Down the drain

When it comes to leakage, much of the emphasis to date has focused on putting pressure on UK water suppliers to plug the leaks in the nation’s pipelines. However, UK industrial companies should also be trying much harder to do their bit towards minimising water wastage through leakage.

Water leakage is one of those topics that affects everyone, but only really gets the attention it deserves when supplies are perceived to be running short. To put the problem in context, it is estimated that around 3.3 billion litres of treated water are currently lost every year through leakage in England and Wales.

Although there are some efforts to address leakage, restrictions in investment in the UK’s water infrastructure caused by the recent Ofwat determination mean that limited focus is being put on reducing overall leakage any further than its current level of around 23%.

With recent water shortages in some areas of the UK, particularly those that rely on surface-water sources, there is a need for water users at all levels, from the public through to major companies, to ensure they are making every effort to conserve water supplies.

Measuring up

As major water users contributing to a consumption of around 9.8 billion cubic metres of water each year, many of the UK’s industrial companies could be doing much more to save water. In most cases, it would appear that the best first step would be to measure their consumption.

According to a recent survey of 420 UK businesses by Envirowise, around two-thirds of the respondents stated that they neither measure nor
This is backed by findings from the Federation House Commitment 2020, an Envirowise-backed initiative aimed at getting companies in the food and drink industry to reduce water usage. These findings include examples of factories often leaving hoses to drain all day, wasting around 43,000m3 of water every day.

Proof of the savings that measuring water usage can bring is highlighted by the example of Cavaghan & Gray, part of Northern Foods. It installed meters to determine where water was being used, which helped to identify a potato blancher as one of the main users, with 3.3 tonnes of water being used to wash one tonne of potatoes.

This was far in excess of what was needed and therefore a control system was required that allowed the quantity of water per minute to be accurately controlled. Varying water pressure, which made control difficult, compounded this problem.

By installing a system that measures and controls the potato blancher’s water consumption, which includes a Miniflow electromagnetic flowmeter, Cavaghan & Gray is now saving around £6,000 annually, with payback on the installation cost being achieved within just six months.
Unlike these highly visible sources of wastage, leakage can often go unnoticed for years, particularly when the water consumption of a process is not being measured. Even over a short period of time, a small leak can quickly lead to thousands of litres of lost water, meaning that companies could be paying excessively high water and effluent charges that do not reflect their expected consumption.

As in the above example, the best approach to tackling water leakage is to start by measuring actual consumption. This information can then be compared against expected consumption to highlight areas where water wastage, including leakage, may be occurring.

On an industrial site, one approach would be to have water meters on both the incoming supply line and the outgoing effluent line, with separate meters being used to measure the consumption of individual processes. This would enable operators to compare the amount of water being supplied to the site with the amount leaving it, with any ’missing’ water providing an indication of leakage.

By measuring the consumption of key industrial processes or site-specific utilities, it might be possible to pinpoint where exactly the water is being lost, reducing the amount of time needed to trace and rectify the problem.

A similar approach adopted on 1,500 Ministry of Defence sites around the UK has already produced reductions in water leakage of 60% in some cases, with a cumulative reduction in leakage across all sites of approximately two million cubic metres per year.

The project, which is run by Severn Trent Water and Costain (C2C), uses more than 1,100 AquaMaster flowmeters to accurately measure consumption across the sites. ’Gross Meters’ are used to measure the consumption on each site by monitoring the gross incoming water supply. These are also used to continuously validate Statutory Undertaker (SU) revenue meters, which are used by local water companies to generate bills.

’Night-line meters’ provide a critical indication of leakage levels during periods when legitimate consumption is at its lowest. The resulting information is used for leakage cost reduction and billing, as well as to help determine at which point the cost of any further leakage reduction will become uneconomical.

Major industrial users of water are likely to find themselves under the same sort of scrutiny that is currently being focused on UK water suppliers. These industrial users must, therefore, find ways to improve their water consumption performance wherever possible.

Although there is some effort required at the outset of a water waste-minimisation programme, the potential rewards are significant.
Using water more effectively not only yields significant cost savings, but can also help companies to improve their carbon footprint, especially beneficial for those covered by the Carbon Reduction Commitment (CRC) Energy Efficiency Scheme.