by Dr. Emil Javier

Unfortunately, one of the key proponents of these landmark legislations, former congressman of the First District of Bukidnon, and now Laguna Lake Development Authority (LLDA) General Manager, Dr. Nereus O. Acosta, who was plenary speaker, failed to reach Manila Hotel because of the floods which inundated most of the city last week.

Essentially, the conclusion was the Philippines to its credit has made so much headway by way of legislation to make our environment cleaner, safer and healthier. Some progress have been achieved although much, much more remain to be done. The Department of Environment and Natural Resources (DENR) is doing its part reasonably well but ultimately much depend upon the communities themselves, particularly the leadership in the local government units.

WASTE-TO-ENERGY (WTE)  SYSTEMS FOR SOLID WASTE  MANAGEMENT

One of the most pressing environment problems confronting Metro Manila and most other cities and big towns is what to do with mounting municipal garbage. Existing dumpsites cannot accept more garbage but suitable landfill sites are more and more difficult to find as the communities around them rise up in arms to the stench, sanitation and public order problems landfill sites generate.

Actually, the management of solid wastes is best addressed first, by prevention; second, by sorting and recycling of non-biodegradable wastes like plastics, metals and glass and, finally, by treatment and disposal. After the plastics, metals and glasses are recovered, the remaining organic biodegradable wastes can be handled as follows:

•Deposition into sanitary landfills with or without methane gas recovery,

•Incineration for steam or electricity generation, and

•Conversion into some form of powdered solid fuel and also into gasoline and fuel-oil-like products.

The first two options, sanitary landfills and incineration for steam and electricity production are mature technologies. The third option is still under varying stages of technological development and commercialization.

Dr. Filemon Uriarte, a member of the Academy and concurrently President of the National Research Council of the Philippines (NRCP) discussed at length in his plenary paper the pros and cons of the three options and came out strongly in favor of the second option of incineration for steam or electricity production. Uriarte has a chemical engineering degree from UP Diliman, a doctorate from Carnegie Mellon University in Pennsylvania and was Secretary for Science during the Estrada Administration.

As pointed by Uriarte, waste-to-energy technologies including incineration offer a number of advantages over sanitary landfills, namely: 1) elimination of pathogens in solid wastes particularly hospital wastes, 2) possibility of being located in the city closer to the sources of garbage thereby reducing collection costs, 3) significant reduction in waste volume by 90%, 4) elimination of greenhouse gas emissions like methane from landfills, and 5) generation of heat that can be profitably converted into electricity.

The ban on incineration was based on the need to reduce the release into the air of greenhouse gases like carbon dioxide (CO2), methane, sulfur dioxide (SO2) and nitrous oxide (NO2) which are bringing about global warming and climate change. Likewise, to minimize the generation of carcinogenic organic air pollutants principally dioxins and furans.

However, studies have shown that sanitary landfills with methane generation systems consistently produce 2–3 times more carbon dioxide equivalent, sulfur dioxide and nitrous oxide than incineration electricity systems per kilowatt of power generated. Thus, incineration is twice to three times less dangerous than landfills.

The dreaded carcinogenic organic air pollutants, dioxins and furans, are generated from the incomplete burning of organic wastes. The main sources are burning of agriculture and backyard wastes. But worse is the burning of fuelwood which generate these air carcinogens right in the kitchen. Dioxins and furans are generated by moderate burning temperatures of 400–700oC. But for incinerators, the problem is largely eliminated because the burning temperatures in modern incinerators are above 1,000oC.

Moreover, sanitary landfills with methane recovery generate power in the order of 41–84 kilowatt per hour per ton of waste. Modern incinerators on the other hand, generate 470–930 kilowatt per hour per ton of waste, an efficiency factor of 10.

THE SINGAPORE WTE MODEL

Uriarte cited the model of Singapore which generates about 8,400 metric tons of municipal garbage per day, close to the estimated 9,000 tons per day solid wastes collected in Metro Manila. As most of our kababayans who have visited and/or worked in Singapore will attest, the city-state is one of the cleanest, healthiest and safest cities in the world.

Singapore has four working incinerators with a total capacity of 8,200 tons garbage per day producing 198 megawatts (MW) of electricity. A fifth incinerator with an additional capacity of 2,400 tons per day is under construction. The Singapore garbage incineration facilities also recover 22,800 tons of scrap metal each year. Three of their incinerators are located at the coasts but a fourth one sits in the middle of a residential area.

The Clean Air Act (RA 8749) shortsightedly closed the option to safely and neatly dispose solid wastes by incineration at the same time generating electricity to help pay for the costs. The ban on incineration was premised on the need to reduce the release of greenhouse gases into the atmosphere which induce climate change as well as other organic air pollutants injurious to human health. Unfortunately, the prohibition perversely results into the opposite because sanitary landfills generate more of these pernicious gases than outright incineration.

Metro Manila, and other urban centers in the future, should have the option to adopt waste-to-energy systems to manage municipal wastes like Singapore (and many, many other progressive cities in the world). Even now Manila is running out of sanitary landfills.

Time to reconsider the absolute ban on incineration in the Clean Air Act.

***

Dr. Emil Q. Javier is a Member of the National Academy of Science and Technology (NAST) and also Chair of the Coalition for Agriculture Modernization in the Philippines (CAMP).

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Source: http://www.mb.com.ph/time-to-reconsider-absolute-ban-on-incineration-in-clean-air-act-ra-8749/#UUesBTAPKJ6RuijK.99