Our community wanted to use organic materials as compost for community members while diverting the waste from a landfill. Most of the material used in our design came from re-cycled materials. The 500 gallon composter was made to manually rotate at an angle so that the organics would be well broken down. We needed be able to turn the compost material over regularly, add carbon (sawdust), keep it warm enbugh for the composting to work and keep unwanted materials out of the compost. This is our solution.
Materials - Most of these materials were recovered from waste materials.
- the composter frame is made from 4" steel pipe
- a used five hundred gallon oil tank, ( a second tank was used for parts)
- rollers salvaged from mine salvage, ( including bearings)
- a chain drive system including 6 sprockets (#40) and 10' of #40 chain
- 1" keyed shaft
- 2"x 1/4 x24" flat bar
Step 1: Building the Frame
The barrel is held at an angle of about 20 degrees. The barrel is rotated by a chain drive linked to two trammels that support the barrel. The upper end of the barrel is also supported by an additional two trammels.
Each section of the 4" pipe was cut to fit into the vertical pipes. The cross section pipes form both the skids for the whole system and provided rigidity to the frame.
Addition cross members of 2" pipe add to the rigidity.
The crank system is supported by two of the cross members with pillow block bearings and the drive is a one inch keyed shaft.
Step 2: Making the Rollers
The rollers came from a mine conveyor belt. Many had been damaged and it often took two to make a single functioning roller.
The rollers are fixed along a pipe with bearings set in races at each end.
A 1" shaft passes through these bearings and is supported by the 4"x 1/2 flat bar brackets.
Step 3: Making the Barrel
The barrel is made from a discarded 500 gal oil drum.
The end was cut off and the inside of the barrel was sand blasted and steam cleaned.
A baffle goes half way across the inside of the barrel so that organic materials do not fall out the lower door.
A number of triangular baffles are welded along the inside of the barrel. These catch and break up materials.
The end of the barrel was welded back on and circular doors were welded on both ends.
A brace is needed at the lower end of the barrel so that it does not slide down the frame.
Step 4: Using the Composter
We have created a community compost group that has agreed to put only compostable organics in the composter. When a bucket of kitchen scraps are put into the composter, an equivalent amount of sawdust is added. The addition of the carbon adds to the end compost.