Originally published in Directions Magazine; October/November 1996

Let's Talk Trash!

by Paul E.R. Packbier

Lets not beat around the proverbial bush, and grab the issue by its horns: I don’t like garbage, especially yours! I might be able to put up with my own waste piling up for awhile, at least I am intimately familiar with its contents, but I draw the line when it comes to someone else's trash. Guam is facing a challenge these days as it is trying to cope with a growing waste stream and limited disposal facilities. How we deal with our own and our visitors’ trash is a "hot" issue these days, only to be become more of a pressing issue the longer we wait.

WHAT HAS CHANGED?

Historically, little thought has been given to the disposal of waste products associated with rapid development and population growth. Just a century ago, the majority of solid waste generated was mostly benign by today’s standards. The effects of sun, heat, and the corrosive saltwater environment was able to keep up with the generation rates of most degradable waste products and not much thought was given to "management" of our refuge. However, the introduction of man-made materials with the advent of the Industrial Revolution has created new challenges.

OUT OF SIGHT OUT OF MIND?

Initially, the demand for disposal sites was met by finding suitable areas for dumping. Typically these areas consisted of natural depressions in the local topography away from major population centers. The Ordot landfill in Guam was chosen because relatively little preparatory work was needed to create this solid waste "holding" area. The Puerto Rico landfill in Saipan was created by filling in part of a lagoon. Elsewhere in Micronesia, natural depressions and sinkholes in the karst limestone geology, primarily in the coastal areas, are being used as disposal sites.

During the past three decades it has been discovered that these dumps are far from being ideal for their intended purposes. The infiltration of rainwater, combined with liquid wastes disposed of in a dump and the liquids created during the various decomposition processes that take place, create a noxious and often toxic brew commonly referred to as leachate. In addition, combined aerobic and anaerobic decomposition processes taking place within these waste piles create landfill gases that are often flammable and odorous. Experience has taught us that simply putting something in the ground, does not mean that it will be immobilized forever. Leachate is affected by the common laws of physics; pressure, gravity, and the paths of least resistance, which will induce ways out of the intended storage site, commonly by following the natural ground-water gradient in the area. The result is that the holding site is not living up to its expectations and, in contrast, is actually re-releasing waste into the environment. The occurrences of landfill fires at both the Ordot and Puerto Rico dumps are well documented, often caused by spontaneous combustion of methane gas generated and fueled by the abundance of combustible waste. Leachate run-off is not as well documented, but is suspected of releasing metals and other waste by-products into the local environment, and eventually into the ocean.

THE FUTURE OF WASTE MANAGEMENT

Technology has been trying to keep pace with the recent discoveries in landfill releases. The U.S. Environmental Protection Agency (EPA) has promulgated standards for the design of new landfills that include complex liner systems employing leachate capture and control, landfill gas recovery processes, and capping of the waste being stored to minimize rainwater infiltration and provide for vector (rodent) control. These new landfills are called "sanitary" landfills with their main purpose being the protection of human health and the environment. As one can imagine, these new control systems have dramatically increased the design, construction, and operation costs for landfills. The result is that governments and private companies that operate these waste disposal facilities are looking into ways to extend the life of a facility.

HOW TO MAKE IT LAST

With the increase in costs of constructing and operating a sanitary landfill, the focus has shifted to evaluating the waste being disposed of and the recovery of potentially useful resources contained within it. Municipal waste typically contains a large variety of discarded products that can potentially be recovered and used for other purposes. A typical solid waste management facility these days includes a Materials Recovery Facility (MRF). These facilities employ a wide variety of ingenious technologies which separate useable waste products from the solid waste stream. Metal, glass, paper, organics, paper, and plastics have inherent value as recyclable resources that can be sold for revenue. Consequently, these recyclable resources can reduce the ultimate volume of solid waste being landfilled and extend the life of the landfill.

RECYCLING THE ANSWER?

The problem associated with island communities located in this part of the world is that potential markets for recyclables are often located thousands of miles away. The economic factors associated with recycling shift daily. The price of paper or aluminum on the world market today might not guarantee the feasibility of undertaking such effort tomorrow. In the past, on Guam, successful recycling efforts have been limited to scrap metals and aluminum, but recently companies have ventured into the paper recycling business. The limiting factor in making this a profitable venture is the volume that can be generated on-island to make it economically feasible to ship large quantities of recyclable waste to Asian markets.

VOLUME REDUCTION ...

One possible technology that can be employed to reduce the volume of solid waste generated in any given community is incineration. Incineration is far different from open burning of waste, which can produce hazardous or toxic air pollution because of incomplete combustion. During the incineration process, municipal waste is fed into a combustion chamber that attempts high temperature destruction of the waste "fuel." The waste stream is first segregated to remove noncombustible items such as metal and glass. As with any thermal destruction process, air pollution is a major concern. Utilizing "scrubbers" and intricate filtration systems, an incinerator has to be able to demonstrate 99.99+ percentage removal of potentially hazardous air pollutants that could adversely affect human health. The two components left after destruction of the municipal waste are ash and sludge from the filtration system.

... AND ENERGY RECOVERY

Incineration appears to be a viable option for island governments struggling with ways to manage solid waste into the next century and beyond. A well-managed incinerator not only reduces the volume of waste that ultimately needs to be landfilled, it also eliminates the hazards associated with leaching of uncontrolled waste and landfill gasses. Depending on the volume of solid waste generated by the island community, instead of simply incinerating the waste, a waste-to-energy (WTE) facility can be built to capture the resultant energy from the combustion process to generate electricity. The feasibility of such an approach will depend on the quantity and composition of the waste generated daily. The 250 tons per day of solid waste that Guam is expected to produce could potentially produce 5 megawatts of electrical power (which would supply electricity to 1,200 homes).