Single-step mixotrophic algal wastewater treatment: Microbial assessment of effluent

Abstract

Viability of a single-step mixotrophic algal wastewater treatment (A-WWT) system in delivering discharge-quality effluent has been previously demonstrated. This report presents inactivation performance of the A-WWT system and compares it with that of high-rate algal ponds, activated sludge, and membrane bioreactors. Log reduction per unit energy input/volume of wastewater by the A-WWT system is shown to range 6.4–14.6 m3/kWh, while that in the above alternatives ranged 1.3–3.5 m3/kWh. Pathogenicity and virulence of the algal effluent and the potential for formation of disinfection byproducts (DBPs) under chlorination are discussed. Concentrations of seven of the common nitrogenous DBPs in the algal effluent were <50 ng/L.