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
Without having yet clicked on the insinkerator link to read the additional information, I came away from this article with the same question that I’ve had with the ads that I’ve seen in the past for insinkerators that tout their better-choice credentials over landfill, incinerators, and commercial composting (what about home composting?) – namely, do NZ’s wastewaster treatment plants convert the scraps (diverted to them via insinkerators) into energy?
The paragraph in the article seems to answer my question:
“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.”
Well that’s great for those dozens of major cities, but since the answer appears to be “no” for us NZ, I’m interested to know what the environmental impacts are for the disposal of food scraps with an insinkerator into systems that don’t produce energy?
If the power to run the insinkerators is part of a sustainably produced grid and a city has the system in place to use the scraps to create energy, then I’d think this to be a GREAT solution for all the reasons listed in this article. What could be easier for the public than washing it down their drains? We all know the key to getting people to act more green is making it easier/cheaper.
Can someone please educate me on this topic for how it affects us here?
A contentious one, this. Element magazine has spoken to Watercare, which operates the Mangere Waste Water Treatment plant. The plant indeed utilises much of the biogas produced by both sewage and food from in-sink waste disposal units, to the point where much of the electricity needed to run the plant is produced on site.
Watercare says that the amount of food waste is tiny compared to the amount of sewage that goes through the system and it has ‘little or no effect’ on how the system operates.
However some think that it is wasteful of water, and that our sewage system is already at capacity, and during storms some of our beaches are contaminated due to the volumes of stormwater and sewage being too great and mixing with each other at times of high flow.
There is no argument from us that home composting or worm farming is the best option, but for those in apartment style housing or similar it isn’t an option.