WASTE MINIMIZATION AND RE-USE OF PAPER SLUDGES IN LANDFILL COVERS: A CASE STUDY

Abstract

This investigation attempted to find a beneficial use for waste water paper mill sludges by using paper mill sludges as the impermeable barrier in landfill covers. This study investigated the geotechnical properties of seven paper mill sludges for use as the impermeable barrier in landfill covers. Paper mill sludges have a high water content and a high degree of compressibility and behave like a highly organic soil. Consolidation tests reveal a large reduction in void ratio and high strain values that result from the high compressibility. Laboratory permeability tests were conducted onin situsamples, and these samples met the regulatory requirement for the permeability of a landfill cover. To determine the effectiveness of paper sludge as an impermeable barrier layer, test pads were constructed to simulate a typical landfill cover with paper sludge and clay as the impermeable barrier and were monitored for infiltration rates for 5 years. Long-term permeability values estimated from the leachate generation rates of the test indicate that paper sludge provides an acceptable hydraulic barrier.