Biological Nitrogen Removal Database
A manually curated data resource for microbial nitrogen removal
Biological Nitrogen Removal Database
A manually curated data resource for microbial nitrogen removal
Influent:Aquaculture wastewater
Denitrification system:RAS Sulfur-driven denitrification (SDN) systems
Denitrifying reactor:Fluidized
Medium:Sulfur biofilters
Culture taken from:Waste sludge from the production of rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar)
Organism (s) cultured: Rainbow trout (Oncorhynchus mykiss); Atlantic salmon (Salmo salar)
Respiration:Anaerobic
Electron donor:Sulfur
Electron acceptor:Nitrate
Input NO3-N (mg/l):nan
Nitrate removal rate (mg NO3-N/l/h):nan
Denitrification rate (gNO3-N removed/m3/day):nan
Microorganisms identified:Consortium of denitrifying bacteria
Molecular tools:Functional gene identification based on nosZ gene
Major findings:The effectiveness of autotrophic, sulphur-based denitrification reactors as an alternative to conventional heterotrophic denitrification reactors was explored because autotrophic reactors produce less biomass (solids) and can be supplied with sulphur particles, which are cheaper than conventional inorganic carbon sources.
Authors:Christianson et al., 2015
Title:Nitrate removal effectiveness of fluidized sulfur-based autotrophic denitrification biofilters for recirculating aquaculture systems
Pubmed link:None
Full research link:Link
Abstract:There is a need to develop practical methods to reduce nitrate–nitrogen loads from recirculating aquaculture systems to facilitate increased food protein production simultaneously with attainment of water quality goals. The most common wastewater denitrification treatment systems utilize methanol-fueled heterotrophs, but sulfur-based autotrophic denitrification may allow a shift away from potentially expensive carbon sources. The objective of this work was to assess the nitrate-reduction potential of fluidized sulfur-based biofilters for treatment of aquaculture wastewater. Three fluidized biofilters (height 3.9 m, diameter 0.31 m; operational volume 0.206 m3) were filled with sulfur particles (0.30 mm effective particle size; static bed depth approximately 0.9 m) and operated in triplicate mode (Phase I: 37–39% expansion; 3.2–3.3 min hydraulic retention time; 860–888 L/(m2 min) hydraulic loading rate) and independently to achieve a range of hydraulic retention times (Phase II: 42–13% expansion; 3.2–4.8 min hydraulic retention time). During Phase I, despite only removing 1.57 ± 0.15 and 1.82 ± 0.32 mg NO3–N/L each pass through the biofilter, removal rates were the highest reported for sulfur-based denitrification systems (0.71 ± 0.07 and 0.80 ± 0.15 g N removed/(L bioreactor-d)). Lower than expected sulfate production and alkalinity consumption indicated some of the nitrate removal was due to heterotrophic denitrification, and thus denitrification was mixotrophic. Microbial analysis indicated the presence of Thiobacillus denitrificans, a widely known autotrophic denitrifier, in addition to several heterotrophic denitrifiers. Phase II showed that longer retention times tended to result in more nitrate removal and sulfate production, but increasing the retention time through flow rate manipulation may create fluidization challenges for these sulfur particles.