Drought warnings, hose pipe bans: another typical summer in Britain renowned for a temperate climate? John Prescott reminded water companies at the first anniversary of the Water Summit in 1998, water efficiency isn’t just for droughts. Since then Hampshire installs water meters at individual properties on a trial basis and pipes are restored free of charge.
For the last ten years, since privatisation of the UK water companies in 1989, there has been continued investment in the distribution of water. The water companies have reduced leakage as a priority by which the water distribution network has been improved.
CONTROL OF LEAKAGE
Thames Water, dividing its network into districts, has reduced leakage by 50% over the past four years. Flow and pressure meters have been installed with an integrated telemetry system by positioning pressure control valves on the boundary of the districts. As there is an exponential relationship between pressure and leakage, accurate analysis of consumption can be recorded.
Field bus is an important industrial network in the water industry as open standards allow access to useful data, and provide a high level of functionality. However, implementing a field bus protocol, such as LonWorks, has not been easy at Thames Water, where it is not the technology which is inappropriate but the way in which it is integrated into the system. According to Reynolds, “The control philosophy is completely different and with a record for standardisation [at Thames Water] the change would be costly and inefficient.”
At Essex and Suffolk waste water treatment works an open control system has reduced maintenance costs. Norman Gould, project manager explained: “Operating the works prior to the rebuild was labour intensive – the new design incorporates high levels of automation.” Auma Matic Profibus motor controls were fitted to existing actuators which are employed for flow control and isolation and are connected to various parts of the treatment process under the control of a PLC. The modular design of Auma’s actuators enabled existing actuators to be retrofitted with Auma Matic Profibus motor controls. The conversion to the Profibus open standard was installed effectively as the control system is compatible with the existing system.
It is evident that the water companies are spending money on an improved distribution network where investment has more than doubled since the early 1980s. Additionally, Cardiff Waste Water Treatment Works has installed inflow and outflow valves controlled by the Auma Matic Profibus.
AN EVOLVING INDUSTRY
Perhaps the driving force behind tighter control systems is the increase for metering water and the quality of water delivered to customers. The water companies have also been encouraged to be competitive amongst themselves. Reynolds commented that this is not something that they are endorsing. However, Thames Water is nonchalant: “The industry is exciting and evolving with lots of opportunities, with greater pressure from increased competition between companies,” said Reynolds.
In the near future, the water industry may become a highly competitive market, as large UK companies view North America as an untapped resource due to the fact that the US water industry is fragmented. The UK companies could have a lot to offer in terms of experience in control and instrumentation from an organised platform.