Constructed wetlands as recirculation filters in large-scale shrimp aquaculture

Effluent waters from shrimp aquaculture, which can contain elevated levels of phosphorus, ammonia, nitrate, and organics, must be managed properly if shrimp aquaculture is to achieve sustainability. Constructed wetlands are ecologically beneficial, low cost treatment alternatives proven capable of reducing suspended solids, biochemical oxygen demand (BOD), nitrogen, phosphorus and heavy metals from wastewater of many sources. The goal of this study was to determine how well a constructed wetland performed as a filter in a full-scale shrimp aquaculture operation. A 7.7 ha (19 ac) mesohaline (3–8 ppt) constructed wetland treating 13,600 m 3 per day (3.6 MGD) of effluent from 8.1 ha (20 ac) of intensively farmed shrimp ponds at the Loma Alta Shrimp Aquaculture Facility (LASAF), located along the coast of the Gulf of Mexico in semi-arid South Texas, was found to reduce concentrations of total phosphorus (TP), total suspended solids (TSS) and inorganic suspended solids (ISS) by 31, 65 and 76%, respectively, during recirculation, and maintained consistently low levels of mean BOD (