Food for Thought: The Most Earth-Friendly Way to Dispose of Food Waste

Consider the apple core. From an environmental perspective, what’s the most responsible way to dispose of it, or a banana peel, or any food waste?

A new study about the impact of various food waste disposal systems has shown that putting it into a garbage disposer results in lower global warming potential than putting it in the trash and sending it to a landfill. That’s a key finding of the Life Cycle Assessment (LCA) commissioned by InSinkErator, a division of Emerson, and the world’s leading manufacturer of food waste disposers.

As set forth in the report, if a community of 30,000 households (the size of Newport Beach, Calif.) were to switch from sending food scraps to the landfill to using a disposer instead, the reduction in global warming potential would be the equivalent of eliminating nearly 2,100 tons of carbon dioxide emissions. This is akin to eliminating about 4.6 million miles of car traffic.

According to the EPA, landfills are a major source of methane, a greenhouse gas at least 21 times more potent than carbon dioxide. Because food scraps are a significant component of waste that municipalities send to landfills, diverting it for recycling into resources is becoming a major goal of cities worldwide. Enter food waste disposers, which pulverize food scraps and send the resulting slurry to the various wastewater treatment systems evaluated in the LCA.

Many advanced wastewater treatment plants can convert food scraps into renewable energy through a process called anaerobic digestion. At these plants food scraps can also be turned into fertilizer products, also known as biosolids, which can help build healthy soils.

Unlike studies that review and compare competing products, the LCA assesses the environmental impact of the four primary systems for managing food scraps – wastewater treatment, landfills, incineration and advanced composting. Camp Dresser & McKee (CDM) conducted the initial analysis used by PE INTERNATIONAL, Inc. (formerly PE Americas) to produce the LCA following ISO 14040 standards, including review by an independent panel of experts.

The LCA analyzed several critical environmental impacts: global warming potential (trapping heat that would otherwise pass out of the earth’s atmosphere), eutrophication potential (excessive vegetative growth in bodies of water from high concentrations of nutrients), acidification potential (increase in the acidity of water and soil), smog formation, and the energy demands associated with each system.

The report states that food scraps processed through a wastewater treatment plant with anaerobic digestion and cogeneration can even result in a reduction of global warming potential. It also concludes that processing of food scraps at these advanced wastewater treatment facilities has lower energy demand – less than landfills, incineration and centralized composting.