Traditional Medical Waste Treatments

By Lupe Perez

Editor's Note:

Lupe Perez was a student in Roberta Barbalace's Environmental Technologies 240 - Solid Waste Management class at Rio Hondo College in Whittier, CA in the fall of 1999. This paper was submitted as part of her requirements for that class and was reprinted with her permission.

During the summer of 1988, several instances of medical wash-ups grabbed the attention of the public and Congress. The scene was one of a beautiful sunny beach. A closer look, though, revealed medical waste buried in the soft sand. The signs went up. Beach Closed. Contamination Danger. No Swimming. Congress responded by implementing the Medical Waste Treatment Act.

The Medical Waste Treatment Act

Law enacted by the US Congress to study the medical industry's waste production, treatment, storage and disposal. The Study included several Great Lake States and New England States. Several procedures and documentation production were implemented to develop a tacking system. "The tracking system for medical wastes designates record keeping requirements for facilities that generate over 50 pounds (22.68Kg) a month of medical waste and requires the use of four-part form for any off-site shipment of medical wastes" (70 OTA).

"According to the MWTA requirements, generators must separate regulated medical wastes from general refuse, meet storage requirements (if such wastes are stored before treatment), and package regulated wastes in labeled, rigid, leak-resistant containers" (70 OTA).

The law took effect in June 1989 and the findings were to be reported by the EPA to Congress by September 1991. Its purpose was to determine if and how the Federal Government should regulate medical waste.

The conclusions of the survey provided information on the type of generating facilities, waste types, and quantities generated. The types of facilities included physicians, dentists, medical groups, nursing homes, hospitals, and veterinarians. The basic types of waste generated by the facilities were sharps, blood or body fluids, laboratory waste, surgical specimens, isolation waste, chemotherapy and contaminated animals (14 IWMB).

Medical Waste Generators

Waste generators were broken down into two categories: Small Quantity Generators (SQG) and Large Quantity Generators (LQG). This was necessary to adequately identify their waste and provide guidelines and regulations. "The Medical Waste Tracking Act categorizes a facility as a small quantity generator or a large quantity generator based on the amount of medical waste a given facility generates in a month. LQG's are those which produce at least 200 pounds per month of medical waste. LQG's generally consist of hospitals, nursing homes, clinics, medical groups, county or city health departments and laboratories. Physicians, dentists and veterinarians in private practice are most commonly small quantity generators" (8 IWMB). From the SQGs, physicians contributed the highest percentage of waste.

After determining the type of generator, the Study analyzed the composition of the generated medical waste. "Sharps wastes constituted the largest volume of medical wastes generated by each category of SQGs" (13 IWMB). The next highest waste type is blood and body fluids followed by the other categories mentioned previously. Generally, the LQGs waste generation was similar to the SQG's. The job of determining the type of waste being generated was an important one. It was necessary to determine what these generators were putting out and how to define and categorize the waste stream.

Defining Infectious Waste

The words used to describe "infectious waste" are various. The terms used include: biohazardous waste, biological waste, medical waste, hospital waste, medical hazardous waste, infective waste, microbiological waste, pathological waste, and red bag waste. The industry also struggles with the acceptable definition of infectious waste. The regulatory agencies are not in complete agreement when defining medical waste but one can conclude from the recommendations that the following are classified as infectious waste: "human blood and blood products, cultures and stocks of infectious agents, pathological wastes, contaminated sharps, contaminated laboratory wastes, contaminated waste from patient care, discarded biologicals, contaminated animal carcasses, body parts, and bedding, contaminated equipment and miscellaneous infectious wastes" (34 Reinhardt). For our purpose, focus and attention will be made on contaminated sharps, blood and blood products and pathological waste since these wastes are the higher percentage of the medical waste stream. "Contaminated sharps include hypodermic needs and syringes, intravenous needles, scalpel blades, lances, disposable pipettes, capillary tubes, microscope slides and cover slips and broken glass. Human blood and blood products include serum, plasma and other blood components. Pathological waste of human origin include tissues, organs, and body parts removed during surgery or autopsy" (13 OTA). For all of the waste types, the regulatory agencies have recommendations for the best type of treatment for the different types. One thing that will surprise those who are not in the medical industry is the discharge of waste into the sanitary sewer.

The Environmental Protection Agency provides suggestions and recommendations for treatment methods for each infectious waste type. Sharps represent a special hazard due to their ability to prick and contaminate someone who is handling them. Blood and blood products are generally thought to be very hazardous since we identify the transmission of the HIV and HBV viruses with blood. Pathological waste must be transformed before it can be sent away to the landfill. God forbid the sanitation worker wake up to find someone's liver or heart in the dumpster. So, the EPA suggests that all sharps be placed in rigid, puncture resistant container.

On a visit to the doctor's office to get an injection, you will notice that red locked box used for this purpose. Once the sharps go in the container, it is nearly impossible for an unauthorized person to remove them. Sharps are collected and then decontaminated by either incineration or steam sterilization. If they are steam sterilized, the sharps must be ground or crushed.

