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Coca-Cola Anderlecht Site
High purity oxygen waste water treatment with a small footprint
Coca-Cola invested in OXY-DEP VSA technology for waste water treatment
Coca-Cola’s development and quality control laboratory in Belgium needed
to increase its wastewater treatment capacity, but space was limited and
the company wanted to prevent unnecessary expenditure. Air Products
stepped in with its OXY-DEP VSA technology, which has provided excess
capacity in a compact and economically-priced package.
Soft drinks manufacturer Coca-Cola faced a growing challenge at its
laboratory in Anderlecht, Belgium. Rapid growth in the amount of
wastewater produced at the site meant that the existing effluent
treatment plant was becoming seriously undersized. “Our treated effluent
risked exceeding the legal limits for both BOD (biological oxygen
demand) and suspended matter,” explains Sebastien Berlanger, Facilities
Manager with Coca-Cola Services at Anderlecht. We had to do something
about it, and quickly.” But the necessary engineering work was always
going to be a problem at the Anderlecht site, which is more like a
modern office block than a factory. There was limited space for a new
treatment plant, and with the existing plant situated underneath a car
park, even minor upgrades were likely to be difficult. Luckily, Air
Products was able to supply an innovative solution based on its compact
on-site oxygen generator. The COD (chemical oxygen demand) treatment
capacity of the plant has almost tripled, leaving Coca-Cola plenty of
room for future growth, and the whole job was accomplished at effective
cost and with very little upheaval. It’s a success story that both
Coca-Cola and Air Products are proud of.
Create and test
Anderlecht is home to Coca-Cola’s second-largest suite of
laboratories worldwide, and handles work for 17 European countries plus
several in Africa. Three hundred people, of 17 different nationalities,
work in this modern building, which dates from 2000. Today the site has
four main activities: R&D and quality control in products and packaging,
financial services, IT, and marketing within Belgium. Rapid growth in
the development of new products is one reason for the shortage of
effluent treatment capacity. A few years ago, says Mr Berlanger,
Coca-Cola used to launch two new products a year in most European
countries. Recently this has increased to four new products a year,
which means testing at least 50 potential new products in the
laboratory. More testing means more sugar and other organic compounds in
the wastewater, and hence more COD. Another big source of COD is the
testing of trade samples – products bought from shops right across
Europe and sent to Anderlecht for quality control. Anderlecht’s trade
sample lab employs 50-70 people and every month it analyses 6,000
samples, all of which end up in the wastewater system.
When the conventional route fails
By November 2002 the risk for shortage of treatment capacity had
become serious and Coca-Cola started looking for ways to solve the
problem. The existing water treatment system was based on an SBR
(sequential batch reactor) with a basin volume of 80m3 and a capacity of
450 human equivalents/day (population equivalent or pe), or about 50kg/d
COD. To allow room for future growth, the company calculated that it
would need a plant with a capacity of 120kg/d COD. The Anderlecht site
does not have any engineering resources of its own, though it has a
preferred partner company for small projects. A new wastewater treatment
plant would have been beyond the scope of this partnership, so Coca-Cola
sought the advice of wastewater treatment specialists. But the
specialists were unable to come up with a low-cost and efficient
solution. One firm suggested a complete new water treatment system. A
second company proposed a new and expensive filter system. “There were
other ideas, but none were cost effective,” says Mr Berlanger.
Try the unexpected
As sometimes happens in business, the solution to Coca-Cola’s
problem lay in a chance encounter between prepared minds. In a hotel bar
one day, local Air Products representative Thierry Jamin fell into
conversation with an executive from Coca-Cola who knew about the
wastewater problem. Mr Jamin explained that Air Products offered a range
of solutions for boosting the capacity of wastewater treatment plants.
He noted the specific issues which Coca-Cola faced at Anderlecht and
presented the challenge to the Air Products’ OXY-DEP team. And so a
partnership was born. OXY-DEP systems rely on the ability of high purity
oxygen to improve wastewater treatment by replacing or augmenting
conventional aeration. The capacity of a treatment plant is often
limited by the rate of oxygen dissolution, which in turn depends on the
concentration of dissolved oxygen. Compared to atmospheric air, which
contains 21% oxygen, pure oxygen dissolves nearly five times faster.
