Desalination without chemicals: Bonaire’s modular plant and the application of direct osmosis cleaning (DOC)
Iris Sutzkover-Gutman*, Irina Zaslavschi
IDE Technologies, 2 Hamatechet St. Kadima, Israel
*Corresponding author
https://doi.org/10.5004/po2024126
ABSTRACT
This paper reviews the performance and operational aspects of the WEB Bonaire HATO desalination plant (5,600 m3/d), operating as a chemical free plant, to minimize any environmental impact on the Caribbean Island environment. The seawater is of standard salinity at ~3.6% and hence, the SWRO system is designed to operate at a relatively low water recovery level of ~40% and the use of antiscalant is thus not required. However, although the seawater is characterized by a low load of particulate matter, it also contains a high load of dissolved organic matter, with a tendency to heavily foul up RO membranes. To mitigate the fouling, IDE’s Direct Osmosis Cleaning (DOC) system has been introduced as a central and unique feature in the SWRO system design. The DOC system utilizes Net Driving Pressure (NDP) reversal and direct osmosis, similar to the typical suck back phenomenon that occurs in any RO system when it shuts down. However, with the DOC mechanism, direct osmosis is used for cleaning without shutting down the system. This paper presents two independent observations aimed at evaluating the effectiveness of the DOC procedure at the HATO desalination plant: (1) a presentation of evidence for local organic matter removal and (2) its effect on the SWRO system long-term differential pressure pattern. Of particular note, is the successful implementation of the DOC technology that provides a sustainable and environmentally friendly solution for water production on the island, while maintaining high availability and operational efficiency.
Keywords: SWRO; DOC; Fouling; Cleaning; Direct osmosis
