Abstract: Aerobic wastewater treatment systems may include a treatment tank having a tank interior. An aeration chamber may be provided in the tank interior. A wastewater inlet conduit may be disposed in fluid communication with the aeration chamber. An air inlet conduit may be disposed in fluid communication with the aeration chamber. A diffuser may be provided in the aeration chamber. The diffuser may be disposed in pneumatic communication with the air inlet conduit. A clarifier in the tank interior may include a vertical outside clarifier wall portion. An inside clarifier wall portion may be disposed at an acute angle to the outside clarifier wall portion. A clarifier interior may be formed by and between the outside clarifier wall portion and the inside clarifier wall portion. A clarifier inlet may establish fluid communication between the aeration chamber and the clarifier interior. An effluent outlet conduit may be disposed in fluid communication with the clarifier interior.