TY - JOUR
T1 - Heterotrophic denitrification of aquaculture effluent using fluidized sand biofilters
AU - Tsukuda, Scott
AU - Christianson, Laura
AU - Kolb, Alex
AU - Saito, Keiko
AU - Summerfelt, Steven
N1 - Funding Information:
The authors wish to thank an anonymous foundation funding source for their gracious support. This research was supported by the USDA Agricultural Research Service under Agreement No. 59-1930-5-510 . A debt of gratitude is also due to Karen Schroyer for sampling and lab analysis.
Publisher Copyright:
© 2014 The Authors.
Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.
PY - 2015/1/1
Y1 - 2015/1/1
N2 - 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 3.9m, diameter 0.31m; fluidized sand volume plus biofilm volume of 0.206m3) operated at a hydraulic retention time of 15min and a hydraulic loading rate of 188L/minm2 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±14g NO3-N/(m3biofilterd)) 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 6-10m), 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.
AB - 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 3.9m, diameter 0.31m; fluidized sand volume plus biofilm volume of 0.206m3) operated at a hydraulic retention time of 15min and a hydraulic loading rate of 188L/minm2 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±14g NO3-N/(m3biofilterd)) 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 6-10m), 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.
KW - Carbon
KW - Denitrification
KW - Fluidized sand biofilter
KW - Nitrate
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U2 - 10.1016/j.aquaeng.2014.10.010
DO - 10.1016/j.aquaeng.2014.10.010
M3 - Article
AN - SCOPUS:84922439622
SN - 0144-8609
VL - 64
SP - 49
EP - 59
JO - Aquacultural Engineering
JF - Aquacultural Engineering
ER -