A preliminary assessment of utilizing fluidized bed ash in landfill liner applications

Abstract

A preliminary study was conducted to assess the possible utilization of fluidized bed ash (FBA) as a liner material. This material was selected based on its unique characteristics. It was anticipated that the pozzolanic properties would produce a hydraulic barrier with a low hydraulic conductivity and toxicity analysis would show no leachable metals. This hypothesis was tested utilizing FBA by itself and in combination with a clayey soil. Cursory physical and engineering tests were performed on the FBA and FBA/soil mixtures with regard to factors relevant for liner applications. Both the 100% FBA and the FBA/soil mixtures (15% and 40%) were found to have a hydraulic conductivity that was lower than federal requirements (1 × 10 -7 cm/sec). Also, the Toxicity Characteristics Leaching Procedure (TCLP) test results indicated that FBA was nonhazardous; therefore, it may not be a threat to groundwater. However, liner integrity may be in jeopardy due to the brittle nature of the FBA and FBA/soil mixtures, and also from the formation of ettringite.

Challenges in Recovery of Valuable and Hazardous Elements from Bulk Fly Ash and Options for Increasing Fly Ash Utilization

“…Fly ash collected from the air-controlled equipment and dumped with bottom ash. This blend of this mixture is called FBA [15]. The calcium percentage in FBA is more than in fly ash.…”