Hydrothermal carbonization process: Fundamentals, main parameter characteristics and possible applications including an effective method of SARS-CoV-2 mitigation in sewage sludge. A review

Hydrothermal carbonization is a thermochemical conversion process that is used as an opportunity to convert biomass and organic waste in the presence of water into solid biofuel, liquid, and gaseous products. It is a low-energy alternative for transforming waste of different origins: sewage sludge, lignocellulosic biomass, algae and other types of waste. This paper reviews the process carried out on sludge. The properties of the resulting products depend on the process parameters, which include residence time of reaction, pH, water content and temperature. The correct adjustment of parameters is very important and has a significant impact on the properties of hydrothermal products, offering different possibilities for various applications of products in their respective fields. The influence of the process parameters, the characteristics of the liquid and solid products and use of products, mostly hydrochar, are widely discussed.