Abstracts Accepted for Session 6: Carcass Treatment

Ambient Alkaline Hydrolysis and Anaerobic Digestion for Management of Poultry Mortalities

Joshua Z. Arias, Tim Reuter, Brandon H. Gilroyed

University of Guelph Ridgetown Campus and Alberta Agriculture and Forestry, Bridgetown, Ontario

Alkaline hydrolysis (AH) for mortality management typically involves subjecting carcasses to highly basic solutions under conditions of elevated temperature and pressure. While highly effective at solubilizing carcasses, eliminating pathogens, and preventing uncontrolled emissions to the environment, the equipment for conducting AH has limited throughput and high capital cost. Further, the AH process produces a saline, caustic hydrolysate with high chemical oxygen demand that must be treated prior to environmental release. Because of these drawbacks, AH has not been readily adopted for mortality management to date. Anaerobic digestion (AD) technology uses microbial activity to convert organic substrates into methane-rich biogas, which can be utilized as a renewable energy source. While anaerobic digestion can be utilized for mortality management, there are challenges associated with carcass storage and handling, biosecurity, and process stability. While AD could be used for routine mortality management, capacity does not exist to handle mass mortality events during emergency management. In this study, we evaluated combining an ambient alkaline hydrolysis process with subsequent anaerobic digestion of hydrolysate as a method for disposal of whole broiler chicken carcasses. AH was conducted at ambient temperature (21 °C) and pressure (99 kPa) using 2, 4, or 8 M potassium hydroxide (KOH). All AH treatments solubilized broiler carcasses within 20 days, resulting in a caustic (pH > 14) hydrolysate. Alkaline hydrolysate was effectively neutralized by mixing with corn silage and anaerobic digestate. The neutralized mixture was used as a substrate for anaerobic digestion in bench top continuously stirred tank reactors and biogas production was assessed. Anaerobic digestion of neutralized hydrolysate reduced volatile solids by >96% for all treatments. Highest methane yields were observed from the 2 M KOH treatment (607.2 ± 47.9 g mL-1 VS), while the 8 M treatment produced the least (207.5 ± 204.3 g mL-1 VS) over a total of 42 days. Conducting AH under ambient conditions would eliminate the drawbacks of limited throughput and capital cost, while combining the process with AD provided an outlet for caustic hydrolysate that produced renewable energy as biogas. Because ambient AH does not require any specialized equipment and results in biosecure stabilization of solubilized carcasses, the process is highly scalable and could be an ideal option for rapidly managing mortalities during an emergency outbreak.

Presentation: Session 6.1

Rapid Mortality Disposal Using Containerized Composting

Jim McNelly

St. Cloud, Minnesota

In 1973, forced aeration was first used for composting at the Compost Research Station at the USDA BARC facility in Beltsville, Maryland. Critical design parameters such as carbon to nitrogen ratios, homogeneity, porosity, moisture, distribution of air and oxygen levels were established. Known as the Beltsville Aerated Static Pile (ASP) method, this blower, perforated pipe and mound system was considered a novel improvement over static piles or windrows. In the Federal 40 CFR 503 rules, the USEPA recognizes ASP technology as an approved methodology for composting raw or digested wastewater treatment biosolids. In the 503 rules section on approved Processes to Further Reduce Pathogens (PFRP), 72 hours of continuous temperature over 55C using ASP composting is certified to reduce fecal coliforms to background levels under 1000 count most probable number per gram. To meet the 503 rules for PFRP, windrows, however, must achieve a minimum of fifteen unique 24 hour periods over 55C coupled with a minimum of five turnings. Numerous studies show that HPAI virus is killed by exposure to even modest composting temperatures and consequently, static pile composting inside the bird house is currently the standard methodology used for catastrophic mortality management such as the 2015 HPAI outbreak. Logistics of mobilizing carbon sources such as wood chips, biosecurity, site containment, equipment availability, operator certification and the physical properties of the poultry houses, however, proved problematic. Some poultry barns were too low to accommodate front end loaders and in many cases, there was insufficient moisture in the bedding and wood chips to achieve uniform static pile temperatures. The large size of some of the turkeys, particularly those over 8 kilos, proved challenging as well. Composting periods up to four months were not uncommon and static pile composting was often impractical inside broiler and layer houses. The sheer volume of disposing two million or more birds and associated manure was simply overwhelming and many facilities resorted to landfill disposal and other less desirable management strategies. Acquiring tens of millions of tons of wood chips within a several day period after euthanization was simply not feasible. As a composting consultant with over forty years’ experience, a founder of the US Composting Council and long term participant in APHIS catastrophic mortality research and task force teams, I proposed a method of using modified Intermodal shipping containers as a method of poultry carcass, litter and manure management using ASP technology that would achieve destruction of the virus in less than four days and rapidly render the compost suitable for outdoor stockpiling and land application. Containerized composting has been used successfully in a variety of applications since the early 1990s and is a recognized method of batch composting using ASP protocols. The proposal called for rapid deployment of containers, blowers, pipe, floor sealing, chassis, cranes, mobile grinders, trailers, large front-end loaders. Rated at either 10 tons capacity per hour for turkey or broiler houses and 50 tons per hour for layer operations, this approach was designed to empty a turkey house of birds and bedding in less than a week enabling building sanitizing and resumption of farming operations. In this presentation, we will present this containerized ASP approach in greater detail showing how the composting containers could be rapidly deployed, sealed, plumbed and filled using ASP and material handling methods that prevent fugitive aerosols and vector exposure.

