Studies with spiral wound Donnan dialysis contactor for nitrate removal from contaminated water

• Published in: Journal of water process engineering 2023-08, Vol.54, p.103878, Article 103878
• Main Authors: Verma, Akshaya Kumar, Akodwaa-Boadi, Kofi, Ronen, Zeev, Oren, Yoram, Gilron, Jack
• Format: Article
• Language: English
• Subjects: Donnan dialysis; IEMB; Kinetic modeling; MATLAB; Nitrate removal
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2023.103878

In the present study, we investigated nitrate removal using Donnan dialysis aiming to scale up a process capable of treating 1 m3/day or more. Four different anionic membranes, FAD, FAS, and FAB by Fumatech GmbH and PCA 100 from PC-Cell, were screened in batch Donnan dialysis experiments with nitrate and/or sulfate using chloride as the driving ion. FAD, FAS and FAB showed similar nitrate flux while PCA 100 produced significantly lesser nitrate flux under experimental conditions. Based on the higher selectivity for nitrate over sulfate, FAS was preferred over FAD membrane. A spiral wound module contactor was fabricated each with the FAS and FAD membranes. The steady-state performance of the system revealed excellent nitrate removal at the selected operating conditions, successfully eliminating an average nitrate loading rate of 5.0 kg NO3−/m3/d and producing 30 ± 5 mg/L nitrate. Nitrate transport modeling using MATLAB was performed to predict exit nitrate concentration at any point along the path length of membrane at the given set of conditions. The output of the simulated model came out to be in reasonable agreement with the exit nitrate concentration measured experimentally, reflecting its robustness.