Researchers on the REFRESH project have undertaken a two-step evaluation of the key waste streams within Europe having significant environmental impact.  Thirty-seven priority waste streams (previously defined in the Medium List of Waste Streams Appropriate for Valorisation) were further reviewed to produce a list of the top 20 waste streams for modeling and detailed research. The resultant list includes well-known examples like spent grains and other organic waste streams from the production of alcoholic beverages (ales, lagers, cider, wines and spirits), press cakes from vegetable oil processing and meat & dairy side-streams such as slaughter by-products and whey protein.  Fruits & vegetable waste streams that are often considered to have lower environmental impacts are represented by apple pomace, orange peel/juicing residues and tomato pomace.

The report provides clear focus to the REFRESH project regarding those waste streams that are present in high volumes with high environmental impact. These waste streams – often used as animal feed - can be further studied and evaluated to see if these impacts can be reduced.