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 : Septic Systems

♦ Activity: California population -

♦ Greenhouse gas: Methane ( CH4 )

► Year 2004 —

● Greenhouse gas emission estimate —

Amount: 13,973 tonnes of CH4 Emitted (349,313 tonnes CO2 Eq.)
Basis: Calculation
Calculation: [California Population] * [Proportion in septic systems] * [Septic systems CH4 Emissions Factor] * [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

● Activity level used in calculations —

Activity: California population = 35,752,765 person
Basis: Data
Reference: CDOF (2016). State of California, Department of Finance, E-6 Population Estimates for Cities, Counties and the State, with 2010 Benchmark. Sacramento, California. Accessed January 2016. http://www.dof.ca.gov/research/demographic/reports/view.php

● Parameters and Constants used in calculations —

Parameter: Proportion in septic systems = 0.1
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: Septic Systems CH4 Emissions Factor = 10.7 g / 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
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: 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: 391 g of CH4 per person
9,770 g (i.e. 9.77 kg) of CO2eq. per person
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