45    FULL-SCALE ANAEROBIC TREATMENT OF LOW
STRENGTH BREWERY WASTEWATER AT
SUB-OPTIMAL TEMPERATURES
Andre de Vegt, Manager of Technology
Paques, Inc.
Exton, Pennsylvania 19341
Tom Vereijken, Senior Process Specialist
Paques B.V.
Balk, The Netherlands
Freddy Dekkers, Process Technologist
Bavaria B.V.
Lieshout, The Netherlands
INTRODUCTION
Anaerobic treatment is usually limited to high strength wastewater at temperatures in the 30° to
40°C range. This paper describes the operation of a full-scale Upflow Anaerobic Sludge Bed (UASB)
reactor treating the effluent from a combined brewery, malting and soft drink plant. Pilot testing
showed that this low strength effluent (1600 mg/L COD) could be effectively treated at sub-optimal
temperatures (17° to 24°C). The full-scale anaerobic reactor was started up in 1985. The systems
successful operating history, has been credited for improved performance of the downstream Carrousel aerobic polishing system. Over the years, the brewery has increased production capacity thereby
increasing wastewater flow by 30% and wastewater COD concentration by 50°7o. To accommodate
the future load increase, a second anaerobic reactor, consisting of three independent operating compartments, is under construction and will be commissioned in 1992. Operational results will be
discussed.
WASTEWATER COMPOSITION
Bavaria B.V. operates a combined brewery, malting and soft drink plant in Lieshout, The Netherlands, since 1719. The family owned company operates its own energy plant (6.3 MW), distribution
network and process water and wastewater treatment plants. They presently employ 675 people full
time. Production is 24 hours per day, 5 days per week with the highest beer and soft drink production
in the summer months. Since the introduction of a successful alcohol-free beer in 1988 the company
has increased production capacity significantly. Production for 1990 in the Lieshout plant was 2.6
million hectoliters (hi) of beer, 1.3 million hi of soft drinks and 70,000 tons of malt. This makes it the
second largest brewery in the Netherlands. Bavaria is one of the few companies that produces its own
malt and a large part of the malt is exported to breweries worldwide.
Beer, soft drink and malt production are water intensive and wastewater is produced at various
locations. Figure 1 shows the average wastewater composition of the three different production
processes.
In the malting process barley is steeped, germinated and kilned under controlled conditions. Wastewater generated during this process is mainly a combination of excess steeping and cleaning water. It is
relatively cold (10° to 15°C) and of low organic strength (800-1200 mg/L COD).
In the brewing process barley malt is first coarsely ground and mixed with water in a mash tank.
During the mashing, enzymes convert starch into fermentable sugars. The grains are then strained and
the liquid, called wort, is directed to a brew kettle where the wort is brought to a boil and hops arc-
added. When the brew is complete the hops are strained, the wort is cooled to the right temperalurc
and transferred to the fermentation tanks. Here, yeast is added and the wort is converted to beer.
From the fermentation tanks the beer is transferred to lager tanks. The final stage consists oT
packaging the beer in the bottling plant. Wastewater generated in the brewing process results mainly
47th Purdue Industrial Waste Conference Proceedings, 1992 Lewis Publishers, Inc., Chelsea, Michigan 4X1 IS.
Printed in U.S.A.
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