Northumbrian Water is set to
save £100,000 a year on pump
running costs following a
project with ABB Drives
Alliance member, Quantum
Controls, to install ABB low
voltage AC drives on its
anaerobic digester tanks.

Quantum Controls fitted
two low voltage AC drives to
one of the tanks. As well as
giving the ability to reduce
motor speeds, avoiding
foaming of liquid in the tank
which interfered with the
volume of methane being
produced, it demonstrated a
cost saving through the
reduction of the energy used
by the motors. Quantum
Controls measured the
difference in power between
two pumps running
simultaneously, with the first
pump being star-delta and
the second being controlled
by a low voltage AC drive.

Quantum Controls
calculated overall savings of
£107,000, giving a payback
period of 0.27 years.

Northumbrian Water will
also be able to reduce its CO2
footprint by over 700 metric
tons a year, giving an extra
saving of £8600 under the
UK carbon tax credits
scheme. This brings total
savings to £115,000; return
on investment is 92 days.