A legitimate question to raise: what is the connection between earthworms and municipal sewage sludge treatment?
What kind of worms?
Many species of worms are to be found in the nature. However, not all species are suitable for working purposes.
The treatment of communal sewage results in large quantities of sewage sludge, a by-product that has imposed a considerable load on the environment in the recent decades. As a result, the elaboration of environmental-friendly procedures has become a priority worldwide. The main trend of technological development was the environmental-friendly disposal of the decomposition products of organic substances, supported by (environmental) impact assessments and measurements, and the separation of recyclable by-products, such as methane and compost.