Outflow dynamics in a French system of vertical wetlands operating with an extended feeding cycle

The possibility of using the first stage of the French System (FS) of vertical wetlands composed of only two units in parallel requires hydraulic investigations to allow a better understanding of its operation under tropical climatic environments. This study evaluated the pattern of the outflow hydr...

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Bibliographic Details
Published in:Water science and technology 2019-02, Vol.79 (4), p.699-708
Main Authors: de Andrade Moraes, Mirene Augusta, García Zumalacarregui, Jorge A, Trein, Camila Maria, Ferreira, Vinícius Verna M, von Sperling, Marcos
Format: Article
Language:English
Subjects:
Brazil
Chemical oxygen demand
Climate
Duration
Dynamics
Evapotranspiration
Feeding
Filtration
Hydraulic gradient
Hydraulics
Hydrographs
Infiltration rate
International conferences
Outflow
Percolation
Permeability
Precipitation
Rain
Rainfall
Sanitation
Science
Sewage
Sludge
Storage
Tropical climate
Waste Disposal, Fluid - methods
Water pollution
Wetlands
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Summary:The possibility of using the first stage of the French System (FS) of vertical wetlands composed of only two units in parallel requires hydraulic investigations to allow a better understanding of its operation under tropical climatic environments. This study evaluated the pattern of the outflow hydrograph along an extended cycle of operation (seven days of feeding) and the influence of the sludge deposit, rainfall occurrence and duration of pulse application on the outflow hydrograph in a modified full-scale FS in Brazil. The results indicated that, as the feeding cycle days increased, there was an increase in the time of filtration and the internal storage of the liquid volume, probably due to a reduction in the filter permeability. Greater hydraulic gradient favoured the infiltration velocity, decreased the amount of liquid stored within the system, and delayed the loss of permeability. The sludge layer contributed to a momentary liquid retention, and also allowed greater evapotranspiration, reducing the liquid volume to be treated. The sludge deposit seemed to hinder the liquid percolation, especially at the end of the cycle, modifying the hydraulic conductivity of the filter as a whole. Intense rainfall events demonstrated that precipitation could modify the flow dynamics within the system.
ISSN:0273-1223
1996-9732
DOI:10.2166/wst.2019.088