Nutrient removal in a constructed wetland treating aquaculture effluent at short hydraulic retention time

Johanne Dalsgaard*, Mathis von Ahnen, Christopher Naas, Per Bovbjerg Pedersen

*Corresponding author for this work

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Abstract

We examined the longitudinal and seasonal removal of dissolved and particulate nutrient components in a free water surface (FWS) constructed wetland treating all the effluent from a commercial recirculating rainbow trout Oncorhynchus mykiss farm. The wetland consisted of a meandering, 0.7 m deep channel with a total FWS area of 5811 m(2), a total hydraulic loading rate (HLR) of 2.23 m d(-1), and a total hydraulic retention time (HRT) of 0.32 d. Bi-weekly, 24 h composite samples were obtained along the wetland for 1 yr and analysed for dissolved and particulate nutrient components. Furthermore, a short sampling campaign assessed the sedimentation of particles (5 to 200 mu m). A first order kinetic plug flow model was fitted to the longitudinal data, and a first set of area-based removal rate constants (k(A)) for this wetland type was derived. Sedimentation led to particulate nutrient removal, but there was no annual net removal of dissolved nutrients aside from an infinitesimal removal of phosphorus. Microbial removal processes were substrate-limited, and removal rate constants followed an annual cycle presumably coupled to available plant surface area and temperature. Denitrification was limited by low carbon availability and high oxygen concentrations, and the wetland became a net producer of nitrate at times due to oxygenation of ammonia. In summary, dissolved nutrients were largely not removed and the wetland was over-dimensioned for particulate nutrient removal. This new insight should be taken into account in future efforts to improve the treatment performance of similar types of aquaculture wetlands operated at short hydraulic retention times.
Original languageEnglish
JournalAquaculture Environment Interactions
Volume10
Pages (from-to)329-343
ISSN1869-215X
DOIs
Publication statusPublished - 2018

Keywords

  • FISHERIES
  • MARINE
  • WATER
  • TEMPERATURE
  • DENITRIFICATION
  • PERFORMANCE
  • BIOFILTERS
  • SYSTEMS
  • DESIGN
  • CARBON
  • IMPACT
  • FLOW
  • Recirculating aquaculture
  • End-of-pipe
  • Constructed wetland
  • Hydraulic retention time
  • Dissolved nutrients
  • Particulate nutrients

Cite this

@article{c8b8f102fd314694b9c45506505e60df,
title = "Nutrient removal in a constructed wetland treating aquaculture effluent at short hydraulic retention time",
abstract = "We examined the longitudinal and seasonal removal of dissolved and particulate nutrient components in a free water surface (FWS) constructed wetland treating all the effluent from a commercial recirculating rainbow trout Oncorhynchus mykiss farm. The wetland consisted of a meandering, 0.7 m deep channel with a total FWS area of 5811 m(2), a total hydraulic loading rate (HLR) of 2.23 m d(-1), and a total hydraulic retention time (HRT) of 0.32 d. Bi-weekly, 24 h composite samples were obtained along the wetland for 1 yr and analysed for dissolved and particulate nutrient components. Furthermore, a short sampling campaign assessed the sedimentation of particles (5 to 200 mu m). A first order kinetic plug flow model was fitted to the longitudinal data, and a first set of area-based removal rate constants (k(A)) for this wetland type was derived. Sedimentation led to particulate nutrient removal, but there was no annual net removal of dissolved nutrients aside from an infinitesimal removal of phosphorus. Microbial removal processes were substrate-limited, and removal rate constants followed an annual cycle presumably coupled to available plant surface area and temperature. Denitrification was limited by low carbon availability and high oxygen concentrations, and the wetland became a net producer of nitrate at times due to oxygenation of ammonia. In summary, dissolved nutrients were largely not removed and the wetland was over-dimensioned for particulate nutrient removal. This new insight should be taken into account in future efforts to improve the treatment performance of similar types of aquaculture wetlands operated at short hydraulic retention times.",
keywords = "FISHERIES, MARINE, WATER, TEMPERATURE, DENITRIFICATION, PERFORMANCE, BIOFILTERS, SYSTEMS, DESIGN, CARBON, IMPACT, FLOW, Recirculating aquaculture, End-of-pipe, Constructed wetland, Hydraulic retention time, Dissolved nutrients, Particulate nutrients",
author = "Johanne Dalsgaard and {von Ahnen}, Mathis and Christopher Naas and Pedersen, {Per Bovbjerg}",
year = "2018",
doi = "10.3354/aei00272",
language = "English",
volume = "10",
pages = "329--343",
journal = "Aquaculture Environment Interactions",
issn = "1869-215X",
publisher = "Inter Research",

}

Nutrient removal in a constructed wetland treating aquaculture effluent at short hydraulic retention time. / Dalsgaard, Johanne; von Ahnen, Mathis; Naas, Christopher; Pedersen, Per Bovbjerg.

