EMISSION RATES OF ODOROUS COMPOUNDS FROM PIG SLURRIES

Techniques to identify odorous compounds and to determine their emissi on rates from liquid wastes are described. Odorous compounds, or odora nts, were analysed by GC-MS and odour concentration was measured by ol factometry after being emitted from slurry under controlled environmen tal conditions using a specially designed odour emission chamber. The slurries were obtained from pigs fed commercial and reduced crude prot ein diets and stored for 6 weeks, the effects of age and sex upon the odours produced in the headspace of the chamber were evaluated. The ma jor odorous compounds were identified as belonging to the sulphide, vo latile fatty acid, phenolic and indolic chemical groups. The mean emis sion rates from 200 litres of stirred slurry samples with a surface ar ea of 1 m(2) using a wind speed of 4 m s(-1) were 1.35 million Odour U nits min(-1) for odour and 214, 2.15, 0.21, 0.44, 0.068 and 0.02 mg mi n(-1) for hydrogen sulphide, ammonia, phenol, 4-methyl phenol, 4-ethyl phenol and indole respectively. Sex and sex/diet interaction effects were demonstrated for emission rates. (C) 1998 SCI.