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 demonstration 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. In the past, conductivity profiling has generally been used as a process tool for leak detection within an RO system. However, using similar equipment, it may provide a similar function as EC monitoring currently used for regulatory compliance. Work described in this paper has automated the process of conductivity profiling such that operators no longer need to collect the data by hand. Equipment was installed for operators to have access to conductivity-profile reports on SCADA, which enables them to observe issues in a timely manner utilizing built-in alarms and warning protocols. The apparatus consists of a single conductivity probe as to minimize the capital costs and variations between probes. SPI developed a statistical-analysis framework based on the USEPA’s Membrane Filtration Guidance Manual. The developed model differentiates between the diffusive properties of RO membranes with flow associated from integrity breaches, resulting in higher removal credits. Benefits of automated profiling include increased frequency of data collection, more consistent data, faster (automated) analysis, enhanced monitoring and response times, and cost savings. This work demonstrates automating conductivity profiling of RO systems can potentially be used as a monitoring strategy to verify system integrity, and ultimately, serve as a potential tool for RO systems to receive a higher LRV.
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