Environmental Impact

What is 'Environmental Impact'?

The United States Environmental Protection Agency (EPA) promotes composting as a sustainable waste management practice with several environmental benefits, particularly in the context of reducing carbon emissions.

By measuring waste diversion through Recipe weight and volume, composting programs and facilities can quantify their Environmental Impact and contributions. These key metrics support the sustainability of composting initiatives and promote environmentally responsible waste management initiatives.

The calculations incorporated within the AEYD recipe stem from the Washington State University-Puyallup (WSU) compost mixture calculator, developed by Andy Bary and Craig Cogger. Further upgrades were made by Cary Oshins, CREF, and Jorge Montezuma, PE, with troubleshooting conducted by Loi Chau, BAAMQD.

Calculating Impact

Environmental Impact is calculated and displayed when Recipes can provide the relevant data - the total weight in pounds. If there are no Recipes to base calculations from, this element does not display.

The EPA WARM model is applied to composting Recipe results with an emission factor (EF) of -0.2 Metric Tonnes of CO2e per US ton of ingredients or feedstock composted.

Combining the EFs for these steps provides the final EF for composting in WARM: (Collection & Transportation) + (Mechanical Turning) + (Direct Soil Carbon Storage) + (Carbon Stored in Humus Compounds) = Net Composting Emissions In numerical terms, this is equivalent to: 0.02 MTCO2e + 0.02 MTCO2e + -0.07 MTCO2e + -0.17 MTCO2e = -0.20 MTCO2e”

• Collection and mechanical turning add 0.04 MTCO2e

• Application to soil sequesters 0.24 MTCO2e

The EPA WARM Model Applied

1. Waste Diversion (Tons)

Quantifying waste diversion in tons is based on the resulting weight of Product Recipes or the total weight in pounds.

$$2,000lbs = 1 ton, or 1lb = 0.0005 tons$$

2. Carbon Sequestration or CCS (MTCO2e)

The common abbreviation for "carbon sequestration" is "CCS," which stands for "Carbon Capture and Storage."

The EPA WARM model gives a credit of 0.2 tons of CO2e per ton of feedstock composted for soil carbon sequestration.

$$Total Solids in pounds * 0.0005 * 0.2 = MTCO2e$$

3. Net Zero (No. PAAE)

"Net zero" refers to the balance between the amount of greenhouse gas emissions produced and the amount removed from the atmosphere.

AEYD utilizes a Typical Passenger Vehicle emissions for comparison:

A typical passenger vehicle emits about 4.6 metric tons of CO2 per year. This assumes the average gasoline vehicle on the road today has a fuel economy of about 22.2 miles per gallon and drives around 11,500 miles per year. Every gallon of gasoline burned creates about 8,887 grams of CO2.

$$Total Solids in pounds * 0.0005 * 0.2 = MTCO2e / 4.6$$

Sources

1. The Composting Handbook

2. EPA.gov

   • EPA WARM model estimates

   • Green Vehicles