title: Use of biochars in anaerobic digestion.
abstract: This study investigated the behavior of biochars from pyrolysis (pyrochar) and hydrothermal carbonization (hydrochar) in anaerobic digestion regarding their degradability and their effects on biogas production and ammonia inhibition. A batch fermentation experiment (42°C, 63 days) was conducted in 100mL syringes filled with 30 g inoculum, 2g biochar and four levels of total ammonium nitrogen (TAN). For pyrochar, no clear effect on biogas production was observed, whereas hydrochar increased the methane yield by 32%. This correlates with the hydrochar's larger fraction of anaerobically degradable carbon (10.4% of total carbon, pyrochar: 0.6%). Kinetic and microbiota analyses revealed that pyrochar can prevent mild ammonia inhibition (2.1 g TANk g(-1)). Stronger inhibitions (3.1-6.6 g TAN kg(-1)) were not mitigated, neither by pyrochar nor by hydrochar. Future research should pay attention to biochar-microbe interactions and the effects in continuously-fed anaerobic digesters.
authors.affiliation: APECS Group, Leibniz Institute for Agricultural Engineering Potsdam-Bornim, Max-Eyth-Allee 100, 14469 Potsdam, Germany. Electronic address: jmumme@atb-potsdam.de.
authors.forename: Jan
authors.initials: J
authors.lastname: Mumme
authors.affiliation: Department of Plant Science, McGill University, Macdonald Campus, 21111 Lakeshore Road, Ste-Anne-de-Bellevue, QC H9X 3V9, Canada.
authors.forename: Franziska
authors.initials: F
authors.lastname: Srocke
authors.affiliation: APECS Group, Leibniz Institute for Agricultural Engineering Potsdam-Bornim, Max-Eyth-Allee 100, 14469 Potsdam, Germany.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Heeg
authors.affiliation: APECS Group, Leibniz Institute for Agricultural Engineering Potsdam-Bornim, Max-Eyth-Allee 100, 14469 Potsdam, Germany.
authors.forename: Maja
authors.initials: M
authors.lastname: Werner
mesh_terms: D000641:Ammonia / Q000494:pharmacology; D064751:Ammonium Compounds / Q000032:analysis; D000693:Anaerobiosis / Q000187:drug effects; D001419:Bacteria / Q000187:drug effects / Q000378:metabolism; D056804:Biofuels / Q000382:microbiology; D001709:Biotechnology / Q000379:methods*; D002606:Charcoal / Q000378:metabolism*; D007700:Kinetics; D008697:Methane / Q000096:biosynthesis; D017641:Zeolites / Q000494:pharmacology
chemical_list: D064751:Ammonium Compounds; D056804:Biofuels; C540010:biochar; D017641:Zeolites; D002606:Charcoal; D000641:Ammonia; D008697:Methane
keywords: Ammonia inhibition; Anaerobic digestion; Biochar; Degradation kinetics; Methanogenic microflora