On-farm Composting of Large Animal Mortalities

A major issue facing modern society is waste management, and the best method to manage agricultural and animal wastes for agricultural use (soil conditioning and agricultural production) is by recycling through composting. From a scientific point of view, the composting process is started and managed under controlled environmental conditions rather than accepting the results of natural, uncontrolled decomposition. The design of successful composting systems requires an understanding of biological, physical and chemical processes such as carbon and nitrogen uptake and heat production and transfer. When managed properly, composting improves the handling characteristics of any organic residue by reducing its moisture content, volume and weight. The process increases the value of raw wastes by destroying pathogens and weed seeds and creating a media for the production and proliferation of beneficial organisms. The study of waste production and management lends itself to interdisciplinary study and farm composting provides an opportunity for real-world problem solving with cooperative learning groups. This work is organised in three parts. In the first one, we review developments on the composting as an animal wastes management strategy through the analysis of objectives and conditions for composting, facilities and alternatives, composting ingredients and qualities of compost. The second part, devoted to show the composting as a suitable method for carcasses disposal, contains the formulation and general principles of the method and the specific procedures, with their advantages and disadvantages. At the end, a new closed semi-continuous composter designed for the in-situ composting of animal mortalities, developed at the University of Valladolid, is presented.

Journal of the American Veterinary Medical Association, 2009

Compost Science & Utilization, 2010

Lack of uniform heating and peak temperatures lower than 55°C reduce the utility of beef cattle mortality composting. In a previous study, beef cattle mortalities were placed on a 40-cm straw base and covered with 160-cm manure, and compost reached 50°C with 20% reduction in bovine mitochondrial DNA (a 171bp fragment; Mt171) at 160-cm depth after 147 d of static composting. Two modifications from the previous study's methodology were made: (1) carcasses were raised to 100-cm depth by placing them on an additional 60-cm layer of manure and (2) feedlot manure with 60% moisture content at construction was used. Temperature profiles at depths of 40, 100, and 160 cm all reached 55°C after 7 d, and remained above 55°C for at least 70 d. The bovine Mt171 fragment was degraded 75% by d 112 and 86% by d 230 at 100-cm depth. Carcass soft tissues were almost completely decomposed, with a 99% reduction in genomic DNA and a 92% decrease in Mt171 fragment after 230 d. Levels of coliform bacteria were below 10 CFU g -1 dry wt at all depths on d 230. The modified cattle mortality composting system was characterized by higher peak temperature, longer uniform heating, and faster bovine tissue degradation compared to the previous study. This biocontained composting system could offer effective containment and control of a disease outbreak in which the infectious agent is sensitive to temperatures between 55-62°C.

EFSA Journal

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2008

Compost Science & Utilization, 2000

Four studies explored the feasibility of year-round composting of lamb and mature sheep mortalities within the arid climate of the Canadian prairies. In all studies, a ratio of 2:1.:1 (manure : mortalities : chopped straw) was maintained, although depth of the mortality layer within the bin, number of layers of mortalities per bin, age of animal (lamb or mature sheep) and time of year (summer or winter) were varied. Composting neonatal lambs in the spring/sufiuner was successful whether a single layer (n=15 lambs, weight 99.7 kg) or two, separated layers of mortalities (n=41. lambs, weight 198 kg) were added to a2.4 m3 open bin. Residual bone, wool and soft tissues were negligible after the lamb compost had completed one heating cycle. In contrast, composting mature sheep in the falllwinter was more difficult due to: (L) over wet manure (3t% dry matter) resulting in continuous anaerobic decomposition of carcasses; (2) fat/grease accumulation when composting a layer of carcasses TL cm in depth (weight of sheep 1020 kg). For mature sheep mortalities, 2 heating cycles were required to eliminate soft tissues and wool. As compost in all studies heated in excess of 50oC in the primary and/or secondary bin, bacterial isolates taken after the compost completed the secondary heating rycle were all innocuous species. Provided that compost is protected from excessive moisture and compost is aerated by turning into a secondary bin, a2:'J.:'J. (manure:mortalities:straw) ratio allowed for year-round composting of lamb and mature sheep mortalities.

2000

These operational standards have been written to allow people to comply with the composting portions of the Michigan Bodies of Dead Animals Act and accompanying Rules. It is written for those who have made a decision to compost to manage on-farm mortality, meat processing by-products, or carcasses found along roadways (whole bodies or as parts). These operational standards describe methods which may be used in Michigan, including: details about site selection, sizing the composting system, and how to manage the composting process most effectively. These standards do not include specific information about the microbiology of composting, the history of composting, the justifications for composting, composting equipment, and the composting of manures and other vegetative materials. Such information may be found in several of the supporting documents listed in the RESOURCES and REFERENCES section below.

1995

compost piles. We built six piles in 2.5 m x 1.5 m concrete block pens of an idle hog growing barn. We built another pile, the fourth, in an isolation room because we included pseudo- rabies virus (PRV).The ratio, on a weight basis, of ingredients added was I part pig carcass, 0.1 part wheat straw (or 0.2 part peanut hulls),

2010

Composting experiences have been developed to evaluate the availability of a composter to decompose animal carcasses. These experiences were conducted over a four year period with poultry, under different operational parameters (aeration cycles, composting recipes and temperatures). The amount of carcasses and co-composting materials added was recorded during each loading of the composter. Additionally, pH, conductivity and redox potential were recorded during composting processes, on a weekly basis, and for the final product. Samples for physico-chemical analyses were also taken. Gases released from the decomposing material (CO2, CH4, NO2 and NH3) were measured on a weekly basis by an automatic analyser. Temperatures of the material mass inside the composter and outside the composter were recorded continuously with Pt-100 sensors and a data logger device. Agricultural evaluation of the final product was determined by the procedure described by Zucconi et al. (1985). Composting has ...