A Single Tube Contactor for Testing Membrane Ozonation

Abstract

A membrane ozonation contactor was built to investigate ozonation using tubular membranes and to inform computational fluid dynamics (CFD) studies. Non-porous tubular polydimethylsiloxane (PDMS) membranes of 1.0 – 3.2 mm inner diameter were tested at ozone gas concentrations of 110 – 200 g m−3 and liquid side velocities of 0.002 m s−1 – 0.226 m s−1. The dissolved ozone concentration could be adjusted to up to 14 mg O3 L−1 and increased with decreasing membrane diameter and liquid side velocity. Experimental mass transfer coefficients and molar fluxes of ozone were 1.1∙10−5 mol m−2 s−1 and 2.4∙10−6 m s−1, respectively, for the smallest membrane. CFD modelling could predict the final ozone concentrations but slightly overestimated mass transfer coefficients and molar fluxes of ozone. Model contaminant degradation experiments and UV absorption measurements of ozonated water samples in both ozone (O3) and peroxone (H2O2/O3) reaction systems in pure water, river water, wastewater effluent and solutions containing humic acid show that the contactor system can be used to generate information on the reactivity of ozone with different water matrices. Combining simple membrane contactors with CFD allows predicting ozonation performance under a variety of conditions leading to improved bubble-less ozone systems for water treatment.

Passive Ozone Injection through Gas-Permeable Membranes for Advanced In Situ Groundwater Remediation

“…29 In general, the higher the liquid velocity, the higher the expected diffusion rate, 31 up to a maximal diffusion capacity of the membrane. 21,32 Previous studies examined ozone diffusion rates in extremely high liquid velocities (up to three orders of magnitude higher than the velocities applied in the current study), though the obtained ozone diffusion rate values were comparable to those reported here. 21,32 For example, experimental diffusion rate values of 2 to 10 μmol s −1 m −2 were reported by Zoumpouli et al for a PDMS membrane with 0.6 mm wall thickness, 110− 200 g m −3 ozone gas concentration, and up to 0.25 m s −1 liquid velocity.…”

“…21,32 Previous studies examined ozone diffusion rates in extremely high liquid velocities (up to three orders of magnitude higher than the velocities applied in the current study), though the obtained ozone diffusion rate values were comparable to those reported here. 21,32 For example, experimental diffusion rate values of 2 to 10 μmol s −1 m −2 were reported by Zoumpouli et al for a PDMS membrane with 0.6 mm wall thickness, 110− 200 g m −3 ozone gas concentration, and up to 0.25 m s −1 liquid velocity. 32 In another study, where a porous membrane was used as a gas contactor, the obtained ozone diffusion rates were 2−3 μmol s −1 m −2 .…”

“…21,32 For example, experimental diffusion rate values of 2 to 10 μmol s −1 m −2 were reported by Zoumpouli et al for a PDMS membrane with 0.6 mm wall thickness, 110− 200 g m −3 ozone gas concentration, and up to 0.25 m s −1 liquid velocity. 32 In another study, where a porous membrane was used as a gas contactor, the obtained ozone diffusion rates were 2−3 μmol s −1 m −2 . 21 Except for the higher examined liquid velocities, these studies also apply different experimental configurations, which may affect the ozone concentration gradient.…”

Proposal for a tiered approach to evaluate the risk of transformation products formed from pesticides residues during drinking water treatment

“…This continuous operation enables the combination of multiple treatment processes. A lab-scale ozonation combined with a post-treatment biological active sand ltration in a continuous experimental setup has already been established [101]. Due to the modular nature of the experimental setup, it is possible to investigate different water treatment schemes through rearranging the treatment modules.…”