title: Improving composting as a post-treatment of anaerobic digestate.
abstract: This work investigated the influences of practical parameters upon composting of digestate. The yardsticks for evaluation were digestate stabilization, nitrogenous emissions mitigation and self-heating potential. The results suggest choosing an "active" bulking agent like dry wood chips (WC) which served as free-water and nitrogen sink through composting. At an optimal volumetric WC:digestate mixing ratio of 4:1, nearly 90% of the initial NH4(+)/NH3 were fixed, which reduced significantly nitrogenous emissions. This mixing ratio also improved the stabilization and self-heating potential. Using small particle size WC increased narrowly O2 consumption and reduced NH3 emission. Storing used WC prior to recycling reduced 40% N2O emission compared to directly recycled WC. Recycling compost helped to decrease NH3 emission, but quadrupled N2O emission. The optimal aeration rate (15Lh(-1)kg OM0) which was lower compared to composting of organic waste, was enough to ensure the O2 supply and ameliorate the self-heating potential through composting of digestate.
authors.affiliation: Irstea, UR GERE, 17 avenue de Cucillé, CS 64427, F-35044 Rennes Cedex, France.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zeng
authors.affiliation: Irstea, UR GERE, 17 avenue de Cucillé, CS 64427, F-35044 Rennes Cedex, France.
authors.forename: Amaury
authors.initials: A
authors.lastname: De Guardia
authors.affiliation: Irstea, UR GERE, 17 avenue de Cucillé, CS 64427, F-35044 Rennes Cedex, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Dabert
mesh_terms: D000693:Anaerobiosis; D004203:Disinfection; D006813:Humidity; D009584:Nitrogen / Q000032:analysis; D009930:Organic Chemicals / Q000302:isolation & purification; D010101:Oxygen Consumption; D010316:Particle Size; D059027:Recycling; D012037:Refuse Disposal / Q000379:methods*; D012987:Soil; D014934:Wood / Q000737:chemistry
chemical_list: D009930:Organic Chemicals; D012987:Soil; D009584:Nitrogen
keywords: Ammonia; Anaerobic digestate; Bulking agent; Disinfection; Nitrous oxide