05.12.2011  
 

B.C. Winery Ferments Water

Tantalus Vineyards purifies wastewater in sequencing batch reactor

 
by Peter Mitham
 
Tantalus waste system
 
Tantalus' waste water treatment facility includes an innovative 'Bio Cube' that eliminates odor, giving the building a fresh-earth smell.
 
Kelowna, British Columbia, Canada—A municipal-grade water-treatment system promises to yield irrigation water for a British Columbia winery this year. Tantalus Vineyards installed a sequencing batch reactor (SBR) last year as part of the development of a new, 13,000-square-foot winery building that’s seeking LEED (Leadership in Energy and Environmental Design) certification. The treatment plant, designed by Enviro-Stewards Inc. of Elmira, Ontario, occupies a compact, 900-square-foot building next door.

“We were trying to fit out a completely sustainable growing and winemaking system. I think part of that is treating our own waste,” winemaker David Paterson told Wines & Vines.

SBR systems are part of several livestock operations and breweries, but few wineries use them. Some greenhouses also have investigated water treatment systems aimed at reusing water and reducing demand from local systems. Smaller municipalities such as Pemberton and Whistler, B.C., a host of the 2010 Winter Olympics, use SBR systems. The project cost isn’t disclosed, but Tantalus general manager Jane Hatch indicated the cost was significant for a small winery. Tantalus produces approximately 3,000 cases per year.

The process is fairly straightforward: Wastewater—including process water from the winery, grape waste and sewage—enters a 12,000-liter anaerobic fermentation tank. The bacteria tackle it, Paterson explained, and then 6,000 liters at a time are pumped through a single-batch reactor where the oxygen content of the mixture is raised to 6 milligrams per liter.

Microbial reaction
“It’s gone from a very anaerobic—no oxygen—state to a very aerobic state, and then a whole new microbial reaction takes place, and that keeps mixing several times, depending on flow rate,” Paterson said. (Part of the beauty of the SBR system is that it allows for a constant flow of water into the initial tank, allowing for a more compact system than many conventional systems.)

The aerated mixture then enters a final 12,000-liter tank where solids drop to the bottom, and the top 6,000 liters are decanted into a third part of the system where bag filters and ultraviolet filtration kills any remaining bacteria.

“It can be used at that stage for irrigation or gray water in toilets,” Paterson said. The whole process takes about eight to 12 hours when the system is working at peak capacity. The less water entering the system, the longer the time spent before decanting and filtration, and in turn the cleaner the water is.

Becoming familiar with how to operate the system effectively takes longer, however. “The biggest challenge for us is flow. When we’re making wine in September, October, November, we’re getting a lot of high-nutrient, high bio-oxygen-demand waste going into the system, which in turn feeds the microbes,” Paterson said. “Come this time of year, we’re having very little flow go through, and what flow we’re having is basically snowmelt with very little nutrient.”

This means greater attention is required to maintaining the health of the microbial cultures in both the aerobic and anaerobic fermentation tanks. The good news is that Paterson’s expertise as a winemaker gives him an understanding of how to keep microbes healthy enough to perform. “It’s like having a big, stinky ferment,” he said.

Dog food for bacteria
One solution that seems to be working is serving the bacteria dog food high in amino acids to bolster the culture in preparation for a higher influx of wastewater. The seasonal dynamic of the flow also means Tantalus has had to consider where to channel the water once it’s cleaned up.

“Our next step, now that we’ve got the system working and we know that we can use it,” Paterson said,  “is how do we use it?”

Gray water is ideal for toilets and irrigation, but peak flows through the processing plant occur when water is least needed in the vineyard. A holding tank doesn’t make economic sense, so Tantalus is considering post-harvest irrigation so water can rest in the soil for vines to use the following spring.

In the meantime, Tantalus is resting easy in the knowledge that it’s reducing its overall water consumption and not returning dirty water to the environment.

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