Analysis turnaround times are at least 24 hours for indicator microorganisms and may be weeks or months for pathogenic protozoa and viruses. These turnaround times are not sufficient to verify water quality, with respect to distribution times of water in water reuse schemes. Hazard and critical control point (CCP) frameworks are incorporated to ensure that appropriate water quality is verified in real time. Successful application of CCPs requires a clear demonstration of how online monitored parameters indicate the treatment effectiveness of pathogen removal barriers. MBRs remove pathogens via a number of mechanisms including, size exclusion by the membrane, enhanced size exclusion by a dynamic fouling layer on the membrane surface, biological degradation within the activated sludge and adsorption to sludge flocs and subsequent wasting. The complexity of pathogen removal mechanisms in MBR has so far prevented development of a rigorous CCP based method to validate treatment performance. In previous validation research, WaterVal, bench scale studies were used to demonstrate a logarithmic relationship between filtrate turbidity and LRV. In this work, the same logarithmic relationship proposed in WaterVal was demonstrated at a full scale MBR facility for the firs t time. The aim of this paper is to compare and contrast prior bench and current full scale results in-order to better define the acceptable critical limits for turbidity and corresponding LRV achieved by MBRs. This study is the first to confirm the proposed logarithmic relationship between filtrate turbidity and LRV in MBR at a full-scale facility. According to both the model and full-scale data, relatively high turbidities (>>0.5 NTU) are needed in order to observe low LRVs (< 2). This data is significant, as it is the one of the first demonstrations of how a site-specific correlation of turbidity and LRV could be achieved at full scale in order to set meaningful critical limits. Applying appropriate critical limits will provide all stakeholders with confidence in recycled water quality whilst reducing whole of life costs for MBR owners. The presentation will describe the approach that can be followed to calibrate turbidity and LRV on other full scale MBRs in an effort to better understand recycled water quality in real time.
This presentation is available to AMTA Members only.
Speaker
- Kurt Dahl
Company
- Permeat Partners
Event
- AMTA/AWWA Membrane Technology Conference, Las Vegas
Session
- AMTA/AWWA Membrane Technology Conference
Date
- 02/22/22
Media
Keywords
- Pathogen Log Reduction, CCP, MBR
Reference
- 9715-DP2872