by Dr. W K Townend
The regular emergence of mutated viruses tends to throw the management of healthcare waste into the high profile spotlight and the emergence of the current case of the A(H1N1) swine influenza virus is a case in point. Wherever there is human activity waste is produced, and this is no less true in the field of healthcare for humans and animals.
In carrying out this activity the waste which is produced contains hazardous material, this has a greater risk than waste produced in other activities and causes infection, injury and even death, as well as causing damage to the environment. It is therefore of greater importance that the hazardous material is identified immediately after it has been produced and then segregated so that it can be isolated from other wastes, transported safely and treated to render it safe.
The management of waste from healthcare facilities in many countries falls far short of the minimum standards required. The World Health Organisation (WHO) is conscious that there is a need to substantially improve the situation and is constantly seeking to achieve this; it is now in the process of revising and updating its handbook Safe Management of Wastes from Healthcare Activities originally published in 1999. The handbook will recommend safe, efficient, sustainable, affordable and culturally acceptable systems for the management of healthcare waste.
The interest in the management of healthcare waste amongst academics is increasing. Recent research in this area indicates that in countries like Palestine, Serbia, Iran and Bangladesh, there are no overall government strategies or guidelines. Even where there are regulations in place in countries such as India, unsafe practices like the reuse of syringes, both with and without sterilization, increases the risk of blood-borne viral diseases. In addition, in India the awareness of proper practices among personnel in healthcare is very low, due in the main to the lack of training. In large parts of the world un-segregated healthcare waste is placed in dumps where there are people both living and scavenging on the sites with the inevitable risks to health.
The management of healthcare wastes is a relatively new phenomenon; even in the most advanced systems in the higher income, industrialized countries, improvements are still steadily being made in order to deal with the methods which are being developed for the diagnosis, surgery and the treatment of patients.
Developing a national policy and legislation
A national policy is the first and key step in creating a sustainable healthcare waste management system for any country. First, the policy should be designed to take account of all international agreements that the country has signed up to; and secondly, it should address the international principles decreed for environmental protection as well as of the health and safety issues that are required to protect human health and the environment.
The policy should be designed to ensure that informed decision making is available at a political level, and to require that the policy is carried out at all levels in the community. The policy should be reviewed at regular intervals and should also take into account the stage of development that has been reached and the progress that should be made by setting achievable targets in an iterative process. The principles to be taken into account, are as follows:
- The ‘polluter pays’ principle implies that all producers of waste are legally and financially responsible for the safe and environmentally sound disposal of the waste they produce.
- The ‘precautionary’ principle is a key principle governing health and safety protection. It is defined and adopted under the Rio Declaration, Principle 15, as: ‘Where there are threats of serious or irreversible damage to the environment, lack of full scientific certainty should not be used as a reason for postponing cost-effective measures to prevent environmental degradation.’
- The ‘duty of care’ principle stipulates that any person producing, handling or managing hazardous substances, or related equipment, is ethically responsible for using the utmost care in that task.
- The ‘proximity’ principle recommends that treatment and disposal of hazardous waste takes place at the closest possible location to its source in order to minimize the risks involved in its transport.
- The ‘prior informed consent principle’ requires that all parties involved in the production, storage, transport, treatment and final disposal of hazardous and infectious wastes, are to be licensed or registered to produce, receive and handle named categories of waste. In addition, only licensed organizations and sites are allowed to receive and handle the waste.
In addition, there are two important Conventions which the country (when creating its policy) will have to take account of, particularly if they are a signatory to that Convention. They are:
- The Basel Convention on the Control of Trans-boundary Movements of Hazardous Wastes and their Disposal The Basel Convention regulates the trans-boundary movements of hazardous and other wastes applying the ‘prior informed consent’ procedure (shipments made without consent are illegal). This convention is the most comprehensive global environmental treaty on hazardous and other wastes.
- The Stockholm Convention on Persistent Organic Pollutants (POPs) The Stockholm Convention is a global treaty to protect human health and the environment from POPs. POPs are chemicals which remain intact in the environment for long periods, they become widely distributed geographically, accumulate in the fatty tissue of living organisms, and are toxic to humans and wildlife.
In addition to these Conventions, the Agreements on Sustainable Development (decided on at the World Summit in Johannesburg in 2002) will have to be taken into account. The principles of sustainable development have not been fully addressed by international and national organizations when advising upon best practice for healthcare waste management. This is now a priority, and the focus worldwide on the management of resources and the issues of sustainability has begun to concentrate attention on this issue.
For example, in the UK, ecological footprinting and a mass balance analysis has been carried out in the National Health Service (NHS) in England and Wales, and is reported upon by Barrett et al (2004) in Material Health. In the NHS the rates for recycling are very low, on average at 1.8%, compared with the potential of 62% for household-type waste produced in medical establishments.
The paper, Guidelines for the evaluation and assessment of the sustainable use of resources and of wastes management at healthcare facilities’, Townend and Cheeseman Waste Management and Research (2005: 23: 398408) sets out guidelines and a toolkit that can be used by managers of healthcare facilities to evaluate and assess the quantity of resources and wastes at their facilities enabling the principles of sustainable development to be improved.
