Introduction

During an Avian Influenza outbreak the bird carcasses need to be euthanized and destroyed with as little handling and movement as possible to prevent further spread of the disease. There are not many options for accomplishing that task. One of the most successful methods is the use of Air Curtain Burners manufactured by Air Burners, LLC. These machines have been successfully deployed in animal disease outbreaks around the world and many of the technical or scientific reports from these deployments are available on the Air Burners website or by re-quest from Air Burners.

Animal Carcass Burning

Because air curtain burners burning wood waste develop very high burn chamber temperatures, portable Air Burners fireboxes have been utilized numerous times around the world for disaster clean-up where it was necessary to incinerate animal carcasses, especially from diseased animals that required special disposal procedures, such as in the case of animals affected by BSE or Avian Influenza. In the case of BSE, the emphasis lies on the destruction of the Prions requiring temperatures above 850ºC (approximately 1560ºF) constantly for a prolonged period of operating times. In the case of the Avian Flu, the emphasis lies on avoidance of cross contamination in the field and rapid destruction of massive quantities of birds on site. The minimum temperature that must be sustained to render the influenza virus ineffective is much lower, around 72ºC (approximately 162ºF). Temperature fluctuations are therefore less critical.

Many Air Burners machines have been purchased by government agencies to meet bio-terrorism contingencies, as Agriculture-Terror is an ongoing concern. Air Burners fireboxes are the only portable field option available to safely destroy a large herd or flock of animals poisoned in a bioterrorism attack. The machines can be transported, delivered and be operational within hours of an outbreak.

Bird Carcasses
Conventional disposal practices, such as burial in the ground and landfill disposal, do not lend themselves well to the safe disposal of massive quantities of birds infected with the highly contagious bird flu virus. Burial and land-filling are not desirable, because of the lack of control over the containment of the virus to keep it from spreading to other birds and possibly mammals. Incineration is the most effective solution. Incineration in conventional MSW incinerators and auto-claves is not practical and economical for the safe destruction of large volumes of bird carcasses due to high cost of transportation and the low throughput associated with these types of incinerators. In contrast, disposal in portable refractory walled fireboxes is the most suitable and cost effective option to safely destroy large carcass volumes on site. Employing this method obviates the need to trans-port disease-ridden carcasses over public roads thereby minimizing cross contamination.

Some bird carcasses, such as chickens that contain high levels of water, must best be introduced into the firebox immediately upon euthanization, as they tend to decompose very rapidly in the open environment. Wild birds that have died from the bird flu must be collected swiftly and completely to avoid their consumption as food by mammals and vultures. The cross contamination of mammals, such as cats or badgers is of extreme concern, as it would manifest the spreading of the virus across species and possibly mutations of the virus which is very resilient and can survive in the environment at quite extreme conditions. It is the fear of such mutations that may result and have resulted in the contraction of an H5N1 type virus by humans in Asia and the Middle East.

Technical Discussion
This Technical Memorandum provides an understanding of the “standard” methods that have been employed to date using the Air Burners air curtain burners. In addition, this memorandum provides a technical overview of two new developments on the Air  Burners machines:

1)  The newly patented Diesel burner augmentation for areas where wood is scarce. The fireboxes can be fitted with automatically controlled Diesel burners. These DB-Versions can be operated as standard fireboxes and their combustion capacity can be augmented on an as-needed basis by flame burners, should wood waste be scarce to support combustion of carcasses or other waste streams.

2)  Air Burners fireboxes are available as R-Versions for self-loading and self-unloading by the use of standard US or UK roll-off trucks.

Standard Firebox Use
The standard fireboxes were originally designed to be used as an environmentally friendly alternative to open burning of wood waste. Their primary purpose is to control particulate matter (smoke) generated from burning wood. This is accomplished by directing an “air curtain” across the top of the open firebox (#4 in Figure below). This air curtain traps a majority of the smoke particles (#5) and causes them to re-burn in the extremely hot area just below the air curtain and just above the burning wood waste. The temperatures in this area can exceed 1400ºC (approximately 2500ºF). The principle of air curtain incineration and operational videos are available for more details on our Web Site. www.airburners.com.

The S-Series fireboxes lend themselves best for bird carcass destruction. They are fully self-contained and they do not require any set up at site. The units are ready to load and start burning as soon as they are off the trailer. They are fully portable and transportable on a variety of standard trailers, including standard self-loading and unloading trailers and roll-off trucks.

