HDT 69/70:

Waste Management in Health Care Centers

Ago-Dic 1997

Eng. Gladys Monge

Spanish version: HDT 69/70: Manejo de residuos en centros de atención de salud

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Introduction

A health care facility is a hospital, nursing home, clinic, polyclinic, medical center, maternity, first aid room and any establishment where any level of human or animal care is practiced, for prevention, diagnosis, treatment and rehabilitation, and research.

These establishments generate waste that represent potential risks to health whose inadequate management can result in serious consequences for the hospital community health, the staff responsible for external waste management and the general population.

Inadequate management of hospital solid waste has negative environmental impacts that are evident in segregation, storage, treatment, collection, transportation and disposal. The consequences of these impacts affect not only human health but also to the air, soil, surface and underground water; to which is added the aesthetic degradation of the natural landscape and urban centers.

Due to traditionally the priority of a health center has been patient care, it has given less importance to the environmental problems that could result, in many cases creating a vicious cycle of diseases resulting from poor waste management.

 
 

A study conducted in Mexico supports an indicator of 3 kg/bed/day. It is estimated that 10 to 40% of these wastes can be classified as hazardous due to their pathogenic nature (OPS, 1991), while the rest can be considered as household waste.

With the implementation of an environmental management policy, health care facilities will avoid the adverse consequences that could cause their waste on health and the environment. However, it is important not to alarm the public or exaggerate the risks, for a non-existing problem.

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Classification of solid waste in health care facilities

2.1 Classification proposed by CEPIS in the “Guidelines for the internal management of solid waste in health care facilities”

This guide, developed by CEPIS, aims to guide the implementation of a solid waste management system in hospitals, in order to control and reduce health risks associated with the management of hazardous waste. The guide proposes a simplified classification system that considers:

Infectious Waste

Infectious waste are generated at different stages of health care (diagnosis, treatment, immunization, research, etc.) and contain enough quantity or concentration of pathogens to contaminate an exposed person. These wastes may be, among other materials from patient isolation rooms, biological materials, human blood and blood products, anatomical-pathological and surgical waste, sharps waste and animal waste.

Special Waste

Special wastes are generated mainly in the auxiliary services for diagnosis and treatment and usually have no contact with patients or infectious agents. They constitute a health danger for their hazardous characteristics such as corrosivity, reactivity, explosiveness, toxicity, flammability or radioactivity. They can be, among others, chemicals and hazardous waste, pharmaceutical waste and radioactive waste.

Common Waste

Common waste are those generated by administrative, auxiliary and general activities not considered in the above categories. They do not represent health hazard and its characteristics which are similar to those from normal household wastes. Included in this category are papers, cartons, boxes, plastic, leftover from food preparation and waste from the cleaning of patios and gardens, among many others.

2.2 Classification of the World Health Organization

• General waste.
• Pathological waste.
• Radioactive waste.
• Chemical waste.
• Infectious waste.
• Sharps waste.
• Pharmaceuticals waste.

2.3 German classification

• General waste.
• Pathological waste.
• Radioactive waste.
• Chemical waste.
• Infectious waste.
• Sharps waste.
• Pharmaceuticals waste.

2.4 United States Environmental Protection Agency (EPA) classification 

• Crops and stored samples.
• Pathological waste.
• Human blood and blood products waste.
• Sharps waste.
• Animal waste.
• Isolation waste.
• Unused sharps.

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Hazards and risks in the management of hospital solid waste

The group that is mostly at risk posed by infectious waste from hospitals are workers in health facilities, especially nurses and cleaning staff, followed by workers handling waste outside of the hospital. In the dumps / landfills where various materials are retrieved for sale, the risk is serious. However, there is no data on the incidence of injuries and infections in those situations. It is rare that the victims are patients or the general public.

Workers who are injured more often are practical nurses, professional nurses, staff from housekeeping and cooking. The annual injury rates in these occupations are between the range from 10 to 20 per 1,000 workers. Among all types of workers who are in contact with medical waste, the ones that perform the sanitation (garbage collectors) are those with the highest occupational injury rate, approximately 180 per 1,000 workers per year, i.e. more than twice the rate of all US workforce.

The problems identified in Latin America and the Caribbean regarding the management of hospital wastes are (J. Monreal, 1991):

• Infectious injuries caused by sharps to the hospital cleaning staff and the staff who handle solid waste.

• The risks of infection outside hospitals for personnel handling solid waste, those that recover waste materials and the general public.

• Infections in hospitalized patients due to poor waste management.

