"I have a large volume of old horse manure. Would I be able to compost this in an O2Compost system?"

ANSWER: It is unlikely that we can generate much heat with manure that has been sitting for more than six to eight weeks. Old manure has already composted (albeit slowly and anaerobically) leaving insufficient energy for thermophilic composting. To achieve pathogen and weed seed destruction, our goal is to achieve pile temperatures of 131° F, or higher, for a minimum of three days. This is quite easy with fresh manure. With old manure, you may get some heating but it is improbable that we could reach these temperatures for the desired length of time.

When we work with clients who have completed construction of their new O2Compost system, we always recommend starting with fresh manure. Once the system is up and our clients have experienced success, they can add a small portion of their old manure (say 10% to 20% by volume) in with the new, if they choose. In this case, the manure would be "along for the ride".