Effects of Several Physicochemical Factors on the Biodegradation of 1,4-Dioxane by Microbial Consortium CDIK-3 Enriched from Industrial Wastewater

Abstract

Objective : With the ultimate aim of application for effluent treatment, the relationships between 1,4-dioxane degradation by microbial consortium CDIK-3 and several relevant physicochemical environmental parameters were investigated.Methods : Microbial consortium CDIK-3 enriched from an industrial wastewater sample developed to grow aerobically with 1,4-dioxane as the sole carbon substrate was used to evaluate the degradation of 1,4-dioxane depending on the various environmental parameters and HPLC methodology was used to measure residual 1,4-dioxane in the test consortium.Results and Discussion : The microbial consortium, designated CDIK-3, was originally enriched from industrial wastewater sample. Complete depletion of 1,000 mg/L 1,4-dioxane was achieved in this experiment within 168 h. Effective 1,4-dioxane degradation was observed in slightly alkaline conditions (pH 8) and 30℃. The effect of supplemented carbon and nitrogen (<i>e.g</i>., glucose, yeast extract, ethylene glycol, tetrahydrofuran) on the 1,4-dioxane degradation by the CDIK-3 test culture was evaluated. The results indicated that the addition of glucose, yeast extract, or tetrahydrofuran accelerated bacterial growth compared to growth in the absence of supplemented carbons. In contrast, the addition of low concentrations (≤100 mg/L) of ethylene glycol accelerated 1,4-dioxane degradation, but the degradation of 1,4-dioxane was delayed in the culture to which high concentrations (≥200 mg/L) of ethylene glycol were added.Conclusions : 1,4-Dioxane as a wastewater contaminant can be removed by the microbial consortium CDIK-3 enriched from industrial wastewater. Effective 1,4-dioxane removal was obtained by the control of various physicochemical parameters. These results provide clues for understanding improved 1,4-dioxane degradation by microbial consortium CDIK-3 with relevant environmental parameters and possible applications in the processing of industrial wastewater containing relatively high 1,4-dioxane concentrations.