UV Disinfection Technology Saves Cambridge Water Money

Cambridge Water plc has recently installed three InLine+ DVGW*-validated medium pressure UV disinfection units from Berson (The Netherlands) at its rural Euston Pumping Station. Between them the three units treat up to 724m3/hour of water, which is then delivered via a 55km delivery main to storage reservoirs that serve the city of Cambridge.

An important feature of the Berson UV technology provided to Cambridge Water is its UV-Tronic+ V5 PLC controller, the latest version of Berson’s UV-Tronic controller range. Based on a rugged industrial PLC and with an RS485-based ModBus interface, the UV-Tronic+ V5 links to the site’s SCADA control system and allows users to set up and manage the UV system’s operating parameters to exactly match their requirements.

Older versions of the UV-Tronic already had the capacity to control multiple streams and treatment chambers, a feature that is particularly useful where a treatment plant has variable water parameters such as flow or transmittance, as it allows shutdown of individual UV chambers when not required, reducing power consumption.

The new UV-Tronic+ V5 has enhanced features which makes it possible to individually control the power level of up to six chambers simultaneously to suit the flow conditions for each stream, further minimising power consumption. Additional new features include greatly extended monitoring and control via Modbus, increased manual control functionality to ease maintenance and servicing, and the capacity to individually calibrate UV sensors when running in DVGW mode. A built-in modem can also be used to provide remote monitoring and diagnosis and for software upgrades.

In addition, when UV monitors on the inner wall of the UV chamber register a fall in the UV level, the controller is designed to trigger automatic wipers on the quartz sleeves protecting the UV lamps. The wipers remove any built-up deposits on the sleeves, ensuring uninterrupted protection against microbial contamination. An additional benefit of automated wiping means no chemicals are required for cleaning, an especially important feature when it comes to drinking water disinfection.

“The UV-Tronic+ V5 is a very useful feature of the Berson UV system,” commented Bob Clifforde, Cambridge Water’s Electrical Engineer. “By allowing us to control each UV chamber individually it not only greatly simplifies operations but has also reduced our operating costs.”

Providing primary disinfection followed by marginal chlorination using hypochlorite, the UV system was installed as an alternative to chlorine-only disinfection. “We selected UV for this remote location as it is so much more convenient than transporting chlorine from our Cambridge depot, over 50km away. There are savings too over the cost of buying and transporting the chlorine gas,” added Bob.