Pilot Testing for Validation of Log Removal Credit for Reverse Osmosis and Nanofiltration Membranes

Application of potable water reuse in the U.S. has become more widespread to meet the water demand in areas with increasing population and dwindling water sources. Different treatment trains have been applied to ensure the proper log removals of pathogens and protozoa are met and the water is safe for consumption. Reverse osmosis (RO) and nanofiltration (NF) are trusted and prolific membrane treatment technologies used in water and wastewater treatment that have effective removal of bacteria, dissolved ions, and viruses. Research has demonstrated up to 4-log removal of viruses by RO. However, when applied in potable water reuse applications, it only receives a log removal value (LRV) credit of 0.5ñ2 if any at all. Direct integrity testing (DIT) through the molecular marker approach can be used for LRV validation where either native or added markers are used to demonstrate the LRVs by RO and NF. Testing different markers and assessing RO and NFís capability for removal is therefore needed and will help provide valuable knowledge that regulators and treatment plants can use to assign the appropriate and proven LRVs for RO and NF.