The commercial wastewater treatment system
Septic systems and other onsite wastewater treatment systems are common in single-family homes, large-scale applications, such as at restaurants, apartment buildings, schools, commercial areas and residential subdivisions, not to mention wineries, produce much higher strength wastewater that has to be treated much differently than a residential system.
In this article, we go through some of the ways we can treat wastewater in commercial applications with an assortment of advanced treatment systems and related products designed for onsite treatment of wastewater on a larger scale, with a study of wineries.
Wastewater Treatment for Wineries
British Columbia is home to a number of award-winning, internationally recognized vineyards and wineries. In this article, we’ll explore the unique challenges that winemaking presents to on-site wastewater management and accompanying opportunities for innovative solutions to the production and management of wastewater.
To enjoy a glass of wine is to hold the world in your hand. In any glass of wine are history, poetry, philosophy, science, human health, economics and myriad other points of reference.
No wonder, then, that wine is so popular is most every culture! And also no wonder that wine production occurs wherever the climate allows grapevines to be nurtured. British Columbia is no exception.
This article draws from the Winery Process Wastewater Management Handbook, published by the British Columbia Wine Grape Council. The handbook is a comprehensive treatment of how to understand, monitor, refine and manage water use and the production of wastewater in winery operations.
It provides clearly detailed best practices, explains the ‘why’ as well as the ‘how,’ and provides a number of case studies of wineries that have dealt with a range of wastewater challenges and successfully turned their practices toward sustainability. If it isn’t already the “bible” of wastewater management for wineries in BC, it soon will be.
A (Very) Brief History of Wine Making in British Columbia.
The first vineyard planted in British Columbia, in the mid-1800s, was at an Oblate (Catholic) mission near Kelowna, for the purpose of making sacramental wine. Priests making wine on the frontier did not exactly stimulate a major industry, and Prohibition stymied what little winery growth there was in the early 20th century.
Real growth in British Columbian wine production began in the late 1980s, with a humble 13 wineries registered in the province at that time. Subsequent growth was encouraged by the importation of European grapevine cultivars and by developments in international trade and federal regulations that encouraged expansion in winemaking.
Today, there are more than 250 wineries in British Columbia, cultivating close to 5,000 hectares of grape vines and exporting over $20 million worth of wine each year.
British Columbia’s wine growing landscape is unique, active and draws international attention. It would be a thrill to spend this article exploring the tremendous variety of outstanding wines being produced in BC.
However, we’re here for a more prosaic, but very important, part of the background scene in wine production: wastewater. So open up a bottle of your favourite local vintage, and enjoy reading about the cutting edge of sustainable environmental and wastewater practices being put into practice by BC’s top wineries.
Delicious Wine; Challenging Wastewater
Wine production presents unique challenges to onsite wastewater treatment systems, principally because there are greater volumes of it compare to other commercial operations and because effluent strength is elevated as well.
Vineyards and their associated wineries bring the complexities of agricultural operations and commercial operations together onto one footprint of land.
Winemaking requires a lot of equipment, from harvesting baskets, grape crushers and juice transfer lines to fermentation tanks and bottle washers.
Keeping all that equipment clean, and the many processes involved in winemaking, requires fairly significant volumes of water, so wineries, in turn, generate greater volumes of wastewater.
Crushed grape residue, the dregs of fermentation (i.e., “lees”), residual alcohol and a variety of harsh cleaning agents all result in wastewater that is not only voluminous, but of high strength too, in terms of biochemical oxygen demand (BOD), suspended solids, elevated acidity or alkalinity, and harsh chemicals.
As with any food or beverage production facility, or agricultural operation, there is also the potential for odour issues associated with processing grapes and wine production.
We might discuss the “nose” of wine as a pleasing factor related to taste, but the residue of winemaking, the leftover grape residues, yeasts and lees have a powerfully sour odour that is much less pleasing.
