Posted on May 27, 2016 by Charles F. Becker
In 1991, Iowa passed a law prohibiting the delivery of yard waste to landfills. It was during a time when there was a general panic that landfills were filling up too fast. Twenty-two states have passed similar laws. They all saw it as a win-win: compost could be created and sold by the city and the landfills would last longer. A couple short decades later, several states have had second thoughts. In 2015, Iowa passed a lawthat allows certain landfills to start accepting delivery of yard waste. The reasoning is instructive.
Landfills contain a staggering amount of potential energy. The tires, paper products and plastic wastes, when burned for energy recovery, could light up a town. But the cost of getting the BTUs out of the waste doesn’t make economic sense – yet. There are exciting, new processes on the horizon that will have us mining that garbage for the energy sink it actually is, but that is still a ways off. One form of energy recovery that is economically viable, however, is methane recovery. As the garbage breaks down, it gives off methane gas that can be captured and burned. Many landfills across the country do this type of recovery and find it simple and profitable.
To effectively produce methane, however, garbage must degrade. The recycling push of the 80s and 90s took away the really good degradables from the waste stream – boxes, newspapers and yard waste were targeted as prime recyclables. The effect was that the best fuel for garbage degradation (and thus methane creation) was banned. Sure, it went towards the worthy goals of paper recycling and creation of high quality compost, but at what cost?
Iowa decided to look into that question. They considered the cost of producing compost from yard waste and compared it to the cost of recovering additional methane that would be made possible by returning the green gold of yard waste to the landfill degradation process. As it turns out, recycling loses.
The analysis turned on a number of factors:
· The cost of buying, maintaining and fueling the trucks, machinery and facility needed for composting would be eliminated resulting in a yearly savings of $2 million;
· Methane recovery would increase from the equivalent of powering 11,000 homes to powering 18,000 homes;
· According to a study commissioned by the city of Des Moines, annual greenhouse gas emission would be reduced by 11% and the landfilling option would provide more than three times the greenhouse gas benefit presented by composting.
Sierra Club is on record as opposing the trend (Georgia, Arkansas, Florida and Nebraska also now allow landfilling of yard waste) because it will result in landfills reaching capacity sooner. In the case of one Iowa landfill, its estimated life would be reduced from 2054 to 2052. Also, Sierra Club argues that more uncaptured greenhouse gases will be produced, but this seems to ignore the net savings from the other GHG reductions identified in the study.
I don’t have any idea whether returning yard waste to landfills is a net positive for the environment. As counterintuitive as it seems, it appears to hold promise. And if it does, where else might full cost accounting be used to guide environmental legislation? At least some states are asking the question – and I suspect more will follow.
Tags: MSW Landfills, Methane, Recycling
Greenhouse Gases (GHGs) | Solid Waste