The effects of substrate and C:N ratio on water quality in denitrification systems for brackish water aquaculture
Recirculating aquaculture systems (RAS) accumulate dissolved nitrate in the water, which can harm animals. Denitrification can be used to remove nitrate, although some strategies can be expensive and difficult to operate. The purpose of this project was to help simplify denitrification techniques to...
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-03-01
|
| Series: | Aquaculture Reports |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2352513425000109 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1832087467314905088 |
|---|---|
| author | Andrew J. Ray Leo J. Fleckenstein Mark E. Johannemann Jill C. Fisk |
| author_facet | Andrew J. Ray Leo J. Fleckenstein Mark E. Johannemann Jill C. Fisk |
| author_sort | Andrew J. Ray |
| collection | DOAJ |
| description | Recirculating aquaculture systems (RAS) accumulate dissolved nitrate in the water, which can harm animals. Denitrification can be used to remove nitrate, although some strategies can be expensive and difficult to operate. The purpose of this project was to help simplify denitrification techniques to facilitate long-term water reuse. Two experiments were conducted: one to testing various substrates in denitrification reactors (Experiment 1), and another to investigate lower carbon: nitrogen ratios on suspended growth denitrification systems (Experiment 2). The results of these experiments were then applied to on-farm demonstrations. Experiment 1 had a control with no media, and three treatments containing either plastic bio-media, expanded clay pellets, or woodchips. Experiment 2 had a control receiving no carbon (0:1) and three treatments with varying C:N ratios (0.2:1, 0.5:1, and 1:1). For experiment 1, nitrate was reduced in all treatments even without media; this fact provided motivation for Experiment 2. In Experiment 2, all of the treatments had significantly lower nitrate-N than the control. The 0.5:1 and 0.2:1 treatments had almost complete removal of N, while the 1:1 had high nitrite-N. The initial nitrate-N was 298.1 mg L−1; the final concentrations in each treatment were: 0.2:1 = 2.3, 0.5:1 = 2.3, and 1:1 = 15.5 mg L−1. Subsequent tests at shrimp farms using the 0.2:1 C:N ratio resulted in almost complete removal of nitrate-N. In one case, nitrate-N was reduced from 493 to 1.4 mg L−1 in 7 days. These results demonstrate that simple, suspended growth denitrification can be highly effective at nitrate removal. |
| format | Article |
| id | doaj-art-2a213126766e4e0d9fd602521c7d2e4e |
| institution | Kabale University |
| issn | 2352-5134 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Aquaculture Reports |
| spelling | doaj-art-2a213126766e4e0d9fd602521c7d2e4e2025-02-06T05:12:21ZengElsevierAquaculture Reports2352-51342025-03-0140102624The effects of substrate and C:N ratio on water quality in denitrification systems for brackish water aquacultureAndrew J. Ray0Leo J. Fleckenstein1Mark E. Johannemann2Jill C. Fisk3Corresponding author.; School of Aquaculture and Aquatic Sciences, Kentucky State University Land Grant Program, Frankfort, KY 40601, USASchool of Aquaculture and Aquatic Sciences, Kentucky State University Land Grant Program, Frankfort, KY 40601, USASchool of Aquaculture and Aquatic Sciences, Kentucky State University Land Grant Program, Frankfort, KY 40601, USASchool of Aquaculture and Aquatic Sciences, Kentucky State University Land Grant Program, Frankfort, KY 40601, USARecirculating aquaculture systems (RAS) accumulate dissolved nitrate in the water, which can harm animals. Denitrification can be used to remove nitrate, although some strategies can be expensive and difficult to operate. The purpose of this project was to help simplify denitrification techniques to facilitate long-term water reuse. Two experiments were conducted: one to testing various substrates in denitrification reactors (Experiment 1), and another to investigate lower carbon: nitrogen ratios on suspended growth denitrification systems (Experiment 2). The results of these experiments were then applied to on-farm demonstrations. Experiment 1 had a control with no media, and three treatments containing either plastic bio-media, expanded clay pellets, or woodchips. Experiment 2 had a control receiving no carbon (0:1) and three treatments with varying C:N ratios (0.2:1, 0.5:1, and 1:1). For experiment 1, nitrate was reduced in all treatments even without media; this fact provided motivation for Experiment 2. In Experiment 2, all of the treatments had significantly lower nitrate-N than the control. The 0.5:1 and 0.2:1 treatments had almost complete removal of N, while the 1:1 had high nitrite-N. The initial nitrate-N was 298.1 mg L−1; the final concentrations in each treatment were: 0.2:1 = 2.3, 0.5:1 = 2.3, and 1:1 = 15.5 mg L−1. Subsequent tests at shrimp farms using the 0.2:1 C:N ratio resulted in almost complete removal of nitrate-N. In one case, nitrate-N was reduced from 493 to 1.4 mg L−1 in 7 days. These results demonstrate that simple, suspended growth denitrification can be highly effective at nitrate removal.http://www.sciencedirect.com/science/article/pii/S2352513425000109DenitrificationNitrateRecirculating aquaculture systemsShrimpSustainable RAS |
| spellingShingle | Andrew J. Ray Leo J. Fleckenstein Mark E. Johannemann Jill C. Fisk The effects of substrate and C:N ratio on water quality in denitrification systems for brackish water aquaculture Aquaculture Reports Denitrification Nitrate Recirculating aquaculture systems Shrimp Sustainable RAS |
| title | The effects of substrate and C:N ratio on water quality in denitrification systems for brackish water aquaculture |
| title_full | The effects of substrate and C:N ratio on water quality in denitrification systems for brackish water aquaculture |
| title_fullStr | The effects of substrate and C:N ratio on water quality in denitrification systems for brackish water aquaculture |
| title_full_unstemmed | The effects of substrate and C:N ratio on water quality in denitrification systems for brackish water aquaculture |
| title_short | The effects of substrate and C:N ratio on water quality in denitrification systems for brackish water aquaculture |
| title_sort | effects of substrate and c n ratio on water quality in denitrification systems for brackish water aquaculture |
| topic | Denitrification Nitrate Recirculating aquaculture systems Shrimp Sustainable RAS |
| url | http://www.sciencedirect.com/science/article/pii/S2352513425000109 |
| work_keys_str_mv | AT andrewjray theeffectsofsubstrateandcnratioonwaterqualityindenitrificationsystemsforbrackishwateraquaculture AT leojfleckenstein theeffectsofsubstrateandcnratioonwaterqualityindenitrificationsystemsforbrackishwateraquaculture AT markejohannemann theeffectsofsubstrateandcnratioonwaterqualityindenitrificationsystemsforbrackishwateraquaculture AT jillcfisk theeffectsofsubstrateandcnratioonwaterqualityindenitrificationsystemsforbrackishwateraquaculture AT andrewjray effectsofsubstrateandcnratioonwaterqualityindenitrificationsystemsforbrackishwateraquaculture AT leojfleckenstein effectsofsubstrateandcnratioonwaterqualityindenitrificationsystemsforbrackishwateraquaculture AT markejohannemann effectsofsubstrateandcnratioonwaterqualityindenitrificationsystemsforbrackishwateraquaculture AT jillcfisk effectsofsubstrateandcnratioonwaterqualityindenitrificationsystemsforbrackishwateraquaculture |