10:15 AM - 10:30 AM
[MIS14-06] ORP Controlled Facultative Anaerobic Nitrate and Nitrite Reduction in an Ongoing Groundwater Mesocosm Study
Keywords:Mesocosm, Nitrate, Biogeochemistry
This ongoing mesocosm study is being conducted to identify the conditions that initiate Nitrate and Nitrite Reduction by Facultative Anaerobic Bacteria in groundwater and low carbon wastewater without a significant organic carbon loading from either natural or anthropogenic sources.
Inhibition of Nitrate Reduction by very low concentrations of Dissolved Oxygen under these conditions has been observed at in-situ groundwater remediation sites, ex-situ biotreatment systems, and within the Mesocosm.This is due to the bacteria selecting the greater metabolic efficiency of using Oxygen as the electron acceptor even if Nitrate is present in significantly greater abundance than Oxygen.
The facultative anaerobic use of nitrogen oxides as electron acceptors is dependent upon the dissolved oxygen and dissolved organic carbon concentrations in the aqueous system. Facultative anaerobic systems can reduce the nitrogen oxides from nitrate to nitrite to nitric oxide and nitrous oxide before yielding N2. The onset of Facultative Anaerobic Nitrate Reduction at the “Nitrate Gate” is an important benchmark of conditions during biological treatment of Organic and Inorganic pollutants in Groundwater.
There is significant variability in the ranges of estimated Nr/NOx emission rates to the atmosphere from aqueous sources such as wastewater treatment facilities, solid waste landfills, groundwater springs, surface water, and wetlands. Substantial uncertainties also exist for understanding the conditions by which the Nr compounds are microbially converted to other Nr compounds. Therefore, understanding these relationships is important to provide for improved measurement and management of the Nr compounds in the built, agricultural, and natural environments.
Inhibition of Nitrate Reduction by very low concentrations of Dissolved Oxygen under these conditions has been observed at in-situ groundwater remediation sites, ex-situ biotreatment systems, and within the Mesocosm.This is due to the bacteria selecting the greater metabolic efficiency of using Oxygen as the electron acceptor even if Nitrate is present in significantly greater abundance than Oxygen.
The facultative anaerobic use of nitrogen oxides as electron acceptors is dependent upon the dissolved oxygen and dissolved organic carbon concentrations in the aqueous system. Facultative anaerobic systems can reduce the nitrogen oxides from nitrate to nitrite to nitric oxide and nitrous oxide before yielding N2. The onset of Facultative Anaerobic Nitrate Reduction at the “Nitrate Gate” is an important benchmark of conditions during biological treatment of Organic and Inorganic pollutants in Groundwater.
There is significant variability in the ranges of estimated Nr/NOx emission rates to the atmosphere from aqueous sources such as wastewater treatment facilities, solid waste landfills, groundwater springs, surface water, and wetlands. Substantial uncertainties also exist for understanding the conditions by which the Nr compounds are microbially converted to other Nr compounds. Therefore, understanding these relationships is important to provide for improved measurement and management of the Nr compounds in the built, agricultural, and natural environments.