The Composting Chamber

The Bio-Drum

The unique Sun-Mar Bio-Drum replicates the perfect environment for composting; combining moisture, warmth, organic material and oxygen. This design is patented.

The Bio-Drum allows aerobic microbes to flourish, which accelerates the breakdown of the waste.



There is a waste inlet port at the top of the drum that allows the waste, along with a bulking agent, to enter the drum. In order to aerate the composting matter, periodically turn the handle (on the front of the self-contained unit or on the side of the central units) to rotate the drum. The inlet door will automatically close during this process to ensure that no compost leaves the drum.

When it is time to empty the contents of the Bio-drum, you will need to release the drum locker and turn the drum backwards. This will force the inlet port to open, allowing the compost to drop into the finishing drawer.

After this process is complete, the bio-drum will lock itself back into place and the drum will be ready to receive new waste.



Supplying Oxygen

The Bio-Drum system ensures the compost is thoroughly mixed and oxygenated. In fact, The Bio-drum is the most effective and simplest way to achieve this kind of oxygenation.

Every time you rotate the drum, the entire pile of compost is imbued with oxygen. Oxygen is integral to the composting process. It allows aerobic bacteria to break down compost quickly and without any unpleasant odours.

Moisture control

Our patented Bio-Drum offers a moisture control benefit that is exclusive to the Bio-Drum design. Moisture control is integral to successful composting.

If the moisture content is below 40% the composting process will slow down and eventually stop. The Bio-Drum is designed so that direct heat is never applied to the compost, meaning it won’t dry out. The regular tumbling process also distributes the moisture evenly through the compost.

When moisture rises above 60%, oxygen begins to dissipate from a compost pile, leaving it to become increasingly anaerobic (similar to a septic system). The Bio-Drum system, however, works to avoid this by allowing excess fluid to drain through a screen at the base of the drum into an evaporation chamber. This optimizes the speed of the composting process.

Temperature Control

As the microbes work, they generate heat, which is largely retained in the compost pile by virtue of its mass. Ordinarily, this provides adequate heat to attain optimum composting conditions. However, in colder locations, where the ambient temperature is regularly below 13 degrees C, we generally supply a 240-volt unit, which includes a heater. The heat output is controlled by a thermostat to prevent the compost from drying out, which would otherwise slow down the processing.

The perfect environment for Aerobic Bacteria

The enemy of composting is anaerobic bacteria; an uneven distribution or lack of oxygen, and excess moisture harbour such bacteria. Anaerobic bacteria create nasty odours and inhibit waste from breaking down quickly. Aerobic bacteria transform waste into carbon dioxide and water, leaving behind simple salts, which are perfect for re-absorption by plants.

The exceptional oxygenation, moisture and temperature control created by the Sun-Mar Bio-Drum provides the ideal environment for aerobic bacteria to flourish and break down organic waste rapidly and without odour.


Composting Chamber


Evaporation Chamber


Finishing Drawer