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With winemaking comes wastewater, a side effect that increases
exponentially with the growing demand for the fermented juice
of fine grapes. Table wine consumption in the US continues
to rise after recently reaching a record high of 232 million
cases per year. Consequently, winery wastewater management
can be just as intricate as the formula behind the aroma,
color, and bouquet of the most coveted selection in the cellar.
Affected by far greater scrutiny from regulatory agencies
and a neighboring public, as well as by energy conservation
and sustainability needs, effective winery wastewater management
has never been more important.
The caliber and popularity of a particular wine may present
a challenging wastewater treatment scenario. Consider that
as sales increase, wineries must expand their operations.
Facilities will typically outgrow one wastewater handling
and treatment method after another. Regulations continue to
tighten and compliance becomes costly. Simple sewer connections
are no longer feasible or even possible. The operation turns
to septic tanks and leach fields only to find that the system
becomes clogged with the high solids in the waste. The next
step is the wastewater pond, which can tie up several acres
of valuable vine land. The significant levels of dissolved
sugars in the winemaking process are measured in the effluent
as biological oxygen demand (BOD). With the “shock loading”
of high BOD levels, odorous wastewater ponds can turn the
noses of even the most passionate wine lovers.
So what’s a nice winemaker to do? Bottom line, treating
winery wastewater requires customized, specialized solutions
based upon specific factors at a given facility—such
as its wastewater volume and seasonal load variation, its
property size and available land, and its proximity to surface
waters and residential areas. An operation’s current
economics and future expansion plans also play a part.
But common to all wineries, regardless of size or situation,
are the distinctive and highly fluctuating characteristics
of raw winery wastewater. During the crush season, pH, BOD,
total suspended solids (TSS), and nitrate levels are elevated.
The seasonal nature of the business means that pH can range
from 2.5 to 11, and BOD discharge levels may approach 5,000
ppm, with values as high as 20,000 ppm.
With all of these issues in the mix, many winemakers are
collaborating with wastewater consultants, engineers, and
system manufacturers to identify the most cost-efficient OWT
technologies—ones that deliver a solid return by ensuring
long-term environmental regulation compliance, while minimizing
the treatment site footprint. Today’s forward-thinking
wineries may also seek the cost savings from the reuse of
treated wastewater for irrigation, or even the ability to
create usable energy from the biogas byproduct of certain
treatment methods.
Converting Ponds
Into Bioreactors
Elutriate Systems of Arroyo Grande, CA, specializes in rapid
BOD digestion wastewater systems, especially those that can
maximize the treatment potential of a traditional pond system.
“If we can’t make bigger ponds, let’s make
the existing pond far more efficient,” says Glenn Wensloff,
who heads the company.
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| Fine bubble diffusers are positioned
at the bottom of the Hahn Estates Winery wastewater treatment
pond. |
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| Clos du Bois uses a Biothane high-rate
anaerobic biodigester for faster, more efficient wastewater
processing, and energy savings benefits. |
Wensloff works one-on-one with wine makers and fruit processors
to turn their conventional “facultative” ponding
systems into effective “bioreactors.” He explains
that facultative systems have three different layers based
upon the aeration provided by traditional floating aerators.
The top layer, with its high dissolved oxygen level, is where
most of the BOD digestion occurs. The middle layer is a transition
zone. The bottom layer is anaerobic, or devoid of oxygen.
This is where the bacteria, which actually consume the BOD,
are digested. “The facultative pond is a carryover from
the sewer industry and, when fecal waste is involved, this
process works well as it digests bacteria in a beneficial
manner. But for the winery wastewater, it’s a poor design.
In the wine industry, it is much more astute to view the bacteria
from wastewater as a ‘compost tea.’ This is a beneficial
non-fecal bacteria that is good for the soil and eliminates
the need for both fertilizers and pesticides,” he says.
To meet the regulatory and operational requirements of a
recent expansion at the award-winning Hahn Estates Winery
in Monterey County, CA, Wensloff worked with the facility
to ensure that its new ponding system would function as a
rapid-acting aerobic digester, treating wastewater to the
level where it could be reused and applied to the vines through
a drip irrigation system. To accomplish that, the conventional
floating aerators concept was scrapped and replaced with a
fine bubble diffuser system that utilizes a blower to deliver
high volumes of air at low pressures through diffusers, producing
very small bubbles for greater operation efficiency. “The
pond is now an aerobic digester with the aeration occurring
on the bottom of the pond, and the entire pond volume rapidly
digesting the BOD. The bacteria, which traditionally dropped
from suspension, are now kept in intimate contact with the
high BOD influent. The efficiency of the new system (which
utilizes the existing footprint) increases tremendously,”
Wensloff says.
