The primary means of disposing of biohazardous material has been incineration. Prior to 1997, 90 percent of all biohazardous waste was incinerated.
It was in that year that the Environmental Protection Agency issued the Hospital Medical Waste Incinerator standards. These standards started a shift away from incineration of biohazardous waste to other methodologies, principally autoclaving.
The EPA does not have direct authority over how biohazardous waste is eliminated. That generally is within the province of each state. In California, the California Department of Public Health establishes protocols for the elimination and disposal of biohazardous waste. What the EPA does regulate is the manner in which hazardous materials are discharged into the environment.
The EPA expressed concern over the pollutants that are released into the air via the incineration of biohazardous materials. With that noted, these pollutants are significantly less dangerous than the biohazardous materials that are incinerated in the first instance.
The two most common methods for disposing of biohazardous materials are:
Other less widely utilized methods for disposing of biohazardous materials are:
- Chemical disinfection
- Microwave treatment
Definition of Biohazardous Waste
A definition of biohazardous waste has been developed by the University of California:
Biohazardous waste is potentially infectious waste. Biohazardous waste can include blood, bodily fluids, and other biological material. It can also include other physical items contaminated by these fluids and other biological materials. These waste items are deemed a potential danger to the public and the environment.
As noted a moment ago, historically incineration was by far the most common way to dispose of biohazardous waste. It remains the most commonly utilized means of eliminating biohazardous material today. With that said, other methods, particularly autoclaving, are increasingly becoming more widely utilized.
Three types of incineration are most commonly utilized to dispose of biohazardous waste in the United States, according to the EPA. These methodologies are:
- Controlled air
- Excess air
- Rotary kiln
Controlled air is the most common type of incineration process utilized to dispose of biohazardous waste. In fact, over 95 percent of biological waste eliminated via incineration is done so through the controlled air process, according to the EPA. Controlled air is also known as starved-air incineration, two-stage incineration, or modular combustion.
Controlled air incineration is a two-step process. Due to the manner in which it works, almost no solid whatsoever remain after the process is complete. As a result, no additional gas-emission scrubber is added to the system to clean gas being discharged into the atmosphere as a result of the incineration.
Excess air incineration involves smaller units. This type of incineration is also called batch incinerators, multiple chamber incinerators, or retort incinerator. Rather than being operated on a continuous basis, this type of incinerator is run in batches. It is not utilized as commonly as the controlled air derivation, but is used more frequently than the rotary kiln.
The third most commonly utilized type of biohazard waste incinerator is the rotary kiln. The rotary kiln is similar to the other two types of incinerators with one primary difference. As the name suggests, the waste being incinerated is rotated during the burning process. Because of this rotation, a bit more solid residue is left behind than is the case with the other two types of incinerators. Thus, a rotary kiln typically has an add-on gas cleaning device.
The autoclave is becoming more widely utilized as a means of disposing of biohazardous waste. The operational principle behind an autoclave is relative simply in its design. An autoclave is equipment that delivers steam generated heat that is under high pressure into a sealed chamber containing biohazardous material. This process is called autoclaving. This process results in the decontamination or sterilization of whatever materials have been placed into an autoclave, including biohazardous materials.
An autoclave sharply reduces the emission of any type of pollutants into the environment. Another benefit of an autoclave is found in the fact that it readily permits the elimination of biohazardous materials on site.
Avoiding the transport of biohazardous waste has significant benefits that include:
- Elimination of the risk of accidental release of biohazardous materials during transport
- Reduces the number of people who handle biohazardous materials
- Lowers the cost associated with the disposal or elimination of biohazardous materials
- Lowers the potential exposure of the general public to biohazardous materials