Final Pretreatment Filters for Reverse Osmosis Desalination

摘要

The objective of this research was to demonstrate that filter media containing ultrafine ion exchange resins(UFIER) can reduce the SDI of municipally treated surface water to 3 or less and serve as a final filter to protect RO membranes. The feasibility of using UFIER floc as a 'bound flocculant' was demonstrated on a small commercial precoat filtratopm system. Further testing is recommended on two specific precoat compositions (a low SDI/short run and a moderate SDI/long run) to determine if the results on Philadelphia city water are reproducible using other feeds. A supplier of diatomaceous earth precoat filters for pretreating RO feed would be an appropriate choice for this testing.