Assessment of enhanced phytoremediation of shrimp aquaculture wastewater by endophytic bacteria-inoculated floating treatment wetlands

In Vietnam, the major problem for the sustainability of the shrimp aquaculture industry is the management of shrimp aquaculture wastewater. A promising solution to remediate pollutants in shrimp aquaculture wastewater is to use floating treatment wetlands (FTWs) in combination with pollutant-degrading bacteria. Hence, this study aimed to evaluate the effect of inoculation of endophytic bacteria isolated from Man Trau grass on the remediation of shrimp aquaculture wastewater in FTWs vegetated with grass (Brachiaria mutica). The results showed that FTWs only vegetated with B. mutica removed organic and inorganic pollutants from shrimp aquaculture wastewater and a significant reduction was observed for total dissolved solids (TDS), chemical oxygen demand (COD), ammonium (NH4+-N), nitrate (NO3--N), and phosphate (PO43--P) with efficiency is 60, 71, 80, 65, and 73%, respectively. Interestingly, the efficiency removal was further improved by the inoculation of endophytic bacteria. The combination of plants and bacteria produced the highest removal of COD (73%), NH4+-N (96%), NO3—N (80%), PO43—P (81%), Cu (95.3), and Fe (93.4%). Moreover, the inoculated bacteria were validated their presence in water as well as in roots and shoots of the vegetated plant. In addition, the treated water output met the wastewater discharge standards of the World Health Organization. Therefore, the results suggest endophyte-assisted FTWs are a suitable approach for the remediation of shrimp aquaculture wastewater.