Odours can have a negative impact on the winery itself if it is trying to attract visitors to its tasting rooms and potentially impact neighbouring communities. Good neighbourly relations and good publicity dictate that winery odours are well controlled.
We’ll dig into these issues of volume, strength and odour in a bit, and then we’ll explore the variety of innovative on-site wastewater treatment options available for wineries. But for any of that to make sense, we first need to understand the very basics of wine production.
Wine production 101
This brief overview won’t turn you into a winemaking expert, but it will help make sense of winery wastewater and the unique challenges it presents for on-site treatment.
Generally, winemaking is a ten-step process.
- Growing the grapes. Viticulture is the practice and science of growing grapes. The cultivar, or specific variety of grape, is the main determinant of wine type and flavour, but climate, rainfall, soil type and the particular environment of the vineyard also affect the growth and flavour of wine grapes. These factors have so much impact that wines from British Columbia, for example, and even distinct vineyards within BC, will to the discerning oenophile have completely unique characteristics, distinct from a French, Australian or even Californian wine.
- Harvesting the grapes. Harvesting is timed to the particular grape variety and to the type of wine to be produced, and typically occurs sometime between August and October in the northern hemisphere. Grapes are harvested by hand or mechanically, and the stems and leaves are removed to begin the wine production process. Note that winemakers distinguish two major periods of the year: vintage, the time of year when the wine is being produced, and non-vintage when the year’s grapes are growing and the winery itself is not producing wine. Wineries have to manage a high degree of variability in the strength and volume of their wastewater because of this distinction.
- Stem and crush the grapes. For better or worse, this step no longer involves bare feet in a barrel of grapes; machinery removes the stems from the harvested grape clusters and the grapes are then sent to a press and crushed to extract the juice. This step separates the skins from the juice and pulp. (Interesting note: juice is separated from the grape skins for white wine, for red wine the skins are left in the juice to give it colour. That’s just one of the countless production variations, apart from grape variety, climate and the timing of the harvest that leads to the tremendous variety of wines.)
- Fermenting. The extracted juice is transferred to large vats to ferment, in which yeast converts the sugars in the juice into alcohol. This typically takes anywhere from 10 to 30 days. Specific yeast strains are added, and local, wild variants of yeast also enter the grape juice on its way to fermentation. This is another factor in the specific tastes that characterize each winery and each vintage. Fermentation tanks vary considerably in size, from hundreds to tens of thousands of litres. So again, when we consider winery cleaning processes, sizeable tanks result in significant wastewater production
- Drain the wine. Liquid “free-run” wine is allowed to drain from the fermentation tank into barrels. At this point, you’ll notice that the winemaking process involves no small amount of equipment – harvest baskets, machinery for de-stemming, crushing and straining, fermentation and storage tanks, and a lot of plumbing to move the juice from one stage to the next. Tanks present a straightforward cleaning task, but crushing, straining and filtering equipment, and plumbing, present high-surface area meshes and closed systems. These, in particular, require high pressure and/or high volume water, and harsh cleaners that lead to wastewater volume and strength challenges. All to make sure the “nooks and crannies” of the winemaking operation are squeaky clean.
- Pressing. The free-run wine represents about 80% of the total wine volume. After it is allowed to drain, the remaining 20% trapped in the crushed grape pulp is pressed to extract the remaining wine, collected separately as “press wine.”
- Mixing. The press wine is then mixed with the free-run wine at specific ratios, determined by the vintner, that achieve a particular balance and taste for the wine.
- Clarification. Wine at this stage still has an appreciable amount of suspended solids in it – mostly grape pulp, yeast and yeast waste products. Since nobody likes chunky wine, the wine is clarified to remove the solids. Clarification is done either by filtration or allowing the solids to settle and syphoning the clarified wine off the top of the barrel. (Or both, or another of several alternate methods.) The residue of wine solids is called lees. Lees are a major source of suspended and dissolved organic material that contribute to the strength of winery wastewater.