Among the technical problems can be mentioned inadequate separation of hazardous wastes at the point of origin due to insufficient personnel training. This causes hazardous waste represent 10-40% of the total waste, instead of being less than 10%. In addition, sharps are not properly stored, which explains the numerous injuries to waste management staff.

Very often hospital waste are dumped to landfill along with municipal waste, with the exception of human body parts that are buried separately for cultural reasons. A large percentage (57-92%) of the incinerators used by some hospitals do not work satisfactorily, and this increases the risks to health and the environment.

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Stages in the Medical Waste Management

4.1 Segregation

 
 

Unless the staff have received the proper training, these may consider waste management as a matter of little importance, since they ignore what happens after these wastes have been removed from the surgery room.

Waste separation is focused on relatively small amounts of residuals that need to be separated. the Inadequate separation represents a risk to staff and the public and also significantly raises the costs of waste management because requires to give special treatment to a large amount of waste when it is only required for a small part.

Each of the waste considered in the classification adopted by the hospital should have a clearly identified suitable container (fig. 1). Color plastic bags (fig. 2) and special Sharps containers (fig. 3) are both used at this stage. Hospital staff should be trained to associate the colors of the bags with the type of waste disposed within. The bags may be suspended within a structure with cover or placed in a rigid container; the end of the bag should be folded over the edge of the container and must have a lid.

The size and number of containers should be appropriate to the expected amount of waste generated in the room. The container should not be too heavy when filled; must be able to be easily handled by one person. In all rooms, except for isolation wards should have a common waste container to prevent the personnel to increase the amount of waste requiring special treatment unnecessarily.

It is important to clearly identify the containers and bags for each type of waste, which also has a preventive effect since all hospital employees will feel responsible for what they place in each bag.

4.2 Handling and Storage

The bags and waste containers must be sealed and taken to a special storage place where they will be placed in separate piles according to the color of the bags, twice a day or more in operating rooms and intensive care units. The site should be safe and have facilities to permit cleaning in case of waste spills. the universal biological waste symbol should be at the door of the storage area, in waste containers and in the freezers or refrigerators used for this purpose.

Common waste can be taken directly to an outer container which may be collected by the municipality.

The use of pipelines to dispose of bags by gravity must be avoided due to the waste can spread outside the ducts and this will generate bad odors and attract insects. The staff responsible for handling medical waste must wear clothes and personal protection implements  for hygienic reasons and to avoid skin lesions.

Vehicles for waste transportation should be stable, quiet, hygienic, proper design and should allow the transport with minimum effort. Hazardous waste must never be transported with municipal waste; and must use special closed vehicles. Also, these wastes should never be transferred, and must remain in the same vehicle from the place in which are generated to the place of treatment and disposal.

In the planning of collection and internal transport of the waste generated in a health care facility should be considered:

• The timing and frequency of collection, which should be known by all staff.

• Avoid high risk routes and choose the shortest route between the place of generation and storage.

• Identify the collection vehicles and internal transport according to the type of waste and disinfect them regularly.

The collection and external transport should take into account the following points (fig. 4):

• Vehicles must be internally lined with stainless steel or aluminum to provide a smooth, impervious surface, in order to avoid spills of any material. Angles and corners must be covered to prevent the accumulation of residual material. Must be provided with a locked door and a ventilation system.

• The contaminated waste transport vehicle must display on the front and back a painted sign that corresponds to the type of waste transported with letters with at least 80 mm height.

• The height of the platform or box load should not exceed 1.20 m. When the vehicle capacity exceeds 1 tonne it must have mechanical unloading devices.

• Once the route is finished, the vehicle must be cleaned and disinfected in an appropriate place. Process residuals must be properly disposed.

• The vehicle must have the necessary equipment for cleaning and disinfecting occasional spills.

4.3 Treatment

Among the technologies available for treating infectious waste may be mentioned the incineration, the autoclave (sterilization by steam) and microwave treatment, among others. The inadequate design or incorrect operation of the treatment systems can generate environmental pollution problems, so it is important to prevent this possibility the proper selection of technology and personnel training  in charge of its operation.

• Remove the infectious or hazardous potential prior to waste disposal.
• Reduce its volume.
• Turning surgery waste (body parts) to unrecognizable.
• Prevent improper reuse of recyclable items.

4.3.1 Incineration

The waste are burned under controlled conditions to oxidize the carbon and hydrogen present in the waste. This method is used to treat various types of waste. Non-burnable materials remain as waste. Incinerators must have a dual chamber; a primary with temperatures between the 600 and 850 ° C; and a secondary with 1,200 ° C also must have the filter and a gas scrubber.

The main advantages of this method are the reduction of volume and mass of the material that will be disposed to landfills and the possibility to recover energy to generate steam or electricity.

