The waste remaining in the tumbler module consists of paper products, low and high-density polystyrene products. Low density polystyrene products float quickly to the surface while paper products stay down in the water flow. The flow of water and waste is passed under a vacuum system which pulls the polystyrene floating on the surface up into the vacuum system and deposits it in a container or conveyor system. The system then removes the paper products from the water flow by means of a screening operation. Water is recycled through the system by means of a rotating barrel filter system and storage tank.
Sorted polystyrene is dropped into a container and processed for shipping to a recycling facility.
The production machine was tested in Los Angles at a material recovery facility that collected food service waste form over 50 locations. The equipment w orked very well in removing low-density polystyrene from the waste stream. A study was completed on the operating parameters and the efficiency of the sorting system. It was found that the system would be more valuable if there were more low-density polystyrene in the waste stream, because much of the waste was contaminated paper that could not be recycled. It was also determined that it would be more efficient to have smaller sortation systems nearer the location were the waste was generated to prevent contamination and reduce transportation problems.