&lt;b&gt;Effect of reversal of the flow direction on hydrodynamic characteristics and plants cultivated in constructed wetland systems

Gheila Corrêa Ferres Baptestini,Alisson Carraro Borges,Antonio Teixeira Matos

doi:10.4025/actascitechnol.v38i1.27864

<b>Effect of reversal of the flow direction on hydrodynamic characteristics and plants cultivated in constructed wetland systems

Gheila Corrêa Ferres Baptestini, Alisson Carraro Borges + Show 1 more

Open Access

https://doi.org/10.4025/actascitechnol.v38i1.27864

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Abstract

The objective of the present study was to evaluate the effect of reversal of the flow direction, when used the surface flow as an operating criteria, on hydrodynamic characteristics and plants grown in horizontal subsurface-flow constructed wetland systems (HSF-CWs). For this purpose, six HSF-CWs were used: two non-cultivated (HSF-CWs 1 and 4), two cultivated with Tifton 85 grass ( Cynodon spp.) (HSF-CWs 2 and 5) and two cultivated with Alternanthera ( Alternanthera philoxeroides ) (HSF-CWs 3 and 6). It was made a reversal in the flow direction of the HSF-CWs 1, 2 and 3. The reversal of the wastewater flow direction was performed when the superficial flow of the wastewater applied ( SF ) reached 50% of the length of the HSF-CWs. There was a single reversal for each system, on different dates. Reversing the flow direction promoted distinction on the dry matter yield of Tifton 85 grass. This was not observed in HSF-CWs cultivated with Alternanthera. The reversal of the wastewater flow direction promoted, in principle, the extinction of the SF advance in the HSF-CWs, but did not prevent its return. Waiting for the SF to reach 50% of the length was not the best criterion for reversing the flow direction.

Highlights

Horizontal subsurface flow constructed wetland systems (HSF-CWs), used in the treatment of wastewater, have advantages such as reduced cost and simplicity of operation, low mechanization demand, low maintenance requirement and good rates of efficiency (Fia, Matos, Fia, Borges, & Teixeira, 2012; Prata, Matos, Cecon, Lo Monaco, & Pimenta, 2013; Zhang et al, 2014).One of the main problems related to these systems, and that became evident in the last twoActa Scientiarum
The presentation of the results was discriminated for horizontal subsurface-flow constructed wetland systems (HSF-CWs) 2 and 5 cultivated with Tifton 85 due to the reversal of the flow direction
Each system was subjected to different treatments, called HSF-CW 2i and HSF-CW 5ni

Summary

Introduction

Horizontal subsurface flow constructed wetland systems (HSF-CWs), used in the treatment of wastewater, have advantages such as reduced cost and simplicity of operation, low mechanization demand, low maintenance requirement and good rates of efficiency (Fia, Matos, Fia, Borges, & Teixeira, 2012; Prata, Matos, Cecon, Lo Monaco, & Pimenta, 2013; Zhang et al, 2014).One of the main problems related to these systems, and that became evident in the last twoActa Scientiarum. Technology decades, is the increase in clogging of the porous medium (Knowles, Dotro, Nivala, & García, 2011). This phenomenon is characterized by clogging of the pores with a resultant reduction in porosity, mainly in front of the system. The consequences include modifications to the hydrodynamic conditions of the porous medium, such as reduced hydraulic retention time, surface runoff and resulting decrease in the treatment efficiency of the system (Knowles et al, 2011; Nivala, Knowles, Dotro, García, & Wallace, 2012).

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