Author: Jonny Lupsha, Freelance News Writer
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Recycling collection bills are skyrocketing, forcing cities to scale back or even stop recycling, according to an article in The New York Times. Increased costs result from recycling companies trying to recoup losses suffered due to fewer buyers in the global scrap market. Recycling is one of three waste disposal methods used today.
For years, China was the world’s largest buyer of recyclable materials. However, China has complained that too many non-recyclable items were mixed in with the recyclables they purchased from other countries, eventually resulting in the refusal to accept recyclables at all. India and Thailand have voiced similar concerns, restricting their own purchases of scrap. Now, recycling companies are charging cities and taxpayers more to recoup the losses they’re suffering due to other countries’ lack of interest in papers and plastics. In turn, U.S. communities are scaling back or eradicating their recycling programs and returning to dumping waste in landfills or incinerating it. Can burying and burning foot the bill, environmentally speaking?
Landfills and Their Complications
Modern dumps are referred to as sanitary landfills. Rather than simply being an open plot of land in which to store garbage, they’ve evolved to fit modern needs. “A modern sanitary landfill is a technological system designed by environmental engineers to return solid waste to the earth in a way that maximizes the use of available land and minimizes harm to the environment,” said Dr. Stephen Ressler, Professor Emeritus from the United States Military Academy at West Point. Dr. Ressler said that organic material begins to decompose in landfills, and is aided by rainwater. However, the rainwater is contaminated with dissolved matter like metals, becoming a toxic liquid called leachate. Landfills prioritize the capturing and removal of leachate to prevent water contamination.
Decomposition also creates a byproduct called landfill gas—an explosive gas comprised mainly of methane and carbon dioxide—that landfills also seek to capture and dispose of. “In the United States, the Clean Air Act Amendments of 1996 require the systematic collection and control of landfill gas not just for safety reasons, but also because methane is considered to be an extremely potent contributor to climate change—at least 25 times more potent than carbon dioxide,” Dr. Ressler said.
Solutions for Landfill Byproducts
In order to filter out leachate, landfills are formed by digging 25-foot-deep square pits in the earth. These pits are then covered with a layer of compacted clay, then a geomembrane like a plastic sheet, followed by a layer of gravel and plastic pumps that capture leachate and funnel it down to lower levels. Next in the landfill layer cake is a durable synthetic fabric known as a geotextile and finally a layer of protective soil or sand. This intricate filtration system ensures that leachate remains separate from streams, rivers, and other supplies of groundwater.
As waste is dumped into the landfill, leachate goes down and landfill gas goes up. The gas is typically piped to a flare, where it is burned off above ground. “But today, an increasing number of landfills are incorporating recovery systems that put landfill gas to more productive use by any of three methods: either by burning gas in a nearby industrial boiler to produce hot water, using it to generate electricity by powering an onsite gas turbine or steam turbine that drives a generator, or processing the gas for sale to a local gas company,” Dr. Ressler said.
Incineration: Pros and Cons
According to Dr. Ressler, burning waste reduces its weight by 80 percent and its volume by 95 percent. Furthermore, the heat that incinerators cause can be used to generate power and its only byproduct, ash, takes up a fraction of the space that landfills do. So why does only one-sixth of garbage find its way to incinerators?
“Most importantly, the emissions caused by incineration are highly toxic,” Dr. Ressler said. “These can be controlled—to some extent—by pollution control devices called baghouse filters, but these devices are expensive, and safely disposing of the toxic fly ash they capture can be a significant challenge.” Second, incineration causes a considerable amount of carbon dioxide emissions. Third, solid waste is a very low-quality fuel as-is, so sorting expenses pile up and eventually outweigh the benefits of using municipal waste as a fuel alternative.
Environmental and financial costs of landfills and incinerators remain high even as recycling costs climb and cities stop recycling altogether. Unless the global scrap market is salvageable through smarter recycling, “burying and burning” may need to play catch-up and become more efficient.
Dr. Stephen Ressler contributed to this article. Dr. Ressler is Professor Emeritus from the United States Military Academy at West Point. A registered Professional Engineer in Virginia, he earned a B.S. from West Point and an M.S. and a Ph.D. in Civil Engineering from Lehigh University, as well as a Master of Strategic Studies from the U.S. Army War College.