Surprisingly enough, the sanitary sewer provides a place to put the blood and blood products refused by our medical waste generators. "Reportedly, about 23 percent of hospitals dispose of blood and body fluids to sewers and about 14 percent grind solid infectious wastes and discharge them to sewers using a grinder similar to that used for in-sink home garbage grinding" (62 OTA). It is crucial that hospital have the proper plumbing to avoid clogging and overflow (plumbers be beware). When doctors operate, body parts could end up in the waste stream. These body parts need special attention. The EPA does not allow for the discharge of body parts to landfills due to aesthetic reasons. Therefore, body parts are incinerated or steam sterilized following by shredding or grinding. As you can see, medical waste sometimes requires more than one type of treatment process to complete the job.

Types of Treatment

Incineration is the burning of waste in temperatures ranging from 1,800°F to 2,000°F (982°C to 1093°C). The waste is fed into the first chamber where the waste is exposed to very high temperature causing and maintaining combustion. The second chamber continues to burn the waste and convert it to carbon dioxide and water. A boiler is used to convert water into steam. This steam has the potential to create energy similar to the process used in Municipal Waste Incinerators. The steam can be used to produce electricity to run a hospital, homes, or businesses.

Autoclaving or steam sterilization is a process where waste is exposed to steam for a sufficient temperature/pressure/time period to assure the destruction of microorganisms. Waste is placed into a chamber and steam is introduced. Steam temperatures are usually maintained at 250°F (121°C) or slightly higher and the process runs for 15 to 30 minutes (28 OTA). Autoclaving is used by medical waste generators to disinfect waste and remove the potential hazard to waste handlers. This is a primary treatment and is usually followed by secondary treatment including landfilling, shredding and incineration.

It is lawful to discharge liquid waste into the sanitary sewer system and it is no surprise that the local sewer authorities be concerned with the components of such waste. It is important to know the type of liquid waste being flushed down the tubes to adequately provide secondary treatment.

Much of the waste treated by autoclaving and shredding ends up at the sanitary landfill. Incinerator ash also finds its way to the landfill. Landfill disposal is the preferred option for most treated waste and treatment residues (126 Reinhardt).


It is important to note that the treatment of medical waste varies based on the type of waste. Medical waste is also very likely to undergo more than one process. Hospitals and doctors, for example, generate, treat and store waste. Specific containers and drums are used to store waste, which will later be transported to off-site treatment locations. Red bags are steam sterilized using specific tags, which change color. The tags are used to identify sterilized red bags from infectious red bag. This provides some reassurance for the sanitation workers.

Most hospitals have the equipment to disinfect their waste while smaller institutions may not. Once the waste is disinfected, the waste is stored and prepared for transportation. Licensed haulers are contracted to provide the service of picking up medical waste. The transportation of medical waste requires the use of a manifest system as transporters are required to track the movement of medical waste.


The process of incineration provides the advantage of volume reduction as well as the ability to dispose of recognizable waste and sharps. On site incinerators provide a quick and easy way of disposing medical waste. The ash that results from combustion can be sent to a sanitary landfill. The disadvantage lies in the incinerator emissions. These emissions may contain gases that are toxic. The implementation of air pollution controls can decrease the volume of particulates released.

Autoclaving or steam sterilization represents the ability for generators to treat their waste in a cost-effective way. The equipment saves space and is easy to maintain. Red bags are easily disinfected in autoclaves. The destruction of pathogens is highly effective. The problems come after autoclaving is complete and transportation is required. Many landfills and incinerators give generators a difficult time when accepting their red bags fearing the red bags contain infectious waste. It becomes necessary for the individual generators to develop a personal relationship with their landfill/incinerator operators to soothe their minds and gain their confidence.

Both autoclaving and incineration require exact and precise operation and maintenance. The operators of these machines must be trained continuously. The equipment must be kept up and repairs must be made as required.

Regulatory Agencies

Environmental Protection Agency has the authority to regulate medical waste management under the Resource Conservation and Recovery Act. Occupational Safety and Health Administration (OSHA) is the primary authority for regulating work place standards and employee health and safety. OSHA prepared the blood-borne pathogens rules and regulations. This document provides guidance and protects employees from occupational exposure to infectious materials and wastes. Centers for Disease Control (CDC) has provided experience and recommendations with the identification of infectious waste. CDC issues notice and advisories jointly with OSHA. Other government agencies such as health & safety, toxic substance control agency, and sanitation department are responsible for requiring medical waste generators to comply with the necessary procedures and documentation required by law.

Medical waste is not something we think about everyday. It might come to mind while on a visit to the doctor's office or after giving birth. Where does that syringe or that afterbirth end up anyway? No one wants to turn on the T.V. and see medical waste washing up on our beaches anymore. So, Congress along with the EPA made medical wash-ups less likely. The laws and regulations require that the medical industry continue to strive for the best treatments and disposal methods. Technology continues to build and improve on itself, helping to keep our beaches clean.

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