Treatments of effluents from Litopenaeus vannamei shrimp cultures through sedimentation, filtration and absorption

Efficiency in removing particulate matter and dissolved nutrients from the effluents of reproductive tanks of the shrimp Litopenaeus vannamei was evaluated on the laboratory scale using three treatments sedimentation, filtration by Crassostrea rhizophorae and absorption by Ulva fasciata. For each treatment, we used a six-hour water residence time. For the sedimentation stage, tanks were filled with 90 L of the effluent. For the filtration stage, tanks were filled with 20 L of the supernatant resulting from the effluent after sedimentation. For the absorption stage, tanks were filled with 15 L of the supernatant resulting from the effluent after filtration. At the end of each treatment we collected 500 mL to analyze the water quality. During sedimentation, turbidity, chlorophyll-a and total suspended solids were reduced in 93.8%, 94.5% and 65.9%, respectively. The filtration treatment, achieved high levels of efficiency for removing bacteria (89.3%) and chlorophyll-a (100%). The absorption treatment reduce orthophosphate (PO(4)(-3)), ammonia (N-NH(4)(-)) and nitrate (N-NO(3)) in 53.6%, 49.6%, and 70.2%, respectively, compared to the control tanks. Combined sedimentation, filtration and absorption treatments reduced total bacteria (95.1%), turbidity (97.1%) total suspended solids (81.3%), chlorophyll-a (99.1%), ammonia (54.1%), nitrite (58.0%), nitrate (69.2%) and orthophosphate combination of sedimentation, filtration and absorption significantly, improved the water quality of Litopenaeus vannamei shrimp culture effluents.