Reducing the cost of effluent treatment

Thames Water
200T DI
Waste water management
Industry / Vertical:


Thames Water is one of the largest suppliers of tap water in the UK. With more than 8 million customers in London and the South East, the company delivers a staggering 2,600 million litres of fresh, clean water to customers every day.

Also responsible for the collection and treatment of waste water to 14 million customers, Thames Water operates 350 sewage treatment works around the South East of England. Every year Thames Water removes and treats more than 4 billion litres of sewage.


The safe and effective management of waste water and effluent is vitally important to Thames Water. Any error in waste water treatment risks a potential environmental disaster. Additionally the water companies are regulated by the Environment Agency and even relatively small spills can cause breaches of service level agreements leading to fines and other action.

For these reasons, Thames Water needed to ensure that its complex effluent treatment plants are highly reliable and that any malfunction of equipment is alerted quickly and effectively.

Separating water from effluent requires the use of settlement tanks. Rotation arms in these tanks enable the separation of water from solids, allowing the former to be treated and the latter to be pumped away. If the rotation arms are not functioning, either delivering water to the tank or rotating effectively, the risk of spillage and potential contamination increases. This issue is complicated because, unexpectedly, sewage works are often located in remote environments where immediate access to engineering support is not always available.

Thames Water wanted to be alerted of any malfunction of these rotation arms in a timely and effective manner and sought support from leading UK manufacturer of wireless solutions, Wood & Douglas.


Wood & Douglas’ 200T digital input transmitter is a wireless remote monitoring product that combines the monitoring of rotation with change of state switched applications.

This enabled Thames Water not only to identify when a rotation arm had stopped rotating but also the reason for the malfunction – whether this was due to the water flow being too low or a malfunction in the arm itself.

This was important to Thames Water because it enabled the company to understand the root cause of the malfunction, and therefore deploy the right maintenance team quickly to site.

Up to four 200T transmitters link to a single 200 RM central receiver, creating a point-to-point alarm link incorporating both rotational and switched monitoring. This provided a low cost, reliable wireless monitoring solution that Thames Water could deploy at remote sites, safe in the knowledge that any issue on site would be swiftly and effectively escalated.

The Wood & Douglas solution enabled Thames Water to deliver a more reliable monitoring service at a vastly reduced cost, as it removed the need for regular site inspections at remote works. Since up to 40% of operators’ working time is spent travelling, this generated significant savings and gave maintenance crews a head start by knowing what the local problem was likely to be.

  • Reliable wireless monitoring and alarm system for effluent treatment
  • Lower cost through reduction in maintenance visits
  • Able to reliably alert the root cause of malfunctions


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