Simultaneous removal of carbon, nitrogen and phosphorus from hypersaline wastewater by bioaugmented intermittently aerated biological filter (IABF)

Simultaneous removal of carbon, nitrogen and phosphorus from hypersaline wastewater by halophiles bioaugmented intermittently aerated biological filter (IABF) was systematically investigated in this research. The bioaugmented IABF showed significantly improved simultaneous nutrient removal efficiency in salinity range of 6-11% compared to the uninoculated IABF although the benefit of inoculation was no more evident with further increase in salinity. As high as 12% difference in COD removal efficiency, 18% difference in TN removal efficiency and 14.6% difference in TP removal efficiency were observed between the inoculated and uninoculated IABF. Reactor performance was negatively affected by backwashing at hypersaline conditions. However, inoculation of halophiles reduced the biofilm recovery time after backwashing. Growth curve of halophiles, as well as biomass loading and dehydrogenase activity, at different salinities were studied to explore the bioaugmentation mechanism. Excellent correlation was observed between the halophile growth curve, biomass loading and DHA and the removal efficiency of the organic pollutant, which can be used to predict the biofilter performance in removing the organic matters through the analysis of halophiles growth curve, biomass loading and DHA in the reactor.