- Ageing. The new wine is transferred into wooden barrels or stainless steel tanks and aged to let the flavours mature.
…And of course Bottling. The final product is put into bottles, ready for market. It sounds like the fun, simple last step in the winemaking process, but like in the previous steps, a good amount of machinery is involved. Bottles – lots of them – need to be cleaned, sterilized and purged with an inert gas (nitrogen, usually) to keep out air that could lead to spoilage. The wine has to be transferred from the barrels or tanks into the bottles, which are then corked and labelled.
Now that we understand winemaking basics, we can turn our attention to how these processes impact winery wastewater production.
Let’s stop here to remind ourselves of the obvious: vineyards and wineries are essentially combined agricultural and manufacturing operations that make products for human consumption.
…Because of that, every step in the process has requirements for scrupulous cleaning of everything that touches that product, wine, from starting materials to the end product.
As much as the agricultural component implies intensive water use, the cleaning requirements for the manufacturing component implies additional demands on water availability as well as the generation of high volume, high strength wastewater.
Good water and wastewater management is fundamentally an economic opportunity for a vineyard and winery.
Sustainable practices are not just about the cost of water and wastewater treatment, although these are significant.
Sustainable practices ensure against negative impacts on neighbouring communities and the local environment – for example, unpleasant odours, groundwater contamination, or eutrophication of surface waters – that are problematic in their own right and can generate negative publicity.
Such practices also present a marketing opportunity, attractive examples of how a commercial operation can maintain and even enhance a rich, resilient and diverse local environment through its water and wastewater management, and this can be as much of a draw as the wine itself!
Water Use in Vineyards and Wineries
Because wastewater volume is one of the key characteristics of winery septic considerations, it’s helpful to review how water is used in growing grapes and making wine.
As we’ll see later on in this article, understanding and managing water use is a critical first step in operating an economically viable and environmentally sustainable winemaking operation, with significant impacts on effective wastewater treatment.
The growth and sugar content of grapes on the vine is what makes a successful vintage and the ultimate taste of the wine.
So, grapevines may be irrigated to ensure adequate soil moisture while the crop is growing and developing. Irrigation, then, is the first input of water that a vineyard and winery must take into consideration.
Although irrigation water, of course, is not part of the wastewater stream – it’s going into the soil and the grapes, not the septic tank, after all – it is part of a winemaking operation’s overall water use. Water use and wastewater treatment should be understood holistically.
Any potential reuse of treated or semi-treated (i.e., “grey water”) wastewater for irrigation has a positive impact on winery operations overall because it accomplishes two conservation goals at the same time.
First, it eliminates or reduces fresh groundwater or surface water is drawn for irrigation. Second, it provides a reliable means of distributing wastewater volume back into the environment while at the same time exploiting the capacity of the soil under the vines for continuing treatment and removal of nutrients.
Cleaning equipment is the number one source of water use in a winemaking operation, and the major input into the wastewater stream.
About two-thirds of all water used by a winery, at various stages in the process, goes towards cleaning the grape bins used for harvesting, the de-stemming and crushing machinery, the juice collection apparatus, and transfer lines and fermentation tanks.
Floors in the crushing and fermentation area also need to be cleaned regularly, and wine bottles need to be washed and sterilized before they are filled.
The winemaking process is water intensive, but not the only water requirement a winery needs to meet.
Wineries may have boilers for heating, small laboratory operations for testing during the winemaking process, and worker facilities, for example, restrooms and locker rooms, all of which require an adequate water supply and feed into the wastewater stream.
Wineries are not just “wine factories.” They are a part of the local tourism industry, so they often have a tasting room, a gift shop, and may even serve as event and wedding venues.
That, of course, implies public facilities such as restrooms, kitchen facilities, a bar area and exterior landscaping.
These, of course, create additional requirements for water as well as presenting additional inputs to the wastewater stream.
