
Photo by Dominic Ebenbichler/Reuters.
Compost Confusion
Down and Dirty With Disposal Science
To create that fuel, waste water must travel through an anaerobic digester. This apparatus “relies on microbes to consume effluent waste and produce methane biogas, which can be turned into heat and electricity,” explains Michael Keleman, manager of Environmental Engineering at InSinkErator, the leading manufacturer of garbage disposers. Disposers facilitate that process much more efficiently than trash collection, Keleman says—waste water gets there within three hours.
The catch: Waste-water plants must be specialized to handle the sludge and transform it into a sustainable bio-product. New York City has 14 such treatment facilities, each of which features an anaerobic digester, says Keleman—meaning that the wholesale adoption of garbage disposers in all five boroughs could, in theory, significantly reduce waste, cut costs, and offer the city a highly efficient, alternative renewable energy source.
Debunking the Myths
So why does garbage disposal skepticism persist? Urban planners are full of doomsday predictions about sewage spill-over, but many experts disagree: Even if every single one of the 3 million residences in New York City installed a disposer—an unlikely prospect to begin with—that would mean 3 million gallons of clear slurry water added to a sewer system capable of handling a daily average of 1.2 billion gallons. “To suggest that garbage disposals would contribute to sewage overflow is the proverbial drop in the bucket,” says Steisel, who is a chemical engineer by training. “You won’t suddenly see a cabbage floating down the street.”
Maybe not, but landlords may still be reluctant to install the fixtures because of first-time installation costs (which can exceed $600), concerns about maintenance, or because they simply aren’t aware disposers are permitted to begin with. Perhaps the greatest block to in-sink disposal adoption, however, are our own misconceptions about them. “Disposers are much more advanced than they used to be” says Carol Baricovich, director of marketing communications at InSinkErator. She and Keleman have worked to dispel other common concerns. Water and electricity use are minimal (according to InSinkerator, disposers account for less than 1 percent of a household’s daily water usage, and the total energy cost is about $0.50 per year); the devices don’t require much maintenance and often last a decade or more; clogged pipes are rare because scraps are entirely pulverized; almost everything can go down the disposer (veggies, fruit, meat, pizza), and newer models are nearly silent (and not deadly).
The DEP, however, cautions that further study of disposers is necessary. Deputy Commissioner at the Bureau of Wastewater Treatment Pam Elardo explains, “High rates of penetration for garbage grinders could have negative environmental consequences, especially given the increasingly demanding regulatory context for nitrogen discharges and combined sewer overflows.”
Such concerns—algae blooms that feed on waste-water nitrogen adversely affect marine life—are legitimate, but may not be supported by the science. Advocates of the disposer maintain that food waste has a far lower nitrogen component than sewage. And, although widespread installation of disposers might transfer some costs to water resource agencies (since pipes, not trucks, would need to ferry out organic waste) or temporarily inconvenience landlords, comparative-cost studies strongly suggest that the devices are less expensive and far more sustainable than truck-based collection, notes Kendall Christiansen, an environmental affairs consultant who helped launch food disposers in New York City after their citywide legalization. “In my single-family home,” says Christiansen, “my choice is three feet to my disposer or 50 feet to take my organics bin to the curb.”
The garbage disposer should be seen not as the only solution to unchecked waste, but part of a suite of green household initiatives—one component of an urban tool kit that helps cities tackle the problem of waste management, carbon emissions, even food security. Waste is inevitable, but when it comes to conservation, the humble garbage disposer punches above its weight.