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QUANTIFICATION OF METHANE EMISSIONS AND DISCUSSON OF NITROUS OXIDE, AND AMMONIA EMISSIONS FROM SEPTIC TANKS, LATRINES, AND STAGNANT OPEN SEWERS OF THE WORLD
Citation:
Doorn, M. J. AND D. Liles. QUANTIFICATION OF METHANE EMISSIONS AND DISCUSSON OF NITROUS OXIDE, AND AMMONIA EMISSIONS FROM SEPTIC TANKS, LATRINES, AND STAGNANT OPEN SEWERS OF THE WORLD. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-99/089 (NTIS PB2000-101018), 1999.
Description:
The report gives results of a first attempt to estimate global and country-specific methane (CH4) emissons from sewers and on-site wastewater treatment systems, including latrines and septic sewage tanks. It follows a report that includes CH4 and nitrous oxide (N2O) estimates from treated industrial and domestic wastewater. The study uses an emission factor that expresses CH4 emissions in terms of removed Chemical Oxygen Demand. Combined global CH4 emissions from latrines, septic sewage tanks, and stagnant open sewers are estimated to be 29 Tg/yr, with lower and upper bound ranges of 14 and 49 Tg/yr, respectively. These ranges reflect boundaries in the parameters that could be quantified through measurements; i.e., the emission factor and Chemical Oxygen Demand loadings. Major uncertainties in the estimates are associated with the degrees to which wastewater in developing and eastern European countries is treated in latrines or septic tanks, or removed by sewer. Also, the amount of wastewater that is discharged into stagnant open sewers and the degree to which anaerobic decomposition takes place in these sewers are highly uncertain. Latrines in rural areas of developing countries such as China and India are believed to be the single, most significant source of CH4, accounting for roughly 12 Tg/yr.