Manure management for hog operations

Start here, because foam is the condition on this page that can kill someone. Foam forms when gas from digestion gets trapped in a stabilized bubble layer instead of releasing. In a deep pit finishing barn it can build several feet thick and push up through the slats into the animal space.

What makes it a hazard is the methane held inside those bubbles. Methane is explosive in air between roughly 5 and 15 percent. A foaming pit stores a large volume of it a few feet beneath the floor of a building that contains heaters, motors, welders, power washers, and static — any of which is a sufficient ignition source. Flash fires and explosions in foaming hog barns are documented. They have leveled buildings, killed thousands of pigs, and injured and killed people.

The second hazard arrives without ignition. When a heavy foam layer collapses during agitation, it can release enough hydrogen sulfide at once to be immediately lethal. People have died in the barn and people have died going in after them.

If you have foam in a barn right now, treat it as an active hazard: maximum ventilation during agitation, no ignition sources, nobody inside during agitation, gas monitoring. Then call. Foam is not one problem: methane foam, mechanical foam from agitation or pumping, and thick or slimy foams need different treatment protocols, so we identify the foam before recommending a product. The immediate safety steps come first regardless of what you treat with.

Yes, mostly because the manure differs. Gestation barns produce relatively consistent manure with moderate fiber. Farrowing adds bedding and washdown water, which dilutes the pit but adds cellulose. Nursery manure is higher in undigested feed because young pigs waste more and digest less efficiently. Finishing barns produce the largest volume and, on high-fiber or distillers-grain rations, the highest foam risk on the site.

Structure matters as much as stage. A deep pit holds months of manure under the animals and stratifies heavily. A pull plug system moves manure out on a shorter cycle, so it accumulates less but still stalls. A shallow pit feeding an outside lagoon splits the problem across two structures, each needing its own attention.

This is exactly why PitCharger sells consultatively. A 4,000-head finishing barn on a deep pit with distillers grains and a 1,200-head gestation barn on pull plug are different problems, and different problems require different treatment approaches.

Odor moves first. Producers can often notice a significant change within the first week, with continued improvement through the second and third weeks and into the first month, and some have noticed a substantial change within the first 24 hours. A year-long Iowa State/Farmland study, as reported by PitCharger, showed approximately a 50% reduction in hydrogen sulfide, ammonia, and overall odor compared with untreated buildings.

Crust weakens and breaks up over the following weeks, and fly pressure falls behind it as the breeding surface goes away. Foam timing depends on the type of foam and the protocol matched to it.

What you can see depends on the manure system. In a shallow pit, changes can often be noticed within the first month because the pit is checked and emptied more frequently. In a deep pit, treatment may be working and changing the manure below the surface long before those changes are easy to see. With eight feet of manure below the slats, the system can continue improving even when the visible surface looks much the same.

Bottom solids reveal themselves at pump-out. Loads pump more easily, agitation reaches suspension sooner, and significant results are normally measured after about six months. A livestock producer in Mankato, Minnesota reported recovering approximately 200,000 gallons of usable lagoon capacity after treatment.