1. Field of the Invention
The present invention relates to a waste feed system and, more particularly, to an infectious waste feed system for feeding infectious waste materials, such as hospital waste, to a combustor.
2. Description of the Related Art
Infectious waste can be defined as that waste which, unless processed, disposed, stored, collected or transported with caution, is or may be contaminated by disease-producing microorganisms or may harm or threaten human health. The term infectious waste includes, among others, the following types of waste: waste generated by hospitalized patients who are isolated, or on blood and body fluid precautions in order to protect others from their communicable disease; cultures and stocks of etiologic agents; animal waste blood and animal blood products which are known or suspected to contain contagious zoonotic pathogens, and human waste blood and blood products; tissues, organs, body parts, blood, and body fluids that are removed during surgery and autopsies; wastes that were in contact with pathogens in any type of laboratory work; carcasses and body parts of animals exposed to contagious zoonotic pathogens; waste biologicals, for example vaccines, produced by pharmaceutical companies for human or veterinary use; and food or other products or equipment that is discarded because of contamination with etiologic agents.
Many of the above types of infectious wastes are generated at hospital sites. Hospitals are currently experiencing much difficulty in properly disposing of this waste. This is, in part, because the waste generated at the hospital sites includes a variety of constituents having different moisture contents and densities.
By its nature, hospital waste is a material that is difficult to handle and feed by mechanical means because of its extremely heterogeneous and possibly wet and sticky nature. The problems of handling and feeding such waste are exacerbated by the potential of the waste to be infectious and/or toxic. While incineration in a fluidized bed combustor is technically feasible and has a number of advantages, the waste must first be reduced in size to avoid problems in the fluidized bed such as de-fluidization, bed material agglomeration, disruption to combustion air and fuel distribution, and poor combustion.
A critical area in the incineration process for infectious hospital waste in a fluidized bed combustor is the ability to safely and reliably feed the waste into the combustor. The feed system must be able to properly handle the waste without creating atmospheric contamination and without posing undue health risks to operators. Relevant Pennsylvania codes require that compactors, grinders, or similar comminuting devices may not be used to reduce the volume of infectious waste before the waste has been rendered non-infectious. Therefore, the waste must reach any incinerator in a sealed container. However, for effective destruction in the fluidized bed, size reduction to two inches, or possibly smaller, is desired. In order to comply with the regulations and yet provide sized waste materials that are acceptable for incineration in a fluidized bed, it is necessary to have a waste feed system, including a size reduction system, which is an integral component of the combustor both in terms of mechanical attachment and control systems. Thus, after the waste has entered the feed/size reduction system, the process should be fully automatic and further human intervention or contact should not be required.
Accordingly, it is an object of the present invention to provide a waste feed system that is an integral component of a combustor, both in terms of mechanical attachment and control systems.
It is another object of the present invention to provide a waste feed system that is fully automatic and interconnected with the combustor so that human intervention or contact is not necessary after the waste has entered the waste feed system.
It is yet another object of the present invention to provide a waste feed system that controls the rate at which waste is introduced into the combustor and that prevents the emission of toxic substances.
Still another object of the present invention is to provide a cost-effective and reliable apparatus which does not cause atmospheric contamination or pose undue health risks to operators.
Additional object and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.