Abstract: A wastewater treatment method includes the steps of supplying a wastewater influent having nutrients for a population of phototactic heterotrophic microorganisms to an aerated bioreactor. At least a portion of the nutrients is converted into the phototactic heterotrophic microorganism population. The wastewater influent and the phototactic heterotrophic microorganism population together form a bioreactor effluent that is transferred to a light clarifier. The bioreactor effluent is concentrated in the light clarifier to form a low-solids effluent and a high-solids effluent. The concentration is performed by inducing the population of phototactic heterotrophic microorganisms to phototactically self concentrate through exposure to a light having at least one of an intensity and a wavelength sufficient to cause the phototactic heterotrophic microorganism population to migrate away from a source of the light. The high-solids effluent is then dewatered to form a concentrated biomass paste.

Abstract: A wastewater treatment method includes the steps of supplying a wastewater influent having nutrients for a population of phototactic heterotrophic microorganisms to an aerated bioreactor. At least a portion of the nutrients is converted into the phototactic heterotrophic microorganism population. The wastewater influent and the phototactic heterotrophic microorganism population together form a bioreactor effluent that is transferred to a light clarifier. The bioreactor effluent is concentrated in the light clarifier to form a low-solids effluent and a high-solids effluent. The concentration is performed by inducing the population of phototactic heterotrophic microorganisms to phototactically self concentrate through exposure to a light having at least one of an intensity and a wavelength sufficient to cause the phototactic heterotrophic microorganism population to migrate away from a source of the light. The high-solids effluent is then dewatered to form a concentrated biomass paste.