Two liquid storages on the same site received the same finishing hog manure. One of the storages was the control while the other was aerated by a wind powered mechanical system. Samples were taken at day 0, 45 and 90. Liquid samples were analyzed for BOD5, aerobic and anaerobic plate counts, total N, ammonia, and total suspended solids (TSS). Odour samples were taken at the same intervals and evaluated using as dynamic olfactometer to determine odour threshold values. Air samples taken at the start and end of the evaluation were monitored for ammonia, methane, total phenols, volatile fatty acids (VFA) and hydrogen sulphide.

Differences between the two storages were evident from the first two sets of tests. Higher odour emission potential from the control storage coincided with high BOD, phenolic and VFA concentrations. VFA was a good indicator of odour offensiveness. The test storage average level of 113 mg/l after 90 days was well below 230 mg/l, the level considered to be associated with offensive manure odours. The test storage BOD was 535 mg/l, a reduction of 23% after 90 days. the range of TSS in the test storage at various depths was greatly reduced indicating a well agitated and aerated manure storage. Flux chamber results did not coincide with odour emission potential tests. Possibly due to a 3 degree Celsius higher surface temperature in the test storage.

The wind driven aerator effectiveness maintained the odour potential of the test storage below that of the control storage in spite of receiving fresh manure weekly. The aerator in this project is a cost effective means of controlling odours from liquid manure storage.