Well, I know no one wants to.
But should we?
Yes.
I have no interest in discussing what I know to be the standard wastewater 'policy' in craft breweries. But if you're in the industry, you very well know exactly what I mean.
Wastewater is the forgotten by-product of breweries. So much so, there are ample videos of breweries pouring 'a bad batch' directly down the drain on social media, with their jubilant marketing team exclaiming 'LOOK AT WHAT WE SACRIFICE FOR QUALITY' the irony is incredible.
Well, thank god these breweries have a wastewater EQ tank right... Right?
Those cringe videos aside, I see wastewater as the forgotten byproduct because wastewater:
Goes in a drain and we never see it again
Has zero impact on the quality of the beer
Is easy to ignore
Rarely gets tested
Is wastewater
So why should we care about wastewater in breweries?
Here are a bunch of very valid reasons why wastewater treatment is important for brewery sustainability:
Pollution Potential
Breweries generate large volumes of wastewater containing organic matter, chemicals, and cleaning agents. Without proper treatment, this wastewater can pollute rivers, lakes, and groundwater.
Yeast is especially bad, it often continues to ferment in sewerage when combined with beer, wort or adjuncts stealing oxygen, multiplying and creating pressure.
2. Damaging Sewer Infrastructures
Not one person in the UK supports water companies and how they have been running since privatisation in 1989. But my political views are not what is important here.
Untreated brewery waste causes significant damage to sewer pipework, especially our good friend caustic soda.
Damaged sewer systems cause leaks into waterways, rivers, reservoirs, the sea and other bodies of water and untreated brewery waste causes significant environmental issues.
3. Getting Caught
If you need fear as motivation, the punishments for getting caught are severe.
First, you will be put under special measures, meaning you will get routinely tested every 2 weeks at random points of the day without warning.
Fail 2 more and you will either be fined or you will be banned from putting a single litre of anything down the drain.
Worried about rising costs? You should be a lot more worried about the cost of tankering your entire wastewater requirements every week.
Also, imagine being the brewery that got banned from using the water, or heavily fined for polluting waters, the PR would be a disaster, rightfully so.
4. Social Responsibility
We are far past the age of sacrificing the environment for profit. So it's time you showed some respect.
What Do The Water Companies Measure In Wastewater? And How?
Before we get into this, a disclaimer. What I have written is a generalisation based on my experience with multiple water authorities. This can be substantially different to your water authority, so always check with them before using any of the numbers in this article.
Ok, disclaimer out the way, there are 4 key measurements for trade effluent. The specifications will vary, but let me tell you, they are tight.
Chemical Oxygen Demand (COD)
Description: Measures the amount of oxygen required to oxidise both organic and inorganic matter in the wastewater.
Causes: Wort, Beer, Yeast and Trub (whirlpool and dry hop)
Significance: High COD levels indicate a high concentration of pollutants that can deplete oxygen in receiving water bodies, harming aquatic life.
Measurement: COD is measured by adding a strong chemical oxidant to the wastewater sample and determining the amount of oxidant consumed, typically using titration or spectrophotometric methods.
Limits: 1000-2000 mg/l (please check local authority)
Biochemical Oxygen Demand (BOD)
Description: Measures the amount of oxygen microorganisms require to decompose organic matter in the wastewater over a specified period (usually five days).
Causes: Wort, Beer, Yeast and Trub (whirlpool and dry hop)
Significance: High BOD levels can lead to oxygen depletion in water bodies.
Measurement: BOD is measured by incubating the wastewater sample at a specified temperature (usually 20°C) for a set period (usually 5 days) and measuring the decrease in dissolved oxygen using a dissolved oxygen meter.
Limits: 500-1000 mg/l (please check local authority)
Total Suspended Solids (TSS)
Description: Measures the concentration of suspended particles in the wastewater.
Causes: Spent Grain, Hops, Yeast and Trub
Significance: High levels of TSS can lead to sedimentation in water bodies, affecting aquatic habitats and water quality.
Measurement: TSS is measured by filtering a known volume of the wastewater sample through a pre-weighed filter, drying the filter to a constant weight, and calculating the mass of solids retained.
