Sorption and diffusion of volatile organic compounds through two thermally treated drill mud wastes

Abstract

Onshore thermal treatment of offshore drilling mud waste generates a mineral by-product, referred to in this paper as thermally treated drill mud waste (TTDMW). Environmental regulations can result in the generation of significant quantities of this material, and hence it would be beneficial from a sustainability perspective to identify a value-added recycling use for this material. Recycling TTDMW into a primary compacted soil barrier system for municipal solid waste landfills represents one such possible reuse. It is hypothesized that residual amounts of organoclays and organic carbon in the TTDMWs will act as a beneficial sorbent to low levels of volatile organic compounds (VOCs) often found in municipal solid waste leachate. To assess this hypothesis, two different TTDMW materials (from Nova Scotia and the United Kingdom) were subjected to batch and diffusion testing to assess VOC sorption. It is shown that partitioning coefficient (Kd) values obtained from diffusion testing were generally lower than those obtained from batch testing. Contaminant migration modelling of a hypothetical TTDMW barrier system using measured VOC sorption levels is presented in the paper to provide some relevance to the results obtained.Key words: drill mud waste, sorption, VOC, diffusion, landfill liner.