A Study of the Impacts of Periodic Ozone Residuals on Biologically Active Filters

Abstract

The research presented in this article investigated the effects of ozone residuals on the biological performance of a biologically active anthracite/sand filter. In addition, the impact of residuals of hydrogen peroxide (H₂O₂), added as an accelerator of natural ozone decay, was investigated. Experiments were performed at laboratory scale using four parallel filter columns. The periodic presence of O₃ (1-2 hours per week) at concentrations of 0.1-0.2 mg/L in the influent of an anthracite/sand filter had a negligible effect on the biological removals of acetate and formate. This was likely the result of the observed rapid decrease of the O₃ concentration in the top part of the filter. The periodic presence (1-2 hours per week) of H₂O₂ (∼0.5 mg/L) in the influent of an anthracite/sand filter had no measurable effect on biological acetate and formate removals.

Key Words:

• Ozone
• Biofiltration
• Biological filtration
• Hydrogen peroxide
• Acetate
• Formate
• BOM removal inhibition
• Biomass
• Anthracite/sand