Role of three different plants on simultaneous salt and nutrient reduction from saline synthetic wastewater in lab-scale constructed wetlands

João M Jesus; A C Cassoni; Anthony S Danko; António Fiúza; Maria-Teresa Borges

doi:10.1016/j.scitotenv.2016.11.074

Role of three different plants on simultaneous salt and nutrient reduction from saline synthetic wastewater in lab-scale constructed wetlands

Sci Total Environ. 2017 Feb 1:579:447-455. doi: 10.1016/j.scitotenv.2016.11.074. Epub 2016 Nov 18.

Authors

João M Jesus¹, A C Cassoni², Anthony S Danko¹, António Fiúza¹, Maria-Teresa Borges³

Affiliations

¹ Centre for Natural Resources and the Environment (CERENA), Department of Mining Engineering, University of Porto, Rua Dr. Roberto Frias s/n, 4200-465 Porto, Portugal.
² CIIMAR, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal.
³ Biology Department, Science Faculty, Porto University (FCUP), Rua Campo Alegre s/n, 4169-007 Porto, Portugal; CIIMAR, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal. Electronic address: mtborges@fc.up.pt.

PMID: 27871753
DOI: 10.1016/j.scitotenv.2016.11.074

Abstract

Constructed Wetlands (CWs) can be a valuable technology to treat high salinity wastewaters but it is not known their potential for removal of both nutrients and salt, and the type of plants to use. This study evaluated the effect of three plants on salt reduction and simultaneous nutrient removal in CWs microcosms with expanded clay and in hydroponic conditions. Initial values of the synthetic wastewater tested were EC=15dSm^-1, SAR=151; NH₄⁺-N=24mgL^-1; PO₄^3--P=30mgL^-1 and NO₃^--N=34mgL^-1. With expanded clay CW removal efficiency for NH₄⁺-N was 21, 88 and 85%, while for NO₃^--N, it was 4, 56 and 68% for Spartina maritima, Juncus maritimus and Arundo donax, respectively. PO₄^3--P was adsorbed completely in the expanded clay. However, in hydroponic system, removal efficiencies for NH₄⁺-N were 53 and 50%, while PO₄^3--P removal was 89 and -14% for Spartina maritima and Juncus maritimus, respectively. Nutrient removal in planted microcosms was statistically higher than unplanted controls for NH₄⁺-N and PO₄^3--P. However, salt removal was apparent in the hydroponic system only after 23days of HRT, despite clear salt excretion visible in both Spartina maritima and Juncus maritimus. This study demonstrates the potential of two halophytic plants for saline wastewater treatment. However, salt removal in such a scenario could not be well documented and might prove to be impractical in future work.

Keywords: Constructed wetland; Halophytes; Hydroponics; Nutrient removal; Saline wastewater; Salt uptake.