Water flow patterns in subsurface flow constructed wetlands designed for on‐site domestic wastewater treatment

Scientists at the Tennessee Valley Authority (TVA), and in collaboration with the U.S. Environmental Protection Agency (EPA), are continuing to develop and refine an innovative wastewater treatment system referred to as reciprocating subsurface-flow constructed wetlands. Reciprocation relates to patented improvements in the design and operation of paired subsurface-flow constructed wetlands, such that contiguous cells are filled and drained on a frequent and recurrent basis. This operating technique turns the entire wetland system into a fixed-film biological reactor, in which it is possible to control redox potential in alternating aerobic and anaerobic zones. Reciprocating systems enable manipulation of wastewater treatment functions by controlling such parameters as hydraulic retention time, frequency of reciprocation, reciprocation cycle time, depth of reciprocation, and size and composition of substrate. These improved wetland technologies have been used for treating municipal/domestic wastewater, high strength animal wastewater, and mixed wastewater streams containing acids, recalcitrant compounds, solvents, antifreeze compounds, heavy metals, explosives, and fertilizer nutrients. Results from selected treatability studies and field demonstrations will be summarized with respect to conceptual design and treatment efficacy.

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Seeking a way to promote the use of constructed wetlands for domestic wastewater treatment in developing countries

Water Science & Technology ◽

10.2166/wst.2011.229 ◽

2011 ◽

Vol 63 (4) ◽

pp. 654-659 ◽

Cited By ~ 20

Author(s):

F. Zurita ◽

M. A. Belmont ◽

J. De Anda ◽

J. R. White

Keyword(s):

Developing Countries ◽

Wastewater Treatment ◽

Constructed Wetlands ◽

Subsurface Flow ◽

Domestic Wastewater ◽

Treatment Efficiency ◽

Zantedeschia Aethiopica ◽

Domestic Wastewater Treatment ◽

Anthurium Andreanum ◽

Strelitzia Reginae

The aim of this study was to evaluate the domestic wastewater treatment efficiency as well as the survivability of commercially valuable ornamental plants in subsurface flow wetlands (SSFW) for domestic wastewater (DWW) treatment in laboratory and pilot wetland studies. The laboratory scale study included five different species (Zantedeschia aethiopica, Strelitzia reginae, Anthurium andreanum, Canna hybrids and Hemmerocallis dumortieri) that were evaluated in horizontal flow subsurface treatment cells. All the plants survived during the 6-month experimental period demonstrating high wetland nutrient treatment efficiency. In order to validate and expand these preliminary results, a pilot-scale wetland study was carried out in SSFWs under two different flow regimes (horizontal and vertical flow). Four ornamental species were tested during a 1-year period: Zantedeschia aethiopica, Strelitzia reginae, Anthurium andreanum and Agapanthus africanus. The removal efficiencies were significantly higher in the vertical subsurface-flow constructed wetlands (VFCW) for all pollutants, except for nitrate (NO3-N), total nitrogen (TN) and total suspended solids (TSS). These results show that it is feasible to use select non-wetland plants with high market value in SSFWs without reducing the efficiency of the wastewater treatment system, although future work should continue in order to apply this technology in a large scale. The added value of floriculture in treatment wetlands can help to promote the use of constructed wetlands (CW) for domestic wastewater treatment in developing countries where economical resources are scarce and water pollution with DWW is common.

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Considerations on design and implementation parameters of domestic wastewater treatment by subsurface flow constructed wetlands

Engenharia Sanitaria e Ambiental ◽

10.1590/s1413-41522019102334 ◽

2019 ◽

Vol 24 (4) ◽

pp. 809-819

Author(s):

Lis Eveline Athaydes Fadanelli ◽

Alceu Gomes de Andrade Filho ◽

Giovana Kátie Wiecheteck ◽

Maria Magdalena Ribas Döll

Keyword(s):

Wastewater Treatment ◽

Constructed Wetlands ◽

Subsurface Flow ◽

Domestic Wastewater ◽

Previous Treatment ◽

Temperate Climate ◽

Operational Parameters ◽

Urban Centers ◽

Domestic Wastewater Treatment ◽

Operational Criteria

ABSTRACT Constructed wetlands might be an alternative for communities away from urban centers and not served by a domestic wastewater treatment system. The purpose of this study was to provide instructions for the implementation of subsurface flow constructed wetland systems. To that end, we gathered information regarding the construction aspect, plants, and operational parameters used in systems which already operate in the country and the respective efficiency of these sets after previous treatment. The system in real scale proposed by Oliveira et al. (2005) was prominent among those that presented the highest efficiency. It was preceded by upflow anaerobic reactor built in brick, with macrophyte of the Typha genre, crushed stone at the entry and exit of the system, and sand in its intermediate portion. It required 1.04 m² surface area per inhabitant in humid temperate climate and hot summer, 1.71 m³ d-1 flow, and one-day hydraulic detention. The considerations presented here might help the construction of this kind of system, regarding dimensional and operational criteria.

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