EXAMINING THE POSSIBILITY OF EXTENDING NITRATE ADDITION ACTIVITIES IN THE FRESHWATER RESERVOIRS
Location
Session 1 (Room 1302)
Session Format
Oral Presentation
Your Campus
Statesboro Campus- Henderson Library, April 20th
Academic Unit
Department of Civil Engineering and Construction
Research Area Topic:
Engineering and Material Sciences - Civil
Co-Presenters and Faculty Mentors or Advisors
Dr. Francisco Cubas Suazo
Abstract
The artificial nitrate addition by a Water Reclamation Facility (WRF) to the Occoquan reservoir has been considered as an efficient way of maintaining water quality by preventing the release of unexpected substances from the reduced sediments. This management strategy of works best for the warmer months when thermal stratification occurs but becomes inefficient from beginning of fall turn over when concentration of dissolved oxygen becomes ubiquitous and hence it is assumed that there is no denitrification in hypolimnion. This inefficiency in nitrate depletion by denitrification lasts till the following thermal stratification. That’s why, the Upper Occoquan Service Authority (UOSA) keeps WRF’s supply of nitrogenated water stopped during this long part of the year. However, preliminary examination of the field data collected for years indicates that nitrate depletion occurs though at a lower rate before the onset of thermal stratification and in between thermal stratification and fall turnover. These periods have been termed as ‘Shoulder Months’ when the denitrification is expected to be minimal yet exists. This study aims at justifying the possibility of extending nitrate addition activities to the shoulder months. Results of the lab experiments proved that denitrification occurred in sediments not in water when there was oxygen concentration ranging from 2 mg/l to 6 mg/l in the overlying water. Lower denitrification rates in sediments during shoulder months were the result of nitrate transport limitations of the system, as nitrate had to travel deeper into the sediments to reach the anoxic layer, and not the result of lower denitrifying bacteria activity. Field data revealed that in April 15- May 01 and October 01- November 15, when the water temperature was >12ºC, oxygen concentrations ranged in between 8 – 2 mg/L, revealing a high oxygen and nitrate demand before the onset of thermal stratification and fall turnover. The results will help reexamine the criteria which the denitrification models are based on since majority of the water system management authorities depend on this type of models.
Program Description
This research justifies the possibility of extending nitrate addition activities in the freshwater reservoirs
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Presentation Type and Release Option
Presentation (Open Access)
Start Date
4-20-2022 11:00 AM
End Date
4-20-2022 12:00 PM
Recommended Citation
RISADUZZAMAN, KM, "EXAMINING THE POSSIBILITY OF EXTENDING NITRATE ADDITION ACTIVITIES IN THE FRESHWATER RESERVOIRS" (2022). GS4 Georgia Southern Student Scholars Symposium. 50.
https://digitalcommons.georgiasouthern.edu/research_symposium/2022/2022/50
EXAMINING THE POSSIBILITY OF EXTENDING NITRATE ADDITION ACTIVITIES IN THE FRESHWATER RESERVOIRS
Session 1 (Room 1302)
The artificial nitrate addition by a Water Reclamation Facility (WRF) to the Occoquan reservoir has been considered as an efficient way of maintaining water quality by preventing the release of unexpected substances from the reduced sediments. This management strategy of works best for the warmer months when thermal stratification occurs but becomes inefficient from beginning of fall turn over when concentration of dissolved oxygen becomes ubiquitous and hence it is assumed that there is no denitrification in hypolimnion. This inefficiency in nitrate depletion by denitrification lasts till the following thermal stratification. That’s why, the Upper Occoquan Service Authority (UOSA) keeps WRF’s supply of nitrogenated water stopped during this long part of the year. However, preliminary examination of the field data collected for years indicates that nitrate depletion occurs though at a lower rate before the onset of thermal stratification and in between thermal stratification and fall turnover. These periods have been termed as ‘Shoulder Months’ when the denitrification is expected to be minimal yet exists. This study aims at justifying the possibility of extending nitrate addition activities to the shoulder months. Results of the lab experiments proved that denitrification occurred in sediments not in water when there was oxygen concentration ranging from 2 mg/l to 6 mg/l in the overlying water. Lower denitrification rates in sediments during shoulder months were the result of nitrate transport limitations of the system, as nitrate had to travel deeper into the sediments to reach the anoxic layer, and not the result of lower denitrifying bacteria activity. Field data revealed that in April 15- May 01 and October 01- November 15, when the water temperature was >12ºC, oxygen concentrations ranged in between 8 – 2 mg/L, revealing a high oxygen and nitrate demand before the onset of thermal stratification and fall turnover. The results will help reexamine the criteria which the denitrification models are based on since majority of the water system management authorities depend on this type of models.
