Membrane fouling is ubiquitous and has a significant impact on the operation of membrane plants. Although the impact of fouling may be mitigated via the modification of pretreatment processes, inefficient cleaning can affect the extent of irreversible permeability loss, leading to the premature replacement of membranes. The challenges of having efficient membrane cleaning rise from the complicated and dynamic nature of membrane fouling. In addition, the proper tools to qualify and quantify membrane fouling are in great need of developing. Although fouling materials are usually classified into different types, such as inorganic, organic, biological etc., it is the interactions between different fouling materials and resulting structure of fouling layers that may require cleaning using different and multiple cleaning reagents in certain cleaning sequences. Based on the analyses of membrane cleaning results from 33 membrane plants, in the majority of cases (88%) the causes of membrane fouling are attributed to natural organic matter (NOM) or the combination of NOM and iron. In some cases, the sequence of cleaning steps also has a significant contribution to cleaning efficacy. This may be related to the structure of fouling layers. Concentration, pH, temperature, and cleaning duration were identified as major variables affecting cleaning efficacy. The impacts of those variables on membrane cleaning showed a complex interdependence of different variables and could be case-specific.
This presentation is available to AMTA Members only.
- Charles Liu, PhD, PE, BCEE
- Pall Corporation
- AMTA/AWWA Membrane Technology Conference, Long Beach, CA
- AMTA/AWWA Membrane Technology Conference
- Membrane, Ultrafiltration, Microfiltration, Cleaning, Fouling