Constructed wetlands for treatment of harvest
effluents from grow-out ponds of the Amazon river
prawn
Alexandre Augusto Oliveira Santos
1,2
& Antonio Fernando Monteiro Camargo
1,2
1
CAUNESP – UNESP, Aquaculture Center, Jaboticabal, Brazil
2
Departament of Ecology, Institute of Biosciences, UNESP, Rio Claro, Brazil
Correspondence: A F M Camargo, CAUNESP – UNESP, Aquaculture Center, Prof. Paulo Donato Castellane, 14.884-900 Jabotica-
bal, SP, Brazil. E-mail: afmc@rc.unesp.br
Abstract
Effluent discharges from aquaculture can reduce
water quality in receiving water bodies and that
strategies or practices to reduce this are necessary.
One possibility is to reduce, or eliminate, water
renewal in grow-out ponds. In this study, we elimi-
nated water renewal in grow-out ponds associated
with the culture of 40 individuals m
2
of Amazon
river prawn (Macrobrachium amazonicum). At the
end of the culture period it was, however, necessary
to drain the pond to harvest the prawns. An experi-
ment was performed in triplicate, in which the
water supply characteristics and harvest water
characteristics of ponds were evaluated. To reduce
these concentrations of total N and P, an aquatic
macrophyte (Eichhornia crassipes, water hyacinth)
treatment system (CWs) was adopted. The
water characteristics in the CWs were evaluated
after 1, 3, 7, 14 and 21 days. The water supply of
ponds presented the average concentrations of
0.67 0.32 mg L
1
and 17.4 14.7 lgL
1
of
total-N and total-P respectively. The harvest effluent
of ponds had elevated concentrations of different
forms of nitrogen (4.44 mg L
1
of total-N) and
phosphorous (100.9 lgL
1
of total-P). After 1 day
of the experiment we found the following reductions
in key nutrients in treatment system containing
E. crassipes: 90%, 78% and 45% reductions in
the concentrations of particulate matter, orthophos-
phates and nitrates respectively. We noted that after
3 days the nitrates had been reduced by 53%. We
concluded that 3 days of this treatment was suffi-
cient for the removal of the additional nutrients that
had accumulated in the Amazon river prawn ponds.
Keywords: CWs, removal efficiency, Macrob-
rachium amazonicum, Eichhornia crassipes, macro-
phytes, water hyacinth
Introduction
The farming of aquatic organisms, including
shrimp, provides social and economic benefits, but
has raised concerns relating to associated environ-
mental impacts (Goldburg & Triplett 1997). Only
21–22% of nitrogen and 6% of phosphorus sup-
plied in the diet are assimilated by the shrimp
(Jackson, Preston, Burford & Thompson 2003).
Thus, the majority of nitrogen and phosphorus
remains, in a dissolved or particulate form, in the
water or in sediments, or becomes incorporated
into other organisms. Aquaculture effluents pro-
duced by feed or discharged by various animals
into natural waters can have a number of negative
impacts on the environment (Cho & Bureau 2001),
including the promotion of eutrophication. To pre-
vent eutrophication, several alternatives can be
considered, such as effluent treatment to remove
nutrients and particulate matter from aquaculture
effluents. The use of constructed wetlands (CWs) to
treat aquaculture effluents is a solution that has
been recently used (Henry-Silva & Camargo 2006,
2008). This system has a number of advantages: it
is a natural process, has high process stability, and
it is cost-effective. Furthermore, CWs are relatively
simple to build and operate, which is particularly
desirable in developing countries (Trang, Konn-
erup, Schierup, Chiem, Tuan & Brix 2010).
The use of aquatic macrophytes for water
treatment has been shown to be very efficient in
© 2014 John Wiley & Sons Ltd 2676
Aquaculture Research, 2015, 46, 2676–2684 doi: 10.1111/are.12423