Hydrogen sulfide emission rates and inter-contamination strengths in a fan-ventilated confined-space manure storage

Hydrogen sulfide (H ₂S) was used as an indicator gas to investigate the effectiveness of forced ventilation of confined-space manure storages. Hydrogen sulfide emission rates from stored manure and inter-contamination (the process by which a portion of the exhaust contaminant gas re-enters a ventilated confined airspace through the fresh air intake) strength were measured. The data were part of an overall research goal to develop and validate computational fluid dynamics (CFD) modeling protocols to simulate H ₂S removal from fan-ventilated confined-space manure storages. The emission rates were measured under typical forced-ventilation airflow conditions for three temperature regimes and two air recirculation rates. An exponential regression model was identified to characterize the emission rates. The inter-contamination was quantified using inter-contamination strength, which was defined as the ratio of contaminant concentration at the fan intake to the concentration in the air exhausted from the manure storage. The inter-contamination strengths were measured for several typical ventilation strategies for storages with three cover types: solid, fully slotted, and partially slotted. Measured inter-contamination strengths were 0.24, 0.28, and 0.28, respectively, for storages with solid, fully slotted, and partially slotted cover types and with fan intakes directly above the storage cover.