Concentrations of malodorous compounds in swine wastes during storage

Abstract
A study was undertaken to examine the effect of storage temperature on the malodour of swine slurry. Two storage temperatures were tested, ambient temperature (22–25°C) and 4°C. The effects of the storage on both the separated solids from the slurry and on the filtered slurry were included so as to ascertain which fraction of the slurry contained the major portion of malodorous compounds. The process was monitored by using a static headspace sampling gas Chromatograph (HS‐GC) technique which recorded the changes in the concentrations of the major malodorous compounds in swine slurry, volatile fatty acids, phenols and indoles. Results showed the effect of temperature on the storage of slurry, filtrate and solids to be significant in the initial 40 days. They also revealed that the malodorous compounds were primarily to be found in the soluble fraction of swine slurry. An initial accumulation and later depletion of the VFAs, phenols and indoles in the slurry, filtrate and solids indicated that the decomposition of fibre and protein preceded limited methanogenesis. Finally, the results confirmed the HS‐GC technique to be a useful analytical method for monitoring quantitatively the presence during storage of the major malodorous compounds in swine waste.