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Constructed wetlands as biofilters in closed recirculating tank culture systems of asian tiger shrimp (penaeus monodon)

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The study was conducted to monitor the real-time status of toxic compounds to P. monodon in intensive recirculating aquaculture system integrated constructed wetlands (CWs) designed with surface flow (SF), vertical subsurface flow (VF) and horizontal subsurface flow (HF), and to examine removal efficiency of contaminants in different CWs. | Journal of Science and Technology 54 (2A) (2016) 84-90 CONSTRUCTED WETLANDS AS BIOFILTERS IN CLOSED RECIRCULATING TANK CULTURE SYSTEMS OF ASIAN TIGER SHRIMP (PENAEUS MONODON) Ngo Thuy Diem Trang1, *, Le Minh Long1, Do Thi Thu Quynh1, Hans Brix2 1 College of Environment and Natural Resources, Can Tho University, 3/2 Street, Ninh Kieu District, Can Tho City, Vietnam 2 Department of Bioscience, Aarhus University, Nordre Ringgade 1, DK-8000 Aarhus C, Denmark * Email: ntdtrang@ctu.edu.vn Received: 1 April 2016; Accepted for publication: 15 June 2016 ABSTRACT The study was conducted to monitor the real-time status of toxic compounds to P. monodon in intensive recirculating aquaculture system integrated constructed wetlands (CWs) designed with surface flow (SF), vertical subsurface flow (VF) and horizontal subsurface flow (HF), and to examine removal efficiency of contaminants in different CWs. Plants used in the system were cattail (Typha sp.), elephant grass (Pennisetum purpureum) and unplanted systems used as referenced samples. Recirculating rate per day was 50 % of total water volume in tanks. Water from culture tanks was purified by passing through SF, VF and HF then return to original tanks without water exchange in entire study period. After 72 days, concentration of NO2-N, NH4-N and NO3-N was building up over study period and was not significantly different among treatment systems (except the concentration of NO3-N). At the end of study period, NH3 concentration was below the toxic threshold for P. monodon in according to Circular No. 45/2010/TT-BNNPTNT. P. monodon grew slowly and the survival rate was as low at 30 %, 43 % and 60,5 % in the HF, SF and VF systems, respectively. The average water volume added in each tank in entire study period was 393 ± 1,7 L. Despite of low survival and growth rates, the integration of CWs in intensively recirculating shrimp systems helps to improve water quality in accordance to Circular No. 45/2010, to diminish pollutant .