Halophytes as vertical-flow constructed wetland vegetation for domestic wastewater treatment

M S Fountoulakis; G Sabathianakis; I Kritsotakis; E M Kabourakis; T Manios

doi:10.1016/j.scitotenv.2017.01.090

Halophytes as vertical-flow constructed wetland vegetation for domestic wastewater treatment

Sci Total Environ. 2017 Apr 1:583:432-439. doi: 10.1016/j.scitotenv.2017.01.090. Epub 2017 Jan 20.

Authors

M S Fountoulakis¹, G Sabathianakis², I Kritsotakis³, E M Kabourakis³, T Manios²

Affiliations

¹ Department of Viticulture, Horticulture and Plant Protection, Institute of Olive Tree, Subtropical Crops and Viticulture, Hellenic Agricultural Organization-"DΕMETER", Heraklion 71307, Greece; Department of Agricultural Technology, Technological Educational Institute of Crete, Heraklion 71410, Greece. Electronic address: mfountoul@staff.teicrete.gr.
² Department of Agricultural Technology, Technological Educational Institute of Crete, Heraklion 71410, Greece.
³ Department of Viticulture, Horticulture and Plant Protection, Institute of Olive Tree, Subtropical Crops and Viticulture, Hellenic Agricultural Organization-"DΕMETER", Heraklion 71307, Greece.

PMID: 28117162
DOI: 10.1016/j.scitotenv.2017.01.090

Abstract

Recent findings show that halophytes have the ability to accumulate salts in their tissues, making them a very interesting group of plants for domestic wastewater treatment in constructed wetlands (CWs). In that case, it might be possible to reduce the salinity of the final effluent, which is a crucial parameter for wastewater reuse in agriculture. During this study three halophytes, Atriplex halimus, Juncus acutus and Sarcocornia perennis, were tested for phyto-desalination of domestic wastewater in a vertical flow constructed wetland (VFCW) and compared with common reeds (Phragmites australis). In addition, the effect of this alternative vegetation on the overall performance of the system regarding organic matter, nutrients, boron and pathogen removal was monitored. The organic loading rate (OLR) was about 21gCOD/m²/d and the hydraulic loading rate (HLR) was 95mm/d in both cases. Promising results were obtained for A. halimus, which shows high biomass productivity and significant capability to accumulate salts, mainly Na, in its tissues. A positive effect on pathogen removal efficiency was also recorded. However, nitrogen concentration in the effluent of the VFCW planted with halophytes was found to be higher than in the effluent of the VFCW planted with reeds. Finally, no significant effect on organic matter and phosphorus removal efficiency was observed from the use of halophytes in place of reeds.

Keywords: Coliforms; Electrical conductivity; Salinity; Treatment wetland.