The waste enters the plant after passing through the radiometric gate and the entrance weighing station to calculate the gross weight; the vehicles unload the waste into the pit and leave the plant after being weighed a second time to determine the unladen weight. The plant is equipped with a pit with a capacity of around 20,000 m3 for the unloading and storage of waste. The waste is moved to the waste to energy lines by means of two bucket crane systems operating on a single level of runways. The medical waste is delivered to the incinerator separately from the remaining waste on dedicated conveyor belts, without going via the waste pit.

The progress of the waste in the combustion chamber is obtained thanks to the movement of a single 18gradi inclined grate divided into two parallel sectors composed of 5 zones each and independently adjustable according to the set process parameters. The waste on the grate undergoes drying, combustion and slagging treatments. The movement of the waste is adjustable through special devices that change the speed of the ach bars. Heat removal is ensured by the boiler integrated in the combustion chamber with walls shielded by boiler pipes up to the base of the grate. The combustion air of the incinerators is sucked in, thus keeping the pit under vacuum to avoid the spread of odours to the outside air. In case of shutdown of both lines, a special deodorisation system can be put into operation that sucks the air and, after having purified it through filters, returns it to the atmosphere. The combustion process is automatically regulated by the supervision and control system, which establishes the coordinated criteria of the progress speed of the different sectors of the grate, the flow rate and distribution of primary air, secondary air and smoke recirculation, to guarantee the optimal temperature and oxygen concentration in each area of the combustion chamber. At the end of combustion, the residual slag falls into an extinguishing well, it is then placed on a vibrating surface that sends it to the right slag pit. From here the slag is taken by the crane operator via overhead crane with a bucket and it is then loaded on trucks that will transport it to the authorised special waste landfill. The gases produced by the combustion are sent to the post combustion chamber the size of which ensures that fumes remain at a temperature above 850gradiC for at least two seconds. By means of appropriate nozzles positioned at the inlet of the post combustion chamber, the recirculating fumes (intended to reduce nitrogen oxides) and the secondary air that completes the oxidation of the fumes are injected at high speed. Two methane fuelled support burners, which turn on automatically based on the fume temperature, ensure that this temperature is maintained, even if there is waste with a low calorific value. In the post combustion chamber, the first fume purification stage is also carried out, through the injection of an ammonia solution for nitrogen oxide abatement (Selective Non Catalytic Reduction SNCR process). A supervisory role is carried out by the control room which monitors all the phases of the process and all the parts of the system 24 hours a day, thus constantly guaranteeing their safety and correct operation.

Downstream of the post combustion chamber of the incinerator for Lines 1 and 2 there is a vertical recovery boiler; above the grate on Line 3 there is a vertical and horizontal recovery boiler (integrated incinerator boiler system). the steam generator on Line 1 has a capacity of approximately 18 t/h of steam at a temperature of 380gradiC and a pressure of 44 bar; the steam generator on Line 2 has a capacity of 18 t/h of steam at a temperature of 380gradiC and a pressure of 44 bar; the steam generator on Line 3 has a capacity of 51 t/h of steam at a temperature of 380gradiC and a pressure of 46 bar.

The combustion fumes that exit the boiler pass to the treatment system, which is divided into several phases: gas humidification in the quencher, dry reaction, physical dusting in the bag filter, fume scrubbing in the wet scrubber and DeNOx and DeDiox effect (nitrogen oxides and dioxins abatement) in the SCR process (catalyst). To facilitate the effectiveness of abatement, in the quencher, or quencher, the temperature of the fumes is lowered from 160 200gradiC (boiler exit temperature) to 150gradiC. In the first part of the cyclone quench tower, coarse dust is separated by the fumes. In the second part of the tower, the fumes are cooled by the introduction of sprayed water and consequent evaporation. Downstream of the quencher the reagent is injected “in line”, which has the dual purpose of improving the abatement of pollutants in the fumes and reducing consumption in the next washing tower. The next step is the dust extraction of the fumes in the bag filter, formed by multiple internal cells working independently. Part of the powders discharged from the filter are recirculated and sent to the dry reaction section in order to maximise the use of the reagents, and the other part is sent to the two powder storage silos through a pneumatic conveying system. Outside the filter there is a primary smoke fume heat exchanger, which performs the dual function of cooling the outgoing fumes to facilitate the absorption of acidic substances in the scrubber and to heat the outflow from the washing tower before entering the SCR system. The scrubber is divided into two stages, an acidic one and a neutral one. In the lower section, the absorption of acids takes place. The recirculated water based solution is partially flushed out and sent to the water treatment system. In the upper stage, SO2 and the remaining traces of acids still present are removed. The neutralisation stage with 30% caustic soda solution includes a plate system for the contact of fumes/liquids. To improve the abatement of heavy metals, an organic precipitating agent is injected. Before exiting the washing tower, the fumes pass through a drop separator for the removal of entrainment to prevent their passage in the smoke/fume exchanger. The fumes coming out of the scrubber pass through the primary smoke/fume exchanger and are sent to the preheating system, made to reach the optimum temperature for catalytic reaction (220 240gradiC). The system consists of a secondary smoke/fume heat exchanger fed by the fumes exiting the SCR reactor, as well as a steam exchanger and a methane burner, which provide additional thermal contribution to reach the desired temperature. The DeNOx DeDiox (SCR) process uses a 25% ammonia solution necessary for the NOx reduction reaction, which allows the abatement of nitrogen oxides and dioxins. Before sending the purified fumes to the chimney, heat recovery in a tertiary exchanger is carried out that preheats the condensate in the thermal cycle. The combustion fumes are sucked in by the draught fan which is located downstream of the scrubbing section and upstream of the catalytic Denox system (nitrogen oxide abatement) and the chimney.

The steam produced supplies the three turbines, one for each line, which operate the three phase synchronous alternators for the generation of electricity. The energy produced, purified for self consumption, is introduced into the national grid at 20 kV (MV) (line 1 and 2) and at 135 kV (HV) (line 3). The installed generation power of the system is 18.3 MW. The steam discharged by the turbines condenses in shell and tube heat exchangers which use the water from the nearby Piovego canal as a coolant. The condensed water is reused when it re enters the degasser.