High silica concentration in RO concentrate

Haidari, A.H.; Witkamp, G. J.; Heijman, Sebastiaan

doi:10.1016/j.wri.2022.100171

High silica concentration in RO concentrate

Title

High silica concentration in RO concentrate

Author

Haidari, A.H. (Hatenboer-Water)
Witkamp, G. J. (King Abdullah University of Science and Technology)
Heijman, Sebastiaan (TU Delft Sanitary Engineering)

Date

2022

Abstract

Silica scaling is one of the major scaling challenges in Reverse Osmosis (RO). The safe operation practice is to keep the silica concentration below 150 mg/L in RO concentrate. This study addresses the effects of divalent cations such as calcium and magnesium on silica scaling in a seawater RO installation used as a pretreatment to Eutectic Freeze Crystallisation (EFC). Results showed that in the absence of antiscalant and divalent cations a sustained silica concentration of approximately 280 mg/L in concentrate is possible without declining membrane permeability. At a higher concentration of divalent cations, the membrane permeability decreased. Membrane autopsy and analysing destructed membrane showed a relatively low magnesium and a high calcium concentration on the membrane after adding divalent ions into the solutions. It is concluded that in absence of divalent cations and without antiscalant the limits of 150 mg/L silica can be extended to 280 mg/L for 6–8 h.

Subject

Membrane fouling
PHREEQC
Reverse osmosis
Silica scaling

To reference this document use:

http://resolver.tudelft.nl/uuid:d5e45404-552c-4ca3-86dc-9085e28b6c0f

DOI

https://doi.org/10.1016/j.wri.2022.100171

ISSN

2212-3717

Source

Water Resources and Industry, 27

Part of collection

Institutional Repository