Pit Additive Tests


Odor emission has always been a challenge for intensive animal operations. Various pit additives continue to be developed and improved to mitigate odor and manure solids. A commercial, biological-based additive was evaluated in a laboratory setting for effectiveness in reducing manure solids, and gas and odor concentrations. This project was funded by USDA RBDG program. Both semi-long-term test (3-month) and long-term test (6-month) were conducted to mimic manure storage and pit additive treatments.

In the long-term test, each reactor was ventilated at 2 L/min of filtered room air using a piston air pump. Concentrations of ammonia and hydrogen sulfide of the exhaust were measured every month, while odor concentrations were measured at the middle and end of the test. No significant difference was observed for pH, ammonia and hydrogen sulfide concentrations between the control and treatment groups, while hydrogen sulfide concentrations were more variable. Reduction of total solid and volatile solid was observed for the 200% dosage group.

Odor reductions for the 100% and 200% treatment groups were reduced (although not significantly different) by 21.6% and 11.2% for the third month sampling, and were reduced by 56.0% and 80.0%, for the sixth month sampling, respectively. Odor concentration, after logarithm transformation, was significantly reduced by the 200% dosage treatment at the end of the test (p = 0.013). Nutrient contents were similar among the groups, which confirmed that the additive did not alter manure nutrients during the six-month testing period. Future research should consider improved manure loading and storage conditions, and include field tests.

Final report of this pit additive study can be viewed here:

Final Report of Pit Additive Tests

Pit Additive Tests

Reactor set up using schedule 40 PVC tube and cap, and ventilation system, for long-term additive test.