Aart van den Boogaart
Oneofthewaste products of the brewing process is brewers' grains,
the residue of barley and other grains used in making beer. Brewers'
grains are usually sold to farmers as cattle feed, but the Heineken
brewery in Ama, Nigeria, couldn't do that because the livestock
industry in the surrounding area is insignificant.
WASTEASASOURCEOFENERGY
The amount of waste produced is consider
able, however. The Ama brewery produces
10 tonnes of brewers'grains per brew. With
10 brews a day, that makes 100 tonnes of
waste (enough to fill five 20-foot containers)
to be processed every day.
If left untreated, the wet brewers' grains -
water makes up three-quarters of the volume
-start decomposing after one day. Drying
the material is one way of extending its
storage life, so that it can be transported at
a later date, but it does have drawbacks.
'It's expensive to dry the brewers' grains.
It's energy-intensive,' says Aart van den
Boogaart, a utilities specialist at Heineken
Technical Services, 'and labour-intensive,
too, because once the material has been
dried, you still have to package, store, sell
and transport it.'
Another solution is to burn the brewers'
grains in a boiler, using a method developed
by a Brau Union brewery in Austria, where
transportation was a problem. The great
advantage of this method is that the energy
it produces can be recycled to generate
steam or heat water for the brewing process.
Burning 15 kg of brewers'grains generates
about half the energy needed to make one
hectolitre of beer, which will reduce the Ama
brewery's fossil fuel consumption by 3,000
tonnes a year and its greenhouse gas emis
sions by 8,000 tonnes.
'The cost of energy is such that the invest
ment in building a boiler to burn brewers'
grains can be recovered in five years,' says
Aart van den Boogaart, Heineken's lead
engineer on the construction of Ama brew
ery's boiler, which will enter service in
August 2004.
Brewers grains recycling
performance of Heineken world-wide,
Brewers grains recycling: application
performance of Heineken world-wide,
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