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Topcal S CPC310 data sheet - .PDF file.

The Topcal pH system from Endress and Hauser has enabled United Utilities to improve throughput, the quality of centrate and the quality of cake produced at its wastewater treatment works in Willowholme, Carlisle.

The Willowholme facility treats the equivalent of 100,000 people’s waste, 24 hours a day. The resultant solid waste is treated to make it suitable for return to the environment. In the final stage of the solid waste treatment process, the collected sludge is dosed with lime in order to kill pathogens and produce a sludge that is suitable to be dried in centrifuges.

It is important to achieve the precise measurement of the pH within the lime-dosing tanks. Historically, this has proved to be an extremely difficult measurement to perform, with previous efforts failing to provide the accurate control of the lime dosing required. The pH of the dosed sludge has to reach a set level to ensure full pathogen kill and to ensure the correct consistency of sludge is sent to the centrifuges.

As a result of the unreliable measurements generated with the existing systems, the team at Willowholme had been forced to carry out manual checks rather than relying on the installed pH equipment — which led to a reduced time envelope for processing the sludge.

The contractor on site approached Endress and Hauser for a solution to the problem, and Topcal — a fully automated self-cleaning and self-calibrating pH system — was proposed. Specified in conjunction with the appropriate pH sensor and a retractable holder, two systems were supplied.

Click on the link above to download the data sheet for the Topcal S CPC310.

Key benefits of product application

  • Topcal is fully configurable to suit the conditions and processes into which it is being installed, allowing for different cleaning times, variable calibration intervals and the option to hold the sensor out of the process if required.
  • The Topcal equipment was installed by the contractor and commissioned by Endress and Hauser staff before being monitored and handed over to United Utilities. During the trial period, manual checks were made of the pH against the Topcal unit to prove the reliability and accuracy of the system and to provide the operators with confidence in its ability.
  • Throughout their time in operation, both Topcal units have proved to be extremely reliable and accurate. According to United Utilities, the real advantage has been the saving in man hours that has been achieved at Carlisle because the team’s confidence in the system allows for autonomous control of the process.
  • The result is that the entire lime-dosing process now operates automatically, with the dosing controlled via the Topcal pH measurement at a time to allow maximum throughput.


Endress+Hauser is a global leader in measurement instrumentation, services and solutions for industrial process engineering. With over 8,000 employees worldwide, the Group generates annual net sales of more than Euro1.1 billion.

The Endress+Hauser Group

Endress+Hauser is a global leader in measurement instrumentation, services and solutions for industrial process engineering. The Group employs 13,000 personnel across the globe, generating net sales of more than 2.1 billion euros in 2015.
With dedicated sales centres and a strong network of partners, Endress+Hauser guarantees competent worldwide support. Production centers in 11 countries meet customers’ needs and requirements quickly and effectively. The Group is managed and coordinated by a holding company in Reinach, Switzerland, with UK headquarters in Manchester. As a successful family-owned business, Endress+Hauser is set for continued independence and self-reliance.
Endress+Hauser provides sensors, instruments, systems and services for level, flow, pressure and temperature measurement as well as analytics and data acquisition. The company supports customers with automation engineering, logistics and IT services and solutions. Our products set standards in quality and technology.
We work closely with the chemical, petrochemical, food & beverage, oil & gas, water & wastewater, power & energy, life science, primaries & metal, renewable energies, pulp & paper and shipbuilding industries. Endress+Hauser supports its customers in optimising their processes in terms of reliability, safety, economic efficiency and environmental impact.
Founded in 1953 by Georg H Endress and Ludwig Hauser, Endress+Hauser has been solely owned by the Endress family since 1975. The Group has developed from a specialist in level measurement to a provider of complete solutions for industrial measuring technology and automation, with constant expansion into new territories and markets.

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