Hi all…not too long ago the Flint water crisis drew our attention to the observation that changing the raw water source to a drinking water treatment plant needs to be done with due care and diligence. There are a number of considerations that could and should be taken into account. A 2017 article in the journal Water Research “reviews the contaminants that develop in the water distribution system and their characteristics, as well as the possible transition effects during the switching of treated water quality by destabilization and the release of pipe material and contaminants into the water and the subsequent risks.” Figure 5 provides a framework for potential transition effects evaluation before switching the supply-water quality.
The review is an interesting read and it is an ‘open access’ paper so you should be able to download it. If you are interested in the Flint event itself check out the Flint Water Advisory Task Force final report.
Bill
Potential impacts of changing supply-water quality on drinking water distribution: A review
Gang Liu, Ya Zhang, Willem-Jan Knibbe, Cuijie Feng, Wentso Liu, Gertjan Medema, Walter van der Meer
Water Research Volume 116, 1 June 2017, Pages 135-148
https://www.sciencedirect.com/science/article/pii/S0043135417302099?via%3Dihub
https://ac.els-cdn.com/S0043135417302099/1-s2.0-S0043135417302099-main.pdf?_tid=be15509f-d0d5-4f62-955c-01177bf2d0ed&acdnat=1526067483_9769e8c5a105c02f7aee5becfa703dcb
ABSTRACT
“Driven by the development of water purification technologies and water quality regulations, the use of better source water and/or upgraded water treatment processes to improve drinking water quality have become common practices worldwide. However, even though these elements lead to improved water quality, the water quality may be impacted during its distribution through piped networks due to the processes such as pipe material release, biofilm formation and detachment, accumulation and resuspension of loose deposits. Irregular changes in supply-water quality may cause physiochemical and microbiological de-stabilization of pipe material, biofilms and loose deposits in the distribution system that have been established over decades and may harbor components that cause health or esthetical issues (brown water). Even though it is clearly relevant to customers’ health (e.g., recent Flint water crisis), until now, switching of supply-water quality is done without any systematic evaluation. This article reviews the contaminants that develop in the water distribution system and their characteristics, as well as the possible transition effects during the switching of treated water quality by destabilization and the release of pipe material and contaminants into the water and the subsequent risks. At the end of this article, a framework is proposed for the evaluation of potential transition effects.”
