Elemental Sulfur and Metal Sulfide Minerals for Autotrophic Denitrification: Applications to Aquaculture, Groundwater Treatment, and Domestic Wastewater Treatment

Author

Erica Amah Dasi, University of South Florida

Graduation Year

2022

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Civil and Environmental Engineering

Major Professor

Sarina J. Ergas, Ph.D.

Committee Member

Romy Chakraborty, Ph.D.

Committee Member

Jeffrey A. Cunningham, Ph.D.

Committee Member

James R. Garey, Ph.D.

Committee Member

Ramon Gonzalez, Ph.D.

Committee Member

Emmanuel Talla, Ph.D.

Keywords

Biological nutrient removal, Nitrogen, Phosphorus, Sphalerite, Sulfur oxidation

Abstract

Nutrient pollution of waterways, from excess N and P, is a global concern that results in harmful impacts the environment, human health, and aquatic animals. This dissertation harnesses sulfur autotrophic denitrification to remove nutrients from groundwater, domestic wastewater, and wastewaters produced from marine recirculating aquaculture systems (RAS). Part 1 evaluates the denitrification performance of woodchips and elemental sulfur in cyclic denitrification filters (WS-CDFs) integrated into marine RAS operated under saline conditions. Part 2 investigates the use of metal sulfide minerals, with and without oyster shells, for supporting nutrient removal from groundwater in batch reactors. Part 3 assesses the feasibility of metal sulfide minerals and oyster shell sequencing batch biofilm reactors (SBBRs) for domestic wastewater denitrification. Sulfurimonas, Thioalbus, Defluviimonas, and Ornatilinea were notable populations in the WS-CDFs that contributed to the removal of organics and NO₃^- under saline conditions. Rhodocyclaceae, Myxococcales, Sphingobacteriales, Thiobacillus, Ignavibacterium, and Candidatus Brocadiaceae removed 90% NO₃^- from groundwater in batch denitrification reactors with sphalerite and oyster shells. Precipitation and adsorption onto the sphalerite and oyster shell surfaces may have caused complete PO₄^3- removal in these reactors. Consistent NO₃^- removal was observed for the SBBRs, with an average denitrification rate of 0.28 mg/(L·d) for Cycles 1 and 2. However, SBBRs only achieved 44% PO₄^3- removal. Biomass enrichment on sphalerite may have limited PO₄^3- removal adsorption onto Fe(OH)₂ or Fe(OH)₃ at the mineral surface.

Results from this dissertation provide an improved understanding of sulfur autotrophic denitrification. This dissertation research has several novel aspects. To the best of my knowledge, this research is the first to address the themes of Parts 1-3. A novel SBBR emerged from this dissertation, which can serve as the basis for future research with sphalerite and OS. Results from this research may also be applied to develop nutrient removal technologies that treat other waters that include urban runoff, agricultural runoff, septic tank effluents, as well as wastewaters produced by seafood processing, and tanneries. Results from the microbial community analysis can be useful for bioaugmentation and can assist with optimizing sulfur autotrophic nutrient removal technologies.

Scholar Commons Citation

Dasi, Erica Amah, "Elemental Sulfur and Metal Sulfide Minerals for Autotrophic Denitrification: Applications to Aquaculture, Groundwater Treatment, and Domestic Wastewater Treatment" (2022). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/10288