Wood Fuel
To date the most common way to incinerate the bird carcasses is using highly burnable wood waste as the “fuel” to burn the carcasses. The Firebox is operated in its normal manner burning wood waste. Once the fire is hot enough the carcasses can be loaded into the firebox for incineration. In order to be successful, the operator will have to observe a wood weight to carcass weight ratio of at least 1:1 (i.e., 10 tons of carcasses will need 10 tons of wood waste). The drier and more burnable the wood waste is, the hotter and cleaner the incineration operation will be and the higher the through-put. Detailed instructions are available upon request from info@airburners.com.

New Diesel Burner Firebox Series
For use in disaster recovery operations and in locations where wood is not readily available to be used as the burning “fuel,” then our newly introduced S100DB and S220DB fire-boxes should be deployed. These fireboxes are based on our standard S-Series refractory walled air curtain burners, but they have been equipped with multiple powerful Diesel fuel burners below the air curtain on the manifold side of the firebox and include automatic control features. The primary purpose of the Diesel burners is to dry the waste material to a point where it can support combustion without the burners. Then the burners would be turned off and the waste material continued to be loaded at a rate that would not smoother the existing fire. The air curtain would help to reduce the particulate release and provide air for combustion. If the heat value in the fireboxes drops to a level that causes excessive smoke then the diesel burners can be reignited to bring the temperatures back up. In extremely difficult circumstances the burners can be used continuously.

Transportation
The Fireboxes can be transported by flat bed truck as depicted below or
they can be transported by a standard self loading roll-on, roll-off truck.

S327 Transported on Step-deck Tractor-Trailer

S111DBR and Air Burners Roll-Off Truck

Operation
Site preparation, start-up, and loading procedures are basically the same procedures for wood burning as with carcass burning in our air curtain burners. Air Burners, LLC operating manuals for the appropriate model that is being used should be consulted. These operating manuals can be freely downloaded from our Web Site at www.airburners.com/ab-opmanuals.htm.
Fuel Loading Start the fire as outlined in the Air Burners operating manual. The most important issue in preparing to burn carcasses is to insure that you have a good hot fire base before you load any carcasses. This start-up preparation usually takes one to two hours of wood only burning. It must be made certain that the entire bottom of the firebox is covered with at least two feet of burning hot material (hot coals). If you load too soon, the carcasses may fall through to the dirt and there will be no heat or fire to burn them. They will eventually burn, but the overall through-put will suffer and smoke will increase.

Charging of Chicken Carcasses

Once loading carcasses has begun the process is to build layers. After each layer of bird carcasses an equal amount of wood must be introduced.

The most common mistake is to “rush the fire.” The through-put will start out low and increase as the day goes on. If you rush the fire by adding carcasses and wood too fast, then the overall temperature will drop, the smoke will increase and the through-put will go down significantly. Remember the wood is your fuel; be sure it is burning strong, before you load more carcasses onto it. This is especially true for chicken carcasses.

Carcass Loading  Using the appropriate loading machinery, try to place the carcasses in the middle section of the firebox. The photo above shows bird carcasses being introduced into a standard S-300 firebox. The important thing to remember is that rapid incineration is all about surface area. If you place a massive pile of carcasses in the middle of the firebox, then the carcasses will incinerate around the entire external area of the carcass de-posits. If you pile that same carcass volume up against the firebox wall, then the carcasses will only incinerate from the exposed areas, and the through-put will slow down.

Loading Equipment  For bird carcasses, a wheeled loader with a rake is practical. Using a wheeled loader with a bucket is also possible, but one of the problems with a bucket is the potential for “scooping” up dirt when picking up the bird carcasses. Dirt smothers the fire, and the more dirt that goes into the firebox the slower the operation will be. An excavator with a grapple works well, if the carcasses are large and mostly intact. It also is effective for loading the wood waste to support combustion.

Shut Down  Once you have finished loading the carcasses continue to add wood until the last load of carcasses has been incinerated, usually in about one hour. Then follow normal shut down procedure described in the operating manual.

Ash Removal  In all of the cases where the residual ash has been tested after the incineration operations using Air Burners machines, the ash has been found to be sterile. For ash removal follow normal procedures outlined in the operating manual. Whether the ashes should be dumped or land ap-plied (buried) is usually a decision of the competent local authorities.

Safety
The unit has an open bottom so it must not be placed on flammable materials such as dry grasses or peat moss. During operations hot embers will fly from the open top. They usually fall very near to the machine less than 30m (100 feet). Al-ways follow the safety procedures outlined in the operating manual.

Only personnel trained in the operation of the air curtain burner should come within 300 feet of the entire operation. This guideline only addresses the basic operation of the firebox and it does not address considerations relative to possibly present contagious or poisonous agents and the procedures and safety requirements governing human exposure to them or environmental issues connected to them. They would be addressed by the HazMat team.

Air Burners LLC Disaster Response Package

 S-111RDB with Roll-Off Truck and Fuel Trailer