The disadvantages are that gaseous emissions can contain pollutants and their operation and maintenance, depending on their size can be complex.

4.3.2 Autoclave Steam Sterilization

In the autoclave treatment, the waste is exposed to high temperatures by injecting high pressure steam and, thereby destroying pathogens (fig. 5). There are three types of autoclave:

• Gravity displacement autoclave with 121 ° C in temperature and from 1.1 to 1.2 atmospheres of pressure.

• Pre-Vacuum Autoclave with 132 ° C of temperature and between 1.84 and 2.18 atmospheres of pressure.

• Retort autoclave with temperatures higher than 204 ° C  and steam pressure higher than 20.4 atmospheres.

Typically temperatures of 121 ° C is accepted with a residence time of half an hour or more depending on the amount of residue. This method is easy to install and operate and exists in the market autoclaves of different capacity. The determining factors are that the residues require a homogeneous distribution in the camera when it has no rotation system; there is little reduction in the volume of waste and needs additional equipment for the steam supply. The indicator of biological control is Bacillus stereothermophilus.

4.3.3 Microwave

In this treatment, the waste are shredded and injected with steam to ensure uniform heat absorption, in that state, are impulsed through a chamber where they are exposed to microwaves (fig. 6). The waste is heated to 95 ° C for 30 minutes. It has a frequency of 2450 MHz and a wavelength of 12.24 cm.

The advantages of this method are its low power consumption, approximately 270 kw/hour; leaves unrecognizable waste and the effluent discharge is insignificant. Its disadvantages are that presents risk of releasing volatile toxic material during treatment process; the milling is subject to mechanical failure and not all sporulating bacteria or parasites are destroyed.

4.3.4 Other treatment processes

Currently mobile equipment for treatment are used (Fig. 7). The advantages of these systems are that they can be used in various establishments; No space is needed for the treatment unit at the health center; and can be used in emergencies at field hospitals. On the other hand, in these units can be placed any treatment technologies either incineration, microwave sterilization, steam sterilization, electron beam and others.

Other hazardous wastes can be eliminated as follows:

• Cytotoxic drugs should be burned or chemically degraded by qualified specialists. They should never be diluted or discharged to sewer.
• Radioactive materials can be returned to the nuclear industry that supplied. Most radioactive waste from medical facilities have a low level of radioactivity and a short half-life, so it can be stored under controlled conditions until they can be treated as other waste. Expert advice is required.
• Pressurized containers should be buried or returned to the manufacturer but never burn or
  mechanically processed.

When selecting an alternative treatment is necessary to make a comparative analysis of the most relevant parameters of each process, and review existing regulations, ease of operation, need for trained personnel, occupational and environmental risks, costs, among others. It is necessary to consider the advantages and disadvantages of each one and find the alternative that best suits the needs of each health care facility.

Table 1 presents a comparative table of various operational factors of some treatment systems.

Table 2 presents the investment costs, operation and maintenance of different treatment systems.

 4.4 Final Disposal

4.4.1 Security Filling

The risks associated with infectious waste landfill are groundwater pollution, soil contamination and direct staff or casual scavengers infection. For these reasons, the most suitable alternative for disposal of contaminated waste that has not been treated is security filling.

The advantage of this method is its security if access is restricted and site is appropriately selected. The disadvantages are that restricted access can not be guaranteed at all times and can be difficult to evaluate the conditions for the security filling.

4.4.2 Encapsulation

Encapsulation is the cheapest option for sharps waste disposal; they are placed in a container until fill three quarters and substances such as liquid cement, bituminous sand or plastic foam are poured to fill the container. When the substance is dried, the container may be disposed in a landfill or within the hospital premises. This method is simple, safe, inexpensive and can also be applied to pharmaceuticals. However, it is not recommended for non-sharp infectious waste.

4.4.3. Emergency Filling

Emergency filling can also be used as a provisional method or short-term, eg in field hospitals (fig. 8). A ditch is dug of one meter wide, two meters long and 1.5 meters deep, preferably in a non-waterproof rocky ground. The trench bottom should be 1.5 meters higher than the unconfined water level.

The wastes are placed in the trench up to a meter and then filled with soil. The process is appropriate for sharps, infectious waste and possibly chemical and pharmaceutical waste. Has the disadvantage of having risks of contamination and can be difficult to prevent segregation at all times.

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Waste minimization

The most effective alternative to face the problem of wastes from health care centers is to minimize their generation through reuse, recycling and reduction of the amount of materials used. Waste minimization should be considered a priority in the waste management program. However, this technique is not applicable to all waste and is not always a practical option because sometimes produces other hazardous waste. It is therefore, necessary to analyze carefully the possibilities of its application.

