Dissolved inorganic nitrogen concentrations and isotopic values of wastewater treatment plants in a semi-arid region

Simple item page
dc.contributor.advisorFelix, J. David
dc.contributor.authorCox, Anthony
dc.contributor.committeeMemberWetz, Michael
dc.contributor.committeeMemberMurgulet, Dorina
dc.contributor.committeeMemberAbdulla, Hussain
dc.date.accessioned2023-10-24T20:51:29Z
dc.date.available2023-10-24T20:51:29Z
dc.date.issued2023-08
dc.descriptionA thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Coastal and Marine System Scienceen_US
dc.description.abstractWastewater treatment regulations evolve as detrimental ecological impacts of wastewater nitrogen loading becomes more apparent. Determining the significance of the N loading contribution of wastewater treatment plants to coastal waters in comparison to other primary N sources is necessary when creating efficient mitigation strategies. However, current research tends to be biased toward nitrate within effluent because it is often the main species of nitrogen entering the environment via the effluent. This work contributes concentration and isotopic data for all dissolved inorganic nitrogen (DIN) in both influent and effluent wastewater from three south Texas wastewater treatment plants equipped with activated sludge secondary treatment. The average (n=30) influent concentration of NH4+ was 2300±1100 µM, NO3- was 40.±35 µM, NO2- was 2.3±7.0 µM, and dissolved organic nitrogen (DON) was 140±41 µM. The average (n=33) effluent concentration of NH4+ was 190±270 µM, NO3- was 520±430 µM, NO2- was 14±8.0 µM, and dissolved organic nitrogen (DON) was 300±290 µM. Average isotopic ratios of influent ?15N-NH4+ (n=28) was 3.9±2.8‰, ?15N-NO3- (n=12) was 15±3.5‰, and ?18O-NO3- (n=12) 19±2.6‰. Average isotopic ratios of effluent ?15N-NH4+ (n=7) was 110±190‰, ?15N-NO3- (n=18) was 16±4.9‰, and ?18O-NO3- (n=18) 7.8±2.7‰. These wastewater isotope signatures local to the study’s semi-arid region were employed in Stable Isotope Analysis in R (SIAR) mixing model and compared to the use of literature signatures to convey the large variability in source apportionment that can be reported if locally characterized endmembers are not used in isotope source contribution models. The regional wastewater isotope signatures provided will help constrain isotope mixing models specific to the semi-arid Gulf Coast which in turn will help create informed nitrogen loading mitigation strategies. The treatment plants did not remove all the DIN in the influent and ~20% was subsequently returned to the environment. It was observed that activated sludge secondary treatment is capable of fully nitrifying raw sewage but is limited with respect to complete denitrification. Understanding the capabilities of activated sludge will help determine which tertiary treatment would be needed to remove excess anthropogenic nitrogen from wastewater. For the treatment plants in this study, simply increasing residence time may increase denitrification efficiency. The efficacy of this and other advanced treatment options should be explored further. Also, an argument for using enclosed aeration tanks to further reduce the release of anthropogenic nitrogen into the environment is given.en_US
dc.description.collegeCollege of Scienceen_US
dc.description.departmentCoastal and Marine System Science Programen_US
dc.format.extent60 pagesen_US
dc.identifier.urihttps://hdl.handle.net/1969.6/97614
dc.language.isoen_USen_US
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/*
dc.subjectisotopeen_US
dc.subjectNitrogenen_US
dc.subjectwastewateren_US
dc.subjectwastewater treatment planten_US
dc.titleDissolved inorganic nitrogen concentrations and isotopic values of wastewater treatment plants in a semi-arid regionen_US
dc.typeTexten_US
dc.type.genreThesisen_US
thesis.degree.disciplineCoastal and Marine System Science
thesis.degree.disciplineCoastal and Marine System Science Programen_US
thesis.degree.grantorTexas A & M University--Corpus Christien_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Scienceen_US

Files

Original bundle

Now showing 1 - 1 of 1
Thumbnail Image
Name:
Cox_Anthony_Thesis.pdf
Size:
736.51 KB
Format:
Adobe Portable Document Format
Download

Collections

Theses