A careful, quantitative accounting of water use is the first step to creating and maintaining a financially viable and environmentally sustainable winemaking operation.
Wastewater input accounting is just as important because it helps to ensure that the on-site treatment works are adequate to the task and resilient enough to accommodate the differences in wastewater generation during vintage and non-vintage or any changes in production processes of volumes.
When your wine is popular and demand increases, you want your treatment system to be able to keep up with your ramped-up production!
What’s unique about winemaking wastewater? Everything! With the exception of irrigation water, all winery water use goes down the drain, carrying with it a number of unique waste components.
These will include waste grapes and juice, grape pulp and skins, sugar, alcohol and yeast, lees, sink and toilet waste, and some fairly harsh cleaning chemicals.
By far the biggest contributor to winery wastewater is from cleaning machinery. Just like the dishes at home, a simple rinse with water will not adequately clean winery machinery.
Typically, caustic (i.e., alkaline) cleaners are used to dissolve grape residues, and then acid cleaners are used to neutralize the caustic cleaners.
Finally, everything gets rinsed down with plain water. Cleaning agents create challenges by causing variability of the relative acidity or alkalinity of the wastewater. Extremes of acidity or alkalinity can harm the microbial populations responsible for breaking down waste during on-site treatment.
Because of this diverse input, winery wastewater is always “high-strength,” meaning elevated organic loads, elevated BOD (greater than 7,000 mg/L compared to less than 250 mg/L in household waste), elevated suspended solids (greater than 3,000 mg/L), salinity, acidity or alkalinity, nutrients (phosphorous and nitrogen) and harsh chemicals.
Further complicating the matter, these loads will vary over the course of the year, with the highest strength and highest volume being produced during the vintage period. Even the local climate, the type of grapes being grown and the type of wine being made will affect the strength and makeup of winery wastewater.
On-site Wastewater Treatment for Wineries
Wineries use a lot of water, and they generate a lot of wastewater. On-site treatment systems for wineries are highly varied.
They can look like larger versions of traditional residential systems, tanks and leaching fields for example, or, they can look more like other agricultural waste systems, with open holding lagoons or dry wells.
But wineries, perhaps more than other agricultural operations, tap into the tourist economy and the consumer sphere, and this is part of the reason that there is a lot of innovation going on with wastewater treatment in the winery business.
Sustainable Winegrowing British Columbia is leading the charge in all areas of grape cultivation and winemaking. Its recommendations on wastewater treatment focus on three main areas;
1) quantifying water use and wastewater production
2) reducing water use and wastewater production and:
3) suitable on-site treatment and innovations in wastewater treatment.
You Can’t Improve What You Don’t Understand…
…so the SWBC best practices guide provides a step by step process to quantify water use and wastewater production.
It includes using flow diagrams to understand the unique details of winemaking operation for a particular winery, from grapes on the vine to a bottle of wine. It is followed by physical monitoring of water use, with the strategic deployment of water meters to track water use over time during vintage and non-vintage periods.
The end goal is to identify problem areas where use is excessive and opportunities for water use to be reduced.
Aim for Less “Waste” in Your Wastewater
We’ve been there. Time to clean up from dinner. One kid carefully scrapes her plate into the trash bin before putting it in the dishwasher, while the other kid puts his crusty plate, loaded with leftover spaghetti and salad, right into the dishwasher.
The cleaning of equipment and floor areas at the winery presents a similar situation, and similar opportunities to keep organic matter out of the waste stream and thereby reduce its strength.
Simple practices like scraping and removing bulk material with bushes and squeegees, and design considerations like effective drain screening in strategic locations, all accomplish reducing wastewater strength at its source.
Some wineries practice the collection of grape solids for composting at off-site facilities, while others wineries are actually connected to municipal systems, but have on-site treatment to reduce the overall strength of the wastewater and so reduce the burden on the municipal system.
