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Investigation of nitrogen contamination of groundwater from landfill disposal of cull onions. Research technical completion report Item Info

Disposal of cull onions in covered landfills has been a suspected source of nitrate contamination of groundwater in the Treasure Valley region of south-western Idaho and eastern Oregon. A field investigation was undertaken, which characterized leachate generation with regard to nitrogen composition and transport. Two full-scale operational landfills were instrumented prior to onion disposal to: (1) determine the physical controls on leachate generation, (2) investigate nitrate transport using a conservative anionic tracer, and (3) determine the fate of nitrogen. Water levels were measured in landfills using PVC standpipes, and hydraulic conductivity was measured at the base of the landfills using constant head permeameters. Matric suctions were monitored using thermal dissipation sensors at depths of 0.5, 1, 1.5, 2, and 3 m below the landfills to observe changes in water content and hydraulic gradients. A bromide tracer was used to estimate leachate flux. These measurements, and results of an analysis of unsaturated hydraulic properties of the underlying matrix using the RETC method (van Genuchten et al., 1991) were used to estimate vertical flow velocities in the matrix. Leachate samples were obtained using pressure/vacuum samplers placed at o.5, 1, 2, 3, and 4 m. These samples and water samples taken from within the landfills were analyzed for NO3-N, NH4-N and TKN. Results from 40 months of monitoring indicate that anaerobic conditions were established during the first two to three months of landfill operation and that nitrification was inhibited. It is hypothesized that hydraulic and overburden pressures forced decomposing organic material into sediment pores and fractures, forming a low hydraulic conductivity lining. Water derived from precipitation runoff and from decomposing onions was retained in the landfills because of the low conductivity lining. This "self-lining" retained water in the landfills and restricted leaching in the underlying profiles to unsaturated flow velocities. [...] Submitted to U.S. Geological Survey.

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Title:
Investigation of nitrogen contamination of groundwater from landfill disposal of cull onions. Research technical completion report
Authors:
Hutchings, Jonathon J.; Hammel, John; Osiensky, James
Date Created (ISO Standard):
1995-10
Description:
Disposal of cull onions in covered landfills has been a suspected source of nitrate contamination of groundwater in the Treasure Valley region of south-western Idaho and eastern Oregon. A field investigation was undertaken, which characterized leachate generation with regard to nitrogen composition and transport. Two full-scale operational landfills were instrumented prior to onion disposal to: (1) determine the physical controls on leachate generation, (2) investigate nitrate transport using a conservative anionic tracer, and (3) determine the fate of nitrogen. Water levels were measured in landfills using PVC standpipes, and hydraulic conductivity was measured at the base of the landfills using constant head permeameters. Matric suctions were monitored using thermal dissipation sensors at depths of 0.5, 1, 1.5, 2, and 3 m below the landfills to observe changes in water content and hydraulic gradients. A bromide tracer was used to estimate leachate flux. These measurements, and results of an analysis of unsaturated hydraulic properties of the underlying matrix using the RETC method (van Genuchten et al., 1991) were used to estimate vertical flow velocities in the matrix. Leachate samples were obtained using pressure/vacuum samplers placed at o.5, 1, 2, 3, and 4 m. These samples and water samples taken from within the landfills were analyzed for NO3-N, NH4-N and TKN. Results from 40 months of monitoring indicate that anaerobic conditions were established during the first two to three months of landfill operation and that nitrification was inhibited. It is hypothesized that hydraulic and overburden pressures forced decomposing organic material into sediment pores and fractures, forming a low hydraulic conductivity lining. Water derived from precipitation runoff and from decomposing onions was retained in the landfills because of the low conductivity lining. This "self-lining" retained water in the landfills and restricted leaching in the underlying profiles to unsaturated flow velocities. [...] Submitted to U.S. Geological Survey.
Subjects:
Waste disposal Onions Leachates Nutrients Groundwater contamination
Location:
Southern Idaho
Collection:
Boise Basin
IWRRI number:
199503
Rights:
Rights to the digital resource are held by the University of Idaho. http://www.uidaho.edu/
Publisher:
Idaho Water Resources Research Institute; University of Idaho
Contributing Institution:
University of Idaho
Type:
Text
Format:
application/pdf
Cataloger:
KIT
Date Digitized:
2017-09-22

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Preferred Citation:
"Investigation of nitrogen contamination of groundwater from landfill disposal of cull onions. Research technical completion report", Idaho Waters Digital Library, University of Idaho Library Digital Collections, https://www.lib.uidaho.edu/digital/iwdl/items/iwdl-199503.html
Rights
Rights:
Rights to the digital resource are held by the University of Idaho. http://www.uidaho.edu/
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