The utilization efficiency of hydrogen peroxide on the removal of volatile organic acids in sand columns

Effects of hydrogen peroxide (H₂O₂) on the removal of volatile organic acids were studied with a series of sand columns. Hydrogen peroxide was used as an alternative oxygen source to enhance the removal of volatile organic acids. In the presence of microorganisms, H₂O₂ was readily decomposed to increase the dissolved oxygen concentrations (DO) in waters. The microorganisms used in this study could tolerate the toxicity of H₂O₂, even if its concentration reached 450 mg/L. The volatile organic acids used in this study were not chemically oxidized by H₂O₂. The results indicated that the concentrations of H₂O₂ required to remove volatile organic acids were higher than those calculated from the theoretical stoichiometry equation. Hydrogen peroxide was not effectively utilized, especially when the concentrations of H₂O₂ were relatively high. When the concentration of H₂O₂ was high, oxygen produced from the decomposition of H₂O₂ might not be effectively utilized by microorganisms and might escape from waters in gaseous form. The ratio of the amount of the volatile organic acid removed to the amount of H₂O₂ added decreased with an increase in the concentrations of H₂O₂. Multi-point injection of H₂O₂ can be used to improve its utilization efficiency, if a higher concentration of H₂O₂ was required.