Efficiency is the name of the game
Jim Plumley of ABB Instrumentation explains how the latest control and monitoring technology can help realise improvements in network efficiency and achieve savings
As part of its efforts to improve the efficiency of the UK's water and waste treatment networks, Ofwat is offering a number of incentives that will reward water operators for achieving savings in their operating and capital costs. Most businesses benefit from improvements in operating efficiency, but for water companies in the UK, the regulatory climate means pressure to run things efficiently is even greater than in many other industries.
This is due to the way Ofwat controls pricing and expenditure throughout the industry. Ofwat and the water companies are currently nearing the completion of the five-yearly consultation process that will enable the regulator to set prices for the period between 2005-2010, with the final pricing structures due for publication in December this year.
As part of this process, Ofwat looks at the relative efficiency of the different companies in terms of both operating and capital costs. For the least efficient companies there are financial penalties that will effectively force them to improve their efficiency in line with their more fortunate counterparts.
At the other end of the spectrum the most efficient companies will receive a bonus. Companies that are more efficient than expected will be able to keep the extra money they save for five years before Ofwat's pricing policy effectively passes on the savings to customers. As an added incentive for the very best performers, however, Ofwat will multiply the savings of the most efficient companies by a factor of up to 1.5, giving the winners even more money to play with over the next five years. In the resulting climate of fierce competition, the water companies will need to do everything they can to improve the efficiency of their regulated operations. This is just the sort of situation where using the latest control and monitoring equipment can help. After all, you cannot control what you cannot measure. It goes without saying the water companies' first priority must be to maintain a safe, high-quality supply to its customers. But in many cases improvements in quality go hand-in-hand with efficiency savings.
There are gains to be made at each stage of the water abstraction, treatment and distribution process, as well as in sewage treatment. Wherever water is being abstracted, for instance, the quality and quantity of the intake must be measured. The specific requir-ements will vary depending on the water source and the region. In the case of Thames Water, the turbidity of the water emerging from its Bell Green borehole in Lewisham, south London, is one important measure of quality.
All the water passes through pressure filters to reach a stringent 0.1 NTU (nephelometric turbidity units), which is stricter than the levels set by the Drinking Water Inspectorate (DWI). By installing specialised turbidity meters, the company can monitor the quality more closely and improve the operating efficiency at the same time.
Alan Barton, Thames Water's project engineer on the Bell Green project, explained: "By accurately monitoring the level of particulate matter in the water, ABB's turbidity analysers help us predict when the filters need to be washed out. This helps us ensure we wash the filters only when we need to, so reducing maintenance time and replacement costs." For Wessex Water, on the other hand, nitrates are one of the main concerns because many its water sources lie below agricultural land. Although nitrate levels in drinking water supplied by Wessex Water are well below the UK and EU limits, levels are on the increase at a number of underground water source sites because of the leaching of nitrates from the farm land above. UV nitrate monitors are being used to provide continuous online measurement of the nitrate levels in the raw water from the aquifers. Depending on the level of nitrates present, the source may be either temporarily taken out of service until the nitrate level decre-ases, blended with a low nitrate source or treated. On sites where treatment or blending is employed, the monitors optimise the level of treatment and the blend ratios required, which minimises the cost and maximises efficiency. As well as monitoring and controlling the treatment process, the nitrate monitors are also being used by Wessex Water to collect data on nitrate levels at the sites.
"By using the monitors to collect data we can explore correlations with rainfall and groundwater levels to better predict future nitrate pollution," said Andy Purvey, supply planner for Wessex Water. He added: "We can also use this information to help us to design more effective and efficient treatment processes." In potable water treatment plants some of the most impressive savings can come from improved monitoring and control of the coagulation process. Introducing an automatic coagulation control system, for example, can potentially save up to £80k in treatment chemicals, along with improved water quality, reduced manpower, lower sludge disposal costs and a reduced risk of inadvertently making trihalomethanes, a possible byproduct of disinfection. ABB's AnalyzeIT UV Organics Monitor 7320 is particularly suitable for coagulation control applications in upland sites, where humic and fulvic acids are the main constituents of the colour content of the water. It gives reliable feed-forward control, virtually maintenance-free operation, reagentless operation leading to low operational costs and eliminating the need for maintenance-prone filtration.
The topic of flowmetering in the water industry is also progressively coming into its own as operators become more sophisticated in their awareness of the options available, particularly for revenue metering and leakage monitoring, offering significant potential cost-savings.
In particular, pressure is being applied on water companies by Ofwat to better identify and address leakages throughout their supply networks. This has already led some to employ new technologies that provide more accurate monitoring and feature capabilities, such as remote GSM communication, which enable leaks and other problems to be traced and rectified immediately. Electronic flowmeters that work on the magnetic, ultrasonic and other principles and incorporate electrical, rather than mechanical sensing equipment, have been around in various guises for some time. Yet their uptake by the water industry has been rather slow, mainly due to a comparatively higher purchase cost than their mechanical metering counterparts. It is, however, useful to know that in most cases, payback on the installation of an electronic flowmeter can actually be achieved in a matter of days. Furthermore, with no mechanical moving parts that can be subjected to wear and replacement, electronic flowmeters not only offer constant accuracy throughout their service life, but also eliminate the cost, time and disruption associated with maintenance. The idea of cost ownership, which takes into account all the costs incurred throughout the life of equipment, instead of just its purchase price, is increasingly being adopted by companies throughout many industrial sectors, not least in the water and waste industry.
One reason for this is the growing trend toward companies out-sourcing responsibility for both the supply and operation of equipment to contractors, who must ensure they opt for the solutions offering best value for money over the long-term. Modern instrumentation technology also enables further value to be derived by making it possible to collect a broad range of data that can be utilised to help improve network performance. In many cases, the sort of investment needed to achieve a better performing network in line with Ofwat's requirements will inevitably be a painful exercise to begin with, both for water operators and their customers, who will more than likely have to bear some of the cost. It is, however, important to consider this against the backdrop of increasing demand pressures on our national water network.
To ensure supply continues to meet demand in future years means maintaining and upgrading the distribution infrastructure. Furthermore, the resulting longer term savings and efficiency improvements will almost certainly benefit both operators and customers alike. For water operators, there is the pros-pect of having more money to play with within Ofwat's five year period, while customers can look forward to longer term reductions in their water bills.