CCWI2017: F11 'Can a Valve Closure Transient Cause Mobilisation of Adhered Particles?'

Dynamic forces induced by hydraulic transients are traditionally associated with structural consequences, however attention should also be given to water quality implications. Conceptually the dynamic forces due to hydraulic transients could mobilise adhered particles and release hazardous material into the bulk water, potentially causing public health and economic problems. This paper presents a set of controlled and systematic experiments that conclusively prove, for the first time, the ability of valve closure transients to mobilise an adhered particle where steady state conditions cannot. This is a significant finding as there is a net decrease in flow, hence pseudo steady state shear stresses, yet the dynamic forces are greater than the initial conditions. Future work will aim to deepen this new understanding of the impact of transients on water quality in Drinking Water Distribution Systems.