What Is a Modular Thermophilic Composting System?

Modular Systems

• Modular composting systems are one type of in-vessel system, also known as bin and closed-reactor systems. Compost modules are transportable, airtight containers that are capable of processing organic material on site or of being hauled away so the material can continue to degrade in another environment. Some modules are simple, with only perforated piping at the bottom to provide air, while others are more complicated. Sophisticated modular systems have programmable controls that automatically maintain optimum moisture and temperature levels, conduct record-keeping, mixing, loading and screening. The latter are primarily used in large-scale composting facilities.

Thermophilic Stage of Composting

• The term thermophilic describes a temperature range compost must reach to destroy most plant, human and animal pathogens. This is between 45 and 70 degrees Celsius, or 113 and 158 degrees Fahrenheit. To be safe, all material in the compost pile should reach 55 degrees Celsius, or 131 degrees Fahrenheit for at least three days at a time. This is accomplished by turning the pile periodically so all the organic waste spends several days in the center, where temperatures are most likely to reach the thermophilic state.

Microorganisms In the Thermophilic Stage

• Only particular species of bacteria and fungi can survive or remain active in the thermophilic stage of composting. Those active at lower temperatures either slip into a dormant stage or die off and then repopulate the compost once its temperatures drop again in the final stages of curing. These thermophilic microorganisms break down the waste's protein structures and further degrade organic material that has already achieved some degree of decomposition. They are most active between 150 and 160 degrees Fahrenheit, but will die or enter a dormant state above 160 degrees. Microorganisms at this stage are instrumental in changing the compost's appearance from slimy, decomposing matter to the crumbly, dark, earthy-smelling material known as cured compost.

Pros and Cons to Modular Thermophilic Systems

• Modular systems that allow or cause compost materials to heat to the thermophilic stage produce a finished product faster than most other composting systems, such as aerated static piles or windrows. Modules also offer urban residents without much space a realistic and odor-free option for composting, as modules offer a high degree of processing controls, including biofilters for odor. Additionally, compost processing companies can haul away modules, clean and return them to the owners for a hassle-free way to reduce organic wastes from the home. However, modular composting systems are more expensive than other at-home options, such as building simple, open-air bins.