Mechanical and Biological Treatment (MBT) is a waste management designation for a wide range of treatment processes. It's such a broad term that it's almost meaingless to the process designer. Many of the treatment methods discussed on this website could be part of an MBT system.
The goals of an MBT system are those of many waste treatment schemes:
The initial treatment is usually a screen to remove large pieces of debris. Depending on the waste stream, these may include wood, hard plastic, paper. These often can be burned for energy.
The fines, which go through the screen are conveyed to equipment where further anaerobic treatment, perhaps by a composting process, breaks down organic constituents. Output from this process may be useful in agriculture. Some output from both the bulk screening and the biological treatment can be landfilled.