Aarhus Convention of the United Nations Economic Commission for Europe
Another important Convention is the Aarhus Convention. Although regional in nature, it is by far the most impressive elaboration of Principle 10 of the Rio Declaration; it stresses the need for citizens’ participation in environmental issues and for access to information on the environment held by public authorities.
In addition, other organizations have an impact on the management of healthcare waste, and, for the sake of completeness, they are set out below:
- 1 Decision VIII/33 of the Conference of the Parties to the Basel Convention on Mercury Waste
- 2 United Nations Committee of Experts on the Transport of Dangerous Goods and the Globally Harmonized System of Classification and Labelling of Chemicals and UN Recommendations on the Transport of Dangerous Goods
- 3 United Nations Economic Commission for Europe
- 4 European Agreement concerning the International Carriage of Dangerous Goods by Road (ADR)
- 5 The International Solid Waste Association (ISWA). In its policy, ISWA advocates that proper attention is given to the safe and sustainable management of waste produced in healthcare facilities, and is carried out by the ISWA Healthcare Waste Working Group.
The Law and enforcement
Once agreed, the policy document creates the framework for developing the legal statutes and regulations. Technical guidelines should then be developed to illustrate how the law is to be implemented. In many countries where the laws have been created, no organization has been given the direct powers to enforce implementation. There should therefore be an organization created with adequate resources allocated and with the powers to carry out enforcement and regular inspections and the audit of facilities.
An example of Technical Guidelines that have recently been brought up to date by the Department of Health in the UK are contained in Health Technical Memorandum 07-01 Safe Management of Healthcare Waste. They are the fourth set of guidelines, and deal with the total system they have been revised and updated as the legislation and practices have changed over the years. While they give an indication of the layout and issues to be addressed, care should be taken in adapting them for use in other countries as they are specific to development in the UK. Technical Guidelines should include guidance on the following issues:
- 1 For ease of application, the definitions of healthcare waste categories, and their classification included in the law, should be repeated in the Technical Guidelines, together with the occupational Health and Safety legislation, environmental legislation and transport legislation; and the national policy should be restated.
- 2 Hospital hygiene and occupational health and safety limits of emission of atmospheric pollutants and measures for the protection of water resources. The responsibilities of public health authorities, the national environmental protection body, the heads of healthcare establishments, the scattered and smaller producers of healthcare waste, and the heads of any private or public waste-disposal agencies involved, should also be part of the Guidelines.
- 3 Waste audits should be an essential part of the management of waste within a healthcare establishment. What you cannot measure you cannot manage, so therefore obtaining the data is paramount in any well-run organization. It always bears a cost, however there is evidence obtained by the UK Audit Commission (1997) to show that proper management of the waste produced can lead to sufficient savings being made to justify the cost of the data collection. The audits should address the following issues: an observation and recording of practices in waste handling; types of receptacles; staff questionnaire to assess level of knowledge; and detailed examination of the waste produced.
- 4 Waste segregation at the point of production is essential for a managed system. The best way to carry this out is by the introduction of a colour-coding system. The colour-coding system has to be uniform throughout the country concerned. A full description of the type of waste to be placed in the colour-coded receptacle is essential. An example is shown in Figure 1 on page 44. In addition, there are requirements for packaging to be considered if the waste is to be transported off-site. These requirements are set out in great detail in the UN Transport of Dangerous Goods recommendations and include the specification for the container and the packaging of the contents, as well as the manifest to accompany the waste and the labelling for the container.
- 5 The storage and transport of the waste on-site as well as off site should be specified. Storage areas should be secure and easily cleansed. On site transport should also be made of materials that can be easily cleansed.
- 6 In hot countries there should also be the requirement to keep the waste cool and removed at regular intervals, e.g. where there is no refrigeration, remove waste every 48 hours in the cool season, and every 24 hours in the hot season.
- 7 The Guidelines should also set out the types of treatment and disposal that can render the hazardous healthcare waste safe. Whatever systems are used, they should fulfil the following criteria: disinfect the waste so that it is no longer poses a hazard to staff or the general public; render unrecognizable anatomical waste; make sharps unusable and no longer recognizable; and destroy the chemicals found in healthcare waste.
Figure 1. An example of a key to colour-coded medical wastes Click here to enlarge image
Treatment and disposal
One of the main functions of treating clinical waste is to minimize the bio hazardous nature of the waste. It is necessary therefore to define the criteria for this to occur.
In 1994, a group in the USA was formed to discuss permitting systems and efficacy criteria it is known as the State and Territorial Association on Alternative Treatment Technologies (STAATT). The minimum requirement for alternative treatment technologies recommended by STAATT is Level III (see Table 1). The systems for efficacy testing for the alternative clinical waste treatment technologies have taken many years to develop and this has been an iterative process, which will continue.
