Published for the Society of Chemical Industry by Blackwell Scientific Publications
Journal of Chemical Technology and Biotechnology vol:85 issue:11 pages:1480-1488
Membrane fouling by humic acids limits the water recovery of nanofiltration in drinking water production. This article investigates if membrane fouling can be reduced by decomposition of humic acids in the concentrate stream by O3 oxidation.
At a specific O3 dose of 2.11 g O3 per g COD (17.0 g m-3 O3 (g) for 20 minutes), a COD reduction of 38% and a hydrophobic COD reduction of 69% is achieved. The membrane permeability of the ozonated solution by NF 270 membranes is higher (20.6 . 10-9 L s-1 m-2 Pa-1) than the permeability if the untreated solution is filtered (2.4 . 10-9 L s-1 m-2 Pa-1). The COD retention of the ozonated solution was similar to the retention of the untreated samples. The addition of H2O2 allows to obtain a better mineralization degree, i.e., UVA removal increased from 53% to 66% if H2O2 was added as from 10 minutes oxidation at the same molar flow rate as O3.
O3 oxidation can substantially alleviate membrane fouling by humic acids in nanofiltration systems and the addition of H2O2 can slightly improve its decomposition.