PATHOLOGICAL WASTE: CLASSIFICATION, DISPOSAL, TREATMENT - MEDICINE - 2025

The medical waste are any unusable material regarded as potentially infectious to humans. These residues can be elements in solid, semi-solid, liquid or gaseous state.

The word pathological classifies it as a type of waste or material that has pathogenic microorganisms. That is, they are capable of producing disease in humans who come into contact with it.

Gloves are often contaminated with pathological residues.

Usually, it consists of objects contaminated with organic tissue from both human beings and animals. Within this category, feces and body fluids such as blood, saliva, urine, among others, are mentioned.

This waste is usually generated in healthcare units and in hospitals. The waste produced in the cleaning of various establishments is also considered pathological. It can be contained in almost any object present in this type of institution.

The knowledge of the objects or pathological waste can help to prevent the contamination of health personnel, and its consequent spread in the community.

Objects that are often contaminated with pathogens include gloves, syringes, dissection forceps, scallops, sterile drapes, gauze, adhesives, and urethral and / or nasogastric tubes.

Due to the danger posed by this type of waste for health personnel and the community, special care must be taken in its disposal. Therefore, there are established rules that classify, categorize and dispose of waste in different ways, as the case may be.

Classification

Some countries have included the classification of pathogenic residues within their health laws and regulations.

Here is a brief description.

Type A

Type A is considered to be waste from cleaning or general sanitation of mainly health establishments.

Type B

Type B pathological residues are those that show signs of toxicity and / or biological activity that can affect humans directly (direct contact) or indirectly (vectors, fomites, etc.).

Type C

Waste from radiology or radiotherapy medical services is considered type C. This category includes type B wastes, if the quantities become industrial.

Provision

Type A pathological residues

The transitional disposition before disposal is in polyethylene bags of at least 60 microns thick, green, duly identified with the number or name of the establishment.

Some Latin American countries allow the use of black bags in green plastic containers, duly identified and logistically distributed in the establishment.

Type B pathological residues

Before disposal, they are temporarily placed in polyethylene bags with a minimum thickness of 120 microns, waterproof and resistant.

In this case, the bags must have a red color, and be duly identified with the identification number or name of the generating establishment. These bags must be placed in buckets with hermetic closing, resistant to heat and shock, properly identified.

The disposal of sharp and / or penetrating objects in these bags is prohibited, even though these wastes are classified as type B. This is done to avoid the bag breaking and, therefore, injuries and contamination of personnel.

Type C pathological residues

The disposal of this type of waste is complex and delicate. It involves a series of steps that depends on the type of waste.

In general, they are arranged in specific bags and containers. These should not be too heavy and should be sized for the amount of waste the room produces.

Finally, they are incorporated into a solid matrix that prevents their dispersion. The most commonly used matrix is ​​cement. The residues are incorporated into the cement and sent to special facilities for storage.

These are designed to prevent radiosotopes from migrating into the biosphere.

In some countries they have opted for underground storage.

Treatment

Pathogenic waste is processed in treatment plants that are responsible for modifying the physical, chemical and biological characteristics of the waste. With this, they lose their harmful capacity.

The objective of the treatment is to reduce the volume and / or concentration of the waste. In this way, they facilitate the transport, disposal or reuse of some materials.

The method used will depend on the type of waste, quantity, the existing technology in the country, costs and factors linked to environmental pollution.

There are several methods used to treat waste. The most common are described below.

Incineration

It is the most widely used method due to its effectiveness and 90% volume reduction.

It consists of the total combustion of organic matter, reducing it to non-combustible ashes. This significantly reduces the weight and volume of waste.

Special care must be taken with the polluting gases produced in incineration. Radioactive waste, gas containers and ampoules with heavy metals cannot be incinerated.

Autoclave

It is a steam sterilization method, with temperatures higher than 100 ° C. This produces the coagulation of the proteins of microorganisms, including those essential for life and reproduction.

It is effective in destroying microorganisms, including spores.

Chemical disinfection

They are often used in waters contaminated by bacteria or viruses. They treat the waters with chemical additives or with ultraviolet light.

Ozone disinfection is even more effective than chlorination disinfection. However, the required infrastructure is large and expensive.

On the other hand, ultraviolet disinfection is less expensive. But, it is not as effective if the water has suspended particles.

Microwave oven

It is an effective method even for bacterial spores and parasite eggs. Doses of 2450Mhz are used for a period of 20 minutes.

It requires a certain level of humidity and the costs are high.

Other dry heat methods

The direct flame method consists of heating an instrument to such a degree, especially if it is metallic, until it is red hot. This is the procedure used to sterilize the inoculation loops in the laboratory.

The other dry heat method is hot air. Water is a better heat transmitter than air. Therefore, a longer period of exposure and higher temperatures are required than the humid heat or autoclave method.

Generally, to achieve sterilization, a temperature of 170 ° C is necessary for at least 2 hours.

References

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3. Health-care waste. (2018, February). Fact sheet. World Health Organization. Retrieved from who.int.
4. Wang, D. Biohazardous Waste. Extranet. Recovered from extranet.fredhutch.org
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