Autor(es):
Jesus, J. M. 
; Borges, M. T. ; Calheiros, Cristina S. C. ; Castro, Paula M. L.
Data: 2012
Identificador Persistente: http://hdl.handle.net/10400.14/10031
Origem: Veritati - Repositório Institucional da Universidade Católica Portuguesa
Assunto(s): Constructed wetland; Phytoremediation; Aquaculture wastewater; Seawater
Descrição
Poster presentation published at page 185 The aquaculture industry discharges large volumes of nutrient rich wastewater, contributing
to eutrophication events. Recent culture intensification methodologies such as
recirculation (RAS) and shallow raceway (SRS) systems discharge wastewater with even
higher nutrient concentrations, though at lower volumes (Rana et al., 2005). Hence, efluent
treatment options are of vital importance. Constructed wetlands (CWs) are a possible but
underexplored treatment solution even for high salinity situations (Lymbery et al., 2006) consisting
of planted shallow channels, relying upon biological, physical and chemical processes
to treat wastewater (EPA, 2000). Therefore, this study aims to extend the knowledge on the
possible use of CWs for aquaculture wastewater treatment, either fresh or saline.
To fulfill this goal, several microcosms were created simulating subsurface systems with
HRT = 7 days and planted with Typha latifolia. Substrate used was expanded clay 8 – 12.5
mm Ø. Macrophyte survival, growth, and nutrient removal (phosphate, nitrite, nitrate and
ammonia) were assessed over a period of 4 weeks. Freshwater (simulated) and saline (real)
fish farm effluents (recirculation SRS, 2.4% salinity) were tested.
Results showed that plants adapted better to freshwater conditions exhibiting higher
growth rate. Plants at 2.4% salinity did not growth in height after 2 weeks, but survival
remained high.The microcosm wetland system was able to treat the effluent by removing 61%, 78% and
98% of NH4, NO2 and PO4, respectively, in fresh water, and 94%; 78%, 34% and 100% of
NH4, NO2, NO3 and PO4, respectively, in saline wastewater. An improvement of removal with
time was observed, suggesting the existence of a system adaptation period. The microcosm
treatment was able to reduce nutrient concentrations to legally acceptable values. Hence,
constructed wetlands can be an adequate solution for aquaculture efffluent treatment. Further
studies are necessary, however, to achieve a better adaptation of the plant used to salinity.
