Use Caution When Pumping Manure From Deep-pits



AMES, Iowa --- Last week another swine barn explosion left one person critically injured. At this time, exact details of the incident are unknown. However, agricultural engineers from Iowa State University Extension and Outreach urge all livestock producers and commercial manure applicators to use extreme caution when pumping manure. 

Deep-pit manure systems, often associated with swine production, raise a particular concern. Liquid manure in pits undergoes slow decomposition, which creates several gases including methane and hydrogen sulfide, both of which can create dangerous situations. The rate of gas release from the manure can be drastically increased when the manure is agitated (stirred) during pumping. This increase is especially true for hydrogen sulfide, which can have a lethal paralyzing effect.

In addition to the concern about gas release from pumping and agitation is the concern about rapid gas release in pits with excessive foam.  It is believed that pits with substantial foam prevent the normal release of methane from the deep-pit facilities. Captured methane can be released quickly when the foam is disturbed by agitation or other activities such as power-washing. The rapid release of methane mixing with fresh air can create an explosive mixture. If this mixture comes into contact with an ignition source, it can cause a flash fire or explosion. 

Minimize risk of injuries and flash fires when pumping manure

Manure handlers should follow these steps to minimize risk of injuries and flash fires:

  • Review your emergency action plan with all workers and have emergency contact numbers available at the site. Additional info at:  http://www.extension.iastate.edu/Publications/PM1859.pdf
  • Prior to agitation or pumping, turn off electrical power to any non-ventilation equipment such as lights and feed motors, and extinguish any pilot lights or other ignition sources. Fully open all ventilation curtains or ventilation pivot-doors, but leave walk-in doors locked to prevent human entry.
  • Run ventilation fans at maximum speed.
  • Ensure that all people are out of the building and clearly tag all doors noting that the building is unsafe for entry during agitation and pumping. Printable hang tags are available at: http://www.iowapork.org/LinkClick.aspx?fileticket=D1HZKnXSSKQ=&tabid=651
  • If significant foam is present, consider pumping without agitation to reduce the risk of fire or explosion, and monitor solids accumulation to decide if agitation is advised at the next pumping event.
  • Do not agitate manure until manure has been pumped and level is at least two feet below the slats.
  • When agitating the manure, keep the jet of pressurized manure below the liquid surface. Don’t let the jet of manure strike walls or columns in the pit.
  • Stop agitation when the manure level does not allow agitation below the liquid surface.
  • Continue maximum ventilation for 30 minutes to an hour after pumping has ended before re-entering the building.
  • NEVER enter a building or manure storage structure when liquid manure is being agitated or pumped.

Manure gases are an unavoidable by-product of liquid manure storage

Strict safety protocols along with proper ventilation and agitation practices can minimize the risk of flash fires and explosions during manure pumping. A video discussing safety practices for pumping from deep-pits can be found at: http://vimeo.com/15463270.

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Additional Contacts :
Kris Kohl, ISU Extension Area Agricultural Engineer, 712-732-5056, kkohl1@iastate.edu
Greg Brenneman, ISU Extension Area Agricultural Engineer, 319-337-2145, gregb@iastate.edu
Kapil Arora, ISU Extension Area Agricultural Engineer, 515-382-6551, pbtiger@iastate.edu
Jay Harmon, ISU Extension Agricultural Engineer, 515-294-0554, jharmon@iastate.edu