NOVELTY - A waste stream containing organic and inorganic wastes is treated by sequentially contacting the waste stream with a first mixture of microorganisms comprising photosynthetic prokaryotic organisms in the presence of light, and then with a second mixture of microorganisms comprising algae in the presence of light.    USE - The methods are used for treating a waste stream, e.g. agricultural and livestock waste.    ADVANTAGE - The invention provides an efficient and cost-effective method of processing agricultural and livestock wastes that utilizes photosynthetic organisms, and produces commercially valuable by-products. The process of the invention maximizes water quality and since the biomass is a valuable resource maximizes biomass growth. The ability to eliminate large concentrations of waste while generating an even higher percentage of nutritional biomass crops.    DETAILED DESCRIPTION - A waste stream (14) containing organic and inorganic wastes is treated by:    (a) contacting the waste stream with a mixture of microorganisms comprising photosensitive prokaryotic organisms in the presence of light in first reaction vessel (6) that is in fluid communication with first photobioreactor (50), with a portion of the waste being assimilated by the mixture to produce a partially purified waste stream comprising the mixture and a second portion of the waste;    (b) removing the mixture from the partially purified waste stream to produce an isolated mixture and a partially purified effluent stream containing the second portion of the organic waste;    (c) transferring the partially purified effluent stream from the first reaction vessel to the second reaction vessel (10);    (d) contacting the partially purified effluent stream with a second mixture of microorganisms comprising algae in the presence of light in a second reaction vessel that is in fluid communication with a second photobioreactor (52), with the second portion of the organic waste being assimilated by the second mixture to produce a purified waste stream comprising the second mixture and purified effluent; and    (e) removing the second mixture from the purified waste stream to produce an isolated second mixture and a purified effluent stream.    An INDEPENDENT CLAIM is also included for a method of treating a waste stream containing organic and inorganic waste, comprising:    (a) contacting a waste stream comprising organic and inorganic waste with a mixture of microorganisms, comprising one or more photosynthetic prokaryotic organisms in the presence of light, in at least one photobioreactor, a portion of the waste is assimilated by the mixture to produce a partially purified waste stream comprising the mixture and a second portion of the waste;    (b) removing the mixture from the partially purified waste stream to produce an isolated mixture and a partially purified effluent stream containing the second portion of the organic waste;    (c) transferring the partially purified effluent stream from the first photobioreactor to at least one second photobioreactor;    (d) contacting the partially purified effluent stream with a second mixture of microorganisms comprising algae in the presence of light in the second photobioreactor, the second portion of the organic waste is assimilated by the second mixture to produce a purified waste stream comprising the second mixture and purified effluent; and    (e) removing the second mixture from the purified waste stream to produce an isolated second mixture and a purified effluent stream.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic diagram of a method for treating a waste stream using photobioreactors.    First reaction vessel (6)    Second reaction vessel (10)    Waste stream (14)    First photobioreactor (50)    Second photobioreactor (52).