Anaerobic digestion of catering wastes: effect of micronutrients and retention time.

Source-separated foodwastes collected from a campus catering facility were processed in bench-scale single-stage anaerobic digesters. The feedstock contained a varied mix of fruits, vegetables, meats and fried foods. A constant organic loading rate (OLR) was maintained with differing hydraulic retention times (HRT). Regular addition of trace elements or prolonged retention time allowed stable digestion at high total volatile fatty acid (TVFA) levels. Reactors on HRT of 25, 50, and 100 days with no micronutrient supplementation exhibited methanogenic failure after approximately 40, 100 and 90 days respectively, while duplicate reactors with micronutrient supplementation maintained stable digestion. An extended HRT of 180 days has so far allowed continued digestion (for reactors with and without micronutrient supplementation) at levels of ammonia nitrogen exceeding 5.7 g l(-1) and volatile fatty acid levels exceeding 15 g l(-1), usually considered inhibitory or toxic.

[1]  M. Alves,et al.  Degradation of Oleic Acid in Anaerobic Filters: The Effect of Inoculum Acclimatization and Biomass Recirculation , 2001, Water environment research : a research publication of the Water Environment Federation.

[2]  M. Gerardi.  The Microbiology of Anaerobic Digesters , 2003 .

[3]  Mauro Majone,et al.  Anaerobic Digestion of Food Industry Wastes: Effect of Codigestion on Methane Yield , 2005 .

[4]  Xavier Font,et al.  Anaerobic co-digestion of a simulated organic fraction of municipal solid wastes and fats of animal and vegetable origin , 2005 .

[5]  A. E. Greenberg,et al.  Standard methods for the examination of water and wastewater : supplement to the sixteenth edition , 1988 .

[6]  B. Ahring,et al.  Thermophilic anaerobic digestion of livestock waste: the effect of ammonia , 2004, Applied Microbiology and Biotechnology.

[7]  A. Venosa,et al.  Effect of iron on the sensitivity of hydrogen, acetate, and butyrate metabolism to inhibition by long-chain fatty acids in vegetable-oil-enriched freshwater sediments. , 2005, Water research.

[8]  J. Oleszkiewicz,et al.  Granulation in anaerobic sludge bed reactors treating food industry wastes , 1989 .

[9]  J. C. Converse,et al.  Improved alkalimetric monitoring for anaerobic digestion of high-strength wastes , 1986 .

[10]  S. K. Bhattacharya,et al.  The effect of ammonia on methane fermentation processes , 1989 .

[11]  M. Takashima,et al.  Mineral requirements for methane fermentation , 1990 .

[12]  P. Kaparaju,et al.  Anaerobic co-digestion of potato tuber and its industrial by-products with pig manure , 2005 .

[13]  P. Lens,et al.  Effect of Long‐Term Cobalt Deprivation on Methanol Degradation in a Methanogenic Granular Sludge Bioreactor , 2002, Biotechnology progress.

[14]  G. Lettinga,et al.  Importance of cobalt for individual trophic groups in an anaerobic methanol-degrading consortium , 1994, Applied and environmental microbiology.

[15]  J. Rintala,et al.  Semi-continuous anaerobic digestion of solid poultry slaughterhouse waste: effect of hydraulic retention time and loading. , 2002, Water research.

[16]  G Lettinga,et al.  Kinetics and mass-transfer phenomena in anaerobic granular sludge. , 2001, Biotechnology and bioengineering.