Composting: Rethinking Food Waste

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Introduction:

With the growth of the human population comes a demand for resources, an increase in consumption and consequently, waste. Greenleaf Communities understands the growing implications of waste – namely food waste. Consumer habits and food supply chain inefficiencies lead Americans to throw out the equivalent of $165 billion each year (Gunders, 2012). Considering the various inputs to food production, producing food requires 10 percent of the total U.S. energy budget, 50 percent of US land, and 80 percent of freshwater consumed in the U.S. (Gunders, 2012).  Not only is food waste an economic loss, it is a detriment to the environment as well. Food that ends up in landfills releases large amounts of methane gas, a harmful greenhouse gas. Composting is a method that can be utilized to reduce the impacts of food waste by transforming organic waste into a useful product that can enhance soil quality and, in turn, water quality.

What is Composting?

Compost Pile – Photo Credit: Joi Ito

Composting is the utilization of aerobic (oxygen-requiring) decomposition processes to produce organic matter, compost, that can improve soil health. The aerobic process is carried out through the activity of microorganisms naturally present in organic material. Optimal levels of oxygen, moisture, and food (e.g. decomposing food waste) create an ideal environment for microbes to thrive (USCC 2008a). These microbes break down material and release water, heat and carbon dioxide (CO2) in the decomposition process. The CO2 produced during this process is considered part of the natural short-term carbon cycle, and is not considered in greenhouse gas emissions computations (USCC 2008b).

On the other hand, as organic waste piles up in landfills, it undergoes anaerobic decomposition due to a lack of oxygen, which produces methane gas. The U.S. Environmental Protection Agency (EPA) states that methane is 25 times more potent than CO2, and that 37 percent of man made methane emissions are attributed to organic waste decomposing in landfills (USCC 2012). It is important to note that organic waste that is high in nitrogen, such as food scraps and grass clippings, under wet and oxygen-limited conditions, can also produce nitrogen oxide (NO2). NO2 is a greenhouse gas estimated to be 300 times more potent than CO2 (USCC 2008b).

Benefits

Studies have supported the various benefits of composting in not only diverting waste from landfills and reducing greenhouse gas emissions, but a myriad of cost-effective solutions for issues in agriculture and soil health as well.

  • Serves as an environmental remediation technology: Compost can be an inexpensive solution for the management of hazardous industrial waste streams and for remediating soil contaminated with toxic organic compounds (solvents and pesticides) and inorganic compounds (toxic metals) by binding contaminants and reducing their leachability (USCC 2008a). For example, many hydrocarbons, found in industrial contaminants in soil and exhaust gas, rapidly degrade in the composting process. Compost has also been found to accelerate plant and microbial degradation of organic contaminants and promote plant growth in toxic soils (USEPA 1998).
  • Captures and destroys 99.6 percent of industrial volatile organic chemicals in contaminated air (USEPA 2017)
  • Provides carbon sequestration: Organic fertilizer increases and better maintains the quantity of organic matter in soils, which increases the buildup of stable organic fraction and creates a carbon sink, thereby reducing the amount of CO2 in the atmosphere (Favino 2008).
  • Reduces the need for chemical fertilizers and pesticides: Compost has the ability to control several plant diseases, and its extensive microbial diversity contains the nutrients needed to promote plant growth (USEPA 1998). Additionally, compost that has not fully matured contains microbes detrimental to plant growth, and is being tested as an alternative to synthetic mulches (USCC 2008a).
  • Enhances water retention (USEPA 2017)

Accessibility

Composting for businesses, institutions and residential areas is available in some regions. With organic waste (i.e. paper, cardboard, food scraps, yard trimmings) making up roughly two-thirds of the solid waste stream, diverting organic waste has the potential to reduce a large amount of GHG emissions and produce rich compost. The Illinois Food Scrap Coalition offers resources to begin composting at your business or home.

 

References:

  1. Favoino, Enzo and Hogg, Dominic (2008). Greenhouse Gases and Solid Waste Management. Sage Publications: Waste Management & Research. Retrieved from: www.sciencedaily.com/releases/2008/02/080225072624.htm
  2. Gunders, Dana (2012). Wasted: How America is Losing Up to 40 Percent of Its Food from Farm to Fork to Landfill. Natural Resources Defense Council. Retrieved from: https://www.nrdc.org/sites/default/files/wasted-food-IP.pdf
  3. The United States Composting Council (2008a). USCC Factsheet: Greenhouse Gases and the Role of Composting: A Primer for Compost Producers. The United States Composting Council. Retrieved from: http://compostingcouncil.org/wp/wp-content/uploads/2015/12/GHG-and-Composting-a-Primer-for-Composters-final.pdf
  4. The United States Composting Council (2008b). USCC Factsheet: Composting and Its Benefits. United States Composting Council. Retrieved from: http://compostingcouncil.org/wp/wp-content/uploads/2010/09/Compost-and-Its-Benefits.pdf
  5. The United States Composting Council (2012). USCC Position: Keep Organics Out of Landfills!. The United States Composting Council. Retrieved from: http://compostingcouncil.org/wp/wp-content/uploads/2012/08/Keeping-Organics-Out-of-Landfills-POSITION-STATEMENT-Final-7-18-12.pdf
  6. United States Environmental Protection Agency (EPA) (1998). An Analysis of Composting as an Environmental Remediation Technology. United States Environmental Protection Agency Solid Waste and Emergency Response. Retrieved from: https://www.epa.gov/sites/production/files/2015-09/documents/analpt_all.pdf
  7. United States Environmental Protection Agency (2017). Reducing the Impact of Wasted Food by Feeding the Soil and Composting. United States Environmental Protection Agency. Retrieved from: https://www.epa.gov/sustainable-management-food/reducing-impact-wasted-food-feeding-soil-and-composting
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