Fouling control of low pressure membrane systems for drinking water applications

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Membranes are a growing popular choice for water treatment due to their ability to consistently produce high quality water regardless of the incoming untreated water quality. However, for membranes to operate effectively over a long period of time they must be optimized for fouling control. Membranes provide a physical barrier to the transport of contaminants to the treated water side, these contaminants foul the membrane which results in decreased water productivity and increased operating costs. The way and extent in which contaminants foul the membrane surface can be reduced by pretreatment options, optimization of physical operational parameters and chemical cleaning. Thus fouling control and prevention is a necessary primary mode of research for membrane technology. To-date polymeric membranes have enjoyed greater success than ceramic membranes in the water treatment field because of their relatively lower costs. Recent innovations, resulting in lower capital costs, in ceramic membrane technology have introduced ceramic membranes as a game player into the water treatment industry as well. Ceramic membranes provide an attractive alternative to polymeric membranes because of their longer operating life, higher chemical resistance, and larger pH tolerances. However, research needs for both ceramic and polymeric membranes still exist, including pretreatment options, physical operating parameters and cleaning methodologies, in particular there is a lack of research in this area at cold temperatures. The objectives of this research are to (1) examine biological pretreatment options for membrane fouling control and (2) further research physical and chemical cleaning methodologies to control fouling in membrane systems to systematically research differences between polymeric and ceramic membrane systems for applications in water treatment with a focus on Canadian climatic needs, particularly the inclusion of cold water analysis. In Canada, at any given time there are approximately 1000 Boil Water Advisories (water.ca), most often tied to small community systems. This research into membrane treatment with cold water conditions is of particular relevance to Canada and may provide an excellent solution to drinking water issues in small and remote communities in Canada, which are often located in Northern regions. While membranes have the potential as a preferred treatment option for small communities because of their ability to produce consistent high quality water under varying raw water conditions, they have received limited application due to membrane fouling and the associated high costs of dealing with a permanently fouled membrane. This research will examines appropriate fouling control methods, with a focus on cold water analysis, for both polymeric and ceramic membranes and is expected to provide practical solutions to drinking water quality issues in small and remote communities in Canada to provide a long term improvement in safe drinking water access and water quality for all Canadians.