Limits: 500-1000 mg/l (please check local authority)
pH
Description: Measures the acidity or alkalinity of the wastewater.
Causes: Chemicals, Beer, Wort
Significance: Extreme pH levels can harm aquatic life and damage sewer infrastructure.
Measurement: pH is measured using a calibrated pH meter or pH indicator strips.
Limits: 6-10 pH (please check local authority)
COD vs BOD
Without going into mind-numbing detail, as you can tell, they measure similar components of wastewater. And you can in fact convert COD to BOD and vice versa. Ultimately COD is quicker to measure so is more often used.
How do water companies calculate brewery trade effluent?
I'm sure this varies from water company to water company, but from my 10 years of experience, their system is extremely unfair.
They will measure your effluent at some point during any working day, and the 1 litre of effluent they measure, they assume this to be EVERY litre of effluent you put down the drain. There's no discussion or reasoning on this either.
So that L they measure better be within specification, otherwise they assume every L you have put to the drain since their last visit has been out of specification.
How to measure your own brewery wastewater
The only way to truly control your wastewater is to measure it yourself, then you're not waiting for the test to tell you if you are succeeding or not, you know yourself. So let's look at how to measure each key parameter.
Chemical Oxygen Demand (COD)
You can measure this in-house, if you are fortunate enough to have a spectrophotometer then you buy some pre-filled cuvettes and get started for ~£90.
If not then Hach has a portable COD test kit, I have never used it, so cannot vouch for it but my experience with Hach itself has always been good.
Check it out here https://uk.hach.com/parameters/cod
The COD value can be used to estimate the BOD as discussed above.
Total Suspended Solids (TSS)
TSS is measured by filtering a known volume of the wastewater sample through a pre-weighed filter, drying the filter to a constant weight, and calculating the mass of solids retained.
Or you can use your spectrophotometer to measure TSS in a similar way to measuring haze in beer.
pH
The least challenging of the 3, measure in the exact way you measure your wort and beer. You do measure your pH, right?
Frequency
Measure all of these every hour on the working week, so at least for 5 days — record data on a spreadsheet and plot charts. Assess the difference between your limits and your reality. Once the 5 days are up switch to less intense monitoring, whatever you feel is necessary.
Quantity
This is trickier as it's not metered and tricky to calculate. A standard figure for rate-to-sewer (RTS) is 85% for breweries. So grab your water bill or look at your annual water usage and take 85% of that as your quantity of sewerage.
How To Treat Wastewater In Breweries
Finally, the good stuff. How to actually treat your wastewater. There are some large CAPEX projects but also a very low-budget approach - which of course is my favourite. I am going to discuss the perfect set-up first, then give you some craft brewery cheat codes later on.
Treating wastewater generally happens in 3 stages.
Stage 1 - Filtration
Filtration is usually a word that conjures fear amongst craft brewers, but fortunately, this filtration is easy. You need to set up a screening filter to stop objects and large particles such as grain, hops etc from entering the sewer. This can be done by placing a filter cap in your existing drain. Debris can now be disposed of either with organic waste or in your bin. A morale-boosting start this.
Stage 2 - EQ/Buffer tank
The second stage is pH balancing. Breweries produce some acidic waste (beer, yeast, wort and some chemicals) and also alkaline waste (chemicals) yet you find if you test your wastewater regularly that generally brewery waste is acidic (around pH 5) and too acidic for legal consent.
So every wastewater treatment setup requires some form of equalisation tank (EQ) or in more brewery terms, a buffer tank.
This will capture your wastewater and allow you to balance the pH back up to the legal limit. It's advised to have a tank capable of holding 1 day's waste, this will give you enough breathing room but also will allow time for heavier solids (yeast, trub etc) to settle to the bottom. They can be disposed of separately.
Balancing pH can happen in various ways:
Limestone or Calcium Carbonate - readily available and fairly inexpensive.
Sodium Hydroxide - yep, our old friend caustic soda, horrendous for sewer systems in concentrate, but an excellent pH riser in doses, it's important to note that it is not the same caustic used CIPs.
