Food waste treatment
Food waste defines edible, raw or cooked substances that are not destined for consumption. Food waste can be thrown away but can also be used to feed animals or be disposed of via biodegradation, through the compost or anaerobic digestion methods, to then be reused as fertilisers.
The anaerobic digestion method involves the degradation of organic matter through the use of microorganisms. This process begins with the removal of non-degradable material and the subsequent trituration of pieces that are to be treated. Once it has been placed inside the appropriate reactors, the material is mixed with bacteria and brought to a preset temperature. This process produces biogas which can be used as an alternative energy source. The material exiting from the reactor is a liquid sludge that must be dehydrated using a screw press.
The screw press is a slow-moving mechanical device in which a conical screw rotates inside a perforated cylindrical filter. During the pressing phase, the liquid sludge is pressed with increasing force against the metal filter. The holes in the filter allow the water to drain out. The remaining sludge is stabilised, refined and used as fertiliser.
In food waste treatment, the Costacurta drilled plate (that forms the filter of the screw press) is a fundamental element of the machine. The plate must have a high thickness to resist pressure, and different kinds of perforations (cylindrical, conical and step drilled) that allow the filtration of water and its separation from the solid material.
In the production of a drilled plate for food waste treatment, the quality of the material used and the precision of the perforations are crucial elements for guaranteeing efficient filtration.