The role of feed composition on the composting process. II. Effect on the release of volatile organic compounds and odours*

Issued as NRCC #41980

Abstract

In this study the influence of four specific feed materials: grass clippings, leaves, cabbage and soya bean meal on odours and VOCs has been studied in a controlled and systematic manner using a commercial feed material in laboratory composters. The results of this study suggest that while some feeds can be composted with the minimum of problems, high levels of specific feeds could be problematic. Based upon the results obtained with the four feeds examined the following general observation can be made: Grass can be satisfactorily incorporated into compost feed at levels up to about 10% without adversely effecting odour emissions or VOC releases. At higher grass levels odours could start to become a problem. High levels of leaves, up to at least 30%, appear to have no detrimental impact on odours or VOC releases. While low levels of cabbage may be acceptable (less than 10%), higher levels can give rise to high emissions of sulphur compounds and result in serious odour problems. It appears that high nitrogen containing materials, when present in large amounts, can lead to serious odour problems associated with anaerobic activity. The presence of ammonia in the VOCs is a clear indication of excessive levels of nitrogen in the compost feed.

Key words:

• Composting
• organic material
• volatile organic compounds (VOCs)
• odours
• emissions

Notes

Issued as NRCC #41980