Secure wheeled storage container Click here to enlarge image
The different treatment methods are shown in the box entitled ‘Treatment Technologies’. The disposal of untreated hazardous healthcare waste (HHCW) in a landfill site is only an option where the authorities are incapable of providing any other means of treatment. In the European Union it is illegal to dispose of untreated HHCW in a landfill site.
Incineration has a long history that has been marred by the problems of gas cleaning causing nuisance to neighbours, together with the production of dioxins which is highlighted by the in the Stockholm Convention. However current state-of-the-art incineration technology means that treatment of HHCW can take place with minimum risk to the environment from air pollution. It can also deal with most HHCW that is produced. The cost both capital and operation will be more expensive than the alternative or disinfection technologies.
The rendering safe of HHCW by the alternative technologies depends on the operational conditions and the nature of the HHCW being produced. The protocols for assessing the efficacy of the technologies have been developed (but only over the past 20 years) and the standards still have to receive international standard approval. There is also a shortage of research material available for the alternative technologies in contrast to that for incineration. In spite of this, there are many alternative technology appliances in operation throughout the world. However new methods are constantly coming on to the market and this requires all concerned to keep an open mind.
From research carried out recently into practices adopted (by a sample of countries) for the treatment of hazardous healthcare waste, it was shown that just as there is a wide range of equipment available, there was an equally wide range of methods adopted by the different countries considered.
The Philippines is a case in point, where several sets of microwave plants were installed in 1999. In a heavily urbanized nation such as the Netherlands, all hazardous healthcare waste is treated in a state-of-the-art gasification plant. All the waste is directed to the plant by the government and the plant forms part of a complex of plants treating other wastes and jointly producing power.
It is difficult to obtain information from low and middle-income countries due to a lack of research. In the worst case scenario, some small hospitals are unaware of the need for special care in handling the waste.
The WHO does recommend incineration using a simple plant (the de-Montford Incinerator) designed to reduce the air pollutants, for use only in extreme cases when carrying out vaccination programmes in low and middle-income countries.
The rapid worldwide spread of viruses is facilitated by the mobility of global society, the speed of air travel, the growth in human population (particularly in urban areas in Asia). In addition, there are infections occurring where micro-organisms are becoming resistant to conventional treatment, e.g. tuberculosis (XDR-TB), Staphylococcus aureus (MRSA, VRSA). Having in place a suitable framework for the management of waste in healthcare facilities will certainly go a long way in assisting the control and spread infection.
The principle of sustainable development should also be addressed in regards to the way that healthcare is delivered. This will be driven by international agreements and the growing public interest in the environment and the demands for improvements.
The treatment of patients in the home or community is growing in industrialized countries, due to improvements in treatment methods, and to reduce the costs of the service and to improve the rate of patient recovery. Safe waste management systems need to take into account these issues. In addition, the growth in new healthcare treatment methods and the waste produced from their use, such as the use of genetically modified micro-organisms and will have to be carefully monitored.
Dr. W K Townend is chair of the ISWA Healthcare Waste Management Working Group
Incineration is the traditional method of treating hazardous healthcare waste. It reduces organic and combustible waste to inorganic incombustible material, resulting in a very significant reduction in volume and weight. Modern state-of-the-art hazardous healthcare waste incinerators can meet the most stringent environmental standards.
Pyrolysis and gasification
Pyrolysis is the process of chemically decomposing organic materials by heat (up to 2500°C) in the absence of oxygen. Pyrolysis results in a gas stream containing primarily hydrogen, methane, carbon monoxide, carbon dioxide, and various other gases as well as volatile organic compounds and inert ash depending on the characteristics of the material being pyrolysed. These gases are then incinerated in a secondary chamber at a very high temperature.
Plasma arc furnaces
The process involves the discharge of an electric current through an inert gas to ionize it. High-temperature plasmas in arc furnaces can convert, in principle, any combination of materials to a vitrified or glassy substance with separation of molten metal.
This process involves the addition of powerful chemicals (disinfectants) to the waste to kill or inactivate the pathogens. Mechanical shredding of the waste is essential as a pre-treatment.
Wet thermal treatment (autoclaves and steam augers)
Autoclaving or steam sterilization systems are so arranged as to bring superheated steam into contact with the waste, performed in a metal pressure vessel of sufficient strength to withstand the required pressures and in a controlled manner. The steam auger operates at atmospheric pressure, and the waste is pre-shredded and treated with steam to disinfect it.
Dry thermal treatment (hot screw-feed technology)
Dry thermal disinfection processes are based upon screw-feed technology where the waste is first shredded and then heated by a rotating auger heated to a temperature of 110°C140°C by oil, or other media circulating through its central shaft.
Microwaves are short, high-frequency electromagnetic waves which are generated in electron tubes with built-in resonators to control the frequency, or by special oscillators or solid-state devices. Most micro-organisms are destroyed by the action of microwaves. The microwave thermal treatment system for healthcare waste operates by agitating the water molecules in or on the surface of the waste materials, causing them to vibrate the vibration produces heat. Macrowaves apply low frequency waves to treat the waste, destroying pathogenic organisms from inside.More Waste Management World Articles