This means that a plant using pure oxygen has a treatment capacity
several times greater than an air-based plant of the same physical size,
or can be physically much smaller for the same capacity. Pure oxygen has
other advantages. It reduces odour problems because there is no
insoluble nitrogen plume to carry volatile substances out of the
treatment basin. Oxygen typically improves sludge flocculation and
settling performance and makes the whole plant more controllable, with
quicker response to load changes. OXY-DEP systems can be used on their
own, or alongside air-based systems to boost the capacity or improve the
performance of existing wastewater treatment plants. Air Products offers
a choice of system capacities, oxygen dissolution methods and oxygen
supply technologies to suit the requirements of individual plants. Most
installations get their oxygen in liquid form, delivered by tanker,
although large plants may use an on-site generator based on large
conventional VSA (vacuum swing adsorption) technology. Neither of these
solutions was ideal for Coca-Cola however because the site’s covered
utilities area was too small to house a liquid oxygen tank or a
conventional generator. Even if there had been enough room, handling
large quantities of liquid oxygen might have caused safety problems in
what is essentially an office building rather than a factory. Happily
for Coca-Cola, there was a solution: OXY-DEP VSA, the latest addition to
the family. Air Products Senior Principal Development Engineer, Chris
Thomas, who pioneered this development, explains that this system is
based on a submerged propeller-type mixer fed from a specially-designed
VSA oxygen generator. Because it works at low pressures and has only a
few moving parts, the VSA generator is compact, affordable, safe and
highly reliable – in fact, just what Coca-Cola needed.
Going underground
The location of the wastewater treatment plant, beneath the car
park, makes efficient use of space and keeps unpleasant smells away from
the occupants of the building. It also posed several challenges for the
specialists at Air Products. The VSA oxygen generator, a box just 1.5m
or so in length, could be installed in the utilities area with no
problems. The 2.2kW mixer-oxygenator was a different matter. This item
is normally submerged in the treatment basin, but for maintenance it
needs to be winched up a vertical steel mast and swung back over the lip
of the basin – a tricky manoeuvre in the underground basin. The solution
in this case was to design a special mast in several pieces. The winch
and the top section of the mast can be removed, so nothing shows above
ground level in the car park.
Another important issue for the designers was the possibility of oxygen
building up in the confined space above the treatment basin or entering
the sewers, where it could cause a fire or explosion. The answer,
explains Air Products’ Chris Thomas, was simply to ventilate the
underground chamber continuously with air. The ventilation is monitored
and interlocked with the VSA control system, ensuring sufficient airflow
whenever the VSA unit is switched on.
The Air Products team also looked carefully at other aspects of
integration, in both design and operation. “Our system had to be
integrated with the existing plant,” says Chris Thomas. “That involved
working closely with the supplier of the existing system to make sure
everything worked correctly. We also had to design an operating strategy
to maximise the benefit of oxygen whilst maintaining the optimum pH in
the wastewater.”
To commissioning and beyond
By July 2003, just six months after the first contact between
Coca-Cola and Air Products, the new oxygen system was ready. With
everything prepared in advance, the actual installation took just a
couple of hours. Commissioning went ahead with no problems and since
then the plant has run smoothly following some minor adjustments. The
VSA generator delivers oxygen at 150l/min, or about 11kg/h. This is
enough to increase the capacity of the plant from 450pe (50kg/d COD) to
almost 1100pe (120kg/ d COD). Since the current load on the plant is
only around 630pe (70kg/d COD), there is plenty of room for future
growth. “We don’t foresee a need to expand the plant in the next few
years,” says Mr Berlanger, “but legislation is getting tighter all the
time, so you never know. In any case we are very happy with the project,
and we would definitely work with Air Products again.” “This project
shows that even complicated wastewater treatment plants can benefit from
oxygen,” says Chris Thomas. “OXY-DEP VSA is easy to fit because of its
low power requirement and small footprint, and it’s a safe solution when
liquid oxygen is simply not an option.” “For Coca-Cola, it provided a
large increase in capacity that allowed the company to meet its legal
obligations without a large investment,” he continues. “It was easy to
install, and thanks to close integration with the existing aeration
system, it’s easy to control.” “We really valued the expertise of the
Air Products team in developing such a clever solution for our
wastewater treatment,” says Mr Berlanger. “They quickly understood the
complexity of our requirements and came up with a package which exceeded
our current requirements. Together we achieved this on budget, as well
as in a short time frame. It was an ideal partnership. Just what we
needed.” <<
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