Stage 3 - Solid Removal
Anaerobic Digestion
Anaerobic digestion is a biological process that breaks down organic matter in the absence of oxygen to produce biogas and nutrient-rich byproducts. Anaerobes metabolise organic compounds, producing biogas primarily composed of methane (CH4) and carbon dioxide (CO2), along with a nutrient-rich slurry known as digestate. For me personally, it was one of the hardest concepts to get my head around, bacteria consuming hop matter, proteins, yeast etc all in a few hours. What was this thing capable of doing?! Either way, I got over it and it makes sense now.
Here's a list of reasons Anaerobic Digestion works
Efficient Organic Matter Removal
Anaerobic digestion effectively breaks down organic compounds present in brewery wastewater, reducing the chemical oxygen demand (COD) and total suspended solids (TSS) to meet consent limits.
Renewable Energy Production
The biogas (methane) produced during anaerobic digestion, can be captured and used as feed-in gas for your boiler.
Resource Recovery
Digestate, the nutrient-rich byproduct of anaerobic digestion, can be repurposed as a soil conditioner or fertilizer, providing a sustainable alternative to chemical fertilizers and closing the nutrient loop.
Potential for Cost Savings
While there are upfront capital costs associated with installing anaerobic digestion systems, breweries can benefit from long-term cost savings through reduced wastewater treatment expenses and energy self-sufficiency.
Environmental Sustainability Anaerobic digestion offers breweries a sustainable wastewater treatment solution that minimizes environmental impact, reduces greenhouse gas emissions, and promotes circular economy principles by converting waste into valuable resources.
Here's a list of reasons why anaerobic digestion does not work
High Initial Investment
The installation of anaerobic digestion infrastructure, including digester tanks, biogas capture systems, and monitoring equipment, requires significant upfront investment, which may pose financial challenges for some breweries.
Operational Complexity
Operating anaerobic digestion systems requires technical expertise in biological and mechanical engineering, as well as regular monitoring and maintenance to ensure optimal performance. Lack of specialized knowledge and training can lead to operational issues and inefficiencies.
Continuous Operation Requirement
Anaerobic digesters (AD) must operate continuously to maintain microbial activity and treatment efficiency. Interrupted operation or fluctuations in organic loading can disrupt the digestion process and affect treatment performance. So you can no longer take a week off brewing, or even a day. Weekends must either be worked on or have an EQ big enough (with enough waste in) to feed it over the weekend. You cannot turn AD plants on/off. They now rule your schedule and life.
Not Free To Run
Most AD plants require a certain temperature in the reactor to ensure the bacteria don't die. This can be a self-maintained temperature but in slow periods additional heating is required. I've seen steam used to heat, which is expensive. I can see how electricity could also be used however I have not seen that with my own eyes.
Size Generally speaking, anaerobic digestors take up space, a premium at nearly every brewery I visit in the UK. I'm yet to see an AD plant fit in a railway arch along with a fully functioning brewery.
In conclusion, AD is the ultimate way to treat your wastewater, but it's far beyond just a capital cost, it is a system that changes the entire way the brewery operates. For large craft breweries the CAPEX cost is attainable, but on the micro-scale, I am yet to see how it could work both on affordability and practicality.
Latest Tech in Wastewater Treatment
As you can see, there are plenty of limitations. However, don't despair. On a site visit to the incredible Hepworth Brewery last year, I was exposed to one of the best AD systems I have ever seen. It fit into a 20ft container and was capable of digesting all brewery waste, without the intense hunger that dictates your production schedule. Furthermore, it produced biogas that was being used as gas for the steam boiler. So not only is it applicable it has an important ROI.
Enter WASE their patented technology cultivates specific strains of bacteria on electrodes, accelerating their effectiveness and also reducing their reliance on high waste volumes.
I won't go too much further as I have made an entire podcast on this which really digs deep into anaerobic digestion and the best tech available for a craft brewer. Check out the episode here.
How To Treat Wastewater Without Spending Money
So the majority of the readers of this article will be most interested in this. How to consent to your trade effluent without breaking the bank. But be warned, this is CAPEX-free but certainly not effort-free.
