Tackling foul odours from wastewater tanks

Aeration may technically be considered a ‘secondary treatment’ step in wastewater management, but when unpleasant odours become a daily reality, addressing the issue becomes a primary concern—especially when those smells start upsetting your neighbours.

Left unresolved, complaints can quickly escalate to visits from the Environment Agency and a flood of negative attention on social media. Comments like “It’s been like this for ages!”, “We can’t even open our windows!”, and accusations that your facility “just doesn’t care” can do lasting damage to your reputation.

Even if your treatment tanks already have pumps or mixers in place—making plenty of noise and surface bubbles—it doesn’t necessarily mean effective aeration is taking place. The real problem often lies below the surface. If solids are settling and rotting at the bottom of the tank, they can produce persistent and offensive odours.
The root of the issue? Insufficient mixing.

While standard pumps may handle most wastewater streams, they often fall short when faced with heavier solids. Poor mixing leads to odour, blockages, pump failures, rising maintenance costs, and even potential overflows.

Why a tougher pump makes sense

It’s a false economy to rely on standard pumps that aren’t designed for solids-heavy wastewater. Investing in a high-performance pump—built to handle tough conditions, reduce particle sizes, and keep solids in suspension—can prevent many operational headaches.

One proven solution is the Landia Chopper Pump, first developed in 1950. As Landia Technical Sales Engineer Howard Burton explains: “Our Chopper Pump uses a powerful cutting system that prevents solids from entering the pump casing. With our AirJet system, which uses angled venturi nozzles, we ensure comprehensive tank mixing and effective aeration.”

Real-world success: from breweries to food producers

At Timothy Taylor’s brewery in North Yorkshire, a wastewater survey by Ogden Waterrevealed that existing pumps couldn’t properly suspend solids in the brewery’s 45m³ balance tank—leading to odour problems. The solution: upgrading to Landia’s AirJet system. 

Nick Berkovits, Second Brewer at Timothy Taylor’s, said: “The improved aeration eliminated odours and gave us a much more consistent, homogenous feed to our DAF unit.”

Food manufacturers also face similar challenges. At KK Fine Foods in North Wales, Landia’s AirJet system has been operating in a 328m³ tank for over seven years with minimal maintenance. Engineering Manager Dave Edmunds described it as: “An unsung hero. It sits there and does its job very well.”

At Deeside Cereals, high levels of fats, oils and greases (FOG)—from ingredients like chocolate and lecithin—once drove COD levels up to 78,000. By modifying tank usage and using the AirJet system, the team now has tighter control over treatment.

Safety, Health & Environment Manager Karl Johnson commented: “We now test before discharge and, if needed, run aeration a bit longer to meet compliance. Daily maintenance is minimal—just a quick visual oil check.”

Cost-effective and energy efficient

Howard Burton adds: “The AirJet system significantly reduces or even eliminates the need for chemical dosing, and with energy prices being what they are, it’s far more economical than traditional blowers.”

In Summary: If odour control is a growing issue, the solution might not be adding more chemicals or running blowers harder. Instead, it may be time to look below the surface—and invest in the right mixing technology to get your tanks properly aerated and solids back in suspension.