Experimental harvesting of wetland plants to evaluate trade-offs between reducing methane emissions and removing nutrients accumulated to the biomass in constructed wetlands

A current trend in environmental practices concerns using constructed wetlands for wastewater treatment. The ecological values of wetlands have long been known. Wetland plants aid in the treatment of water pollutants by improving conditions for microorganisms and by acting as a filter to absorb trace metals. Wetlands now are being considered for industrial, municipal, and home wastewater treatment. Constructed wetlands are an economical and environmentally sound alternative for treating wastewater. These constructed “cells” are designed to function like natural wetlands. In constructed wetlands, water flow is distributed evenly among plants in a cell where physical, chemical, and biological reactions take place to reduce organic materials and pollutants. Increasing numbers of environmentally conscious homeowners are installing wetland wastewater treatment systems in their backyards with the aid of licensed engineers. This installation is occurring despite of the lack of educational materials to aid in site selection, selection of appropriate plant materials, and long-term maintenance. Traditional wetland plant species currently are being selected and planted in these sites, and the resulting effect is often an unsightly marsh appearance. With increasingly more homeowners opting for this alternative system, a strong need exists for educational materials directed at this audience. Therefore, educational resources that can provide information to the public regarding the benefits of wetland wastewater systems, while promoting aesthetically pleasing ornamental plant species is needed. A hands-on guide for installing constructed wetlands, a home page on the World Wide Web, and an instructional video currently are being developed at Texas A&M Univ. These technologies will be demonstrated and the values, needs, and opportunities available for the horticultural industry in the area of wetland construction will be discussed.

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Phytophthora Species Associated with Plants in Constructed Wetlands and Vegetated Channels at a Commercial Plant Nursery Over Time

HortTechnology ◽

10.21273/horttech04300-19 ◽

2019 ◽

Vol 29 (6) ◽

pp. 736-744

Author(s):

Garrett A. Ridge ◽

Natasha L. Bell ◽

Andrew J. Gitto ◽

Steven N. Jeffers ◽

Sarah A. White

Keyword(s):

Plant Species ◽

Constructed Wetlands ◽

Constructed Wetland ◽

Wetland Plants ◽

Plant Production ◽

Alternanthera Philoxeroides ◽

Runoff Water ◽

Commercial Plant ◽

Plant Nursery ◽

Irrigation Runoff

Constructed wetlands have been used for decades in agricultural settings to remediate nutrients and other agrichemicals from irrigation runoff and drainage; however, little is known about the presence and distribution of Phytophthora species within irrigation runoff water being treated in constructed wetlands. Therefore, we collected plant samples from within vegetated runoff collection channels and treatment stages of two constructed wetland systems receiving irrigation runoff at a commercial plant nursery in Cairo, GA, to determine if roots of wetland plants were infested by species of Phytophthora. Samples were collected 12 times, at 1- to 2-month intervals, over a 19-month period, from Mar. 2011 through Sept. 2012. The sample period covered all four seasons of the year, so we could determine if the association of Phytophthora species with roots of specific plant species varied with season. Approximately 340 samples from 14 wetland plant species were collected, and 22 isolates of Phytophthora species were recovered. Phytophthora species were typically isolated from plants in channels receiving runoff water directly from plant production areas; Phytophthora species were not detected on plants where water leaves the nursery. No seasonal patterns were observed in plant infestation or presence of species of Phytophthora. In fact, Phytophthora species were rarely found to be associated with the roots of the wetland plants collected; species of Phytophthora were found infesting roots of only 6.5% of the 336 plants sampled. Species of Phytophthora were not found to be associated with the roots of golden canna (Canna flaccida), lamp rush (Juncus effusus var. solutus), duckweed (Lemna valdiviana), or sedges (Carex sp.) during the study period. The exotic invasive plant species marsh dayflower [Murdannia keisak (33% of samples infested)] and alligatorweed [Alternanthera philoxeroides (15% of samples infested)] were found to have the first and third highest, respectively, incidences of infestation, with smooth beggartick (Bidens laevis) having the second highest incidence of samples infested (22%). Management of invasive species in drainage canals and constructed wetland systems may be critical because of their potential propensity toward infestation by Phytophthora species. Plant species recommended for further investigation for use in constructed wetlands to remediate irrigation runoff include golden canna, marsh pennywort (Hydrocotyle umbellata), pickerelweed (Pontederia cordata), and broadleaf cattail (Typha latifolia). The results from this study provide an important first look at the associations between species of Phytophthora and wetland plants in constructed wetland systems treating irrigation runoff and will serve to further optimize the design of constructed wetlands and other vegetation-based treatment technologies for the removal of plant pathogens from irrigation runoff.

