IN THE early 1990s, the U.S. Environmental Protection Agency (EPA) identified medical waste incinerators as the single largest source of dioxin, a potent carcinogen that has been linked to birth defects, immune system disorders, and other harmful side effects. Incinerators are also a leading source of mercury, lead, and other dangerous air pollutants like furans, acid gases, and particulates.
FUEL storage tank of the dismantled Hoval medical waste incinerator at the Davao regional Hospital in Tagum, Davao del Norte. [photo courtesy of EcoWaste Coalition]
Thermal processes rely on heat to destroy pathogens (disease-causing microorganisms) and are further classified into low-heat (operating below 177°C), which uses moist heat (usually steam) or dry heat (hot air); medium-heat (between 177°C and 370°C), and high-heat (operating from around 540°C to 8,300°C).
Chemical processes employ disinfectants to destroy pathogens or chemicals to react with the waste. Irradiation involves ionizing radiation to destroy microorganisms while biological processes use enzymes to decompose organic matter. Mechanical processes, such as shredders, mixing arms, or compactors, are added as supplementary processes to render the waste unrecognizable, improve heat or mass transfer, or reduce the volume of treated waste.
Local waste treaters like Chevalier commonly employ autoclave technology, a wet-heat treatment using steam to disinfect waste. Others, including private hospitals, use microwave technology, a steam-based, low-heat thermal process with disinfection occurring through the action of moist heat and steam.
Thermal treatment technologies using high-heat processes like pyrolysis and gasification systems have also been promoted as clean non-incineration alternatives, but tests have shown them to be capable of generating dioxins, furans, and other pollutants.
Local healthcare industry insiders say that everything that goes into yellow trash bags (infectious, pathological, pharmaceutical) goes to the waste treater. Sharps can be classified under infectious waste — especially if the hospitals do not have the sharps handlers, needle destroyers, and such — which means they also go to companies like Chevalier for proper disposal. Genotoxic, chemical, and other wastes go to particular TSD (transport, storage, and disposal) facilities capable of handling such waste types.
So far, Chevalier has passed all the inspections done by the various Waste Management Committees of its clients. But it seems it has been having problems with the final disposal of the treated waste. The Department of Environment and Natural Resource Region IV office has been insisting that Chevalier’s dumpsite in San Pedro, Laguna be registered as a TSD facility. But Chevalier says the site’s operator is balking because it fears that the land would have little value left if it is converted into a controlled landfill. The operator has thus barred Chevalier from dumping treated waste there until the matter is settled. Chevalier has been storing the treated waste in its premises in the meantime.
Chevalier pollution control officer Victoriano Andutan Jr. explains that the DENR still categorizes treated waste as hazardous waste. But Andutan argues that this should not be so since the trash has already undergone autoclave/microwave disinfection, rendering it free from bacteria.
Recently, though, his company managed to secure an extension to dump its treated waste at the San Pedro dumpsite until April 2008. Its contract with government hospitals expires at the end of 2007.