Worm-powered innovation cleans up winery wastewater

An aerial view of BioFiltro vermifiltration system at Bonterra Organic Estates in Hopland, California

By Sonya Logan

Vermifiltration, a process that utilises earthworms to treat domestic and industrial wastewater, has been around since the 1990s but its application in the wine industry has been limited but appears to be gaining interest as companies seek to better manage their environmental impacts.

Believed to be the only vermifiltration company in the world specialising in the wine industry, Chilean-based firm BioFiltro has wormed its way (pun intended) into some 10 wineries throughout the US since 2015 and late last year spruiked its system to an audience of winery representatives in South Australia in an online presentation. BioFiltro has just the one installation in Australia currently and that is at Booth Transport’s milk logistics and distribution hub at Strathmerton in northern Victoria.

In a winery context, BioFiltro’s worm-powered patented wastewater treatment system works thus:

Wastewater discharged from a winery is first screened to remove larger solids before arriving at an equalisation tank where probes and sensors monitor the water quality. It is then dispersed evenly atop BioFiltro’s BioDynamic Aerobic (BIDA) system where it percolates down through layers of wood media where worms and microbes capture and digest contaminants.

“By relying on worms for aeration, the BIDA system requires minimally-sized pumps to dose the wastewater over the system,” BioFiltro’s sales engineer Sarah Haupt tells Grapegrower & Winemaker.


“Once treated, water gravity feeds out of the system through exit pipes and is ready for reuse in irrigation in as little as four hours.”


“Once treated, water gravity feeds out of the system through exit pipes and is ready for reuse in irrigation in as little as four hours,” Haupt continues. “Over time, the worms convert nutrients and solids that would otherwise become sludge into vermicompost — a valuable soil amendment that improves soil health, crop yield, water retention and carbon sequestration.”
Haupt says compared with more common winery wastewater treatment systems such as anaerobic ponds, BioFiltro’s solution is more energy efficient, produces minimal noise and odours, is sludge-free, automated and scalable.

“Our existing winery systems treat anywhere from about 3800 litres per day (LPD) to 3.8 million LPD.

“We typically design our wastewater systems for a peak BOD of 7000mg/l and 1000mg/l TSS, though we can certainly handle waste streams with higher levels of contaminants.”

As a general rule of thumb, BioFiltro can treat about 150 litres of wastewater per square meter of BIDA per day, although this is dependent on the characterisation of the wastewater and discharge goals of each winery.

The system is also capable of being supplied in a shipping container style set-up.

“We offer containerised systems for boutique wineries and custom systems for larger volumes,” Haupt says.
Winery waste streams are extremely variable in volume and quality throughout any given year, peaking during vintage. How does BioFiltro handle this ebb and flow?

“We handle the seasonal flows well because the adult worms will essentially hibernate and start eating the filter media (wood shavings). They are also laying cocoons (up to two per week) and those cocoons won’t hatch until conditions are right. Each cocoon has three to 12 viable worms,” Haupt explains. “We have some systems that don’t receive any water for months on end, in which case we’ll design recirculation with treated water to ensure the beds stay moist. The biology can go without ‘food’ for months on end, but moisture is important for the worms.”

Among the first wine industry adopters of BioFiltro’s system in the US were Californian-based Bonterra Organic Estates and Aonair Wines with their installations completed in 2017 and 2015, respectively.

The larger of the two, Bonterra Organic Estates makes around two million cases of wine a year, primarily Cabernet Sauvignon, Zinfandel, Pinot Noir, Chardonnay and Sauvignon Blanc. It produces between 12-15 million gallons (approximately 45-56 million litres) of wastewater a year which was previously treated via a pond aeration system. But a search for a “more sustainable, less energy intensive” form of treatment led Bonterra to BioFiltro, explains the company’s director of facilities and engineering Marc Feyh.

He says the BioFiltro system has been performing well since ironing out an initial issue related to the amount of solids in the winery’s wastewater stream.

