Interface
Dealing with wastes is a common challenge to all societies. The technology has created a wide range of substances that do not exist in nature. Human discards are thus increasingly comprised of plastics, metals and natural materials laced with hazardous substances which in many cases, are difficult or impossible for natural ecosystems to breakdown. The conventional concept of the waste management industry is “Burn it or Burry it”. As the volume, toxicity and persistence of waste increase, the incinerators must be developed accordingly. But in Sri Lanka, most of the incinerators are not much sophisticated according to the requirement.
How it affects?
Persistent Organic Pollutants (POP’s) such as Polychlorinated Biphenyls, Polychlorinated Dibenzo Dioxins, Polychlorinated Dibenzo Furans are the most notorious pollutant associated with incinerators. They cause a wide range of health problems, including cancer, immune system damage, reproductive and development problems. POP’s biomagnify along the food chains. So, those POP’s ultimately enter human digestive system. POP’s are ubiquitous in the environment and in the humans at levels that have been shown to cause death problems and the entire population suffer their ill effects. Incineration in the world are the primary source of POP’s. Incinerators are also a major source of Mercury pollution. Mercury is a powerful neurotoxin, impairing motor, sensory and cognitive functions, and Mercury contamination is widespread. Incinerators are also a significant source of other heavy metal pollutants such as Lead, Cadmium, Arsenic and Chromium.
Other pollutants of concern from incinerators include other halogenated hydro carbons; acid gases that are precursors of acid rain; particulates, which impair lung function; and the greenhouse gases. However, characterization of incinerator pollutant release is still incomplete, and many unidentified compounds are present in air emissions and ashes.
Since the problem of pollutant releases is not solved, the pollutants are simply moved from one medium (air) to another (solids or water). Incinerator ash is highly hazardous but is poorly regulated. Even landfill disposal is not safe, as landfills leak, but in some places the ash is left exposed to the elements or even spread in residential or food producing areas.
Sri Lankan Situation
In Sri Lanka, Disposal of medical waste in government health institutions is carried out by incineration and burning. In addition, large private hospitals (around 10) have their own medical waste incineration facilities. Medical waste incineration data of government hospitals are available with the MOH. Ex: General Hospitals in Ragama, Colombo, Karapitiya, Welisara etc. A Large-scale incineration is processed in Holcim Cement factory, Puttalam (rotary kiln). There is a potential of emitting hazardous gases as the result of burning reactions. Besides, a lot of co-incineration processes can be seen around the companies which produce sludge. Ex: MAS, Thulhiriya. A lot of toxic chemical components are available in the sludge itself and the noxious gases are released under high temperature.
Alternatives
Instead of waste disposal, industries must redesign their products for ease of end-of-life recycling. Organic matters should be composted. There is a potential in segregating hazardous waste from general waste stream. There are cheaper, less technically complicated, and less harmful methods of segregation. A wide range of hazardous wastes, including pharmaceuticals are produced in large quantities in health care facilities. These wastes are not amendable to incinerate. The metals like Mercury, should be eliminated through changes in purchasing and others can be recycled and the rest can be carefully collected and returned to the supplier. Nowadays, wet scrubbers ae used to separate the toxic substances from the main waste stream based on the particle size and theory of density. In Sri Lanka, there is only one medical waste incinerator located in Mulleriyawa, is equipped with a wet scrubber. With the use of that device the levels of Mercury are controlled.
D.M.N.B. Moneravilla (Bsc.sp)