This waste stream is connected to the technical Circular Solution "Energy recovery from the low calorific fraction (LCF) of a mechanical waste treatment plant".
The material is an output flow of the local mechanical waste treatment plant (MWTP) that produces refuse derived fuel (RDF) for industrial fuel for the paper industry, and recovers ferrous and non-ferrous metals. The waste flow in question is humid (< 60% DM) and rich in organic matter (> 60% of FM), which makes it unsuitable for waste incineration, both from the energetic efficiency and environmental point of view. Characteristics of the waste flow in question:
The inputs to the MWTP are bulky wastes, wastes from small businesses, and residual municipal solid wastes (MSW).The process is influenced by the fluctuating proportions of these input streams.
The material is composed of the residues resulting from the following treatment processes: shredding, sieving at mesh sizes of 80 mm and 40 mm, and separation of recyclable metals. A high calorific RDF and a medium calorific fraction for co-incineration are produced by separation of 2D and 3D plastics, and of waste wood.
The waste is granulous, approx. 40 mm maximum in diameter, dark colored in shades of brown, with dispersed particles of other colors, mostly plastics, glass, and crockery shards (Figure 1).
Figure 1: Aspect of the low calorific fraction
The LCF’s grain size is < 40 mm, and its main characteristic is a high content (47%) of organic, biodegradable material (organic fraction, OF). More biodegradable material is present in form of paper, diapers, and similar hygiene materials, summing up to another 10%. Approximately 16% are inert materials, of which glass makes up the most part, having a share of almost 9% in the overall waste composition (Figure 2).
Figure 2: Composition of the LCF (< 40 mm)
The LCF is currently transported to a waste incineration plant (WIP) at about 300 km distance from the waste processing and recycling plant.
The relatively high moisture content of 47% not only means that together with each ton of DM, 470 kg of water are being transported, but also results in a considerably reduced efficiency of the combustion process, which makes the current scenario questionable from the perspective of energy efficiency.