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Photos by Karen Block UC Davis Viticulture & Enology Department.
The Robert Mondavi Institute
The Robert Mondavi Institute for Wine and Food Science, at UC Davis, built in 2011 to be the most sustainable winery in the world and the first winery to receive LEED (Leadership in Energy and Environmental Design).
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Photos by Karen Block UC Davis Viticulture & Enology Department.
Advanced processing
Advanced processing with the capability of being cleaned using automated cleaning (clean-in-place or CIP) to provide better and safer cleaning with significantly reduced water and chemical use.
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Photo by Karen Block UC Davis Viticulture & Enology Department.
Sustainable teaching and research winery
Sustainable teaching and research winery at the RMI (Robert Mondavi Institute).
Reverse osmosis has been used in the wine industry to help refine flavor and alcohol content, but new work being done at University of California at Davis puts this technology at the forefront of water conservation.
Water supply is a growing concern for wineries around the world. Across California extended drought and an influx of new people and industry is creating conflict over an increasingly scarce resource. It’s a familiar situation in many winegrowing regions, including the Okanagan and Vancouver Island.
Dr. Roger Boulton
Dr. Roger Boulton at UC Davis
“It is unlikely that growth trends will reverse themselves in the near term. We will have to invest in technical solutions to use the water we do have more efficiently. The wine industry, glamorous as we may be, will need to come along,” says Eric Dahlberg, president and founder of Winesecrets, in a presentation to the Membrane Technology Forum in Minneapolis in June.
Many wineries are already implementing water conservation practices in the vineyard, but wine production, particularly sanitation, can account for significant volumes of water as well.
According to Dahlberg, winery sanitation requires an average of 6 gallons of water per gallon of wine produced, and with smaller wineries, that ratio can be upwards of 20 to one.
Where traditional water systems take water from a subsurface well or municipal system for single use, researchers at University of California at Davis supported by industry partners have devised a winery sanitation system that captures rain water and reuses it an estimated 10 times. This will allow wine processing without the introduction of water from existing resources.
“It all started with Dr. Roger Boulton at UC Davis asking why are we doing all this to the water when there’s perfectly good water coming out of the sky,” says Dahlberg, who brings expertise in reverse osmosis and membrane-based solutions to the project.
“Water harvesting is interesting, but not necessarily new. What’s really novel here is the concept of getting free clean water, being really careful about what you put into it, and using a special method to re-clean it so you can use it again,” he adds.
The rainwater is collected and passed through a solids filter to remove any debris that might have been on the roof. The stored water is then pumped through a reverse osmosis filter to a second set of galvanized steel storage tanks with a polyethylene liner.
“If there’s nothing in the water and you’re keeping it in the dark, nothing should grow and it should stay fresh,” Dahlberg explains.
The reverse osmosis filtered water can be used for sanitation in the winery. From there, used water goes through a nanofilter. Wine residues that won’t go through the nanofilter membrane is filtered off to the biodigester, and the cleaned water goes to a clean rinse tank, clean high pH tank, and clean low pH tank.
From the three clean tanks, the water circulates to a clean-in-place (CIP) room, where cleaning solutions are recaptured and filtered with 90 per cent recovery of water and buffer salts. Once cleaned, the water is pumped into storage tanks for use in cleaning tanks. Water recovered from cleaning the dirty tanks is fed back into the nanofilter where the wine residues are filtered out, and the liquid that will go through the filter circulates through the system again.
According to the UC Davis model, water should be able to recirculate through the system 10 times or more, resulting in 80 percent reduction in water use for sanitation. The system finds further efficiencies by bringing together the process water and wastewater streams.
“This is becoming more common in larger industries,” says Dahlberg. “The key to cleaning water is reverse osmosis, so if you have to use reverse osmosis anyway, you may as well treat the waste water and commingle with new water coming into the plant.”
As the monetary and scarcity costs of water increase, Dahlberg expects more wineries will be investing in water capture and recovery systems.
Eric Dahlberg
Eric Dahlberg, president of Winesecrets.
“Water is an important input, and they need a plan that is longer than next year,” says Dahlberg, pointing to the severe costs of interruptions to production. “Right now if you need a well to be deepened or cleaned out [in California], you’re looking at two years before the well guys can get to it.”
The benefits add up quickly. Every 230,000 gallons of water recycled with 80 percent recovery is equivalent to 2.5 million gallons of single use water. The water savings can be measured in terms of consumption, or water waste disposal.
Either way, renewable water systems make sense.
“There are already guys talking about starting rainwater capture. The CIP methodology is a little bit more cutting edge,” he explains. “It’s a very sensible and technical, highly workable system.”
“It’s not that hard to set up if you have to. Really all you need is the storage tanks, and all the wineries have storage tanks. The cool thing is if you have a reuse loops, you only have to store a fraction of the water you actually need,” he adds.
Dahlberg and his team at Wine Secrets are currently preparing a GE reverse osmosis filter for the Robert Mondavi Institute for Wine and Food Science at UC Davis, to be installed in July 2016. That will allow the research winery to start filtering the 80,000 gallons of rainwater they have already stored. UC Davis’s team’s next step is to source the nanofiltration unit, and do some small-scale membrane trials.
“We’ll probably have a small commercial version of the nano-gear available once it has been developed,” says Dahlberg. “This is just the beginning of the story, and we’ll be sharing the results as the project develops. Right now it’s more about changing the mindset of the industry than one piece of equipment or another.”■