What do Garbage Disposals have to do with Sustainability?

As wastewater treatment facilities are increasingly installing technology to convert food waste to biogas, garbage disposals could play a big part in creating renewable energy.

Even the most well-informed of green-tech junkies likely overlooked a pair of reports published in early 2011 that could have major implications for the way humanity disposes of its food waste.

Taken together, the two reports, one from the Massachusetts Department of Environmental Protection and the other from sustainability consultancy PE Americas, draw a vivid conclusion: Garbage disposals –  the ones that sit in sink drains churning up food waste before sending it to municipal wastewater treatment facilities – could help slow climate change.

Why? Because wastewater treatment facilities are increasingly adopting a technology called anaerobic digestion that can convert all those discarded banana peels, coffee grounds, and egg shells into biogas, a methane-rich byproduct that can be used for energy generation.

"In fact," as the Massachusetts Department of Environmental Protection pointed out in its report, "contained within the wastewater is ten times more energy than is necessary to treat that water."

That report, prepared as part of the Bay State's extensive efforts to adopt renewable energy, also included this key statement:

If additional organic waste streams are diverted to these facilities to supplement municipal wastewater solids, even greater efficiencies and energy potential can be attained for energy generation onsite and resale to the grid. Such a program leads to environmental benefits from methane capture, renewable energy generation, and organic waste volume reduction.

And what better source of "additional organic waste streams" than the food waste from garbage disposals? Herein lies the upshot of the second report, prepared by PE Americas, that suggests that environmentally conscientious Americans for whom electric cars and solar panels remain prohibitively expensive might want to consider buying a garbage disposal unit.

As it turns out, significantly less than half of Americans use garbage disposals to rid themselves of food waste. Even fewer – around 8 percent, according to the National Resources Defense Council – possess both the time and inclination to compost.

In the United States, most food gets sent to the landfill. Indeed, 54 percent of American food waste – or nearly 34 million tons per year – is sent to landfills, according to the U.S. Environmental Agency. As that food decomposes underground, it produces methane, a greenhouse gas with more than 20 times the potency of carbon dioxide.

Methane emissions from landfills represent a significant environmental hazard, accounting for one-fifth of America's total methane production, according to the EPA.

Garbage disposals, on the other hand, send all that food waste to wastewater treatment facilities, many of which have installed anaerobic digesters that convert the waste into biogas. This process often offsets the energy needed to power the facility so significantly that much of the biogas can be sent back to the grid.

"If 30,000 households in a community switch from disposing food waste in a landfill to use of a food waste disposer," states the PE Americas report, "the global warming potential of disposing of food waste would be reduced 1.9 million kg of carbon dioxide equivalent. This is equivalent to the community not driving 4.6 million miles in the average American car or 100 community members going carbon neutral for a year."

American appliance manufacturers – led by InSinkErator, a leading garbage disposal brand owned by $38 billion Emerson Electric Co. – are beginning to tout the environmental benefits of garbage disposal units, offering an additional lure to those consumers for whom convenience alone is not worth the cost.

"As the leader in the category, we work to educate the general public and others interested in food waste disposers’ role in solving the food waste management challenge," said Carol Baricovich, InSinkErator's manager of brand communications.

InSinkErator has been marketing its latest line of garbage disposers – the Evolution Series – not only for its grinding power, but also as a clean tech innovation. Baricovich pointed out that the Evolution Series has "advanced grinding capabilities, which provide users the benefit of not having to worry about what they can or cannot grind (which may enable them to put more food waste 'down the drain' instead of in the trashcan)."

According to biogasdata.org, more than 1,200 U.S. wastewater treatment plants have anaerobic digesters producing biogas, and InSinkErator is working to get more installed, thus rendering the sustainability benefits of garbage disposals relevant to more consumers.

"We reach out to municipalities regarding the environmental benefits of disposers, and in the process, we frequently have conversations with wastewater officials in North America and abroad," said Baricovich. "Internationally, InSinkErator is in discussion with municipalities (and their attendant treatment plants) in many other countries, including Canada, the U.K., China, Australia, Sweden and others."

Other garbage disposal manufacturers are following InSinkErator's lead. Kris Vernier, a senior spokeswoman for Whirlpool Corporation, which sells garbage disposals under KitchenAid and Whirlpool brands, said her company is "supportive of Emerson's [InSinkErator's parent company] position on this topic and work with them closely."

Likewise, the Association of Home Appliance Manufacturers (AHAM), an industry trade group of which both Emerson and Whirlpool are members, has strongly supported InSinkErator's efforts to promote the environmental benefits of garbage disposals.

"The entire home appliance industry supports and promotes the benefits of food waste disposers," said Jill Notini, AHAM's vice president of communications and marketing. "AHAM supports InSinkErator's efforts to promote these products through waste water treatment facilities."

"Food waste disposers make a very important contribution to the environment," added Notini, "and most people are unaware of what a wise and sustainable choice they are making when they put their food 'down the drain.'"

[Image credits: FoodandYou, Flickr; Andy Shustykevych, Wikimedia Commons; Chris Winters, Flickr]