. The three phase alternator, with rotating diode type excitation, including a water cooling system, is coupled to the turbine by means of a mechanical speed reducer. The 6 kV electricity produced by the alternator is converted to 20 kV and fed into the ENEL distribution network. The energy is partially absorbed by the plant itself to operate its auxiliary services: pumps, transport and collection systems, air blowers and fume extractors. The net electric power available to be fed into the grid is 11.5 MW.

Much care has been devoted to the design and to the methods for management of the fume treatment and emission monitoring systems, in compliance with the rules included in Legislative Decree no. 133 of 11 May 2005 and in implementation of European Directive 2000/76/EC on waste incineration. The treatment system includes:

• injection of urea into the combustion chamber to lower NOx emissions;
• injection of sodium bicarbonate and active carbons upon release of fumes from the economiser to reduce acid (HCl and SO2) and heavy metal emissions;
• final filtration to restrain the particulate matter carried by the fumes before transfer to the chimney stack.