It's important to not compare this to your current method/process, as what you could be doing is illegal. So by their nature, illegal methods of waste disposal are not comparable with legal ways of managing waste.
Drain Filters
As discussed above, installing buckets on drains to capture large objects or any 'accidentals' such as spent grain will prevent them from entering the sewer system. Easy, inexpensive yet effective. Dreamy.
Side Streaming Waste
So in principle, it's very simple. To achieve the tight COD and TSS specs for your trade effluent you need to prevent all organic by-products from entering your drains.
With this simple but effective solution, you can consent or at least get very close to your trade effluent COD and TSS limits. Trust me.
First, let's look at average COD values for the core organic waste products:
Beer
Average COD: Approximately 20,000 to 40,000 mg/L
Wort
Average COD: Approximately 120,000 to 250,000 mg/L
Note: Wort has a very high COD due to its concentration of fermentable sugars and organic compounds.
Yeast
Average COD: Approximately 50,000 to 150,000 mg/L
Note: Spent yeast slurry can have a high COD due to the organic matter, including cell debris and residual fermentable material.
Waste Hops
Average COD: Approximately 60,000 to 100,000 mg/L
Note: Waste hops contribute significantly to COD because they contain organic compounds such as resins, oils, and cellulose, which require oxygen for oxidation.
And a reminder that COD limits are usually 500-1000 mg/L
How To Side-Stream Waste in Breweries
Spent Grain
All packed in lidded containers and sent to a farm. Do not send it to an AD plant, put it back into the food chain. It's the most circular way of dealing with this at the moment.
Whirlpool Trub
All proteins and hop matter can be mixed in with the spent grain. Check with your farmer first, but with such small quantities, it's easy to blend in.
Yeast
Some options here. I would recommend having an IBC (tote for my American readers) that is used exclusively to collect spent yeast. You can sell this as it's high-quality feed to the same farmer you sell your grain to. But you MUST the yeast is dead first. Some heat up, and most use acids to kill it. Murphy and Sons have a product aptly named 'Yeast Killer' which works perfectly. If you can't find a farmer, an AD plant will gladly take this as it's dynamite feed for them.
Another note, do NOT seal the IBC until all yeast has been killed.
Hops
Dry hops can be mixed with the yeast if it's going to an AD plant. If you are selling the yeast to the farmer, then they have to be stored in a separate IBC and sent to an AD plant.
Waste Beer
By far the most difficult to dispose of. It has a low pH and also a high COD. It has to be treated for pH and then diluted to achieve COD specs.
Adjusting pH for Wastewater
A big issue for brewers is the pH. Generally, all brewery waste is too acidic to consent. Some people I speak to say their water authority isn't interested in pH, just another example of why it's important to know your limits.
The only way of really doing this correctly is with an EQ tank. So waste enters a buffer/holding tank where the waste can settle (reducing TSS and COD) then it can be monitored and adjusted for pH. Even on the smallest scales, this is likely to be required.
EQ tanks can be basic and do not require to be stainless, so don't be put off by the cost, plastic is a lot cheaper than stainless steel.
Using the methods described before you can now effectively dose your EQ tank and send it to the drain legally. EQ tanks also provide a buffer for any major 'mishaps'. Whether that's the wrong tri-clamp taken off or a rushed brewer throwing stuff on the floor. An EQ tank ensures this doesn't cause trouble.
Conclusions
So there we have it, that's nearly all you need to know on wastewater, and how to treat it in every sized craft brewery. No one wants to talk about wastewater, because it's boring and we all know generally it's not being dealt with properly.
If you were to ask me to rank the most important aspects of a brewery's sustainability, managing waste water would not hit the top 5 maybe even the top 10. However, if I were to rank the most likely ways breweries are going to get shut down, wastewater would rank in the top 5.
My final note on this is, that we treat wastewater as not our problem but actually it is our responsibility. And we as brewers and inhabitants of this planet are 100% responsible and accountable for our actions. So make wastewater your problem and help the planet turn a few more times.
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