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Developing countries have had extremely limited options for safe waste disposal, especially for used and/or contaminated sharps (lancets, blades, syringes or hypodermic needles with or without attached tubing; broken glass items such as Pasteur pipettes and blood vials, and other invasive devices) that can cause injury and that are associated with significant risk of infection if indiscriminately disposed.

(Infectious waste can also include non-sharps, e.g., materials that have been in contact with blood, its derivatives, or other body fluids, e.g., bandages, swabs or items soaked with blood.) While generally less than 10% of health-care waste is considered infectious, many countries have poorly developed waste segregation practices. This complicates waste management since commingling sharps and other infectious waste with non-infectious waste will increase the amount of waste considered infectious that requires special treatment for safe treatment and disposal.

Resources are extremely limited in many countries, especially in remote areas. Consequently, open pit burning is still widely practiced for health-care waste including sharps, though this practice is objectionable due to emissions, the incomplete disinfection and destruction of the waste, and community complaints.

The volume of health-care waste varies by the size and activity of the clinic/hospital/provider. Small rural clinics may generate relatively small quantities of infectious waste, e.g., 1 to 10 kg of sharps per month. Quantities can be orders of magnitude greater at large urban clinics and hospitals. Quantities can greatly increase during immunization campaigns, e.g., the 2001 measles mass immunization campaign in West Africa (covering all or part of six countries) vaccinated 17 million children and generated nearly 300 tons of injection-related waste. Throughout the developing world, WHO estimates that routine immunizations of children under one year and immunization of women of childbearing age with tetanus toxoid accounted for over one billion injections in 1998, while measles control/elimination activities and disease-outbreak control operations accounted for another 200 million injections in the same year (WHO 1999). These 1.2 billion injections are estimated to produce 12 000 to 20 000 tons of infectious waste. Additional immunizations are anticipated as new vaccines appear and for the poorest countries where vaccines are needed most.

Safe waste disposal options are needed to deal with these quantities, as well as the wastes generated by routine health-care provision.

Incineration has been used for many years. Incineration can destroy or inactive infectious waste, provide significant (>90%) mass and volume reduction of the waste, and render materials (syringes, etc.) unusable. Moreover, it generates enough electricity to carry the burden of one district at a time. Incineration plants provide thermal recycling of refuse fuels. In particular waste and garbage from the following are burned: Waste from private households, Local waste, and Industrial waste. Due to rising amounts of garbage, as well as a stronger environmental awareness, waste incineration is of an ever greater importance. Garbage in many countries was and is still disposed of by simply throwing it on to garbage dumps or in landfills. The decomposition of this garbage on the dumps creates a dangerous mixture of toxic effluents, gases and chemicals, which can endanger the groundwater. By burning the garbage in combustion plants, this danger can be avoided and the energy created in the burning process can be captured and re-used.

Everywhere, where population, industry and prosperity grow, waste incineration can represent safe disposal of waste. Incineration plants are from a process point of view comparable to conventional coal-fired power stations. Many plant components are the same. The capacity or size of an incineration plant is however limited to the garbage amounts which can be burned per year. A medium size plant will burn on average 200,000 tonn of garbage per year.

In developed countries, recent regulatory initiatives have significantly changed the utilization, design and operation of incinerators. In developing countries, controlled air incineration using low cost engineered small-scale facilities has been promoted by national governments and UNICEF and is currently used in a number of countries, often with external support. Small-scale incinerators may be built on-site, locally constructed, fixed and/or portable. Units typically operate for 1 to 6 hours per week or month in a batch or intermittent mode to destroy sharps and other health-care waste. For example, the brick incinerators, designed at De Montfort University by JD Pickens, have been introduced into both remote and urban areas in several countries, e.g., West and East Africa, Kosovo, Sri Lanka, etc. When new and appropriately operated and maintained, these high thermal capacity incinerators can achieve relatively high operating temperatures (700 to 800 C), largely destroying the waste and helping to reduce production and emissions of dioxins and furans in stack gases and ash.