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:Hetetrophic denitrification
Denitrifying reactor:Fluidized
Medium:Sand 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:Waste-based endogenous carbon source
Electron acceptor:Nitrate
Input NO3-N (mg/l):nan
Nitrate removal rate (mg NO3-N/l/h):3.9
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:Heterotrophic denitrification in fluidized sand biofilters using a waste-based endogenous carbon source proved to be an effective technology to remove NO3-N from the effluent of a land-based closed-containment aquaculture system.
Authors:Tsukuda et al., 2015
Title:Heterotrophic denitrification of aquaculture effluent using fluidized sand biofilters
Pubmed link:None
Full research link:Link
Abstract:The ability to consistently and cost-effectively reduce nitrate-nitrogen loads in effluent from recirculating aquaculture systems would enhance the industry's environmental stewardship and allow improved facility proximity to large markets in sensitive watersheds. Heterotrophic denitrification technologies specifically employing organic carbon found in aquaculture system waste offer a unique synergy for treatment of land-based, closed-containment production outflows. For space-efficient fluidized sand biofilters to be used as such denitrification reactors, system parameters (e.g., influent dissolved oxygen and carbon to nitrogen ratios, C:N) must be evaluated to most effectively use an endogenous carbon source. The objectives of this work were to quantify nitrate removal under a range of C:Ns and to explore the biofilter bacterial community using three replicated fluidized sand biofilters (height 3.9 m, diameter 0.31 m; fluidized sand volume plus biofilm volume of 0.206 m3) operated at a hydraulic retention time of 15 min and a hydraulic loading rate of 188 L/min m2 at The Conservation Fund Freshwater Institute in Shepherdstown, West Virginia, USA. Nitrate reduction was consistently observed during the biofilter study period (26.9 ± 0.9% removal efficiency; 402 ± 14 g NO3-N/(m3 biofilter d)) although nitrite-N and total ammonium nitrogen concentrations slightly increased (11 and 13% increases, respectively). Nitrate removal efficiency was correlated with carbonaceous oxygen demand to nitrate ratios (R2 > 0.70). Nitrate removal rates during the study period were moderately negatively correlated with influent dissolved oxygen concentration indicating it may be possible the biofilter hydraulic retention time was too short to provide optimized nitrate removal. It is reasonable to assume that the efficiency of nitrate removal across the fluidized sand biofilters could be substantially increased, as long as organic carbon was not limiting, by increasing biofilter bed depths (to 6–10 m), and thus hydraulic retention time. These findings provide a low-cost yet effective technology to remove nitrate-nitrogen from effluent waters of land-based closed-containment aquaculture systems.