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Greenhouse Gas Emissions from Septic Systems in New York State
Author(s) -
Truhlar Allison M.,
Rahm Brian G.,
Brooks Rachael A.,
Nadeau Sarah A.,
Makarsky Erin T.,
Walter M. Todd
Publication year - 2016
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2015.09.0478
Subject(s) - greenhouse gas , septic tank , environmental science , carbon footprint , environmental engineering , fugitive emissions , nutrient , methane , nitrous oxide , hydrology (agriculture) , engineering , chemistry , ecology , biology , geotechnical engineering , organic chemistry
Onsite septic systems use microbial processes to eliminate organic wastes and nutrients such as nitrogen; these processes can contribute to air pollution through the release of greenhouse gases (GHGs). Current USEPA estimates for septic system GHG emissions are based on one study conducted in north‐central California and are limited to methane; therefore, the contribution of these systems to the overall GHG emission budget is unclear. This study quantified and compared septic system GHG emissions from the soil over leach fields and the roof vent, which are the most likely locations for gas emissions during normal septic system operation. At each of eight septic systems, we measured fluxes of CH 4 , CO 2 , and N 2 O using a static chamber method. The roof vent released the majority of septic system gas emissions. In addition, the leach field was a significant source of N 2 O fluxes. Comparisons between leach field and vent emissions suggest that biological processes in the leach field soil may influence the type and quantity of gas released. Overall, our results suggest that (i) revisions are needed in USEPA guidance (e.g., septic systems are not currently listed as a source of N 2 O emissions) and (ii) similar studies representing a wider range of climatic and geographic settings are needed. The total vent, sand filter, and leach field GHG emissions were 0.17, 0.045, and 0.050 t CO 2 –equivalents capita −1 yr −1 , respectively. In total, this represents about 1.5% of the annual carbon footprint of an individual living in the United States. Core Ideas The GHG emissions of septic systems are not well quantified. We provide the first measurements of GHG emissions over the septic leach field. Leach field N 2 O emissions are significantly greater than control lawn emissions. The majority of septic GHG emissions are released from the roof vent. Septic GHG emissions equal about 1.5% of an American's annual carbon footprint.