Modeling Cometabolism of Cyclic Ethers

Abstract

The biodegradation kinetics of a mixed culture with the ability to cometabolically degrade 1,4-dioxane in the presence of tetrahydrofuran (THF) were studied using a previously published model. Based on a series of batch experiments, the maximum specific utilization rates were determined to be 1.09 mg THF/mg TSS-day and 0.45 mg 1,4-dioxane/mg TSS-day. Half-saturation coefficients of 10.8 mg THF/L and 12.6 mg 1,4-dioxane/L were measured. There was no evidence that 1,4-dioxane biodegradation produced toxic by-products and the presence of 1,4-dioxane did not inhibit THF biodegradation. However, THF may competitively inhibit 1,4-dioxane biodegradation. The model was capable of predicting the biodegradation of 1,4-dioxane and THF at 1,4-dioxane:THF molar ratios of 0.9–3.3.