In-vessel processing of spent mushroom substrate for odor control

Spent mushroom substrate (SMS) was processed in an aerated floor vessel and compared to SMS processed by conventional windrow methodology. The aerated floor vessel design provided portability and ease of use. Three trials were run using SMS obtained directly from commercial mushroom production operations. Temperature and oxygen levels in the aerated and windrow SMS were monitored regularly. Odors were assessed on a weekly or bi-weekly schedule, both olfactometrically using human panels and quantitatively using gas chromatography with flame photometric detection (GC/FPD). Olfactometric assessment showed that the odors were significantly reduced by aeration in terms of intensity and pleasantness ratings. GC/FPD assessments also demonstrated that aeration consistently reduced sulfur compound levels.