Dead Spot Sampling™ meets Flow Cytometry

Dead Spot Sampling™ Graph

After working in partnership with Northumbrian Water, we are optimistic that a new service will offer the industry insight into how water behaves as it moves through their service reservoirs. By comparing the chlorine residual with microbiological data collected at various sample points throughout the internal area of a live system, real feedback on chemical and bacteriological activity can be analysed.

Paul Henderson, the firm’s Business Development Director, hopes this technique may become as standard as taking bacteriological samples (from fixed sample outlets) when investigating problematic assets.

Paul said, “We have always worked closely with our clients, and attend a number of innovation events to get a feel for the current challenges facing the industry. We met Eddie Wrigley, NWG’s Innovation facilitator, at an Institute of Water innovation event and he became interested in our ideas for taking a range of samples across a reservoirs layout using our Dead Spot Sampling™.“

“We aim to see if the design or low turnover could be producing areas of ageing water that could pose a risk to the quality of the water going out into supply, particularly if flows were to suddenly increase. We expected that the standard measurement of free chlorine paired with bacteriological samples would give an indication of performance. In the back of our mind, we always
thought our clients may see further potential, and that is what has happened.”

Iain Weir, Panton McLeod’s Chief Technical Officer is enthusiastic about additional developments which have now allowed cell analysis using Flow Cytometry.

Iain said, “David Harker, NWG Water Quality Scientist, suggested the possibility of using Flow Cytometry to count the abundance and character of cells within the water. I was aware of the technology being used in medical applications and more recently for Legionella testing. The technique utilises fluorescent dyes and lasers to help establish the origin and viability of microbial cells. It was very exciting to see it being applied in conjunction with our existing Dead Spot Sampling™ technology.”

“David, Eddie and the supporting team at NWG have been fantastic to work with, and we plan on honing the practice further on additional sites.“

Dead Spot Sampling™ allows Water Companies to take previously inaccessible samples. Previously only the inlet and outlet positions could be sampled. Now with the use of our dedicated potable water ROV equipment various and numerous positions and heights within a service reservoir, contact tank or water tower can be reached. If required it could also be used to remotely dose the asset.“

Eddie Wrigley, NWG Innovation Facilitator, has been pleased with the progress made in a very short time period but knows that there is still work to be done.

Eddie said, “Due to their reputation for working in live potable water assets we knew we could trust Panton McLeod with one of our critical assets in a “live and in supply” condition. This was essential as we wanted to know how the asset operated in live conditions and not in an isolated state. Without this confidence, the whole project may have struggled to get off the ground.“

“We focused on a reservoir that has two neighbouring cells of the same design and volume. This site offered a good chance to see if different sides of the same reservoir would show different results from samples taken throughout the flow from inlet to outlet.“

“It is still early days but now that we have some data back it looks as if the technology could be a valuable tool in helping us to achieve our outcome of supplying clean, clear drinking water that tastes good.”

For more information, contact the team on 01896 663 330 or email

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