Destruction of 1,4‐Dioxane and VOCs with UV‐H₂O₂ in a high alkalinity groundwater

Abstract

Bench‐scale testing was conducted to evaluate the application of an Ultraviolet‐hydrogen peroxide (UV‐H2O2) advanced oxidation process (AOP) for the destruction of 1,4‐Dioxane (47 μg/L) and varying concentrations of three volatile organic chemicals (VOCs), including trichloroethylene (TCE), tetrachloroethylene (PCE), and 1,1‐dichloroethylene (1,1‐DCE), from three samples of groundwater containing high alkalinity (281 mg/L as CaCO3). The UV doses applied ranged from zero to 5500 mJ/cm2 while the H2O2 concentrations ranged from 0 to 16 mg/L. The results showed that the bicarbonate and carbonate alkalinity greatly dominated the hydroxyl radical consumption and thus the 1,4‐Dioxane destruction rate. The removal of perchlorate, chlorate, and nitrate prior to UV‐H2O2 treatment had no discernable effect on 1,4‐Dioxane destruction, while the removal of TOC increased the rate of 1,4‐Dioxane destruction by approximately 25%. Depending on the combination of H2O2 concentration and UV dose, 1,4‐Dioxane destruction ranged from negligible to greater than 99%.