Presentation: Session 6.2

Efficacy and Efficiency of Poultry Carcass Composting Using Different Mechanical Mixing Equipment for AI Outbreaks

Jennifer Keaten DVM, MPH and Mark Hutchinson, MS

University of Iowa, College of Public Health and University of Maine Cooperative Extension, Bridgton, Maine

The current USDA composting protocols for AI infected poultry have the potential for areas of anaerobic pockets within the windrow due to inadequate mixing and the large carcass size of whole birds. This could lead to ineffective virus neutralization or prolonged composting times and higher resource costs. The purpose of this project was to determine if using a horizontal mixer wagon to mix composting ingredients or a vertical mixer wagon to mix and cut up the composting ingredients is an economical and timely means to accelerate the tissue break-down and obtain optimal temperatures for poultry carcass composting during an AI outbreak. A replicated trial with 3 treatments, Horizontal Mixer (HM), Conventional Layering (CL) and Vertical Mixer (VM), and three replications was initiated at the Compost Research and Education Center part of the University of Maine Forest and Agricultural Experimental Station called Highmoor Farm. Daily temperatures and screened core sample weights (screen weights) on day 0, 16, and 30 were recorded for each of the compost piles. The time to build each replication was recorded and used to help calculate the cost of each method. Data on equipment, carbon material and labor costs were collected from private contractors from the 2014-2016 HPAI outbreak and used to compare costs between methods. All treatment methods reached USDA protocol temperatures to neutralize the HPAI virus. Screen weights for both the VM and HM treatments were lower than the CL treatment. Screen weights decreased significantly from day 0 to day 16 for the VM and HM treatments with no significant change from day 16 to day 30. When comparing costs, the mixer wagon methods were more cost effective than the CL method when using high volume equipment. The data from this study supports the use of a mixer wagon to reduce particle size and mix ingredients for more timely and effective composting of poultry carcasses.

Presentation: Session 6.3

CO2 Culling with Influenza Containment System I.C.S.: Physiological and Ethical Considerations

Ayivi Teteh, Abdelkader Alami, Bram Kamers, Jacob Kokou Tona

University of Lome, Togo, Lokeren, Belgium

This study aims at identifying the strong and weak points of the I.C.S.-bag compared to current killing methods for poultry. This culling method was first evaluated on several ethical aspects with the ‘Animal Disease Intervention Matrix’ (ADIM, Aerts 2006). This system provides governments with a tool to take more ethically justified decisions about animal disease. In a series of gassing experiments on laboratory scale, the changes in the physiological mechanisms and the behavioral changes of the animal after exposure to rising CO2 was investigated. Finally, it was determined if the I.C.S.-bag could contain Highly Pathogenic Avian Influenza (HPAI) for longer time periods. This study was performed by the Istituto Zooprofilattico delle Venezie (IZSVe, Italy). Finally this system was introduced at the University of Lomé, Togo. There the method was used during one of the latest out-brakes. Also, based on the ability of the system to contain HPAI and no leakage when gases are injected into the system, storages tests were conducted on poultry feed and hatching eggs. The results showed that the I.C.S.-bag has (1) a higher ADIM-score, (2) death within 40 seconds and (3) no dispersion of the virus in the environment within 48 hours. The other experiments indicated (4) a higher Feed Conversion Ratio when stored in the I.C.S.-bag, as well as (5) higher hatching rate of day old chickens.

Presentation: Session 6.4