Production of RDF Parona | Pavia
Lomellina Energia SrlParona | Pavia - Italy
- System description: Production of RDF - Refuse Derived Fuel
- Waste processed: Mixed municipal solid waste
- Plant capacity: 200,000 t/year
The small-sized material produced by the screens in the sorting area of the plant is collected by conveyor belts and transferred to the adjacent building to go through a biological stabilization process. Before entering the building, the material is processed by a magnet, which separates small-sized ferrous materials.
The composting process takes place in a closed building, equipped with a ventilated floor, where the material is piled and turned over.
Storage, turning and final recovery of the material are performed by two self-moving turners, which perform the following operations:
• During the waste sorting and treatment operations, a machine automatically piles the material into one of the composting fields, while the second machine
reclaims the stabilized material and sends it to the refining area;
• During the turning operations, a machine reclaims the material to be turned and sends it through a group of conveyors to the other machine that piles it again.
Two longitudinal conveyors, for material handling, have been installed inside the building. A conveyor equipped with a tripper enables material to be unloaded
onto the self-moving machines anywhere along its length. A second conveyor belt, set up at floor level, receives the material reclaimed by the turner and takes it, according to the operation, to the compost refining area (material already stabilized), or to the conveying system feeding the other self-moving machine (material to be turned).
Each self-moving machine is equipped with a sort of bucket elevator, to reclaim the material, and with distribution conveyors. The operation is completely automatic and is based on a numerical control system.To adjust the moisture of the material and speed up biological activity, water from the waste-water tank is sprinkled on the material during turning operations. The ventilated floor consists of 22 independent fields, each of which is equipped with a suction duct with a servo-controlled adjustable damper. Waste air from the floor is sent to the odour control system, together with the air flow coming from the hall ventilation system. The double air-exhaust system keeps the composting building at a slightly negative pressure, so preventing odours from leaving the building.
Two centrifugal ventilators, with variable frequency drive, blow air through a scrubber, where the airflow is humidified, dust abated, and some of the malodorous gases are absorbed. A large biofilter has been set up downstream of the air scrubber. Here, malodorous gases are first absorbed by the superficial moisture of the
filtering material and then digested by the bacteria and molds which formed naturally in the biofilter following plant start-up.