Foaming in swine manure pits is becoming a growing concern for many hog producers. While manure foaming has occurred sporadically for years, incidents are now increasing in frequency and severity. This surge has raised serious safety concerns, as foam buildup can create dangerous conditions for both pigs and people.
In this article, we’ll explain what manure foaming is, why it happens, and how to manage and prevent it safely.
What is Manure Foaming?
Manure foaming occurs when methane gas becomes trapped in stable bubbles that can range from 6 inches to 4 feet deep. These bubbles can contain methane concentrations as high as 50%–70%. Since methane becomes explosive at just 5%–15% concentrations, this presents a serious hazard.
Foaming can:
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Significantly reduce pit storage capacity
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Breach floor slats and damage equipment
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Trigger flash fires or explosions when ignited
Common ignition sources include heater pilot lights, power washers, and welding equipment.
3 Key Factors That Cause Manure Foam
- Gas Source
Anaerobically digested manure produces gases like methane and hydrogen sulfide that accumulate within bubbles.
- Surfactant
Organic compounds or manure components act as surfactants, creating an elastic surface that allows bubbles to form and hold their shape.
- Support Structure
Fine manure solids or fibers provide the structure needed to stabilize the bubbles and prevent them from bursting.
What Research Shows About Foaming
Recent studies have found that manure with higher carbon levels promotes excessive methanogen activity, which shifts the microbial balance and leads to more methane production. This methane flow pushes biological material to the surface, where it stabilizes the foam. This microbial community thrives on fiber and oil, increasing methane levels and making the foam more persistent.
How to Control Manure Foaming
Follow these industry-recommended safety steps before addressing foam in your pit:
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Do not agitate foaming manure, as this can release large amounts of methane quickly.
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Keep barn ventilation running, as 77% of flash fires and explosions occur when ventilation is turned off.
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Turn off all ignition sources like heaters, power washers, and welders before working near the pit.
Once safe, you can use these control measures:
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Apply Agitation Defoamer at a rate of 1 gallon per 100,000 gallons of slurry to knock down foam. It is safe for animals but should be used as a short-term fix.
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Add Coban 90 / Rumensin 90 (Monensin) at 5 lbs. per 100,000 gallons directly into the pit. Warning: this is not safe for pigs to consume and will kill pit microbes, so keep it inaccessible to animals.
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Reintroduce beneficial microbes 2–3 weeks after Monensin treatment by applying Activator Plus (1 lb. per 50 head spaces) to restore microbial balance.
Talk to the Experts at Healthy Farms
Manure foaming is a serious issue—but it can be managed with the right approach. If you’re dealing with foam in your swine barn, contact the Healthy Farms team. We’ll help you choose the best products and create a safe, effective plan for your operation.
