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 : Centralized Anaerobic

♦ Activity: California population -

♦ Greenhouse gas: Methane ( CH4 )

► Year 2002 —

● Greenhouse gas emission estimate —

Amount: 21,790 tonnes of CH4 Emitted (544,754 tonnes CO2 Eq.)
Basis: Calculation
Calculation: [California Population] * [Per Capita biological organic demand (BOD5)]* [Average number of days per year] * [Proportion centrally treated] * [Proportion anaerobic] * ([Proportion anaerobic without primary treatment] + ([Proportion anaerobic with primary treatment] * (1 - [Proportion of BOD removed in primary treatment]))) * [Maximum methane production capacity] * [Methane correction factor for anaerobic systems]
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 = 34,938,290 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: Maximum methane production capacity = 0.6 g / g
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 correction factor for anaerobic systems = 0.8
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 biological organic demand (BOD5) = 90 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
Parameter: Proportion anaerobic = 0.055
Reference: USEPA (various). Clean Watershed Needs Surveys for 2000 and 2004. Data have been extrapolated for years not covered in the surveys. Accessed online at: http://www.epa.gov/cwns/
Parameter: Proportion anaerobic with primary treatment = 0.623
Reference: USEPA (various). Clean Watershed Needs Surveys for 2000 and 2004. Data have been extrapolated for years not covered in the surveys. Accessed online at: http://www.epa.gov/cwns/
Parameter: Proportion anaerobic without primary treatment = 0.378
Reference: USEPA (various). Clean Watershed Needs Surveys for 2000 and 2004. Data have been extrapolated for years not covered in the surveys. Accessed online at: http://www.epa.gov/cwns/
Parameter: Proportion centrally treated = 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: Proportion of BOD removed in primary treatment = 0.325
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: 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: 624 g of CH4 per person
15,592 g (i.e. 15.59 kg) of CO2eq. per person
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