The effectiveness of injected carbon sources in enhancing the denitrifying processes in groundwater with high nitrate concentrations

• Published in: Process safety and environmental protection Vol. 131; pp. 205 - 211
• Main Authors: Park, Sunhwa, Kim, Hyun-Koo, Kim, Deok Hyun, Lee, Gyeong-Mi, Yoon, JongHyun, Choi, Hyojung, Kim, Moonsu, Han, Kyungjin, Kim, Young, Chung, Hyen Mi
• Format: Journal Article
• Language: English
• Published: Rugby Elsevier B.V 01-11-2019; Elsevier Science Ltd
• Subjects: Aquifers; Biological activity; Carbon; Carbon dioxide; Carbon sources; Consumption; Denitrification; Fumarate; Groundwater; In-situ denitrification; Microbial activity; Microorganisms; Nitrate-contaminated aquifers; Nitrates; Nitrous oxide; Population dynamics; Silty clay layer; Single well push–pull test; Test wells; Single well push–pull test; Nitrate-contaminated aquifers; Fumarate; Silty clay layer; In-situ denitrification
• ISSN: 0957-5820; 1744-3598
• DOI: 10.1016/j.psep.2019.08.029

•Confirming that a biological degradation by indigenous microorganisms or chemical degradation by minerals occur.•Confirming that there is no natural decrease of nitric nitrogen by naturally existing indigenous microorganisms.•Promoting a growth and reaction of dechlorination related microorganisms at the site by injecting external carbon sources.•Providing basic factors required for the guideline in managing nitric nitrogen pollutant through active natural attenuation.
The single-well push–pull test (SWPPT) was adapted to quantify in denitrification rates and to assess microbial population dynamics in a highly nitrate-contaminated aquifer (105–311 NO3 mg L−1). In SWPPT through addition of fumarate as carbon source into test wells, significant NO3-consumtion was monitored in the well. The average zero- and first order rate coefficients were 7.85 and 0.82mmol L−1 day−1, respectively. Degradation rate of injected fumarate is 15.22 (zero-order) and 0.51 (first-order) mmol L−1day−1, respectively. Significant fumarate (electron donor, ED) and NO3(electron acceptor, EA) consumption, the production of dissolved CO2 during denitrification tests, and N2O production strongly indicate that the EAs consumption was mainly due to microbial activity. Therefore, SWPPT may be useful for quantifying in situ denitrification rates and for assessing microbial population dynamics in nitrate-contaminated aquifers in Silty Clay layer.