A novel demonstration of adhered material mobilisation by hydraulic transients

Abstract

Laboratory experiments have shown that pipe-wall adhered material can be mobilised by transients, where steady-state hydraulic conditions cannot. This process is critical to managing water quality risks in drinking water distribution systems.

Initial stages of particulate iron oxide attachment on drinking water PVC pipes characterized by turbidity data and brightfield microscopy from a full-scale laboratory

“…Further experiments are needed to better understand the role of daily flow variation and unsteady WSS on particle mobilization. 38…”

“…Flow acceleration has been shown to have an impact on the transport dynamics of material deposits in pipes. 38 Between flushing steps, obvert and invert pipe wall coupon samples were acquired to assess the pipe wall conditions. Bulk water samples were acquired to determine SSC during flushing.…”

Simulating long term discolouration behaviour in large diameter trunk mains

“…20,21 No correlation has been found between pressure and discolouration risk, 22 although hydraulic transients may contribute to material mobilisation. [23][24][25] Material accumulation, and hence discolouration risk, have been reported to be influenced by daily hydraulic conditions, 2,11,26 pipe material 15 and water temperature. 16,27 While some studies have showed temperature and microbial influence on discolouration risk, 16,[27][28][29] the variation of accumulation processes and rates seasonally has not yet been rigorously demonstrated.…”

Physical and water quality indicators assessment in main pipelines: The impact of hydraulic transient events

“…If transient relationships sat above the steady state relationship an area would exist where the transients can cause mobilization, but steady state cannot (green highlight). A direct implication of this research is that by reducing transient events a water utility provider could reduce the risk of discoloration contacts, the major cause of water quality related customer dissatisfaction [22]. As highlighted by Speight "Understanding the processes and interactions occurring within complex, ageing drinking water distribution systems is vital to ensuring the supply of safe drinking water.…”