International Poultry Expo International Rendering Symposium January 29, 2016 Atlanta, GA, USA

Transcription

1 International Poultry Expo International Rendering Symposium January 29, 2016 Atlanta, GA, USA A Comparison of the Safety and Sustainability of Three Methods Used to Process Meat By-Products Charles H. Gooding, PhD, PE Emeritus Professor Clemson University Clemson, South Carolina USA Chemical Engineering Consultant

2 Purpose Examine three alternative methods of handling fallen animal carcasses and meat by-products from food animal slaughter. Anaerobic Digestion Composting Rendering

3 Scope: consider these key factors Biosecurity Environmental sustainability Resource recovery

4 Biosecurity and other HSE issues Rendering is an established industrial process, operated and controlled carefully under a Code of Practice 1 developed by the Animal Protein Producers Industry (APPI). Audits and certification of compliance with the code are conducted by a third party, the Facility Certification Institute 2. Every rendering plant is regulated by local and/or state health, safety, and environmental (HSE) agencies to insure that employees, the public, and the environment are protected.

5 Biosecurity and other HSE issues The rendering industry and individual rendering facilities are regulated at the federal level by the Food and Drug Administration 3 (FDA), the Animal and Plant Health Inspection Service 4 (APHIS), and other components of the US Agriculture Department (USDA). The Food Safety Modernization Act expanded FDA regulatory control over all animal food, including rendered ingredients. Requirements include hazard controls, good manufacturing practices, and extensive recordkeeping. 5

6 Biosecurity and other HSE issues Current health and environmental regulations applicable to composting and anaerobic digestion (AD) vary considerably from state to state. 6-8 Most composting and AD regulations do not address co-processing of meat by-products (MBP) because it is not common practice. Research has shown that co-composting and anaerobic co-digestion of MBP with manure and other materials are possible, but challenging.

7 Biosecurity and other HSE issues AD and composting require strict control of temperature-time conditions to insure that pathogens are destroyed This is especially difficult to achieve in composting due to the heterogeneous nature of the material. Addition of MBP complicates the operation of anaerobic digesters because ammonia released from proteins in MBP inhibits microbial growth. 14 Leachate from compost windrows can harm plants, animals, and humans if it is not collected and treated properly. 10,12

8 Greenhouse gas (GHG) emissions Rendering requires burning of fossil fuels to produce steam for heating, but nearly all of the carbon in the meat by-products (MBP) is retained in the fats and proteins produced. Compared to aerobic degradation of meat byproducts, rendering avoids 75% of potential GHG emissions. 16,19,20 Energy requirements and GHG emissions from codigesting MBP anaerobically are relatively small if CH 4 losses are minimized, but storage of digestate slurry in open tanks can multiply GHG emissions by a factor of

9 Greenhouse gas (GHG) emissions Co-composting of MBP with manure and bulking materials requires minimal electricity, and GHG emissions from equipment used to turn the windrows are also small. 22 But 45 to 75% of the carbon in cocomposted MBP is released as carbon dioxide (CO 2 ) 17,18 and 4 to 20% is released as methane (CH 4 ), 17,18 which has 25 times the global warming potential (GWP) 23 of CO 2. In addition, 6 to 9% of the nitrogen in MBP proteins is emitted as nitrous oxide (N 2 O), 17,18 which has 300 times the GWP 23 of CO 2. Overall cocomposting of MBP emits 3 to 5 times as much GHG as converting all carbon in the material directly to CO 2.

10 Resource recovery Rendering converts about 99% of the fats, proteins, and nutrients in meat by-products into valuable ingredients of animal feeds. 12,16,21 Alternatively, rendering and subsequent chemical processes can be used to convert MBP into biofuels and highervalue industrial materials. 12,16 Anaerobic co-digestion of MBP with manure produces only low-value fuel gas (60-80% methane) and a digestate that can be used as fertilizer. 11,12 Co-composting of MBP with manure and bulking materials converts a small fraction of the MBP into a nitrogen-enriched soil amendment material 12,17,18 that has relatively low economic value 24.

