Program Book - Master Brewers Association of the Americas

P-108
The relationship between water consumption and energy
usage in the malting and brewing industries: Opportunities
and priorities
GARY FREEMAN (1), Miguel Catala Ortega (1)
(1) BRI, Nutfield, United Kingdom
This poster will discuss improving environmental performance
in malting and brewing facilities from the point of view of
interconnections between water efficiency and energy efficiency.
Both malting and brewing processes are energy-intensive and large
consumers of water. As well as charges for carbon dioxide release
and fuel and water prices increasing, there is legislative and public
pressure to act in a more sustainable fashion. The chemical engineer
should consider the environmental impact of the plant in a holistic
fashion to make sustainable modifications or investments. The
largest users of energy in the two industries are malt kilning, wort
boiling and packaging (excluding transportation). The largest
water usages are steeping in the malting process and packaging
and cleaning in brewing (excluding the water in the product). Endof-pipe
technologies that recycle much of the water that would
otherwise be sent to effluent treatment may have a high energy
demand. For example, recycling of a maltings’ steep water is
potentially a very large water saving, but any re-processing will have
a cost in energy. However, these technologies must be appraised
against dwindling water resources, the costs and environmental
impact of the alternative effluent treatment and discharge and the
likely future price of potable water. Water must be considered as
much more valuable when it is hot water; therefore, recovery of
heat, water and chemicals from in-place cleaning processes must
be increasingly prioritized. Similarly, other cleaning strategies
include increased use of lower temperature cleans and monitoring
through automation to minimize cleaning intensity. The costs of
energy and water purchase will be higher in the future; therefore,
projected increases should be factored in to technology decisions
that are made today. It is possible to assess the sensitivity of capital
expenditure to different levels of price rise. Clearly local factors
such as the availability of water will affect any particular decision.
The packaging line is a major user of energy and water, and there
are technological opportunities for improvement. The choice
of package itself will affect the environmental impact; however,
clearly package formats are enormously influenced by retailer and
consumer demands. This poster helps to highlight priorities for both
the site engineer and strategic planner in developing the process in a
suitable manner for the current commercial environment.
Gary Freeman is a chartered chemical engineer and scientist. He
joined BRI in 1989 and is now a senior engineer. He has worked
extensively on brewery and malting processing in areas such as
solid-liquid separation and environmentally acceptable technologies.
In his time at BRI Gary has authored or coauthored 47 chapters,
papers, articles, and convention posters, including 19 original
research communications. In 1991 he passed the Institute of Brewing
& Distilling’s Diploma Membership Examinations with distinction.
He is a Fellow of the Institution of Chemical Engineers. He also holds
a Certificate in Packaging from IOP – The Packaging Society. He is
a member of the Brewing Science Group of the European Brewery
Convention and the Environmental Group of the Institute of Brewing
& Distilling.
120
P-109
Withdrawn
P-110
Application of substrate specific enzymes and bottle-washinglye
for dwell time reduction during anaerobic digestion of
spent grains
THOMAS HERFELLNER (1), Christoph Nophut (1), Günther
Bochmann (1)
(1) Technische Universität München, Freising, Germany
Against the background of rising energy costs and limited options
for waste disposal, organic brewery residues (spent grains, malt
dust, hot/cold break, surplus yeast/sediments, labels, kieselguhr
sludge, wastewater) offer an interesting way of energy recovery.
Due to the inhomogeneous chemical waste composition and the
various solid, pasty and liquid compounds, anaerobic digestion
(AD) represents the most advantageous technology and is, in the
case of wastewater treatment, already state-of-the-art. Concerning
the chemical composition of spent grains there are still problems
in hydrolyzing the lingo-cellulose fraction, which consists of hemicellulose,
cellulose and lignin, in a short time. The performance
of hydrolytic bacteria without any pre-treatment is not enough to
achieve economically advantageous dwell times. Therefore the
effectiveness of a substrate specific enzyme mixture as well as
alkaline treatment were tested in 20 l reactors in laboratory scale.
The experiments were operated in a two stage fermentation system
(first stage: hydrolysis in continuous stirred reactors; second stage:
methanation in fixed bed reactors) with liquid-solid-separation in
between. To evaluate the degradation of spent grains the volatile
fatty acid (VFA) concentration, chemical oxygen demand (COD),
pH-value and ammonium concentration of the liquefied fraction,
as well as the content of fat, protein and fiber of the residual solid
fraction, were analyzed in duplicate. The composition of the
produced biogas was analyzed by gas chromatography and mass
spectrometry (GC/MS). For inducing hydrolysis, seeding sludge
of a municipal wastewater treatment plant was used as inoculum.
By the application of substrate specific enzymes it was possible to
force the liquidation-time of the complete protein and fat fraction
of spent grains. The additional added enzymes also quickened the
microbial hydrolysis of the lingo-cellulose fraction. However, the
dwell time reduction by substrate specific enzymes was not extensive
enough, for which reason alkaline treatment of the remaining lingocellulose
fraction was tested by adding bottle-washing-lye. Within
a few hours the hemi-cellulose fraction was completely liquefied.
The remaining cellulose was treated enzymatically again. After
each hydrolytic step liquid-solid-separation took place. The liquid
fraction was subsequently fermented in a fixed bed reactor. Thereby
the degradation of hydrolytic products to biogas was analyzed.
During the experimental stage no hindrance of the methanation
could be detected. By the application of substrate specific enzymes
in combination with alkaline treatment with bottle-washing-lye the
dwell time of spent grains during anaerobic fermentation could be
reduced below 12 days. An economic process could be proven.
Thomas Herfellner received a diploma and M.S. degree in food
technology from Technische Universität München, Germany. Since
2006 he has been working as Ph.D. student at the Institute of Energy
and Environmental Technology of the Food Industry, which was
renamed the Institute of Resource and Energy Technology in 2007.
His scientific work is on anaerobic fermentation of organic brewery
residues.