title: Effects of temperature and carbon-nitrogen (C/N) ratio on the performance of anaerobic co-digestion of dairy manure, chicken manure and rice straw: focusing on ammonia inhibition.
abstract: Anaerobic digestion is a promising alternative to disposal organic waste and co-digestion of mixed organic wastes has recently attracted more interest. This study investigated the effects of temperature and carbon-nitrogen (C/N) ratio on the performance of anaerobic co-digestion of dairy manure (DM), chicken manure (CM) and rice straw (RS). We found that increased temperature improved the methane potential, but the rate was reduced from mesophilic (30∼40°C) to thermophilic conditions (50∼60°C), due to the accumulation of ammonium nitrogen and free ammonia and the occurrence of ammonia inhibition. Significant ammonia inhibition was observed with a C/N ratio of 15 at 35°C and at a C/N ratio of 20 at 55°C. The increase of C/N ratios reduced the negative effects of ammonia and maximum methane potentials were achieved with C/N ratios of 25 and 30 at 35°C and 55°C, respectively. When temperature increased, an increase was required in the feed C/N ratio, in order to reduce the risk of ammonia inhibition. Our results revealed an interactive effect between temperature and C/N on digestion performance.
authors.affiliation: College of Agronomy, Northwest A&F University, Yangling, Shaanxi, People's Republic of China.
authors.forename: Xiaojiao
authors.initials: X
authors.lastname: Wang
authors.affiliation: School of Chemical Engineering, Northwest University, Xian, Shaanxi, People's Republic of China.
authors.forename: Xingang
authors.initials: X
authors.lastname: Lu
authors.affiliation: College of Agronomy, Northwest A&F University, Yangling, Shaanxi, People's Republic of China.
authors.forename: Fang
authors.initials: F
authors.lastname: Li
authors.affiliation: College of Agronomy, Northwest A&F University, Yangling, Shaanxi, People's Republic of China.
authors.forename: Gaihe
authors.initials: G
authors.lastname: Yang
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D000818:Animals; D001421:Bacteria, Anaerobic / Q000378:metabolism*; D056804:Biofuels; D002244:Carbon / Q000378:metabolism; D002417:Cattle; D002645:Chickens; D008372:Manure / Q000382:microbiology*; D008697:Methane / Q000096:biosynthesis*; D009584:Nitrogen / Q000378:metabolism; D012275:Oryza; D018547:Plant Stems / Q000382:microbiology; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D056804:Biofuels; D008372:Manure; D002244:Carbon; D000641:Ammonia; D009584:Nitrogen; D008697:Methane