A leading independent school has improved its water quality yet significantly reduced its costs by introducing two innovave new products from Next Filtraon
et in 200 acres of Suffolk countryside overlooking the River Stour, near Ipswich,
the Royal Hospital School’s Reverse
Osmosis (RO) system was proving insufficient and expensive to operate, as facilities manager, Nigel Griffiths, explains: “With 11 boarding houses and 57 residential houses, plus visitors and staff, we can have around 1,000 people on site. This gives our team a huge responsibility to ensure that the supply from our borehole to our water tower is of the highest quality - constant and consistent. “The borehole water is naturally hard and high in iron, so needs treatment, but the existing reverse osmosis plant was not only
inadequate for the task, but its energy and maintenance costs were unacceptable.” Griffiths says that
maintenance was required on the site’s filters sometimes up to three times per day, yet despite this, they eventually had to be replaced (at a cost of £6,000). The RO plant was also only just achieving a flow rate sufficient to sustain the water tower, reaching 8m3
WATER TREATMENT Royal standard of water quality
a positive knock-on effect, including the noise of the old system that is no more. “Now we have a system than copes with ease, and the maintenance required is almost zero compared to the two to three times per
day we had previously. Water quality is further improved yet at the same time we have reduced our costs and gained much greater peace of mind, which is a big achievement.”
uThe Royal Hospital School, which has successfully improved its water quality by working with Next Filtraon and Geyser Thermal Energy
costs, bespoke green design engineers Geyser Thermal Energy, working in close conjunction with Next Filtration, were given a six- month trial to show what they could do to improve the school’s water system. Next Filtration introduced its Next Sand mono-bed media to remove the iron (and also ammonia) from the borehole supply, replacing the existing filters that required regular maintenance. A high-purity Clinoptilolite, Next Sand benefits from a high surface area and micro-porous character that provide a filtration performance of <5 micron, compared to 12 to 15 microns for multimedia. This much higher flow rate provides greater
/hour at best – with a borehole pump running 24/7 at an annual cost of £2,500. In addition to the time- consuming maintenance and running costs, it was the loss of the water due to the RO system’s reject function that Griffiths says “really grieved him”.
Originally founded in Greenwich, London in 1712, the Royal Hospital School was also being hit by an annual electricity bill for the RO plant of £2,000, so the search for a superior system began.
After taking samples and making a full review of the installation and running
performance for existing vessels, with filtration through the entire media bed depth providing more than double the capacity of multimedia filtration. It also has a higher dirt holding capacity, so requires less frequent backwashing. For the Royal Hospital School, the lighter weight and lower volume would mean lower capital costs and a longer-lasting product. And because the media is not consumed in the filtration process, a simple periodic backwash keeps the media clean and operating efficiently for five years or more.
Then, to reduce scale, which had become an additional burden on the school’s Facilities
Department, Next Scale Stop was introduced. This product costs nothing to run, and has a bead-media life of three years. Next Scale Stop doesn’t actually release anything into the water. It simply starts a catalytic process of creating micro crystals of scale, which then continue to attract calcium and magnesium ions, preventing them attaching to pipework and metals as they travel through the water system. No chemicals are added to the water and the media does not leach into the water.
“It will take time to see the full effects in the reduction of limescale,” adds Griffiths, “but in some kitchen areas for example, we are already seeing a very positive difference. “Overall, the new system from Next Filtration and Geyser Thermal Energy is proving an excellent buy with a 10-month return on investment. Firstly, we no longer have an inflated electricity bill – and with the addition of a new pump, we are comfortably achieving a flow rate to our water tower of 16-17m3
/hour – about
double what we previously had, enabling off-peak electricity use. Everything has
vacuum degassers with ‘intelligent’ controls
pirotech has completely re-engineered its fully automatic SpiroVent Superior vacuum degassers, introducing two new models with increased performance and ‘intelligent’ controls. The S400 and S600 can service higher volumes of water than ever before and feature menu-guided commissioning as well as remote access and operation via the cloud. The changes have been made in response to the market, which is looking for greater connectivity, alongside reduced energy consumption, delivered with the aid of deaeration products that can operate effectively in today’s increasingly large commercial buildings.
The vacuum degassers work by decreasing the pressure in the vacuum vessel that sits within the unit. This liberates dissolved gases from the system liquid in the vessel and the accumulated gases can then be expelled. Any air left behind leads to corrosion, and a destructive sludge developing, also creating noise from components such as pumps, which cease to work efficiently.
The powerful vacuum degassers are needed because ‘ordinary’ in line deaerators will not work anywhere near as effectively in high-rise offices and other tall buildings. By continuously degassing quantities of the system liquid, the SpiroVent Superior keeps the negative effects of dissolved and liberated gas to a minimum.
A smartswitch continuously monitors the volume of removed air, and will switch off when the minimum dissolved gas level is reached. The S400 can degas 500 litres or water per hour, while the S600 can manage 1,000 litres an hour. The degassers also ensure the system pressure never drops too low, with positive pressure maintained throughout. They also include a Category 5 break tank, which is better suited for the UK market. The break tank ensures that a ‘more than adequate’ backflow prevention is achieved, while avoiding costs associated with the alternative solution of an RPZ (Reduced Pressure Zone) valve.
The SpiroVent Superior S400 and S600 are easy to install and engineers can access quick installation guides by scanning a QR code on their mobile phones.
Once commissioning is complete, control and monitoring can be done using a touch screen on the unit, through a building management system or via the internet on a PC, tablet or smartphone.
uNigel Griths (right), facilies manager at The Royal Hospital School, with Ray Taylor, chief technical ocer at Next Filtraon
uTaylor (le) and Griths discuss the new system from Next Filtraon and Geyser Thermal Energy which has provided a 10month ROI
28 BUILDING SERVICES & ENVIRONMENTAL ENGINEER JUNE 2019
Functions such as on/off, error and alarm reset, and degassing, refill and boiler interlock on/off can be controlled remotely, while parameters can be set for such things as system pressure, refill pressure and boiler interlock. The new SpiroVent Superiors also include a comprehensive unit status and event history, providing real-time data and enabling performance to be tracked in detail over time. For more information on Spirotech’s range of water treatment and system protection products, please visit www.spirotech.co
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