November 09, 2020

Autoclaves for Medical Waste: A Safe and Effective Approach to Waste Processing

Healthcare organizations generate millions of tons of medical waste every year in Canada. A portion of this waste is considered biomedical or infectious, and must be treated before being sent to a landfill or waste-to-energy facility. There are several different medical waste treatment approaches depending on the type of material being generated. The most common method of treatment, autoclaving, is a safe and effective way to protect communities and the environment.

What Is an Autoclave?

Autoclaves have a variety of uses depending on the type of business. In the healthcare industry, an autoclave is a machine that uses high pressure steam for a very specific period of time and temperature to kill pathogens, such as bacteria or viruses. This process disinfects the waste prior to final disposal.  

What Is an Autoclave Used for in Healthcare?

Autoclaves are used in healthcare organizations for a variety of tasks, including sterilizing instruments and equipment. Waste management companies also use this equipment to treat biomedical or infectious wastes prior to their final disposal destination. Pressurized steam is one of the most efficient and effective methods of treating medical waste.

How Do Autoclaves Work?

Once medical waste is placed in the bins that go inside the autoclave, air is evacuated from the vessel, creating a negative pressure. Next, high-pressure, high-temperature steam is introduced for a defined period of time. This validated time, temperature, and pressure is designed to kill the pathogens found in the waste. The lack of air and high-pressure ensure the steam penetrates into the material, raising the temperature throughout, not just on the surface. This is tested through a spore testing process discussed in further detail below. 

Temperatures can range from 121 to 163 degrees Celsius, and pressures can range from 40 to 80 PSI, depending on the autoclave size and amount of material. Waste is typically kept at a high temperature and pressure for 20 to 30 minutes. Once the cycle is complete, steam is evacuated from the autoclave, the pressure is released, and the autoclave is now safe to open. 

What Types of Medical Waste Can Be Autoclaved?

The majority of biomedical waste can be treated through an autoclave. This may include soiled bandages, gauzes, personal protective equipment or other items that are categorized as “yellow bag” waste. Sharps, including needles and syringes, can also be processed in an autoclave if they are not contaminated with hazardous waste.

However, some materials are not well suited for autoclaving, and it is recommended that these materials be separated out and processed by an alternative treatment technology, such as incineration. These materials could include anatomical waste, trace chemotherapy wastes and tubing or needles.

What Happens to Waste After Autoclaving?

After the autoclave treatment process, waste is compacted and can be sent to a landfill. Since the waste has been rendered non-infectious, it is safe to be dispose of alongside other regular trash.   

How Do Waste Management Companies Check the Effectiveness of Autoclaves?

It is important that there are controls in place to ensure that the autoclave treats waste as intended. Companies must follow the manufacturer’s instructions for installation, operation, cleaning and preventive maintenance of the sterilization equipment. Autoclaves must be validated which includes running a cycle and performing spore tests to confirm all waste is properly disinfected. Dual species spores, called Geobacillus stearothermophilus, are used to test the efficacy of its autoclaving process and to validate the appropriate settings. Due to the bacteria's high resistance to heat, it serves as a good indicator of microbial life after a steam cycle. Once validated, the approved parameters are programmed into the control system. After this takes place, those parameters cannot be changed, except by going through the validation process again. Between each cycle, the operator confirms that each cycle ran properly and records this information in a daily log.

It is not uncommon for there to be requirements for bi-weekly spore testing. Spore testing requirements may vary by provincial regulation or permit of the facility and should be done in accordance with the manufacture’s specifications. 

An Expert Partner to Support Biohazardous Medical Waste Disposal

Learn more about Stericycle’s approach to medical waste processing, and how Stericycle’s biomedical waste disposal program can help you ensure compliance.  

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