A steel version of just such a device has been in production for several years.

Lloyd

Here is a link that might be useful: BIOvator

Lloyd .... very interesting product. I note that it is designed for disposal of dead animals and slaughter house waste. They didn't show what the end-product compost looked like.

Thomas...tree -- Your idea might have an application for disposal of food wastes and yard waste. I should think that size would be a factor in who would buy it. Perhaps a composter designed only for plant materials might not need to be so long, as the one designed for carcass disposal, nor need to use metal for sanitation measures. I didn't see the metal product touted for use of manure disposal, which is surely as great a problem for large steer/hog/poultry farms as disposal of dead animals. . Keep us posted on your progress.

Borderbard: "They didn't show what the end-product compost looked like."

yes, they did -- click on PDF file for manual, there are lots of pictures of the product and description of the process
It seems they say it would be best used in cold climates

hey this is great. I didn't realize someone was already selling it. But I would like it tailored to the home user, and I think one way to get people more into doing composting is to make it extremely easy and oderless. So having a long tube in the back yard that lets one drop any organic material into one side, and 20 days later the compost just falls out of the other end into a pile or a wheelbarrow. This would be very attractive and "trendi" because it makes the average comsumer look "green" to his neighbor, but at the same time the end user doesn't have to do much. I found a pdf about a treatment plant in Finland (the country where I live) and it shows also a compost tunnel that not only composts within 7 days, but also heat water. page 11 of http://www.greennetfinland.fi/fi/images/4/4b/Nordic_sludge.pdf

Somwhere also I read that the tunnel can be inclined downward, and open at the end. So fresh air enters the exit point and cools the material that is just about falling out. The heat from the material also goes up, back into the tunnel so that newer stuff at the top can get started sooner with decomposing. This also somehow controls the odor naturally. But I'm thinking with all the modern heat pump technology that there must be a way we can heat our hot water tanks with the excess temperture produced by the bacteria. Anyway, I'm about ready to start sketching these ideas out on the blueprint. I'm pretty sure the home version can be constructed with recycled plastic. Perhaps the tunnel created inside a larger insulated case so that heat transfer pipes and gears can be protected from the elements. If its built into a hill I don't see why one couldn't bury the whole thing so that its out of view. Important thing is that its easy to build and as few parts as possible. And to make it affordable.

The idea is very similar to machines used in various industries to pass material through a process while mixing it. A few I can think of are the gas fired rotary cement kiln, rotary soil desorber (for contaminated soil cleanup - very similar to a cement kiln) and rotary ovens (cookers) used in the food or grain processing industry. My father-in-law has a soybean plant in NE that roasts the beans in such a cooker, heated by steam, to make high quality feeds for dairy farms. It must be a very efficient way to process material, energy-wise, or everyone wouldn't be using it.

Biovator end product:

http://nioex.com/uploads/albums/HPIM0051.jpg

The BIOvator unit was originally designed by the ag industry for the ag industry so yes all the data relates to ag inputs (deadstock). They have tested one for more normal compost inputs but I haven't seen any info on how well it worked. I'd love to try one for community household collection composting but I'm so darn busy I don't have the time (yet). With the insulation built in, I bet I could keep one of these puppies going during a Manitoban winter with just a basic shelter. More pondering required. ;-)

Lloyd

OP was reminiscent of the ball mills; used to process ore at mines is where I saw them but there are many other uses. Google images for ~ ball mill ~ shows several designs. I think, as someone mentioned, I would incline the contraption at one end.

The problem with community collection would be the same as usual ... people would toss things in there they shouldn't, like entire newspapers, lumber, construction material and in some neighborhoods, dead bodies.

No problem as the BIOvator is designed for bodies! ;-)

I was talking to the company and a used 42 foot unit might become available this fall not too far away (15 miles) from me. Now I have to do some serious pondering.

Lloyd