Efficient use of cleaning water is another area where substantial reductions in wastewater volume can be achieved. For example, final rinse water can be redirected to initial rinsing of other items instead of sending it directly to the drain, and in-line testing procedures can reduce or eliminate laboratory glassware cleaning.
Commercial Septic Systems & Treatment Units
As I’ve often written here, there is no ‘one size fits all’ wastewater treatment system. This is, even more, the case for wineries, because, in addition to site topography and physical characteristics, there are loads of variations in each step of the winemaking process, so every winery is unique.
Traditional treatment systems for wineries reflect the agricultural nature of these operations, in that they may involve lagoons, constructed wetlands, and drywells or open filtering beds rather than the leaching fields typical of residential systems.
But, they still feature recognizable components such as receiving and settling tanks, effluent removal, effluent dispersal, and are accomplishing the same overall treatment scheme that is the aim of all treatment systems: settling solids, decomposing waste, and clarifying effluent for secondary or tertiary treatment.
Newer, innovative treatment systems are continually being developed and implemented for the unique wastewater treatment needs of wineries.
The BIDA® system from BioFiltro treats wastewater by filtering it over a bed of red worms and microbes, a system that is all-natural and self-regenerating.
EcoVolt is a modular aerobic treatment system that generates methane gas from the decomposition of waste, which is then used to produce electricity.
The BioGill system is another closed system that uses filtering membranes to support microbial populations to efficiently treat waste in a closed system with a small footprint, for wineries with space limitations.
These are just a few examples of advanced, cutting edge wastewater treatment, so what are the factors to consider? Clearly, the first step for any winery should be to fully evaluate process improvement opportunities, because you don’t want to design and buy a system to handle much higher volumes and wastewater strength than you will be generating after you’ve optimized your processes.
A system that has excessive capacity can be as ineffective as a system with too little capacity. Capital costs, overhead and operational costs should be evaluated in the context of operational savings over the long term, and any potential branding benefit (e.g., when sustainability and environmental responsibility become another selling point for the winery and its products).
Other considerations might include comparing land and space requirements for different systems and whether the footprint of a treatment system might take up valuable land that could be planted with vines).
Examples of Current Systems in BC Wineries
Here are a few interesting examples of operational wastewater system configurations being used in BC. I’ll just provide an overview here, with the aim of illustrating how winery wastewater systems accommodate both specific site features – topology, soil characteristics, and proximity to surface water – and each winery’s specific winemaking operation. For details and diagrams, refer to the Best Practices Handbook).
In two of these examples, we’ll see that the waste stream of the winemaking process – from the crush pad, harvesting baskets and trench drains – is a separate system from washrooms and kitchen operations, while the third example is of a system that combines all winery wastewater into one wastewater stream.
Winery Wastewater Treatment in Practice: A Simple System of Settling and Leaching
One Lake Country winery employs a straightforward system of settling tanks and drywells to receive drainage from the crush pad, trench drains and basket cleaning. Here, two settling tanks are connected in series.
The first tank receives a somewhat vigorous flow from the crush pad and other floor drains and has the dual purpose of allowing solids to settle and of dampening the force of the waste flow so that in the second tank more efficient settling can occur.
This winery’s system employs two drywells, plumbed so that the flow from the settling tanks can be directed to one or both of the wells. A drywell is somewhat analogous to a leaching field in that it allows effluent to flow by gravity through the soil profile for secondary treatment.
The difference is that the well holds a large volume of effluent as it percolates into the soil. As with a leaching field, drywells are not suitable for poorly draining soil, and because drywells are typically deep (to hold a suitable volume of effluent), they have the potential to contaminate groundwater with untreated effluent.
In suitable circumstances as with this winery, though, and with alternating between the two drywells, the drywell system is expected to last many years.
Winery Wastewater Treatment in Practice: Incorporating Aeration to Reduce Wastewater Strength.
In Naramata, a winery wastewater system incorporates an aeration tank connected to receive effluent from the primary wastewater receiving tank.
