Hydrothermal carbonization of co-stream from poultry industry

Large amounts of chicken rest raw material are generated from mechanical deboning of meat and are discarded or used as animal feed. However, this raw material contains considerable amount of valuable components, such as lipids and meat proteins which can be recovered enzymatically. As a result of enzymatic treatment a solid residue is formed containing mainly phosphorus-rich bones. In this study hydrothermal carbonization (HTC) with different processing conditions was used to convert enzymatically treated chicken rest raw material to products containing carbon and nutrients. In HTC organic raw material is heated under moderate temperatures in self-generated pressures using water as carbonization medium producing solid hydrochar, liquid phase and a minor gas phase. The produced hydrochars and liquid fractions were characterized to evaluate HTC's potential from nutrients (P,N) recovery perspective. With lower pH (pH 1) the majority of both N and P were in liquid fraction. With higher pH (pH 6) the majority of P was distributed to hydrochar while N was concentrated in the liquid fraction. The results indicate that the migration of nutrients in HTC can be controlled by processing conditions.