NOVELTY - Reducing (m1) the titer of a biohazard that may be present in a carrier material, either involves providing the carrier material to an anaerobic digestion (AD) reactor and maintaining the rate of biogas production steady during the AD process.    USE - For reducing the titer of a biohazard that may be present in a carrier material; and for producing biogas, where the carrier material comprises a protein rich material i.e. specified risk material (SRM) selected from central nervous system (CNS) tissue (e.g. brain, spinal cord, or their fractions/homogenates/parts); and the biohazard comprises hormones, antibodies, body fluids, viral pathogens, bacterial pathogens, weed seeds, prion (i.e. scrapie prion, CWD prion, or BSE prion) (claimed).    ADVANTAGE - The method enables to titer of prion (i.e. resistant to proteinase K (PK) digestion), that may be present in a carrier material. The rate of biogas production is maintained steady during the AD process and the method enables to achieve greater than or equal to 2 (preferably 4) logs reduction of the titer of the biohazard, after 30 days or 18 days of anaerobic digestion. Prion and its infectivity can be destroyed completely within 30 days, 60 days, or 100 days. Protein-rich SRMs with disinfected prions, instead of being waste materials that require costly treatment for proper disposal, can be utilized by the thermophilic anaerobic digestion (TAD) process to enhance fuel value of biogas in comparison to conventional anaerobic digestion. As a result, multiple social and economical benefits can be simultaneously achieved, including allowing the cattle industry to treat SRMs cost-effectively, meeting certain government mandates, protecting the environment from a possible contamination with prion pathogens, reducing the environmental footprint caused by the disposal of SRM treated by other methods, and at the meantime generating valuable biogas. Thus, thermophilic anaerobic digestion process may well eliminate prions in SRMs effectively via combined enzymatic catalysis and biological degradation by anaerobic bacterial colonies in the system, and turn the protein-rich SRMs into bioenergy and biofertilizers.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for producing (m2) biogas, involving providing to an anaerobic digestion (AD) reactor a protein-rich feedstock, where the rate of biogas production is maintained steady during the AD process.