Biofilter S. Nazzaro Sesia
Agriter SrlS. Nazzaro Sesia | Novara - Italy
- System description: Biofiltration of air from composting process
- Waste processed: Organic waste, garden waste and sludge
- Plant capacity: 94,500 cu.m/hour
The exhaust air coming from the composting of organic waste and sludge is channelled to a large biofilter where odours are controlled before the air is released into the atmosphere. Biological filtration is a very efficient process to control odours deriving from composting. The process includes two steps: first, malodorous gases are absorbed by the superficial moisture of the filter media; then they are digested through the biological process developing spontaneously in the bio-filter. Both processes, whether gas absorption or digestion, need water to take place. It is thus very important to keep the moisture under control in the filtering material made of wood chips. The whole process takes place in the biofilm forming on the chips surface. The flow of waste air is collected through a duct set up under the ceiling of the composting building by a centrifugal blower installed outdoors. In such a way, the building is maintained at negative pressure and ventilation is provided.The blower is equipped with a motor-driven air lock, which closes to reduce absorbed power uring start-up and opens automatically once the equipment is started.
The biofilter floor consists of prefabricated elements made of reinforced concrete, strong enough to withstand the weight of a wheel loader; this facilitates the biofilter maintenance operations. There are openings in the aerated floor elements through which the air coming from the underneath plenum goes through. A sprinkler system has also been designed to keep the biofilter moisture under control.