Efficacy of Continuous Flow Reactors for Biological Treatment of 1,4-Dioxane Contaminated Textile Wastewater Using a Mixed Culture

Abstract

The goal of this study was to evaluate the biodegradation of 1,4–dioxane using a mixed biological culture grown in textile wastewater sludge with 1,4–dioxane as the sole carbon source. The conditions for the long-term evaluation of 1,4–dioxane degradation were determined and optimized by batch scale analysis. Moreover, Monod’s model was used to determine the biomass decay rate and unknown parameters. The soluble chemical oxygen demand (sCOD) was used to determine the concentration of 1,4–dioxane in the batch test, and gas chromatography/mass spectrometry (GC/MS) was used to measure the concentrations via long-term wastewater analysis. Two types of reactors (continuous stirred reactor (CSTR) and plug flow reactor (PFR)) for the treatment of 1,4–dioxane from textile wastewater were operated for more than 120 days under optimized conditions. These used the mixed microbial culture grown in textile wastewater sludge and 1,4–dioxane as the sole carbon source. The results indicated efficient degradation of 1,4–dioxane by the mixed culture in the presence of a competitive inhibitor, with an increase in degradation time from 13.37 h to 55 h. A specific substrate utilization rate of 0.0096 mg 1,4–dioxane/mg MLVSS/h was observed at a hydraulic retention time of 20 h for 20 days of operation in a biomass concentration of 3000 mg/L produced by the mixed microbial culturing process. In the long-term analysis, effluent concentrations of 3 mg/L and <1 mg/L of 1,4–dioxane were observed for CSTR and PFR, respectively. The higher removal efficacy of PFR was due to the production of more MLVSS at 4000 mg/L compared to the outcome of 3000 mg/L in CSTR in a competitive environment.

Impact of Acetate in Reduction of Perchlorate by Mixed Microbial Culture under the Influence of Nitrate and Sulfate

“…Thus, the presence of nitrate hindered the mixed microbial culture from degrading the perchlorate due to the higher reduction affinity of nitrate. Moreover, nitrate is a faster degradation compound compared to perchlorate, and for efficient perchlorate reduction by the mixed microbial culture, nitrate concentration would be minimized [6,10,48,49].…”

“…Thus, the presence of nitrate hindered the mixed microbial culture from degrading the perchlorate due to the higher reduction affinity of nitrate. Moreover, nitrate is a faster degradation compound compared to perchlorate, and for efficient perchlorate reduction by the mixed microbial culture, nitrate concentration would be minimized [6,10,48,49]. and sulfate in exposure to mixed microbial culture A (error bar represents the SD of 3 readings with the maximum SD: 8.6%) (concentration of 400 mg/L, 500 mg/L and 500 mg/L of perchlorate, nitrate and sulfate was used in feed solution as electron acceptor).…”

Anaerobic digestion for treatment of polyester wastewater with different organic loading rates (OLRs)

“…According to recent research, 1,4-dioxane can be biodegraded using both pure and mixed cultures. Lee et al, (2022) found that 1,4-dioxane could be broken down in a mixed biological culture cultivated on textile wastewater sludge using CSTR and PFR reactors. Moreover, biodegradation of 1,4-dioxane in bioreactors, biofiltration systems, and biosparging systems has shown that 1,4-dioxane bioremediation is feasible (Tag and Mao., 2023).…”