Author: Fahimeh Bimakr

Publisher:

Published: 2015

Total Pages:

ISBN-13:

[Truncated] Biofilm formation in drinking water distribution systems (DWDSs) causes detrimental impacts on water quality and infrastructure. Biofilms can also act as a reservoir for pathogens, and are thus of public health concern. To discourage biofilm growth in DWDSs, antimicrobial agents (disinfectants) including chlorine, chloramines and ozone are used. However, these chemicals produce harmful disinfection by-products, many of which are toxic and carcinogenic, and hence their formation should be minimised. The challenge to maintain appropriate disinfection and to avoid unwanted effects of biofilm formation in DWDSs requires the development of new technologies for efficient disinfection and microbial control. Biofilm formation is affected by the type of pipe wall material, especially its surface characteristics, including roughness, surface energy and biological affinity. Pipe materials may also release substances that enhance or inhibit biofilm formation, and so influence the presence and persistence of microbial pathogens. A number of nanomaterials having antimicrobial properties have been proposed for use in water treatment. Moreover, microstructured surfaces and other surface coatings have also been reported to inhibit biofilm formation. In this study a number of polymers of different hydrophobicity including high density polyethylene (HDPE), polytetrafluoroethylene (PTFE) and nylon, with and without embedded copper, as well as a nanomaterial (carbon nanotubes) and marine paint (Hempel X3) were tested for their effects on biofilm formation in a laboratory scale pipe rig containing water from a water supply reservoir (Mundaring Weir, Perth, Western Australia), and compared with the traditional pipe materials stainless steel and concrete. Microbial growth on the tested materials was measured by counting DAPI-stained cells using epifluorscence microscopy, flow cytometry, heterotrophic plate agar, and an ATP assay for measuring cellular activity. Biofouling on all tested materials was detected using all four methods (ATP assay, epifluorescence microscopy, flow cytometry and colony counting) as rapidly as 1 h following installation of the material into the laboratory pipe rig. The results showed that none of the tested materials or coatings showed superior performance in preventing biofilm formation relative to stainless steel or concrete.