Attend the Avista Technologies Technical talk at IDA World Congress 2019
A NEW FAST ACTING LOW PH CLEANER PAVES THE WAY FOR A NEW CLEANING PHILOSOPHY FOR INTEGRATED MEMBRANE SYSTEMS
October 23, Room B 14:00 – 17:00 Session 2.3
Presenter: Fiona C Finlayson, Technical Sales Manager – Avista Technologies – Scotland
For many years ultrafiltration/microfiltration (UF/MF) has been replacing multi-media filtration as a seawater reverse osmosis (RO) or nanofiltration (NF) pre-treatment system. Initially the systems were treated as individual unit operations and optimized as such. However, the similarity in the flux maintenance requirements of the particle removal membranes and the desalination membranes led system designers and the authors to consider a more integrated operating philosophy with the aim of cutting capital and operating costs.
Noting that both RO/NF membranes and UF/MF membranes are cleaned using low and high pH cleaners to remove the mix of organic and inorganic materials originating from seawater the possibility of developing multifunctional formulated cleaners that were effective on both membrane types was investigated. Use of such cleaners would provide reduced stock holding, improved handling safety (over generic products) and reduced risk of misapplication of UF cleaners on RO membranes.
Making RO formulations useful on UF membranes products to be extremely fast acting, liquid for ease of handling and compatible with additional membrane materials. A high pH cleaner was already available on the market that met this specification, so this paper focuses on developing a new low pH product.
This paper details the foulant comparison, the laboratory testing of the low pH product and site application to demonstrate the effectiveness both alone and in partnership with the existing high pH formulation. The resultant low pH cleaner is shown to be fast acting, compatible with seawater and provides successful maintenance of the flux of both UF/MF and RO/NF membranes.
For UF/MF systems the new low pH cleaner provided more than twice the flux improvement of generic alternatives and has resulted in a lower overall cost from a reduction in cleaning frequency. It has proven sufficiently effective to allow it to be applied without a secondary high pH cleaning step, although additional benefits have been achieved by including this periodically.
For NF/RO the low pH cleaner has shown equal or slightly better performance than the previously available products when used in combination with a high pH cleaner. Application of the integrated membrane cleaning products have resulted in lower downtime, less frequent cleaning and hence smoother system operation.
Come join us to hear the full talk!