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University of
Kent , Canterbury :
Pump Regimes
 The
supply regime created recurring bursts on
the distribution network as pumps operated
on a simple reservoir level drop control
mechanism. The violence of the start up caused
pressure surges in the mains giving rise
to regular leaks.
Re-modelling the control regime and changing
the pump sets allowed for a much slower start
up. This along with continuous flow and pressure
monitoring at the revenue meters gave reliable
nightline profiles that were then used as
the basis of focus for baseline reduction.
Consumption savings
equivalent to £21k
per annum have been achieved for a modest
investment of £8k. Rationalisation
of the distribution network has optimised
the fire fighting facilities and reduced
the number of ‘dead legs’ thus
reducing the risk of Legionellosis and other
bacteriological growth. This is a particularly
highly important requirement for this particular
customer.
MoD Deepcut Barracks:
Infrastructure Revision and Leak
Repairs
Following an initial desk top study to
determine the relationship between occupancy
and consumption, this barracks site indicated
very high potential loses and wastage. Logging
the main revenue meter ascertained a nightline
of 25m 3 per hour. Further sub metering and
logging of flows and pressures indicated
loses associated with three discreet areas;
housing, the water tower and medical block.
Standard leakage
detection practices including acoustic
logging and correlation located single
leaks in two of the areas. Repairs and
infrastructure revision surrounding the
water tower caused a nightline reduction
of 10m 3 per hour, equating to a saving of £90k
per annum.
Significant additional verification activity
was necessary to prove that the medical block
had multiple supply leaks, one of which was
under the centre of the building. Many water
regulations contraventions also proved necessary
to rectify and on completion the nightline
dropped further to 7m 3 per hour, which is
an additional 71k per annum saving.
These forward savings
have been achieved for a total investment
of less then £15k
giving a pay back period of less than 2 months.
William Harvey
Hospital :
Internal Over Flow
 A
major acute hospital covering a population
of 75k in the south east of Kent .
Continuous consumption logging showed an
increase in nightline by 3 m 3 per hour from
the standard profile. Our Water Audit team
quickly narrowed the problem down to an area
associated to the supply to the hospital
laundry, located in a multi story block.
The main feed supplied
a header tank with inoperative float control
allowing water to cascade down an internal
overflow and return straight to the foul
drainage system. Simple rectification of
this control mechanism gave rise to a £3.5k
per month saving on water bills to the
East Kent NHS trust.
National Grid
(power converter station):
Leak detection and PRV
As a result of recurring poor pressure
Water Audit were invited to undertake a study
of the supply regime and advise on improvements
in water efficiency for the site.
Various problems were found surrounding
the fire main which had a pressurised system
operating continuously. This suggested down
stream leakage as the operation was pressure
controlled. Additionally, two leaks were
found, under 415,000 volt transformers, on
poorly installed black polyethylene supply
pipes. The rectification of these leaks was
undertaken by specialist contractors due
to the nature and sensitivity of the works.
In order to protect
this particularly sensitive infrastructure
a Pressure Reducing Valve (PRV) was installed
at the commencement of the supply. The
outlet pressure set to 2.5 bar representing
a reduction from 4 bar. This along with
the supply repairs reduced the nightline
by 4 m 3 per hour, a saving of £54k
per annum.
A further benefit of the PRV installation
was to increase the immediate network area
pressure, reducing the number of low pressure
complaint calls from Mid Kent Water customers
in the area.
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