A laboratory characterization of pulp and paper mill solid wastes for potential use as hydraulic barrier material in landfill covers

Fifteen sludges from wastewater treatment systems of pulp and paper mills that encompass major production categories, and eight fly ashes from mill boilers incinerating wood waste, coal, or their combination were characterized for their potential suitability as hydraulic barrier material. Hydraulic conductivity was observed to range over four orders of magnitude for the materials tested. Sludges exhibited hydraulic conductivities between 10{dollar}sp{lcub}-4{rcub}{dollar} and 10{dollar}sp{lcub}-8{rcub}{dollar} cm/sec. The hydraulic conductivity for fly ash ranged between 10{dollar}sp{lcub}-5{rcub}{dollar} and 10{dollar}sp{lcub}-7{rcub}{dollar} cm/sec.; Based on the results of physical and chemical characterization, it was concluded that several of the sludges and one fly ash represent potential alternatives to clay for use as hydraulic barrier materials in landfill covers.