“We have a high level of solids (lees) that enter our wastewater stream at the end of harvest. It took a couple years for BioFiltro to figure out how best to deal with the elevated solids. Now there’s a system in place to turn over and mix the solids resting on the top layer, and it’s been working fine for many years,” Feyh says.

“We still aerate the treated water in our holding ponds until we can land disperse it, so are using more energy than initially thought, but this is more of our process issue vs a BioFiltro limitation. Overall, the system uses approximately 40% less energy than the previous aeration method.”

Feyh says the process has had various tweaks to sensors, pH adjustment and control systems since installation.

“We were one of the first large wineries [to use the system], so there was some trial and error and scaling up issues, but nothing unmanageable.”

He says the treated water is being land-applied and sent back underground to recharge the local aquifer.

“The long lag between when most of the wastewater is generated (harvest to late summer) and when the vines are thirsty (growing season to late spring/early summer) wasn’t as clearly understood going in — this was a Bonterra issue not a BioFiltro issue — which means we hold onto the water longer and have to still aerate it some to keep it fresh before land application.


“We are planning to move towards wastewater reuse in the next couple years by replanting some vineyards with hardier rootstocks that can better tolerate a blended mix of wastewater and fresh water.”


As for the vermicompost, it was initially hoped that this would be directly applied to Bonterra’s vineyards. However, the wood chips in the vermicompost have proven to be too large so it is first taken to a processor for refinement.

Asked for feedback and advice on the system for any Australian wineries interested in the technology, Feyh says: “It’s a great way to sustainably treat wastewater with the organic power of worms and microbes using less energy and chemical inputs [with] no flocculant chemicals required. It also has the potential for treated water reuse.

“Carefully consider the use case scenario of what might be done with the treated wastewater and the timing between when the water is generated vs when it might be used and any storage implications this entails. Also consider that the worm/microbe process doesn’t treat or remove all constituents. For example, sodium levels remain relatively unchanged, but BOD and TSS are greatly reduced. So be sure to have a good understanding of what constituents your wastewater contains and consider what the BIDA system can and can’t remove and whether a secondary treatment step is needed to achieve the overall project goals.”

At the smaller end of the scale than Bonterra Wines is Aonair, based in the Napa Valley, which was established in the late 2000s by long-time Napa winemaker Grant Long Jr and produces around 8000 cases of wine a year, primarily Cabernet Sauvignon. Initially making his wines at other wineries, Long and his wife Megan purchased a hillside property near Lake Hennessey in the Conn Valley in 2015 which boasted several acres of vines and an ageing winery. As he set about modernising the winery, he became aware that Napa County had introduced a requirement “that all new wineries be responsible for processing their own wastewater”, Long explains.

After canvassing various treatment options for the 180,000L of wastewater the winery produces a year, he settled on BioFiltro as the alternatives “were much more expensive, time consuming and required a winery staff member to run them”.

“BioFiltro offered a more streamlined installation, management and easy process,” Long says.

“As the first installation in Napa I knew my system would come with some learning curves. But BioFiltro stood by their work and made changes to accommodate.

“As a wastewater system it has been perfect. It has met all the requirements of Napa County and have had no shutdowns or issues with processing waste. There were some original issues with the smell but that was resolved with some changes to the way the water was processed and the time it sat.”

Aonair reuses the treated water for irrigating its vineyards, resulting in a reduction of its use of well water by 90%, while the vermicompost is used as part of the preparations applied to its replanted vineyards.

Long says the greatest benefit of the BioFiltro system is the cost savings.

“I’m sure all the systems process the water effectively. But BioFiltro offers a ‘crash proof’ system that in almost a decade we’ve never had an issue with it taking what we give it in wastewater. Not to mention not needing a biologist on hand to manage microbial loads and pH,” he says.

This article was originally published in the February issue of the Australian & New Zealand Grapegrower & Winemaker. To find out more about our monthly magazine, or to subscribe, click here!

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