In the production process of organic fertilizer, the construction of ventilation system is very important. By controlling the ventilation rate, the system temperature can be adjusted, the suitable environment for the growth and metabolism of microorganisms can be provided. Therefore, ventilation in composting is necessary. During composting, ventilation has three main purposes: oxygen supply, dehumidification and cooling.

  1. Oxygen demand: the composting process is completed by providing oxygen for the growth, reproduction and metabolic activities of aerobic microorganisms.
  2. Dehumidification demand: ventilation can remove the moisture in the wet raw materials at higher temperature. When the air is heated by the composting substrate, the moisture can be evaporated and the compost materials can be dried.
  3. Cooling demand: ventilation can remove the heat generated by organic matter decomposition to control the process temperature.

The ventilation rate for oxygen supply mainly depends on the content of organic matter in composting raw materials, the proportion of degradable components in organic matter and degradable coefficient, which can be calculated by the chemical composition and degradation degree of organic matter in compost.