A Perspective on Waste-to-energy and "Incinerators"
President RR Duterte's statement during his first SONA ..."To have adequate disposal facilities for the Metro Manila garbage... the adoption of appropriate waste-to-energy facilities will be explored... The technology is coming very fast" elicited strong concerns from some sectors including Civil Society Organizations on the ground that the use of incineration will have"many negative environmental, health and social consequences"
1.1 Waste-to-Energy for Power Generation
Waste to Energy (WTE) involves any waste treatment process to convert non-recyclable waste materials into useable energy through a variety of processes, including combustion, gasification, pyrolization, anaerobic digestion, and landfill gas (LFG) recovery. Due to the huge amount of the municipal solid waste (MSW) produced daily in urban areas, the attentions are focused on MSW processing as the feedstock to such technologies. The most common and widely used MSW-to-energy technologies are incineration in a combined heat and power plant (CHP) and controlled landfill to capture methane from waste (LFG).("Waste to Energy in Malaysia" by Omidreza Sadeghi, etal)
Two of the primary methods for the treatment/management of solid wastes are the use of "Incineration" process and by landfills, the latter either by open dump or sanitary landfills.
As a mode for solid waste treatment incineration provides the benefits of high volume reduction of wastes thus prolonging the life of landfills and allowing energy recovery through the generation of electric power from the heat produced. However, serious issues that apparently borders on misconceptions on the use of Incinerators still exist in the Philippines.
Definition of "Incineration"
In general simple terms, Incineration may be defined as a process for the treatment/destruction of wastes that involves the combustion of organic substances contained in waste materials converting these materials into residual ash, combustion gases and heat. The term "combustion" denotes the involvement of molecular oxygen in the process.
In the Philippine setting, the definition is relevant and socially sensitive and further because of legal implications arising from the definition under the Philippine Clean Air Act, to wit (in italics):
Section 20. Ban on Incineration. - Incineration, hereby defined as the burning of municipal, bio-medical and hazardous wastes, which process emits poisonous and toxic fumes, is hereby prohibited
The Supreme Court Decision ([G.R. No. 147465. January 30, 2002]) on the case involving the Solid Waste Management Project of JANCOM INTERNATIONAL DEVELOPMENT PROJECTS PTY. LIMITED OF AUSTRALIA, ruled the following (in italics).
Sec. 20 of the Clean Air Act pertinently reads: SECTION 20. Ban on Incineration. Incineration, hereby defined as the burning of municipal, bio chemical and hazardous wastes, which process emits poisonous and toxic fumes, is hereby prohibited:x x x.
Section 20 does not absolutely prohibit incineration as a mode of waste disposal; rather only those burning processes which emit poisonous and toxic fumes are banned.”
In resolving garbage problems especially in urban cities like Metro Manila, incineration has been cited as the practical solution (statement of then MMDA Chair Atty Francis Tolentino); however with expressed concern as to whether the Clean Air Act may be violated (Section 20 “Ban on Incineration” above cited)
House Bill No. 3161 titled"An Act Allowing the Use of Incinerators in Burning Municipal, Biomedical and Hazardous Wastes..."was a subject of robust discussions in the Committee on Ecology hearings during the last Congress but was not passed into law. It may likely be introduced again during the current Congress. The intent of the HB which was...."to seek for utilization of incineration as a means to effectively and efficiency manage municipal, biomedical and hazardous wastes...".
The US EPA does not prohibit nor ban solid waste incineration units but instead prescribes the protocol by which permits may be secured for incinerators and similar types of processes. Together with the European Union (EU) similar processes such as gasification (e.g. plasma-usually involving high temperatures andpyrolysis - a thermochemical decomposition of organic material at elevated temperatures in the absence of or at limited oxygen concentrations are included in the definition of Incineration.
2.0 Re-Defining the Incineration Issues and Offering Solutions Thereto
It is evident from the above that the basic issue or controversy arises from the definition in the Philippine Clean Air Act of the term "Incineration".(See footnote 1) It is proposed that instead of being embroiled in the definition or this term, focus should instead be made on the effects on the environment by the particular process that is used for the treatment or destruction of wastes. These effects are measurable in terms of the presence/absence and concentration of "toxic" or "hazardous" substances in the discharges to the environment.