The minimization results in a reduction in management costs, reduced risk of exposure and reduction of occupational accidents and pollution. Some methods to consider in waste minimization are:

• Reducing the amount of materials used, by restricting purchases, use of reusable materials, use of materials that generate less waste, among others.

• Reducing the amount of waste generated, through the separation from the source, waste segregation, among others.

• Recycling and reuse, for which it can be used steam or gas sterilization or other treatment methods.

• Volume reduction techniques, such as incineration, compaction and crushing.

• Energy recovery techniques, such as incineration with a heat utilization equipment through a boiler.

Table 1. Comparative table for some treatment systems.

Adapted from: Reinhardt, P.; Gordon, J. Infectious and medical waste management. Michigan, 1991.

Table 2. Cost Analysis for Waste Treatment Systems in health establishments (*)

(1) Operation daily cost
(2) Annual maintenance cost
Source: Estudio enfoque de las tecnologías de tratamiento de residuos hospitalarios. Ministerio de Salud, Dirección General de Salud Ambiental (DIGESA), Programa de Fortalecimiento de Servicios de Salud (PFSS). Lima. 1996.
(*) Costs shown are referential

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Waste management plan for a health care center

Waste management in health care center begins with the formulation of objectives and the planification of the actions to be taken. A written plan is the tangible evidence of a serious commitment to manage infectious and hazardous waste safely. Figure 9 shows a flowchart of waste management from its generation to final disposal. Planning should consider the strategy; resource assignation according to identified priorities and follow-up actions. Planning is essential to motivate the authorities, health staff and the general public.

It is important to establish a program of control and quality assurance for the waste management system in accordance with the management plan developed. The program involves three phases: the development of policies and procedures; implementation; and verification. The objective is to ensure proper waste handling. Once the policies and procedures of the program have been implemented, it is essential to establish a procedure for verifying and monitoring compliance with the established.

Knowing the amount and composition of waste generated is essential to identify opportunities to implement reuse, recycling and minimization programs, and to set goals aimed to reduce waste management costs.

Waste management should take into account the legal and regulatory aspects, such as the disposal international agreement from the Basel Convention to the Transboundary Movement of Hazardous Wastes and principles such as “polluter pays”, “caution”, “management responsibility”,”proximity”, among others.

The technical guidelines, and policies should be of practical and direct application with clear fundamentals and objectives, and key steps to achieve those objectives.

In short, a waste management plan for a health care facility should consider the following aspects:

• Responsibilities assignment.

• Definition of the management structure and hierarchy.

• Assessment of waste generation and its composition.

• Design and development of the management plan. The plan should:

• Contain the usual procedures and proposals for improving waste management.

• Focus mainly in infectious waste (the most problematic area).

• Be prepared by the person or committee responsible for monitoring waste management.

• Specify individual responsibilities for all procedures.

• Be approved by the administrator of the organization responsible for planning.

• Be updated regularly.

• Management plan implementation.

• Monitoring and evaluation.

• Notify security staff.
• Isolate the accident area.
• Notify authorities.
• Identify the responsible person.
• Identify the product.
• Use of personal protective equipment.
• Prepare and implement action plan.
• Implement the plan of action:
• Area decontamination.
• Disposal of cleaning residuals.
• Event documentation.
• Control.

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Bibliographic References

• Cantanhede, Alvaro. Composición de los residuos de los servicios de salud y los riesgos a la salud de los trabajadores, pacientes, medio ambiente y recursos naturales. En: Encontro de Especialistas em Tratamento e Destino Final de Residuos de Serviços de Saúde, 1997.
• CEPIS. Guía para el manejo interno de residuos sólidos en centros de atención de salud. 2.ed. Lima: CEPIS; 1996.
• Monreal, J.; Zepeda Porras, F. Consideraciones sobre el manejo de residuos de hospitales en América Latina. Washington,D.C :OPS; 1991.
• Organización Mundial de la Salud. Manejo de desechos médicos en países en desarrollo. Informe de consultoría. Ginebra: OMS; 1992.
• Organización Mundial de la Salud. Healthcare waste management handbook; a WHO guide for developing countries (draft). 1997.
• Reinhardt, P.; Gordon, J. Infectious and medical waste management. 2ed. Michigan: Lewis Publishers, Inc. 1991.
• DIGESAMINSA. Programa de Fortalecimiento de Servicios de Salud (PFSS). Estudio “Desarrollo del enfoque de las tecnologías de tratamiento de residuos sólidos hospitalarios”. Lima, 1996.