Hydrothermal carbonization (HTC): Valorisation of organic waste and sewage sludges for hydrochar production and biofertilizers

The products generated within the HTC plants can be adapted to the industry’s requirements by applying further post-treatments enabling the industries to substitute fossil coal, reducing the CO2 emissions and encouraging circular economy. [...] The HTC process acts as an acceleration of the natural coal formation process, working at moderate pressure and temperature (20 bar and 210°C for the Ingelia process), allowing the dehydration of the organic matter and increasing the C-content up to 60 %. [...] The hydrochar can undergo specific post-treatment to reduce the content of K, Cl, P, Ca or Si to the limits accepted in the industry and energy sector, or to modify moisture content and density (by pelletisation or briquetting) with the aim of delivering a product that can be sold as a natural resource for fossil coal substitution. [...] Ingelia HTC Technology flow diagram In a research project Newapp, supported by the European Commission, different feedstocks were tested at the Ingelia HTC plant and the properties of the produced hydrochar were analysed. [...] The analysis highlighted three major contributors to overall environmental impacts; electricity and thermal energy used in the process, CO2 produced in the process, and the organic content in the waste streams impacting the environment when applied to land.