I live not far from Kennett Square, PA. At one point I think they billed themselves as mushroom capital of the world.
In this area they will only pick up your manure pile for the mushroom farms if it is straw and NO shavings.
When we camped at Fair Hill recently you are only allowed to use straw- no cardboard, shavings or wood pellets since the mushroom folks come haul the piles away and will only take straw only.
Back years ago, when I lived in Pennsylvania, I worked for a labor arbitrator who had cases with some of the mushroom growers and their unions. The companies used old mines and quarries for their growing facilities. We used to call them “the mushroom mines”. 
I know we’re horse people, but horse manure is much less noxious and powerful than many other manures. Pig manure and cow manure and chicken litter have something like 3 times or more the nitrogen content of horse manure and would be likely to burn anything they touch unless properly handled and treated.
Horse manure, on the other hand, is innocuous compared to them. I’ve always thought it was okay to sheet compost or spread horse manure in small quantities. I’m talking about 4 or 5 horses and their 200 to 250 lbs or manure per day.
Any type of raw manure can run off into streams and/or leach into ground water, or even blow away. Un-composted manure may contain pathogens, weed seeds, and parasites that really should not be broadcast back into your fields.
Sheet composting is a form of composting in place that will kill grass underneath if appropriate levels of heat are generated. It is generally used on bare or infertile ground to amend poor soils with minimal effort.
[QUOTE=r3dd0g;5161815]
Sheet composting is a form of composting in place that will kill grass underneath if appropriate levels of heat are generated. It is generally used on bare or infertile ground to amend poor soils with minimal effort.[/QUOTE]
That’s us. Row crop land that is seriously lacking in organic matter and tilth. I haul it out to the middle of a soybean field that isn’t irrigated and dump it in a sand blow.
check out:
http://eponline.com/articles/2010/03/31/kentucky-horse-park-taps-stimulus-to-manage-manure.aspx
and
http://www.kentucky.com/2009/11/24/1032156/energy-project-aims-to-make-games.html
not sure the current staus of the processing plants but they were targeted to be ready for WEG
