Indirect potable reuse (IPR) projects via groundwater injections in California utilizing full advanced treatment require MF/UF, RO and UV advanced oxidation to meet pathogen, TOC, trace organic and other requirements specified in the most recent groundwater recharge regulations (California Department of Public Health, 2014). The main functions of MF/UF in IPR train are to greatly reduce solids and pathogen and provide adequate pretreatment for downstream RO process. In drinking water and potable reuse applications, the State Water Resources Control Board Division of Drinking Water awards up to 4 log credit for Crypto and Giardia for MF/UF systems by passing a daily direct integrity test. For IPR via groundwater recharge, a total of 12, 10 and 10 log removal is needed for viruses, Crypto and Giardia that includes credits gained thru retention of water in ground. MBR also utilizes a low pressure membrane technology for solids/liquid separation. The major concern with MBR systems is the lack of direct integrity testing capability for many MBR products currently in the market. Without direct integrity testing or developing a proven and approved method, 4-log Crypto and Giardia credits may not be awarded for MBR systems in CA which require incorporation of additional disinfection barrier(s) to meet the current pathogen removal requirements in groundwater recharge projects and future potable reuse projects (i.e. IPR via surface water augmentation, direct potable reuse). This paper provides an insight on current status of direct integrity testing in MBR systems what alternative testing/monitoring methods or modifications in existing MBR systems are needed to warrant 4-log Crypto and Giardia credits for MBR systems. The findings of this paper are very valuable for agencies, regulatory agencies, consultants and individuals who are involving in potable reuse projects and or helping developing a frame work for forthcoming potable reuse regulations.
This presentation is available to AMTA Members only.
- Ufuk Erdal, PhD, PE
- AECOM Water
- AMTA/AWWA Membrane Technology Conference, Long Beach, CA
- AMTA/AWWA Membrane Technology Conference
- Direct integrity testing, MBR, MF/UF, pathogen credit, Crypto, virus, potable reuse, LRV