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Technical Note — The Use of a Very Large Constructed Sub-Surface Flow Wetland to Treat Glycol-Contaminated Stormwater from Aircraft De-Icing Operations

Water Quality Research Journal ◽

10.2166/wqrj.2002.053 ◽

2002 ◽

Vol 37 (4) ◽

pp. 785-792 ◽

Cited By ~ 7

Author(s):

James Higgins ◽

Michael Maclean

Keyword(s):

Constructed Wetlands ◽

Scale Up ◽

Free Water ◽

Technical Note ◽

Surface Flow ◽

Wetland Plants ◽

Design Parameters ◽

Management Options ◽

Marsh Type ◽

Wetland System

Abstract All of the pollutants found in stormwater runoff at airports, including surface and aircraft de-icing/anti-icing glycols, can be treated and removed to low levels in well-designed sub-surface flow (SSF) constructed wetland systems. There are two common forms of constructed wetlands used for pollution control: those where water flows over the surface among wetland plants (free water surface or marsh type wetlands); and SSF types where the wastewater flows below the normally dry surface of a gravel substrate in which the wetland plants grow. SSF wetlands have no open water to attract waterfowl and are particularly suitable for use at airports. Of the glycol used at Edmonton International Airport (EIA), 80 to 90% eventually entered surface runoff. Edmonton International Airport's operator, the Edmonton Regional Airports Authority (Edmonton Airports) evaluated a number of glycol management options, including constructed wetlands. As a result, a very large SSF wetland system was installed to handle glycol-contaminated stormwater. This paper reviews results of a feasibility study carried out to define design parameters and scale up kinetics for this wetland system, the detailed design that resulted, the SSF wetland's construction, and the start-up of the Edmonton facilities in August of 2000. It also compares the Edmonton wetland system with a similar facility at Heathrow Airport in the United Kingdom.

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Net methyl mercury production versus water quality improvement in constructed wetlands: Trade-offs in pollution control

Wetlands ◽

10.1672/0277-5212(2005)025[0748:nmmpvw]2.0.co;2 ◽

2005 ◽

Vol 25 (3) ◽

pp. 748-757 ◽

Cited By ~ 18

Author(s):

Jelena Stamenkovic ◽

Mae S. Gustin ◽

Keith E. Dennett

Keyword(s):

Water Quality ◽

Quality Improvement ◽

Constructed Wetlands ◽

Pollution Control ◽

Methyl Mercury ◽

Water Quality Improvement ◽

Trade Offs ◽

Mercury Production

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Nutrient content of wetland plants in constructed wetlands receiving municipal effluent in tropical Australia

Water Science & Technology ◽

10.2166/wst.1997.0182 ◽

1997 ◽

Vol 35 (5) ◽

pp. 135-142 ◽

Cited By ~ 10

Author(s):

Margaret Greenway

Keyword(s):

Constructed Wetlands ◽

Municipal Wastewater ◽

Free Water ◽

Nutrient Content ◽

Wetland Plants ◽

Nutrient Concentrations ◽

Tissue Nutrient Content ◽

Significant Difference ◽

Plant Components ◽

Emergent Species

Several pilot wetlands have been constructed in Queensland to treat municipal wastewater. The wetlands are in tropical, subtropical and arid geographical locations. Most wetlands are free water surface and contain a variety of macrophyte types and species. A total of 49 native and 11 exotic species of wetland plants have been identified. This paper examines tissue nutrient content in different species and plant components from 7 wetlands. Most species translocated to the constructed wetlands flourished indicating their ability to tolerate nutrient enriched waters, and tended to have higher tissue nutrient concentrations than their controls in natural wetlands. Submerged and free floating species exhibited higher nutrient concentrations than floating leaved and emergent species. Maximum dry weight nutrient concentrations (mg.g−1) were recorded in duckweed 18 mgP.g−1; 58 mgN.g−1; Ceratophyllum 14 mgP.g−1, 35 mgN.g−1; Monochoria cyanea (a native relative of the water hyacinth) 13 mgP.g−1, 30 mgN.g−1; waterlilies: Nymphoides indica 16 mgP.g−1, 40 mgN.g−1; aquatic vines Ipomoea diamantinensis 10 mgP.g−1, 53 mgN.g−1, I. aquatica 9.5 mgP.g−1, 53 mgN.g−1; Ludwigia peploides 10 mgP.g−1, 52 mgN.g−1; and the water ferns Ceratopteris thalictroides 10 mgP.g−1, 31 mgN.g−1,Marsilea 10 mgP.g−1, 43 mgN.g−1. Emergent species with the highest nutrients (P or N) were Eleocharis sphacelata 9.4 mgP.g−1, 31.7 mgN.g−1, Baumea articulata 8.7 mgP.g−1, 24 mgN.g−1,Typha domingensis 7.2 mgP.g−1, 51.8 mgN.g−1 and Cyperus involucratus 7 mgP.g−1, 44.6 mgN.g−1. Pooled data showed no significant difference between tissue nutrient content in plant components, though nitrogen was highest in the leaves and phosphorus highest in the roots of most species. There was some evidence of spatial variation in tissue nutrient content between different wetlands but it has not been possible to correlate this with nutrient loadings or removal efficiencies.

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