Rotary kilns and controlled air incinerators are preferred design options for thermal treatment of hazardous medical waste. Incinerators consist of both a primary and secondary chamber, with appropriate air emissions controls. Combustion is the primary incineration treatment process, combining waste and oxygen to produce the same stable end product regardless of the type of waste.
A well-designed incinerator has efficient heat to breakdown all organic and many inorganic molecules, allowing reactions between the most volatile waste and the oxygen and nitrogen in the air. This reaction predominantly produces carbon dioxide and water vapour.
However, incomplete combustion in the incinerator waste feedstream and furnace can result in harmful environmental emissions and waste products.
The waste feedstream emits carbon monoxide and carbon-containing particles. Other reactions also occur to produce hydrogen chloride, sulfur oxides, nitrogen oxides, metal oxides and metal vapours.
The furnace is designed to efficiently mix combustion air, gases and vapour from the burning waste. Yet where combustion is incomplete, incineration results in the release of pollutants to the atmosphere. Fly ash is the incombustible particulate matter entrained in the flue gas. The resultant ash in the furnace is bottom ash, both requiring disposal at a regulated waste facility.
The waste products and combustion conditions determine the type and concentration of contaminants in the flue gas. Dioxins and furans are some of the most hazardous products released due to incomplete combustion. Only modern incinerators operating at 850-1100 °C and fitted with special gas-cleaning equipment comply with the international emission standards for dioxins and furans. Heavy metals (in particular lead, mercury and cadmium), acid gases and particulate matter are all pollutants of concern associated with adverse health effects.
Efficient incineration requires optimal design and operation of temperature, turbulence and gas residence time (at optimal temperature). A steady incineration process promotes efficient combustion, resulting in lower levels of emissions and waste products.
Measuring the safe and environmentally sound management of medical wastes can prevent negative health and environmental impacts. Optimisation of operating practises through monitoring and control devices can reduce emissions and improve pollutant capture.
Continuous emissions monitoring technology is a recommended strategy to characterise environmental concentrations for efficient management and control of incinerator facilities.
Norditech Pty Ltd provides innovative solutions for all your emissions monitoring needs. Effective monitoring is key to achieve your work health and safety objectives and meet your compliance requirements. Give us a call for further information on 1300 572 872.