Dynamics of material detachment from drinking water pipes under flushing conditions in a full-scale drinking water laboratory system

ABSTRACT

Discoloration is currently the major cause of consumer complaints worldwide, being mainly caused by the accumulation and mobilization of materials in the inner pipe walls of drinking water distribution systems. The understanding about material detachment from pipe walls is limited due to its complexity and lack of data. The purpose of this study was to examine the initial stages of material detachment from PVC pipe walls during flushing operations using a full-scale laboratory system. Experiments consisted of a material accumulation phase with periods from 40 to 120 days, followed by a material mobilization phase with wall shear stresses above 5 Pa. Results indicated that material detachment mainly occurs during the periods of velocity increase, at rates ranging from 0.5 to 14 mNTU/s. In addition, a second stage of material detachment was observed during steady flow conditions, and a fast detachment event highlighted impacts of curved sections on the mobilization phenomena.

KEYWORDS:

• Discoloration
• cohesive layer strength
• flushing
• drinking water quality

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1. PODDS = Prediction Of Discoloration in Distribution Systems

Additional information

Funding

This work was financed by CAPES – Brazilian Federal Agency for Support and Evaluation of Graduate Education within the Ministry of Education of Brazil. Process nº [88881.128526/2016-01].