SERVICES, PRODUCTS, SOLUTIONS
TURNING MALT WASTE INTO AN ASSET
Checking the quality of the digestate
HRS Heat Exchangers operates at the forefront of thermal technology,
offering innovative and effective heat transfer products worldwide with a
focus on managing energy efficiently.
info@anz.hrs-he.com www.hrs-heatexchangers.com/au
NZ: +64 9 889 6045 AU: +61 3 9489 1866
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British farmers who supply
malting barley to the UK’s
leading producer of malt
products are benefiting
from a novel ‘closed-loop’ system
which turns 80,000 tonnes of
liquid malt waste into a high quality
biofertiliser. This has improved soil
quality and reduced associated
CO2 emissions by more than 1,150
tonnes a year (equal to 300 family
cars).
Based in the English town of
Stowmarket, Suffolk, Muntons is a
leading global producer of highquality
malted ingredients. In the
summer of 2015, the company
completed the installation of a
$10.4m anaerobic digestion (AD)
plant; designed to reduce reliance on
artificial fertiliser, increase traceability,
reduce tanker movements, generate
electricity for use on site, and meet
stringent production standards for
biofertiliser.
A pasteurisation system from HRS
Heat Exchangers was a crucial
part of the process. Muntons
commissioned a ‘3 Tank Batch
Sludge Pasteuriser System’
with energy recovery to treat the
anaerobic and aerobic wastes.
Almost 200m3 (53,000 gallons)
of high liquid waste, with a high
chemical oxygen demand (COD),
is treated each day and as well as
the CO2 savings, the project has
saved Muntons more than $5.95m
in energy and disposal costs to
date. The digestate is stabilised prior
to clean effluent being discharged
and the remaining sludge is then
pasteurised in the HRS 3 Tank unit
and used as biofertiliser.
(SUB)The benefits of pasteurisation
The HRS system works on a three
tank principle; while one tank
is being filled, the second tank
holds the sludge at 70°C, and at
the same time as the third tank is
being emptied (each process lasts
one hour). CHP engine cooling
water is used to heat the sludge
in corrugated tube-in-tube heat
exchangers, which is more
efficient than heating an entire
tank of digestate. HRS has also
incorporated an energy recovery
section to utilise heat which would
otherwise be wasted.
Once pasteurised, the biofertiliser
can be supplied for application
either as a liquid for soil injection
or a de-watered solid for muck
spreading. Muntons are also
working with the University of
Lincoln on a project which has
demonstrated that lettuces
grown with Muntons’ biofertiliser
demonstrate quality and growth
benefits over artificial fertilisers of
similar nutrient concentration.
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