**6.7 Wet oxidation**

The thermal process category includes the wet oxidation of sewage sludge. It utilizes pure or ambient oxygen and occurs in an aqueous phase, and its temperatures lie between 150 and 330°C and pressures of 1 to 22 MPa. The procedure requires

a high temperature to avoid boiling at the necessary temperatures. The procedure involves heat degradation, hydrolysis, oxidation, and conversion of the organic substance in the sewage sludge to water, nitrogen, and carbon dioxide. Two separate regimes operate during the entire operation.


### **6.8 Gasification**

Technologies that make it possible to use garbage as fuel are extremely important. Theoretically, nearly all biological wastes along with a humidity content of 5–30% are able to be successfully gasified, yet not all biofuels can do this. Gasification is known to be influenced by fuel characteristics like surface, size, and moisture in addition to shape, carbon content, and volatile matter. Sludge and other less-priced materials might be useful as the feedstock for gasification. Numerous variables, including the input fuel, reactor type, and others, affect the gasification process' ability to create gas with a given amount of energy. To produce a suitable gas for power production, essential research into the impacts of sludge on gasification is crucial. Gasification technology can be used to both alleviate the environmental issue and turn the sewage sludge into a usable energy source.
