Green compost is produced in open windrows. The waste is arranged in rows in the open air and turned on a regular basis. After approximately eight weeks the material is ready for screening.
The process of open windrow composting is as follows:
- The feedstock is shredded, mixed and placed into windrows.
- The windrows are turned on a regular basis to manage odour, improve oxygen content, distribute heat to regulate temperature and to distribute moisture. The windrows are turned multiple times during the composting process, which takes on average eight weeks, depending on maturity requirements.
- The last part of the process involves screening the compost to remove contaminants such as plastics and metals, and to also grade the compost for various end uses. Oversized materials are also removed and can be put back through the whole process until they have composted down sufficiently.