As a point of note, the recovered
water is pure enough to be considered
of drinking quality. The reason for this
level of puri cation is that it allows the
new recycling plant to make use of
existing water infrastructure. Costs for a
dedicated pipework system would have to
be met if the water was not of the same
quality as its mains-supplied counterpart.
According to Nøhr Bak, ensuring the
recycled water is of drinking quality is
also important from a psychological
perspective. Somehow it feels better to
be using puri ed recovered water, even
for cleaning and sanitising. The quality
of the recycled water means it is also
supplied to the brewery’s employee
shower facilities.
Carlsberg’s total water recycling plant
at Fredericia represents a new innovative
approach to the safe reuse of rinsed
process water, and the project leverages
a number of innovative technologies to
improve water e ciency.
HOW IT WORKS
To provide an overview of the plant’s
function, the system has been designed to
rst evaluate in ows and concentrations,
after which screens are deployed to
remove coarse material from the used
process water.
“The rst really interesting step is
that we then use an anaerobic reaction
process, where bacteria are capable of
converting the soluble organics into
methane, and that methane into biogas,”
explains Nøhr Bak. “The biogas produced
constitutes approximately four times as
much energy as that consumed by the
processes that follow. As a result, the
plant is more than energy-neutral – in
fact we have a surplus. Additionally, the
recovered water returns to the brewery
warmer than it set out.”
Whereas mains cold water is supplied
to the brewery at 8°C, the water recycled
by the new plant is returned at 25°C.
Subsequently, far less heating of the
process water is required for cleaning
the equipment and bottles, which in
turn makes it possible to reduce energy
consumption across the entire site by
9-10%.
Following the anaerobic reaction
process, a biological polishing step is
deployed whereby another bacteria type
removes any remaining organics, as well
as nitrogen and phosphorus. Ultra ltration
(UF) membranes then serve as part of
an installed membrane biological reactor
process before a reverse osmosis (RO)
membrane plant yields 90% recycled
water. The remaining 10%, which has a
concentrated brine content, is discharged
into a municipal sewer to a saltwater
recipient.
Once the RO is complete, an
advanced oxidation process removes
any small organics that pass through
the membranes. A remineralisation lter
subsequently adds a degree of hardness
back to the system, thus avoiding
corrosion in the brewery’s pipework.
Chlorine dioxide is added as a nal step to
maintain disinfection potential.
Arjun Bhowmik, VP production -
western Europe, Carlsberg Group, adds:
“The new water recycling technology
means that Fredericia can become an
important learning platform for all of our
facilities.”
Until nal commissioning is complete
next year, NIRAS will continue to execute
the project, with all the daily challenges
this brings. A topping-out ceremony for
the construction part of the project was
held recently and attended by Denmark’s
Minister of higher education and science,
Ane Halsboe-Jørgensen (pictured, right).
Among the academic stakeholders
within DRIP is the Technical University of
Denmark (DTU), where Lisbeth Truelstrup
Hansen is a professor of microbial food
safety and environmental hygiene.
She states: “DRIP comprises industry
partners that have got together with
universities and government agencies
to solve challenges in the sustainable
reuse of water. Partnerships are
WASTE MANAGEMENT
The water recycling plant focuses solely on
process water used for the sanitation and
cleaning of equipment and bottles
extremely important because they
immediately bring everyone to the table.
For Carlsberg, they’ve been able to sit
down with suppliers who can provide
the optimum equipment to help reach
the required technological solutions.
In addition, government agencies have
been guiding us through the regulatory
framework that we have to abide by.”
WATER, WATER EVERYWHERE...
Water is clearly essential to Carlsberg,
both for its products and its processes.
The company’s aim is to eliminate
wastewater, which means maximising
e ciency, and treating and reusing water
wherever possible. In 2019, Carlsberg
achieved a 12% reduction in water
consumption (from 2015). Building on this
progress requires further investment,
innovation and working in partnership,
hence the decision for a more
concentrated focus on water recycling.
Of course, there is also a huge
environmental factor at play here. In a
changing climate, it is predicted that
drought will become more widespread,
reducing the quality and availability of
water. Such an eventuality is the principal
reason why the company is investing in
the technology, not simply to maximise
e ciency in its breweries, but to increase
the availability of fresh water for the local
communities whose resources it shares.
Having recently celebrated the 40th
anniversary of its Fredericia brewery, the
installation of the new water recycling
plant is helping Carlsberg take a big step
into the future.
Autumn 2020 www.operationsengineer.org.uk 61
/www.operationsengineer.org.uk