Constructed Wetlands for Wastewater Treatment

Hammer, Donald A.

doi:10.1201/9781003069850

Cited by 121 publications

(15 citation statements)

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“…Biological wastewater treatment using aquatic plants is a feasible, eco-friendly, and cost-effective approach [ 7 , 8 , 9 ]. For example, wetlands have been constructed worldwide to improve water quality for domestic reuse, irrigation, and environmental protection; the United States Department of Agriculture (USDA) alone has spent more than US $4.2 billion on wetland restoration and protection, especially through the Conservation Reserve Program and the Wetland Reserve Program [ 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

The Dynamics of NO3− and NH4+ Uptake in Duckweed Are Coordinated with the Expression of Major Nitrogen Assimilation Genes

Zhou

Kishchenko

Stepanenko

et al. 2021

Plants

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Duckweed plants play important roles in aquatic ecosystems worldwide. They rapidly accumulate biomass and have potential uses in bioremediation of water polluted by fertilizer runoff or other chemicals. Here we studied the assimilation of two major sources of inorganic nitrogen, nitrate (NO3−) and ammonium (NH4+), in six duckweed species: Spirodela polyrhiza, Landoltia punctata, Lemna aequinoctialis, Lemna turionifera, Lemna minor, and Wolffia globosa. All six duckweed species preferred NH4+ over NO3− and started using NO3− only when NH4+ was depleted. Using the available genome sequence, we analyzed the molecular structure and expression of eight key nitrogen assimilation genes in S. polyrhiza. The expression of genes encoding nitrate reductase and nitrite reductase increased about 10-fold when NO3− was supplied and decreased when NH4+ was supplied. NO3− and NH4+ induced the glutamine synthetase (GS) genes GS1;2 and the GS2 by 2- to 5-fold, respectively, but repressed GS1;1 and GS1;3. NH4+ and NO3− upregulated the genes encoding ferredoxin- and NADH-dependent glutamate synthases (Fd-GOGAT and NADH-GOGAT). A survey of nitrogen assimilation gene promoters suggested complex regulation, with major roles for NRE-like and GAATC/GATTC cis-elements, TATA-based enhancers, GA/CTn repeats, and G-quadruplex structures. These results will inform efforts to improve bioremediation and nitrogen use efficiency.

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Section: Introductionmentioning

confidence: 99%

The Dynamics of NO3− and NH4+ Uptake in Duckweed Are Coordinated with the Expression of Major Nitrogen Assimilation Genes

Zhou

Kishchenko

Stepanenko

et al. 2021

Plants

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“…WTSs utilize the natural functions of wetland vegetation, soils, and their microbial populations to serve as a biogeochemical filter, efficiently removing low levels of contamination from large volumes of water and protecting natural resources such as rivers, lakes, estuaries and ground waters (USEPA, 1988(USEPA, , 1993Hammer, 1989;Moshiri, 1993;Kadlec and Knight, 1996;Shutes, 2001;ITRC, 2003;Sheoran and Sheoran, 2006;Etteieb et al, 2020;Etteieb et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

“…Metals can be remediated by WTSs through physical settling and sedimentation, chemical removal, and phytoremediation (Sheoran and Sheoran, 2006). WTSs are an alternative to conventional treatment processes such as the addition of chemicals, reverse osmosis, ion exchange, and microfiltration (Hammer, 1989;Odum et al, 2000). They offer a cost-effective, ecologically friendly, "passive" technology that is used worldwide to treat a range of wastewaters and effluents from a variety of sources, including mine drainage, landfill leachates, urban stormwater, and agricultural runoff (Mays and Edwards, 2001;Knox at al., 2006 and.…”

Section: Introductionmentioning

confidence: 99%

Removal, distribution and retention of metals in a constructed wetland over 20 years

Knox

Paller

Seaman

et al. 2021

Science of The Total Environment

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“…These processes occur primarily in three wetland components: sediment, hydrology, and macrophytes (Sheoran and Sheoran, 2006). These natural processes have been employed in many different forms in WTSs designed for water quality improvement (Hammer, 1989;Moshiri, 1993;Kadlec and Knight, 1996;Shutes, 2001).…”

Section: Introductionmentioning

confidence: 99%

“…WTSs are used to eliminate or reduce contaminants that cause adverse effects on humans or the receiving environment. They are an alternative to conventional treatment processes such as the addition of chemicals, reverse osmosis, ion exchange, and microfiltration that are quite costly and sometimes inefficient (Hammer, 1989;Odum et al, 2000). WTSs are man-made "ecosystems" that mimic their natural counterparts.…”

Section: Introductionmentioning

confidence: 99%

Performance of the A-01 Constructed Wetland over 20 Years

Knox

Paller

Mayer

2021

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The A-01 wetland treatment system (WTS) was designed to remove metals from the effluent at the A-01 National Pollution Discharge Elimination System (NPDES) outfall at the Savannah River Site, Aiken, SC. The A-01 effluent flows from a retention basin to a splitter box, where it is distributed to four pairs of cells in series before discharge to a stream. Each treatment cell is a one-acre wetland that contains Schoenoplectus californicus (giant bulrush) and has a nominal 24-hour retention time. The purpose of this research was to investigate metal removal, distribution and retention in the A-01 WTS over a period of 20 years. During 20 years of operation, systematic water and sediment sampling validated the wetlands' performance. After passage through the treatment cells, Cu concentrations were well below permit limits (22 μg L -1 ) during all years of operation, often falling below 10 μg L -1 . Cu removal has been consistent over time, averaging about 80% despite large changes in influent Cu concentrations. Most divalent metals were rapidly removed from the water and held in the sediments shortly after the water entered the treatment wetlands. Average removal of Pb from water by the wetland system was 67 and 74%, respectively, in 2004, and 2020. Comparable values for Zn were 52 and 65%, respectively.Generally, the highest concentrations of Cu, Pb, and Zn were found in the sediment from the first cell in each pair of cells suggesting that most of the Cu, Pb, and Zn in the A-01 effluent was bound to the sediment quickly. Diffusive gradients in thin films (DGT) measurements of Cu and Zn in the sediments were much lower than bulk sediment concentrations. These results suggest that most of the Cu and Zn in the A-01 WTS sediments was not bioavailable, hence not toxic to aquatic organisms, as a likely consequence of adsorption to sediment particles and complexation with organic and inorganic substances.

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Constructed Wetlands for Wastewater Treatment

Cited by 121 publications

References 0 publications

The Dynamics of NO3− and NH4+ Uptake in Duckweed Are Coordinated with the Expression of Major Nitrogen Assimilation Genes

The Dynamics of NO3− and NH4+ Uptake in Duckweed Are Coordinated with the Expression of Major Nitrogen Assimilation Genes

Removal, distribution and retention of metals in a constructed wetland over 20 years

Performance of the A-01 Constructed Wetland over 20 Years

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