Last reviewed on 06-22-2018

Documentation of California's Greenhouse Gas Inventory (11th Edition - Last updated on 11-06-2019)

♦ Category: Waste

IPCC: 4D1 - Wastewater Treatment and Discharge - Domestic Wastewater Treatment and Discharge
Sector: Industrial : Wastewater Treatment : Domestic Wastewater : Anaerobic Digesters

♦ Activity: Biogas production -

♦ Greenhouse gas: Methane ( CH4 )

► Year 2015 —

● Greenhouse gas emission estimate —

Amount: 1,051 tonnes of CH4 Emitted (26,285 tonnes CO2 Eq.)
Basis: Calculation
Calculation: [Biogas Production] * [Proportion of CH4 in biogas] * [Cubic foot to cubic meter] * [Methane density] * (1 - [Methane destruction efficiency])
Reference: USEPA (2015). Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2013. U.S. Environmental Protection Agency. Chapter 7: Waste. http://www.epa.gov/climatechange/emissions/usinventoryreport.html

● Activity level used in calculations —

Activity: Biogas production = 8,628,817,794 cf
Basis: Calculation
Calculation: [Wastewater flow to plants with anaerobic digesters] * [Digester gas production rate] / [Per capita wastewater flow] * [Average number of days per year]
Reference: USEPA (2015). Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2013. U.S. Environmental Protection Agency. Chapter 7: Waste. http://www.epa.gov/climatechange/emissions/usinventoryreport.html
Reference: Not Applicable.

● Parameters and Constants used in calculations —

Parameter: Digester gas production rate = 1 cf / person / day
Reference: USEPA (2015). Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2013. U.S. Environmental Protection Agency. Chapter 7: Waste. http://www.epa.gov/climatechange/emissions/usinventoryreport.html
Parameter: Methane destruction efficiency = 0.99
Reference: USEPA (2015). Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2013. U.S. Environmental Protection Agency. Chapter 7: Waste. http://www.epa.gov/climatechange/emissions/usinventoryreport.html
Parameter: Per capita wastewater flow = 100 gal / person / day
Reference: USEPA (2015). Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2013. U.S. Environmental Protection Agency. Chapter 7: Waste. http://www.epa.gov/climatechange/emissions/usinventoryreport.html
Parameter: Proportion of CH4 in biogas = 0.65
Reference: USEPA (2015). Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2013. U.S. Environmental Protection Agency. Chapter 7: Waste. http://www.epa.gov/climatechange/emissions/usinventoryreport.html
Parameter: Wastewater flow to plants with anaerobic digesters = 2,362,490,070 gal / day
Reference: DATA NOT AVAILABLE - Values were extrapolated from years for which data were available.
Constant: Average number of days per year = 365.2425 day
Reference: USNO (2004). U.S. Naval Observatory, Astronomical Applications Department, Leap Years. Accessed online at: ttp://www.usno.navy.mil/USNO/astronomical-applications/astronomical-information-center/leap-years#http://www.usno.navy.mil/USNO/astronomical-applications/astronomical-information-center/leap-years
Constant: Cubic foot to cubic meter = 0.028316846592 cf / m3
Reference: NIST (2008). Guide for the Use of the International System of Units (SI). Ambler Thompson & Barry N. Taylor (Ed.). NIST Special Publication 811, 2008 edition. National Institute of Standards and Technology, Gaithersburg, MD. http://physics.nist.gov/cuu/pdf/sp811.pdf
Constant: Methane density = 662 g / m3
Reference: USEPA (2013). Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2011. U.S. Environmental Protection Agency. Annex 3.11: Methodology for Estimating CH4 and N2O Emissions from Manure Management. ttps://www.epa.gov/sites/production/files/2015-12/documents/us-ghg-inventory-2013-annexes.pdf#https://www.epa.gov/sites/production/files/2015-12/documents/us-ghg-inventory-2013-annexes.pdf
Constant: Global warming potential of CH4 = 25
Reference: IPCC (2007). Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Solomon S., Qin D., Manning M., Chen Z., Marquis M., Averyt K.B., Tignor M., and Miller H.L. (eds.). http://www.ipcc.ch/publications_and_data/publications_ipcc_fourth_assessment_report_synthesis_report.htm

● Greenhouse gas emitted per unit activity (derived from values listed above) —

Amount: 0.122 g of CH4 per cf
3.05 g of CO2eq. per cf
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