methods and systems for processing waste materials and for manufacturing composite materials are disclosed herein . according to some embodiments , the heterogeneous waste includes a plastic component and a non - plastic component , and the non - plastic component includes a plurality of pieces of waste . the heterogeneous waste is heated to melt at least a portion of said plastic component and reducing a volume of said heterogeneous waste , and then mixed until at least some said pieces are each encapsulated by the melted plastic component . upon cooling , the mixture optionally sets into a composite material . the presently disclosed invention does not require pre - sorting of the heterogeneous waste and is operative to process “ as is ” waste . optionally , the waste is pre - sorted . exemplary uses for the composite material include but are not limited to flooring sheets , construction bricks , thermal insulation , acoustic walls , road paving materials , road beds , ballistic shields shock absorbing flooring , artificial islands , artificial reefs , and marine docks .