There are a number of reasons why spirits producers are particularly vulnerable to high Mogden charges – and these are also the reasons why regulators keep an especially close eye on these types of businesses.
Distilleries face a number of expensive challenges when it comes to dealing with effluent produced during spirits production.
High concentrations of chemical and biological contaminants and unpredictable production rates make disposing of wastewater especially expensive for these kinds of businesses – and as a result, many are draining profit by paying more than they need to in discharge fees to water companies.
In most cases, significant savings can be made by effectively treating wastewater before discharge, which can be achieved cost-effectively through the rental of modular treatment units.
Here’s why:
The more contaminated the distillery wastewater is, the more you pay
For distilleries, as for all companies that discharge effluent into foul sewers, a complex mathematical method is used to calculate trade effluent charges. This equation, known as the Mogden Formula, works out a cost per cubic metre based on the concentration of different types of contaminants in the wastewater.
Many industrial businesses miss opportunities to reduce their charges because their water treatment systems are not up to the task. You can read more details in our blog here:
Reviewing your Mogden Formula: Are you paying too much because of inefficient wastewater treatment?
Why do distilleries often face particularly high wastewater disposal charges?
Spent wash, pot ale, and thin stillage can have COD levels up to 50 times higher than those found in typical food and beverage effluent. This increases Mogden charges and can lead to consent breaches as well as equipment failures when biological treatment systems become overwhelmed. Telltale signs of problems include the presence of dark, odorous effluent, rapid drops in pH levels, and aeration systems running flat out with little improvement.
As a batch-based, rather than continuous process, distilling is vulnerable to big spikes in contaminants tied to key events such as still emptying, cleaning cycles, yeast dumping, and washdowns. This can make treatment systems difficult to stabilise, meaning sites may be in compliance one day but in breach the next. Unpredictability can also make proportional dosing inaccurate - and this is one of the biggest hidden risks regulators look out for.
Pot ale and cleaning chemicals can push pH well outside consent limits. Acidic discharges are common after fermentation and cleaning, and this can have an adverse effect on biological treatment as well as corroding pipework and pumps. Neutralisation tanks and alkali dosing systems are often used to address this, but they are poorly tuned, leading to higher disposal costs.
Yeast, grain fines, and biomass create very high levels of suspended solids, which settle badly, float unpredictably, and risk overloading sludge handling equipment. The Mogden charges for disposing of sludge are very high, making this a common factor in high water company bills. Sludge can also block drains and tanks, which can be costly to remedy.
Distilleries often ramp up production ahead of Christmas or when they are catching up following maintenance periods. This can lead to consent breaches where treatment systems are set up for average, rather than peak levels of production. Modular water treatment systems are essential here because they can easily scale up or down according to need.
Many distilleries are proud to be at historic sites, often in protected buildings, where traditional large treatment plants will not fit. Planning constraints at these sites can also make permanent upgrades difficult to install. Siltbuster’s small footprint, modular solutions work well here because they are highly adaptable, fitting into areas in ways that are just not possible with less flexible systems.
Water companies are under pressure to reduce sewer loading, protect treatment works, and meet river quality targets. It is known that, for the reasons above, distilleries are among the areas where sampling and enforcement are on the increase as utilities seek to meet ever-more stringent targets.
How Siltbuster solutions support distilleries to drive down bills and stay compliant
Distilleries often come to us when something triggers the need to act - for example, Mogden charges suddenly increase, a compliance warning letter lands from the water authority, treatment equipment fails, or plans to expand the business are blocked due to effluent constraints.
Siltbuster’s specialists are able to respond quickly to resolve these issues when they arise. However, prevention is always better than a cure.
Every business is unique, which is why a site visit from a water treatment specialist is essential to identify opportunities to reduce costs.
A typical solution may include several stages, including:
Chemical dosing in dedicated mix tanks can help separate troublesome COD and BOD from the yeast-laden effluent and address pH issues to make later stages of treatment more effective.
Lamella clarifiers, which use a series of sloping plates to encourage solids in wastewater to settle to the bottom, where they can be safely removed. These work especially well with yeast and grain fines, and result in significant COD reduction at a very low energy cost.
In many distilleries, chemical dosing and a lamella tank treat effluent and reduce Mogden charges effectively, without the need for further intervention. However, where required, further stages may be added. These could include:
Dissolved Air Flotation tanks - these use air bubbles to separate solids that are light, fatty, or poorly settling.
Moving Bed Biofilm Reactors (MBBR) - a treatment which uses bacteria grown on plastic carrier media to break down contaminants through natural biological processes.
Siltbuster’s modular treatment units help distilleries make significant savings on Mogden charges.
Built off-site to meet specific requirements, they are delivered as fully packaged plug-and-play systems with a small footprint that can scale in line with demand.
This makes them far more cost-effective and easier to deploy than traditional, large, and cumbersome solutions.
As we have the largest water treatment rental fleet in the UK, we can quickly get the correct treatment to your site so you can start benefitting immediately from reduced Mogden charges and improved environmental performance.
Case Study: Reliable pH control and solids removal for a distillery wastewater treatment plant
The challenge
A distillery required an effective pretreatment solution to protect its downstream biological treatment process and meet strict discharge consent limits. While the removal of suspended solids was essential, the real challenge lay in managing extreme pH fluctuations caused by alternating acidic and alkaline production processes. Without robust pH control, the biological treatment stage was at risk of instability, reduced performance, and non-compliance.
The solution
Siltbuster delivered an integrated D10 dissolved air flotation (DAF) system designed to do far more than simply remove solids. The solution incorporated automated acid and caustic dosing, providing continuous pH correction and ensuring wastewater conditions remained within the optimal operating range.
By stabilising pH levels, the system enabled consistent and effective floc formation, significantly improving settlement performance and maximising suspended solids removal ahead of the MBBR. This integrated approach ensured reliable pretreatment while safeguarding downstream biological processes.
The outcome
The distillery now consistently meets its discharge consent requirements, achieving reductions in BOD and suspended solids while maintaining full compliance with pH limits. The DAF system has become a critical component of the treatment process, delivering stable operation, regulatory confidence, and long-term protection of the MBBR.