Dioxins and Furans
Dioxins and furans are some of the most toxic chemicals known to science; dioxins are labeled by the US EPA as a serious public health threat. Dioxins are a generic term used for group of polychlorinated dioxins (PCDD) and polychlorinated dibenzofurans (PCDF). Hence the term "Dioxins" usually also include the toxic "furans" substance.
There are several isomers in the family of dioxin compounds the most toxic being the –2,3,7,8- tetrachlorodibenzo-para-dioxin (2,3,7,8-TCDD), shown below.
The significance of showing the above formula are:
The single most important concern in Incinerators is the potential discharge of dioxins. Dioxin is formed by burning chlorine-based chemical compounds with hydrocarbons. In addition to cancer, exposure to dioxin can also cause severe reproductive and developmental problems as well as damage the immune and hormonal systems. Dioxin exposure has been linked to birth defects, inability to maintain pregnancy, decreased fertility, reduced sperm counts, endometriosis, diabetes, learning disabilities, immune system suppression, lung problems, skin disorders and lowered testosterone levels.
Temperature is a key factor in determining whether dioxins may be formed, with temperatures of about 400 OC to 600 OC as conducive to dioxins formation. The"residence time"or the time duration that the agents for the formation of dioxins, (i.e. the hydrocarbon and chlorine molecules) are exposed to this range of temperature is also a factor.
The simple science-based resolution of the environmental issues surrounding the use of the "Incineration" process is thus to relate to theemissionsandnotto theprocess or technology involved. A particular treatment or combustion system will have specific temperature ranges and residence times to which specific molecular configurations of the dioxin-forming hydrocarbons as well as chlorine concentration levels present in a waste will dictate dioxin formation.
Moreover, the emissions must be measured when the gases produced in the treatment of wastes reach the air environment and not from the exit of the combustion or incineration equipment.
This is because of concerns that the hot discharge gases which are free of dioxins may recombine and reform the dioxins when the gases cool down to the formation temperature. A simple procedure to address this concern is to subject the discharge gases to shock or sudden cooling and subsequently pass the cooled-down gases to scrubbers. Additionally, post combustion gases may also be further subject to high temperature treatment prior to exit to the atmosphere. In addition if the combustion gases do not encounter a Chlorine atmosphere, the dioxins cannot form.
3.0 Waste-to-Energy (WTE)
There are currently operating WTE facilities in the Philippines, a notable one being the 200 kW Biogas Plant from the Payatas Disposal Facility in Quezon City, the first Clean Development Mechanism project in solid waste management in the Philippines and strictly an “Incineration” Project, from conventional/international definition but not as defined by the Clean Air Act.
Other projects that can be cited are:
The 2 MW Tagum WTE Project employing a form of Incineration called pyrolysis Miscellaneous WTE Biomass Projects using as feeds agricultural wastes are rice hull, bagasse, coconut shell/husk and coconut coir.
In other countries:
The 10 MW WTE power facility in Sri Lanka using 580 MW municipal wastes per day The WTE facility in Taiwan using municipal wastes
It appears that issues against WTE stem from the WTE being invariably connected to Incineration as narrowly defined in the Phl Clean Air Act.
The issues surrounding the use of Incinerators and of WTE Projects can be addressed using science-based approach. Safeguard of the environment is measured and monitored by emissions to the air, water and land resources and to impact on health and may be ensured by ascertaining that the toxic Dioxins are absent when the exhaust gases from the incinerators reach the environment. Monitoring procedures and apparatus are available. Technology interventions may be employed including the use of elevated temperatures, adequate residence time to allow complete dioxin destruction and after treatment of the gases to prevent recombination. The after treatment may be done through quench cooling and the use of scrubber and further re-heating of the exhaust gases.
The legal interpretation of the "Ban" on Incineration has been passed by the Supreme Court.
1 It is recalled that in a forum (circa 1998) sponsored by the National Academy of Science and Technology at the University of the Philippines Dr Rogelio Panlasigui of the DOST and Dr Ed Alabastro of the Air and Waste Management Association, Philippines suggested the adoption of the following alternate version for entry in the Philippine Clean Air Act then being drafted:
Any process which emits poisonous and toxic fumes, is hereby prohibited
The above wording which did not use the term “Incinerator” was thought to have been more strict, scientifically correct and would have avoided the controversies on Incineration.
2Dr Ed Alabastro was involved in the design, construction and operation of a "non burn technology" facility called Molecular Gasification Reduction (MGR) thermal waste conversion facility for a waste recycling plant.
© Copyright 2020. All Rights Reserved