11 For reasons cited on the previous slide, the US EPA Food Recovery Hierarchy 15 ranks animal feeds produced by rendering above products of anaerobic digestion and composting in terms of effectiveness of resource recovery. Resource recovery

12 Summary comparison of GHG emissions and economic value of products 1000 kg Process Meat Process Utility GHG fuel by-products GHG Utility Plant Electricity Conversion Process Energy source Process products

13 Basis: 1000 kg of MBP processed Process Composting Anaerobic Digestion Rendering Electricity, kwh <1 15 to Process fuel, MJ 100 to Utility GHG, kg CO 2 e < Process GHG, kg CO 2 e 2500 to to Total GHG, kg CO 2 e 2500 to to Potential GHG if all C in meat by-products were converted to CO 2 Product 1 N in compost CH 4 in biogas fat amount, kg 10 to to value, $ 10 to to Product 2 none N in digestate protein amount, kg - 20 to value, $ - 20 to Total product value, $ 10 to to to 310

14 Implications and conclusions Small farmers might favor composting as a method of disposing of carcasses along with manure because constructing and operating a compost pile costs less than constructing and operating an anaerobic digester and perhaps less than sending carcasses to an off-site rendering facility. For a large farm or feed lot, anaerobic digestion could be an attractive way to produce fuel and dispose of manure and a limited mass of carcasses relative to the mass of manure produced.

15 Implications and conclusions With respect to biosecurity, environmental sustainability, and resource recovery, rendering is clearly preferable to composting and anaerobic digestion as a method of handling large quantities of animal carcasses and meat by-products (MBP). To insure the health and safety of workers and the public as well as environmental responsibility, regulatory constraints must in place for all methods of meat by-product disposal that are allowed to exist. Within regulatory limitations, cost is likely to be the key factor that determines how individual producers of animal carcasses and MBP handle the material.

16 References cited CIWMB staff. Food waste composting regulations white paper, California Integrated Waste Management Board Gale, P. Risks to farm animals from pathogens in composted catering waste containing meat, Vet. Rec. 155: Berge, A. et al. Methods and microbial risks associated with composting of animal carcasses in the United States, JAVMA 234(1): Masse, D. et al. On farm biogas production: A method to reduce GHG emissions and develop more sustainable livestock operations, Anim. Feed. Sci. Tech :

17 References cited 12. Gwyther, C. et al. The environmental and biosecurity characteristics of livestock carcass disposal methods: a review, Waste Manag. 31: Franke-Whittle, I. and H Insam, Treatment alternatives of slaughterhouse wastes, and their effect on the inactivation of different pathogens: A review, Critical Rev. Microbiology, 39(2): Hejnfelt, A. and I. Angelidaki. Anaerobic digestion of slaughterhouse byproducts, Biomass Bioenerg. 33: Gooding, C. Data for the carbon footprinting of rendering operations, J. Industrial Ecology 16(2): Xu, S. et al. Greenhouse gas emissions during co-composting of cattle mortalities with manure, Nutr. Cycl. Agroecosys. 78: Xu, S. et al. Greenhouse gas emissions during co-composting of calf mortalities with manure, J. Environ. Qual. 36:

18 20. References cited 21. Swisher, K. Market report, Render 44(2): Gulliver, J. and D. Gulliver. On-site composting of meat by-products. Final report: New York State Department of Economic Development, October Solomon, S. et al. Technical summary of contribution of working group I to the 4th assessment report of the IPCC. Cambridge University Press Angelidaki, I. and W. Sanders. Assessment of the anaerobic biodegradability of macro pollutants. Reviews Environ. Sci. and Bio/Tech. 3: Meroney, R. CFD simulation of mechanical draft tube mixing in anaerobic digester tanks, Water Research 43, Ek., A. et al. Slaughterhouse waste co-digestion - Experiences from 15 years of full-scale operation, World Renewable Energy Congress Sweden Liebetrau, J. et al. Analysis of greenhouse gas emissions from 10 biogas plants within the agricultural sector. Water Sci. and Tech. 76(6),

19 Acknowledgements The work described here was funded by the Fat and Protein Research Foundation and was facilitated by many helpful discussions with David Meeker, FPRF and NRA Ross Hamilton, Darling Intl. David Kirstein, Darling Intl. Jessica Meisinger, NRA David Carey, a 2014 Clemson chemical engineering graduate, did much of the original collection, screening, and analysis of greenhouse gas emission data from composting.

20 For further information Contact the author at