Recall that aeration systems encourage the decomposition of organic waste by aerobic bacteria. In this particular system, the sludge that settles to the bottom of the aeration tank is then pumped back into the primary tank, where it is further decomposed.
This configuration is effective for reducing the high strength of the winery’s wastewater to a level that can be accommodated by the next phase of this system, which is a sand dispersal bed. Sand filtration provides a final reduction in suspended solids before the effluent leaches through the underlying soil profile.
This system has been in operation for several years and operates well, yet it also illustrates some of the issues that wineries deal with.
Wastewater strength can vary widely depending on the flow of water down the drain. For a given amount of grape residue (skins, pulp, lees, etc), less water means a higher concentration of organic material, which means higher strength wastewater and more strain on the treatment process.
At this particular winery, drains don’t trap solids very well, allowing them to enter the wastewater stream. So, winery personnel have to carefully monitor the primary tank and frequently have it pumped out.
Also, while the aeration system does a great job of reducing the overall wastewater strength, bubbling air through the wastewater carries the potential to create odour issues around the winery.
The system incorporates a sampling port that allows personnel to sample effluent after it has passed through the sand filter bed, to ensure that the effluent is sufficiently treated when it enters the soil profile. This is a good example of how wastewater systems require monitoring of performance while in operation.
Winery Wastewater Treatment in Practice: A Sequential Batch Reactor.
Our last example is from a winery in Kelowna that employs a sequential batch reactor to handle the bulk of wastewater treatment.
All the winery’s drains, including the kitchen and washroom, empty into a common settling tank. The tank effluent feeds a secondary tank that holds and then delivers a 6000 L batch of wastewater to a bioreactor.
Here, in a series of timed steps, the batch of wastewater is aerated for efficient biodegradation, and the sludge is allowed to settle. Then, the effluent is removed for subsequent disinfection by UV light and filtering. The clean effluent is finally pumped to a dispersal field where it leaches into the soil profile.
A bioreactor of this type yields very clean effluent, so it can be returned to the environment using a dispersal field with a very small footprint, or it can even be used for irrigation. It’s a good choice for smaller wineries with limited land or that is situated close to other commercial or residential properties because it generates effluent that even meets domestic sewage code and eliminates the potential for odours to escape.
Bioreactors are expensive, though. They come with a high capital cost and require experienced personnel for operation and maintenance. Also, the “bio” in bioreactor refers to the aerobic microbes that degrade the waste, and these guys need to be kept alive with some input of organic material, which can present a challenge during non-vintage.
A modern vineyard and winery is a unique agro-ecosystem as well as a commercial beverage producing operation, and designing or upgrading on-site wastewater treatment for a winery requires consideration of both of these characteristics.
Only a holistic approach can be effective here, taking into account the site of operation and available land, the surrounding environment, and the particular grape cultivars and winemaking processes of the operation.
Because wineries also function as part of the tourist economy, they bring people of all backgrounds in close proximity to agriculture.
In that are myriad opportunities to develop, demonstrate and promote sustainable practices in water resources management and habitat enhancement that benefits local environments and local communities.
Our services at GroundStone wastewater
With a myriad of experiences in various wastewater treatment applications, it is our job to ensure you concentrate on what you do best and that means working on your business.
Commercial wastewater treatment can certainly be complex, and let’s face it, although we may be extensively experienced, we might not have all of the answers.
We do however have a great network of people from wastewater treatment unit manufacturers, distributors, technicians, inspectors, regulators and engineers. We’re going to work towards getting you the right system that not only is green for the environment but is efficient to your business needs.
Here’s what one of the builders we have worked with has to say:
As a builder finding great consultants to work with can be frustrating and difficult. The team at Groundstone went above and beyond for getting a problem resolved for us on a project in Lake Country. They are my “go to” for any onsite Wastewater projects
Orchard View Builders