Abstract: An enhanced method and apparatus for driving an immersed flashing light system used for enhancing algae growth is disclosed. The flashing light system includes a plurality of light source elements that are arranged to illuminate the algae. The light source elements are electrically connected to form ".eta." banks of light source elements. Power is supplied to each bank of light sources in a predetermined sequence at regular intervals to substantially evenly supply each bank of light source elements with a series of power pulses while maintaining a substantially continuous load on the power supply. The power pulses are substantially half cycles of a square wave.

Abstract: An anaerobic digester for digesting animal manure and other biologically degradable material contains support media for enhancing the contact between the microbes in the digesting mass and the available nutrients. The digester includes a novel fluid circulation and distribution system. The distribution system prevents build up of heavy material in the bottom of the digester and prevents agglomeration of light material at the top of the digester. The digesting fluid travels over a floating weir into an intake and impeller assembly. The impeller drives the fluid through a conduit located adjacent the floor of the digester. Nozzles in the conduit project the fluid downwardly toward the floor thus causing a sweeping action on the floor. Fluid then flows upwardly past the support media. Risers are provided at the ends of the conduit, which terminate in nozzles at the surface of the digesting liquid.