In: Aquaculture Environment Interactions, Vol. 10, 2018, p. 329-343.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Nutrient removal in a constructed wetland treating aquaculture effluent at short hydraulic retention time

AU - Dalsgaard, Johanne

AU - von Ahnen, Mathis

AU - Naas, Christopher

AU - Pedersen, Per Bovbjerg

PY - 2018

Y1 - 2018

N2 - We examined the longitudinal and seasonal removal of dissolved and particulate nutrient components in a free water surface (FWS) constructed wetland treating all the effluent from a commercial recirculating rainbow trout Oncorhynchus mykiss farm. The wetland consisted of a meandering, 0.7 m deep channel with a total FWS area of 5811 m(2), a total hydraulic loading rate (HLR) of 2.23 m d(-1), and a total hydraulic retention time (HRT) of 0.32 d. Bi-weekly, 24 h composite samples were obtained along the wetland for 1 yr and analysed for dissolved and particulate nutrient components. Furthermore, a short sampling campaign assessed the sedimentation of particles (5 to 200 mu m). A first order kinetic plug flow model was fitted to the longitudinal data, and a first set of area-based removal rate constants (k(A)) for this wetland type was derived. Sedimentation led to particulate nutrient removal, but there was no annual net removal of dissolved nutrients aside from an infinitesimal removal of phosphorus. Microbial removal processes were substrate-limited, and removal rate constants followed an annual cycle presumably coupled to available plant surface area and temperature. Denitrification was limited by low carbon availability and high oxygen concentrations, and the wetland became a net producer of nitrate at times due to oxygenation of ammonia. In summary, dissolved nutrients were largely not removed and the wetland was over-dimensioned for particulate nutrient removal. This new insight should be taken into account in future efforts to improve the treatment performance of similar types of aquaculture wetlands operated at short hydraulic retention times.

AB - We examined the longitudinal and seasonal removal of dissolved and particulate nutrient components in a free water surface (FWS) constructed wetland treating all the effluent from a commercial recirculating rainbow trout Oncorhynchus mykiss farm. The wetland consisted of a meandering, 0.7 m deep channel with a total FWS area of 5811 m(2), a total hydraulic loading rate (HLR) of 2.23 m d(-1), and a total hydraulic retention time (HRT) of 0.32 d. Bi-weekly, 24 h composite samples were obtained along the wetland for 1 yr and analysed for dissolved and particulate nutrient components. Furthermore, a short sampling campaign assessed the sedimentation of particles (5 to 200 mu m). A first order kinetic plug flow model was fitted to the longitudinal data, and a first set of area-based removal rate constants (k(A)) for this wetland type was derived. Sedimentation led to particulate nutrient removal, but there was no annual net removal of dissolved nutrients aside from an infinitesimal removal of phosphorus. Microbial removal processes were substrate-limited, and removal rate constants followed an annual cycle presumably coupled to available plant surface area and temperature. Denitrification was limited by low carbon availability and high oxygen concentrations, and the wetland became a net producer of nitrate at times due to oxygenation of ammonia. In summary, dissolved nutrients were largely not removed and the wetland was over-dimensioned for particulate nutrient removal. This new insight should be taken into account in future efforts to improve the treatment performance of similar types of aquaculture wetlands operated at short hydraulic retention times.

KW - FISHERIES

KW - MARINE

KW - WATER

KW - TEMPERATURE

KW - DENITRIFICATION

KW - PERFORMANCE

KW - BIOFILTERS

KW - SYSTEMS

KW - DESIGN

KW - CARBON

KW - IMPACT

KW - FLOW

KW - Recirculating aquaculture

KW - End-of-pipe

KW - Constructed wetland

KW - Hydraulic retention time

KW - Dissolved nutrients

KW - Particulate nutrients

U2 - 10.3354/aei00272

DO - 10.3354/aei00272

M3 - Journal article

VL - 10

SP - 329

EP - 343

JO - Aquaculture Environment Interactions

JF - Aquaculture Environment Interactions

SN - 1869-215X

ER -