Removal of the Neutral Dissolved Organic Matter (NDOM) from Surface Water by Coagulation/Flocculation and Nanofiltration

Abstract

The objective of this study was to examine the specific fraction of the dissolved organic matter present in surface water, namely the neutral dissolved organic matter, which has been isolated, but has not been previously studied. Ultimately, we aim to characterize its properties using conventional and membrane treatments. This fraction was isolated and concentrated from an Algerian dam (Timgad dam-Batna) using ion exchange resins in a mixed bed form combined with a reverse osmosis membrane. This fraction was eliminated using conventional coagulation/flocculation and a nanofiltration membrane for comparison. The results show considerable efficacies for the treatments, with removal yields of 63% as the chemical oxygen demand (COD) and 69% as the ultraviolet absorbance at 254 nm (UV₂₅₄) by coagulation/flocculation. A removal yield of 79% in terms of the COD and 86% in terms of UV₂₅₄ were obtained following nanofiltration. However, total removal of this fraction is not possible using either technique, which may be problematic during water treatment.

Keywords:

• Coagulation/flocculation
• dam
• nanofiltration membrane
• neutral dissolved organic matter
• surface water

Acknowledgements

The authors would like to thank the National Agency for Dams and Transfers (ANBT) for facilitating access to the sampling sites. We would also like to thank Mr. Nacer Korra, Laboratory Engineer, at the University of Batna 1, for his support. We would like to thank the reviewers and the editor-in-chief for their efforts towards improving our manuscript, and we sincerely appreciate all valuable comments and suggestions, which helped us to improve the quality of this paper.