Last reviewed on 12-01-2023

Documentation of California's Greenhouse Gas Inventory (2023 Edition - Last updated on 12-1-2023)

♦ Category: Waste

IPCC: 4D1 - Wastewater Treatment and Discharge - Domestic Wastewater Treatment and Discharge
Sector: Industrial : Wastewater Treatment : Domestic Wastewater : Plant Emissions

♦ Activity: California population -

♦ Greenhouse gas: Nitrous oxide ( N2O )

► Year 2016 —

● Greenhouse gas emission estimate —

Amount: 142.71 tonnes of N2O Emitted (42,527 tonnes CO2 Eq.)
Basis: Calculation
Calculation: (([CA Population served by biological denitrification] * [Emission factor with nitrification denitrification]) + (([California Population] * [Fraction using wastewater treatment plants]) - [CA Population served by biological denitrification])* [Emission factor w/o nitrification denitrification]) * [Industrial and commercial codischarge factor]
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: California population = 39,128,000 person
Basis: Data
Reference: CDOF (2022). State of California, Department of Finance, E-6 Population Estimates and Components of Change by County. Sacramento, California. Accessed June 2022. https://dof.ca.gov/forecasting/demographics/estimates/estimates-e6-2010-2021/

● Parameters and Constants used in calculations —

Parameter: CA population served by biological denitrification = 388,704 Person
Reference: CARB (2016). Technical support document on GHG inventory methodologies for the 2000-2014 inventory. See Discussion of emissions from wastewater treatment available at: https://ww3.arb.ca.gov/cc/inventory/pubs/reports/2000_2014/ghg_inventory_00-14_technical_support_document.pdf
Parameter: Emission factor w/o nitrification denitrification = 3.2 g / person
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: Emission factor with nitrification denitrification = 7 g / person
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: Fraction using wastewater treatment plants = 0.9
Reference: CWTRC, (2003). Status Report: Onsite Wastewater Treatment Systems in California. Jointly presented by: California Wastewater Training & Research Center, California State University Chico and USEPA Region 9 Ground Water Office. August 2003. http://www.csuchico.edu/cwtrc/Pages/InfoandReoprtspage.htm
Parameter: Industrial and commercial codischarge factor = 1.25
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
Constant: Global warming potential of N2O = 298
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: 3.65 g of N2O per person
1,087 g (i.e. 1.09 kg) of CO2eq. per person