Between the first two ponds in the system, Elutriate Systems
installed a series of clarifiers that allow the bacteria to
fall from suspension. Then the concentrated bacteria are pumped
back to the incoming high BOD influent. The effluent flows
from the clarifier into the second pond, which is also aerated
with fine bubble diffusers. Treated effluent then flows to
an irrigation pond where it awaits distribution as an irrigation
system. Wensloff sums it all up when he says, “The more
critters eating at the food basket, the faster the food is
digested, and the smaller the system has to be. A lesser volume
of water needs to be aerated, treated water is reused, and
the savings quickly compound.”
As Hahn Estates continues to expand its market presence and
winery production, its next wastewater system upgrade will
involve placing a large bioreactor tank upstream from its
ponding system, says Wensloff. “With a tank, it’s
easy to get 20 feet of height. It’s hard to make a pond
20 feet deep. The increased depth you get from the tank allows
for better oxygen transfer to the water, resulting in higher
levels of dissolved oxygen and minimized electrical energy
use,” he says.
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Capitalizing
on High-Rate Anaerobic Digestion
As a grape grower in Sonoma and Mendocino counties, Clos du
Bois is recognized and certified within the sustainable farming
community. In an integrated effort, says the company, it also
utilizes environmentally sound practices at its winery, which
is equipped with a high-rate anaerobic biodigester—the
first wastewater treatment system of its kind at a California
winery. When the operation quadrupled its production in the
last decade to 1.5 million cases, its management chose the
biodigester as a method of sustainable growth. It would require
a footprint of 10,000 square feet, an attractive alternative
to the multiple acres needed for large settling ponds. The
biodigester, which holds 130,000 gallons at peak capacity,
treats the same wastewater volume as that of a three-acre
ponding system.
Manufactured by the Camden, NJ–based Biothane Corp.,
the biodigester uses anaerobic bacteria to break down grape
skins and other matter within the wastewater, ridding it of
much of its wastes within 24 hours. Treated water then flows
to a traditional treatment pond before being used in vineyard
irrigation. Although they incurred considerable upfront costs,
Clos du Bois chose the unique solution, intending to reap
its return in reduced energy costs year after year. Since
its installation, the company says that the new system treats
wastewater faster and more efficiently, while using less energy
than that required by pumps in a pond system. But most importantly,
the anaerobic digester produces methane gas as a byproduct.
The next upgrade for Clos du Bois is capturing this biogas
and reusing it to power other equipment.
“Anaerobic technology was developed in the Netherlands,
with its first North American installation at a Wisconsin
brewery in the 1980s. It has since been applied at yeast plants,
ethanol plants, distilleries, and food processing operations—anything
that uses fermentation in the development of the product,”
says Robert Sax, Ph.D., president of Biothane. The problem
with “conventional aerobic technology,” he says,
is that it generates no energy byproduct, and much of its
conversion process results in the production of biosolids,
which is sludge that requires costly disposal. Among Biothane
technology offerings are high- and low-loaded anaerobic systems,
conventional and high-loaded aerobic systems, anaerobic sludge
digestion and biological gas scrubbing.
Sax says that although advanced treatment technologies have
always been more practical for larger winery operations, the
economics of their use in smaller wineries are changing rapidly.
“Due to skyrocketing fuel and energy costs, smaller operations
will consider anaerobic technology more seriously than ever
before. And, its high-rate digestion approach allows for a
compact design. In the past, small companies couldn’t
see the value in it,” says Sax, adding that under “old
energy price scenarios,” even the largest wineries thought
little about energy savings. “A lot of larger applications
have simply flared the biogas, because there is a cost to
recovering it for use. You have to pipe it, install a burner,
and maintain boilers that accept controls. Even with that
setup required, today’s market is taking a very hard
look at it. Traditionally, companies were always motivated
by an ability to cut wastewater surcharges. Now there is the
additional incentive—valuable energy savings,” he
says.
Writer CAROL WASSON owns JCL
Marketing & Communications Inc.
OW
- November/December 2005
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