Methods and systems of a biosolids concentrator and digester system having an inlet, an equalization/separation tank, an equalization/separation tank-anaerobic tank connector, an anaerobic tank, an anaerobic tank-aerobic tank connector, an aerobic tank, an aerobic tank-clarifier tank connector, and a clarifier tank. The equalization/separation tank has a first aeration tube. The aerobic tank has a second aeration tube. The inlet receives a waste stream and enters the equalization/separation tank at an equalization/separation tank bottom portion and leaves at an equalization/separation tank top portion. The waste stream enters the anaerobic tank at an anaerobic tank bottom portion and leaves at an anaerobic top portion. The waste stream enters the aerobic tank at an aerobic tank bottom portion and leaves at an anaerobic top portion.