Density of Milled and Unprocessed Refuse

Of concern in landfilling for solid waste disposal is minimizing landfill space requirements by maximizing solid waste density. This paper presents the results of investigations into the effect on density of such factors as shredding the refuse, refuse moisture content, landfill machine static pressure and vibrations, machine compaction time, savings in cover soil resulting from the smoother face using milled refuse, and container wall effects during laboratory testing. Milling was shown to increase the density of residential-light commercial solid waste by 15% over unprocessed refuse (dry weight, field scale, equal compactive effort). Laboratory data indicated that the numerical increase in density is approximately constant over a wide pressure range, which means that the percentage increase would decrease at higher applied pressures. The effective refuse density in a landfill (pounds refuse per cubic yard landfill space) increased to 29% by shredding when no daily cover was used, compared to unprocessed refuse, covered daily.