Recent activity in the potable reuse field incorporates reverse osmosis (RO) processes as a requirement to provide pathogen removal and a reduction of other compounds. California has implemented the 12-10-10 log pathogen removal requirement respectively for virus, Giardia, and Cryptosporidium for proposed groundwater recharge projects. Reverse Osmosis (RO) integrity may be determined with measurements from on-line indicators to determine compliance through the use of total organic carbon (TOC) and electrical conductivity (EC). TOC is nominally used for 2-log removal credit while EC is nominally 1.3- to 1.6-log removal credits, which are much lower than RO systems are capable of with regard to pathogenic microorganisms. MS-2 bacteriophage testing of a full-scale Reverse Osmosis system was performed at the Yucaipa Valley Water District (YVWD) during the year 2020. A series of tests were performed to characterize the removal performance over various seasonal and operating conditions, including pre and post Clean In Place (CIP). Testing included the collection of conductivity profiles to further characterize the removal performance difference between individual vessels and stages and identify potential defects. During testing, an intentional compromised vessel was characterized, a suspect element was found, and testing was performed with a substitute nanofiltration membrane element. Results indicate that greater than 5.0 log removal (feed to permeate) was achieved for all tests.
This presentation is available to AMTA Members only.
- James Vickers
- Separation Processes, Inc.
- AMTA/AWWA Membrane Technology Conference, West Palm Beach, FL
- AMTA/AWWA Membrane Technology Conference
- Reverse Osmosis, Total Organic Carbon, Electrical Conductivity