Achieving more than £37k
per year of savings was a key
benefit for Anglian Water
following installation of two
mixing systems for handling
secondary sludge at Colchester
sewage treatment works.

System Mix supplied STM
(Small Tank Mixing) pumped
mixing systems for secondary
sludge tanks at the STW.

They replace four submersible
mixers which were constantly
failing. In addition to poor
mixing, maintenance and
safety issues had to be
addressed each time the
mixers needed to be lifted.

In January 2009 the site
was using one 750kg bag of
polymer per week, at a cost
of £1455 per bag. By August
2009, a minimum of 50%
was being saved in polymer
use, one bag for every two
weeks, with the potential for
further savings if optimised
for longer, giving a saving of
£37,830/year minimum.

There has been a reduction
in anti-foam chemical use,
and the automated system
has saved on man hours as
operatives no longer have to
spend 1 to 2h/day operating
control valves.