This disclosure describes a biochemical reactor with fixed feed conduit. The biochemical reactor may include a tank configured to house immobilized carriers and fluid. The biochemical reactor may include a circulation conduit at least partially disposed within the tank. The circulation conduit may include a circulation inlet opening and a circulation outlet opening. The biochemical reactor may include one or more vanes disposed proximate to the circulation outlet opening. The one or more vanes may be configured to cause the immobilized carrier and the fluid exiting the circulation outlet opening to enter into a helical pattern. The biochemical reactor may include a feed conduit having a feed outlet. The feed outlet may be disposed between a first end and the circulation inlet opening. The feed conduit outlet may be immovable with respect to the circulation inlet opening.