Odour production at professional Agaricus composting sites

[K N and P J Harris]

Mushroom composting.
This has caused quite a few odour problems in Uk. Mainly because the 
enterprise started off on an isolated site "deep" in the countryside 
until a lot of townies thought it cute and built their dream-homes right 
up against the boundary. THEN they noticed that there was a smell, 
complained and often got the site closed down. Our planning laws make 
this possible.

I was involved briefly in trying to help a composter try to reduce 
odours but I think he eventually went under anyway.

One or two things can help.
(1) If manure is used as an activator keep it as dry as possible and 
don't leave it piled up for too long. This is bound to make a real stink 
when moved.
(2) In stage 1 it is very tempting to recycle liquid back onto the 
stack. This is invariably bad news because the stored liquor will 
inevitably go anaerobic and smelly and the redistribution will give a 
superb opportunity for the odours to get spread around to say nothing of 
the possible aerosol problems.
(3) Rinsing down stackyards (to an environmentally friendly drainage 
system obviously) can stop the rich smell that develops when a mucky 
yard starts to dry out in the heat of the sun.
(4) Trials with deodorants suggest they make things worse rather than 
better.

More oddball ideas _ a thick coniferous tree belt may have some small 
effect.
Generous donations of free mushrooms to near neighbours may be just as 
effective.

More seriously, the potential for ammonium release is significant. In 
the Netherlands these operations are more often done inside with air 
scrubbers to reduce ammonium (and also odour) release.

Peter Harris.
Department of Soil Science,
The University of Reading, UK.

AKA  <P.J.Harris at reading.ac.uk>