As a distiller, you’re not just a craftsperson making spirits; you’re also a guardian of the land and water around you. After all, creating spirits is as much about flavour and character as it is about reflecting the environment from which it originally came from – the fields, trees and farms…
As a result, a key part of your role is the management of distillery waste, particularly effluent.
This article serves as a guide some of the intricacies of effluent. We’ll cover what it is, how to measure and monitor its components, as well as some ideas for treating and disposing of it responsibly.
Understanding distillery effluent
We all love to focus on what we are making – world class spirits. That’s the output! Yet distilleries also create a less glamorous by-product: effluent. And it also an output that deserves a lot of attention.
Effluent, essentially, is all wastewater that leaves a distillery, and it’s far more than just unused liquid. It’s not all toxic waste either at all! Effluent can range from liquid that contains organic matter like yeast and other residues from the fermentation and distillation process, as well as waste water with inorganic compounds from cleaning chemicals.
Depending on its constitution, it can have a profound impact on local waterways if not managed correctly. In the worst case scenarios, it can lead to environmental damage and hefty fines from regulatory bodies.
For craft distillers, who often draw inspiration from their natural surroundings, protecting their immediate environment is not just a legal obligation but it ought to be a core value as well.
Monitoring effluent components
To safeguard the environment and adhere to regulations, the first step is for all distillers to become adept at monitoring their effluent. This involves measuring:
- Volume: How much effluent is your distillery producing?
- Suspended solids: What is the concentration of solid materials floating in your wastewater?
- Chemical oxygen demand (COD): How much oxygen is needed to break down the organic material in your effluent?
- Biological oxygen demand (BOD): How much oxygen do the microorganisms in your effluent consume?
- pH levels: Is your effluent acidic or alkaline, and how does this affect its treatment and disposal?
- Temperature: How warm is the effluent, and what implications does this have for its impact on the environment?
The data gathered from these measurements will inform the treatment your effluent needs before it can be safely released or repurposed.
Strategies for effluent volume and loading reduction
The cost of treating effluent can be substantial. Therefore, reducing the volume and loading of your effluent is not only environmentally beneficial but also economically advantageous.
Here’s how you can do it:
- Water management: Every drop counts. Implementing water-saving measures, such as using closed-loop cooling systems, can significantly cut down the volume of effluent.
- Chemical management: By controlling and reducing their use, you can reduce the chemical load in your wastewater.
- Waste by-product management: High BOD substances like pot ale can be a burden on treatment systems. Finding ways to reuse or repurpose these byproducts can alleviate this load. Filtration can also be another good way to reduce the load when making other spirits.
Effluent treatment options
Treatment of distillery effluent is often a multi-stage process, designed to gradually reduce its environmental impact before release or reuse.
The process is typically divided into three stages:
Primary treatment: This is the first line of defence, focusing on removing suspended solids from the effluent. It can be as simple as allowing the liquid to settle in tanks, where the solids fall to the bottom. Adjusting the pH to neutralise the acidity or alkalinity of the effluent is also a part of this stage.
Secondary treatment: Here, the focus shifts to reducing the organic content, measured as BOD and COD. For some whisky makers, examples include biological treatment methods like aerobic digestion using bacteria that consume organic matter in the presence of oxygen. Anaerobic digestion, which does not require oxygen and produces biogas as a by-product, is also an option for some distilleries.
Tertiary treatment: This final stage is about polishing the effluent to remove any remaining contaminants. Advanced methods like reverse osmosis, ultrafiltration, or activated carbon filters come into play. While not always required by law, tertiary treatments can help distilleries achieve near-total purification of their wastewater.
Calculating the probable cost of effluent
The financial aspect of effluent disposal is a crucial consideration for distilleries. It’s going to cost you one way or another. It costs to set up and implement treatment processes before you return it to the grid. However, it also costs to get it removed for you.
In the UK, the Mogden Formula is used to calculate charges for industrial disposal. This formula considers the effluent’s volume, its treatability (measured by BOD and suspended solids), and how it compares to average domestic sewage.
While other countries will have different ways of calculating the cost to the distiller, the principles are very similar.
Therefore, by understanding this formula, distilleries can better anticipate the costs associated with their wastewater and find ways to minimise them.
Process and equipment considerations
As so much of effluent treatment is process driven, selecting the right equipment and designing the sequence of treatment is essential. To calculate what will work for you, start with three areas…
Meters and sensors: Equip your distillery with reliable meters to continually monitor properties like pH and temperature.
BOD, and COD can be calculated in one-off samples sent off to a lab. So long as your process is the same, they will be too. This means that you only need to do these every quarter. That said, send more samples of for testing if there has been a change in material, or if the other properties like temp, pH, volume etc. have changed dramatically.
Automated control systems: Automation can ensure the consistent treatment of effluent, reducing the risk of non-compliance due to human error. Look at areas where you can automate the process, rather than have it as a separate task on the job sheet.
Plant layout: Look at ways to integrate effluent treatment into your distillery’s design, with easy access for maintenance and upgrades. For example, placing settling tanks or bioreactors at strategic points can enhance the efficiency of your wastewater treatment.
Understanding the treatment options, costs involved, and the necessary equipment and processes is a significant step in managing distillery effluent effectively.
Once you’ve calculated what can be done, make a cost assessment. Some solutions are low cost upfront and can create cost savings quickly, others are the opposite. There is no one size fits all approach to ensuring your craft distilling business is sustainable and responsible.
Training staff and making an effluent management plan
By this point, you know how to calculate what you have, and you know your obligations. You have some of the process and equipment that you intend to bring in earmarked. Bring it all together with a plan of action!
Creating a waste management plan involves holistic assessment, customisation and implementation. It’s boring, but look at the bright side – it creates an opportunity in itself.
It allows distilleries to view current waste production and treatment practices (assessment) in one go. Often that’s eye-opening as you never really see it all together at once, let alone multiplied by the amount being made over an extended timeframe.
It gives distillers an opportunity to refine the precess that addresses the specific needs of their effluent, taking into account size, production volume, and local regulations.
Lastly, it also sets clear goals, responsibilities, and timelines for waste reduction and treatment.
Doing it properly will lead to being able to deal with effluent, as well as identify ways to be less wasteful in the first place.
Once the plan is in place, the final element to effluent management is staff education.
Awareness programs that highlight the environmental and financial implications of poor effluent management quickly changes the mindset for those who just think of it as waste water. Once they understand why it needs to be done, helping staff to become proficient in operating effluent treatment systems is next on the list for quarterly training.
Distillery effluent management is a complex but vital aspect of the distilling process. It continues many of the same ideas that go into managing Water and continues them right through to the end of the product cycle.
By embracing sustainability, educating staff, and tailoring waste management plans to their operations, distillers can make their craft sustainable for the environment and for their business.
It ensures that they are not only producing high-quality spirits but also preserving the environment and aligning with regulatory requirements.
