Case Study and Retrospective: Aerobic Fixed Film Biological Treatment Process for 1,4‐Dioxane at the Lowry Landfill Superfund Site

Abstract

An aerobic fixed film biological treatment system has been successfully treating recovered groundwater/landfill leachate containing 1,4‐dioxane, tetrahydrofuran (THF), and other constituents since 2003. The most likely mode of 1,4‐dioxane biotransformation is via a cometabolic pathway in the presence of THF. Pilot studies conducted during the process development phase established a design basis process loading factor of 0.6 g 1,4‐dioxane and THF (as chemical oxygen demand [COD])/g total solids per day and proved the efficacy of the process. Full‐scale design includes the use of three parallel moving bed bioreactors with effluent recycle capability. Removal efficiencies in excess of 98 percent have been documented for 1,4‐dioxane. Evolving operational challenges are associated with recent trends in 1,4‐dioxane pretreatment discharge limitations in combination with ongoing process optimization and increased influent flow rate conditions associated with seasonal precipitation patterns. ©2016 Wiley Periodicals, Inc.

Cometabolic Treatment of 1,4-Dioxane in Biologically Active Carbon Filtration with Tetrahydrofuran and Propane at Relevant Concentrations for Potable Reuse

“…THF performed well as a cometabolite for 1,4-dioxane removal in an attached film biological system, and this finding is consistent with many previous studies. ,, However, it is important to note that THF is not a recommended cometabolite for drinking water or water reuse scenarios because of its carcinogenicity. Still, THF can be suitable for industrial pretreatment purposes.…”

“…9 However, most cometabolic applications are currently limited to groundwater and landfill leachate and have not been tested on reuse water. 20,21 Tetrahydrofuran (THF) has been shown to effectively support cometabolic degradation of high concentrations of 1,4dioxane in landfill leachate, where the two compounds commonly occur together. 21 It is thought that structural similarities between THF and 1,4-dioxane contribute to the efficacy of THF as a cometabolite.…”

“…Theoretically, cometabolism is promising for addressing low concentrations of 1,4-dioxane because the cometabolite acts to sustain the cellular growth and enzyme production needed to drive degradation of 1,4-dioxane to low levels . However, most cometabolic applications are currently limited to groundwater and landfill leachate and have not been tested on reuse water. , …”

“…A drawback to augmenting with THF, however, is that the compound is potentially carcinogenic . Despite its toxic status, THF was the first cometabolite discovered to stimulate 1,4-dioxane degradation and has notable use as a cometabolite in literature. ,, While the health effects of THF deter its applicability in water reuse or drinking water settings, it provides a useful point of comparison for potential alternative cometabolites for cometabolic 1,4-dioxane removal.…”

“…20,21 Tetrahydrofuran (THF) has been shown to effectively support cometabolic degradation of high concentrations of 1,4dioxane in landfill leachate, where the two compounds commonly occur together. 21 It is thought that structural similarities between THF and 1,4-dioxane contribute to the efficacy of THF as a cometabolite. A drawback to augmenting with THF, however, is that the compound is potentially carcinogenic.…”