Effects of low-temperature dry anaerobic digestion on methane production and pathogen reduction in dairy cow manure
- 38 Downloads
Cow manure with bedding is a renewable organic biomass, available around the year on dairy farms. However, its reuse is hampered by many factors including existence of potential pathogens. Efficient and cost-effective dry anaerobic digestion at low temperatures (20 °C and 28 °C) can be used to eliminate pathogens. At the same time, it can provide energy and income to dairy farms. A dry anaerobic digestion process was used in this study to investigate its effect on methane production and removal of pathogens. This operational feasibility study showed that (i) the digester operating at 28 °C obtained 50% higher specific methane yield (0.229–0.286 LCH4/gVSfed) compared to 20 °C. This value was similar to those obtained by mesophilic (35–38 °C) digesters (0.228–0.302 LCH4/gVS), while the net heat energy requirement to maintain the digester temperature was lower in our digesters; (ii) approximately 90–100% pathogens (E. coli, streptococcus, total gram-negative bacteria, Salmonella and Klebsiella) were eliminated in the dry anaerobic digestion process. These results are encouraging to reuse digested material as an alternate economical bedding source for dairy cows.
KeywordsBedding Dairy cow manure Dry anaerobic digestion Pathogen reduction Recycled manure solids
Authors thank the Natural Sciences and Engineering Research Council of Canada (NSERC Project No: EGP-486599-15) and Bio-Terre Systems Inc. for providing financial support for conducting this research.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
- APHA (1992) Standard methods for the examination of water and waste water, 18th edn. American Public Health Association, WashingtonGoogle Scholar
- Cabral C, Eveillard F, Heer L, Oertig M (2014) Tapping into the large potential of organics recycling, using dry anaerobic digestion—the European experience. Paper presented at the The Canadian Waste Resource Symposium, Vancouver 2-4 April, Canada. http://www.swanabc.org/swanabc2_5/lounge/technical-library-docs/doc_download/301-dry-anaerobic-digestion-the-european-experience
- FAO (2013) Tackling climate Change through livestock: a global assessment of emissions and mitigation opportunities. Food and Agriculture Organization of the United Nations. Rome. http://www.fao.org/3/a-i3437e.pdf (Viewed on June 30, 2017)
- Hofmann N, Beaulieu MS (2006) A geographical profile of manure production in Canada, 2001. Statistics Canada, Agriculture Division, OttawaGoogle Scholar
- Li HL, Guo XL, Cao FF, Wang Y (2014) Process evolution of dry anaerobic co-digestion of cattle manure with kitchen waste. Chem Biochem Eng Q 28(1):161–166Google Scholar
- Massé DI, Saady NMC, Rajagopal R (2014a) Psychrophilic dry anaerobic digestion of high solids content dairy manure: long-term operation. Biol Eng Trans 7:99–112Google Scholar
- Plym-Forshell L (1995) Survival of Salmonellas and Ascaris suum eggs in a thermophilic biogas plant. Acta Vet Scand 36(1):79–85Google Scholar
- Generating Renewable Electricity: A Self-Assessment Toolkit (2012) https://www.bchydro.com/content/dam/hydro/medialib/internet/documents/planning_regulatory/acquiring_power/2012q4/self-assessment_toolkit_form_oct2012_ar.pdf. Accessed 8 June 2017