A waste treatment method includes the concentration of selected strains of bacteria in a selected medium in the presence of nutrients and water, under aerobic conditions. This concentrated batch is discharged for downstream applications in wastewater remediation. A cultivation chamber having inlet ports and a circular vent port allows for adequate air introduction and heat release. Aeration is achieved by recirculation of the fluid medium from the top of the apparatus through a pipe that runs the length of the inner wall and is specially configured at the top to minimize cell damage. Fluid can be routed tangentially in clockwise and counterclockwise directions. The conical bottom has an orifice allowing for recirculation of the fluid medium tangentially to the sidewalls. Upon completion of batch cultivation, the medium and bacteria are discharged for downstream applications in wastewater remediation of paper mill, chemical plant, oil refinery, and other industrial effluents.