H13D-1577
Aquifer Biogeochemistry and N Flux to Coastal Waters from Injected Wastewater Effluent in Kāʻanapali, Maui, Hawaiʻi
Monday, 14 December 2015
Poster Hall (Moscone South)
Joseph Fackrell1, Craig R Glenn2, Brian N Popp3, Robert B Whittier4 and Henrieta Dulaiova2, (1)University of Hawaii at Manoa, Geology and Geophysics, Honolulu, HI, United States, (2)University of Hawaii at Manoa, Department of Geology and Geophysics, Honolulu, HI, United States, (3)University of Hawaii, Geology & Geophysics, Honolulu, HI, United States, (4)Hawaii Department of Health, Honolulu, HI, United States
Abstract:
We utilized N and C species concentration data along with δ15N values of dissolved NO3- and δ13C values of dissolved inorganic C to evaluate the stoichiometry of biogeochemical reactions occurring within a subsurface plume originating from underground wastewater effluent injection at Lahaina Wastewater Reclamation Facility (LWRF) and discharging at several nearby submarine springs. Additionally, we compared LWRF time series data, injection rates, and treatment history with submarine spring time series data to assess correlation between input and output variables. We found that heterotrophic denitrification is the primary mechanism of N attenuation within the effluent plume and that chlorination of injected effluent for disinfection purposes may suppress microbial activity responsible for this N attenuation, resulting in increased N loading to the coastal ocean. The replacement of chlorination with UV disinfection may restore the biogeochemical reactions responsible for the N loss in the aquifer and return of N-attenuating conditions in the effluent plume, reducing N flux to coastal waters.
