A new study on the impact of food waste disposal systems reveals that scraping food waste into an in-sink disposer is a better environmental choice than landfills for reducing global warming potential.
The study, a peer-reviewed Life Cycle Assessment (LCA) commissioned by InSinkErator, a business of Emerson /quotes/zigman/225940/quotes/nls/emr EMR +0.63% , reports that disposing of food scraps in landfills produces nearly twice as much global warming potential as food scraps processed through in-sink disposers to wastewater treatment facilities. Put into context, a community of 30,000 households could avoid the equivalent of more than 2,000 tons of carbon dioxide emissions if most of its food scraps went through a disposer to a wastewater treatment facility instead of to a landfill. That is akin to eliminating 4.6 million miles of car travel.
The study also highlights the potential to generate renewable energy by using disposers. Wastewater treatment facilities outfitted with anaerobic digesters - like those serving dozens of major cities such as San Francisco and Milwaukee - can extract energy from pulverized food waste to create heat and power. The remaining biosolids can then be turned into fertiliser products.
“Food waste disposers play a critical role in the environmentally responsible management of food scraps,” said Tim Ferry, InSinkErator president. “Imagine the potential environmental benefits if all of the approximately 50 per cent of U.S. homes with installed disposers regularly bypassed the trash and disposed of food scraps with the disposer instead.”
Conducted under strict protocols, the study analysed four primary systems for managing food waste - wastewater treatment, landfills, incineration, and advanced commercial composting. Key findings include:
- Grinding food waste with a disposer and sending it to a wastewater treatment plant has lower global warming potential than sending it to landfills.
- The system of sending food waste to advanced treatment plants can require less energy than landfill, incineration, and commercial composting – and may also generate energy. This includes the environmental impact from the manufacturing, distribution, use, and end-of-life of the food waste disposers themselves.
- Where food waste is processed through a wastewater treatment plant outfitted with anaerobic digestion and cogeneration, it can result in a reduction of global warming potential – even less than centralised composting facilities.
“In thinking about effective tools for managing food scraps, wastewater treatment systems are often overlooked despite their daily role in turning liquid waste into valuable resources like renewable energy,” said Ferry. “Understanding the environmental impacts of the various methods of food waste disposal enables consumers to make responsible choices for the environment.”
Information about the new study and the InSinkErator environmental story is available at www.InSinkErator.com/green