| Energy
Fairfields Farm becomes first energy-efficient
hand-cooked crisp producer in the UK
Essex-based artisan crisp company and potato producer, Fairfields Farm, has just
opened its brand new anaerobic digester, which allows the business to become entirely
energy efficient.
ccupying the
space of about ten
football fields, the
new anaerobic
digester (AD plant)
has taken two
years to plan and construct and is
located on Fairfields Farm in
Wormingford, Colchester, right
next to the potato farm and crisp
factory.
In simple terms, an AD plant is
rather like a huge concrete cow. It
digests organic matter (waste
potatoes and crops such as maize
and rye) and trillions of
microorganisms anaerobically
digest this to create gas. This gas
is collected, filtered and then
exported to the national grid. A
gas turbine is also on site, which
produces electricity to power the
crisp factory, potato pack-house,
cold storage and offices. The gas
produced for the grid provides
enough power for 4,000 homes.
The AD process also produces
O
organic digestate which is high in
nutrients and is ideal for spreading
back on the fields to help soil
structure and fertility on the farm.
Fairfields Farm has long since
prided itself on its green-energy
efforts, with solar panels installed
on-site; the opening of the new AD
plant takes this one step further.
“Minimising our environmental
impact is very important to us.
We've always made efforts to
reduce waste and be as energy
efficient as possible, so the new
AD plant will allow us to fully
realise our green potential,”
explains Robert Strathern, third-
generation potato farmer and
founder of Fairfields Farm.
“Apart from the obvious
environmental benefits, the
building of this AD plant will also
enable us to better manage our
power supply and remove the risk
of future fluctuations in the energy
market. This keeps us
commercially lean and enables us
to be viable and competitive well
into the future,” he adds.
Machine turns waste plastic into energy
The first systems to use anaerobic digestion technology to turn waste plastics into
energy and fertiliser are being developed in South Australia.
OET Systems
expects to have its
first two machines
– each capable of
processing 20
tonnes of plastic a
week – operating commercially in
about 12 months.
More than one million tonnes of
contaminated plastic deemed unfit
for recycling is sent to landfill in
Australia each year. In the United
States the figure is almost 10
million tonnes.
Inventor David Thompson said
his plastic to energy technology
had so far successfully been
applied to polyethylene,
polypropylene, polystyrene and
expanded polystyrene.
He said the anaerobic digestion
process varied upon disposal
feedstock and depended also
upon temperature and system set
up.
“The POET system prepares
waste plastic in a way that
microbial digestion can take place
quickly and I think that’s really the
key to making it a commercial
P
opportunity,” Thompson said.
“I have already got inquiries
from overseas including a large
consortium in South America that
is really quite interested to get
involved and take the technology
over there.”
POET Systems is a 2017 semi-
finalist in the Australian
Technologies Competition, which
assesses, mentors and promotes
companies providing a uniquely
Australian take on the future and is
open to technologies that have
global potential in a range of
industries.
Winners will be announced at
Technology Showcases in
Melbourne and Sydney in October
and November.
POET is an acronym for
Polymer - Organic - Energy –
Treatment.
The first two POET machines
will be built at wastewater
treatment plants in regional areas
of the Australian state of Victoria.
The same microbes will treat the
plastic and the water
simultaneously. The microbes then
24 | Farming Monthly | August 2017
die and leave behind liquid and
solid biomass, which can be used
as fertiliser, and biogas, which can
be separated into methane and
carbon dioxide.
Thompson, who is based in the
South Australian capital Adelaide,
said the methane could be used to
create heat and energy, possibly
to power the wastewater plant,
while there was also potential for
the carbon dioxide to be captured
and reused.
“So basically the plastics go
into an anaerobic situation in
wastewater where the microbes
digest the plastic and create
energy,” he said.
“This client in Victoria is big on
wastewater treatment plants and
after thinking about his
methodology – there’s over 550
wastewater treatment plants in
Australia and at least half of those
would have anaerobic digestion
facilities attached so it’s a good
opportunity to go down that path.”
Thompson plans to lodge
provisional patent documents for
the technology in the coming
weeks.
He said t he system did not
impact on existing recycling
practices as it targeted plastics
destined for landfill and would add
a new revenue stream for
companies in the waste industry.
“People in the waste industry
have already invested heavily in
infrastructure so they know how to
do the business,” he said.
“If this gives them an additional
opportunity to make money and
take on a segment which hasn’t
been handled before then I’m
happy with that.
“We’ve had a look at a number
of scenarios and where it actually
works as a business model is at a
starting point of 20 tonnes a week.
“So everything I’ve designed
ready for manufacture here in
Australia is based on 20 tonnes a
week and I can scale it up larger
from there.”
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