9.7 What is important to know about gasification?

Gasification describes the thermochemical process that requires a limited supply of oxygen. The sludge/biosolids are heated in this oxygen-starved environment to temperatures ranging from 700 to 1,000°C. The limited supply of oxygen prevents complete combustion. Still, it facilitates the partial oxidation of the sludge, producing mainly syngas composed of carbon monoxide, hydrogen, carbon dioxide, methane, and other trace gases. Char and tar may be by-products of the process.

Gasification requires dewatering and drying as pre-treatment. Like pyrolysis, the dry matter content should be at least 70% to 85%.