Abstract: The present invention generally relates to a process for converting waste to nutrients. Preferably, the subject invention relates to systems and methods for recovering nutrients from wastewaters. More preferably, the subject invention relates to systems and methods for processing anaerobically treated cellulosic stillage generated from ethanol production to recover struvite precipitate. According to the present invention, a sequential batch reactor is provided for recovery of nutrients via struvite precipitation from cellulosic ethanol stillage seeded with stillage fibrous biomass. The effect of seeding using stillage biomass as seeding decreases time for struvite precipitation and settling within the reactor.

Abstract: The subject invention provides advantageous systems and processes for anaerobic digestion of organic waste streams, particularly agricultural waste streams. According to this invention, a new process is provided in which a liquid fraction from an organic waste stream comprising soluble compounds is segregated and incubated in a reactor separate from the solids fraction of the organic waste stream. Digestion of waste in both reactors occurs substantially simultaneously and both reactors produce biogas (thus both reactors function essentially like single stage reactors but allow for continuous or intermittent loading). According to one aspect of the invention, at least one cross-flow baffle is provided for use in an anaerobic digester to collect biogas and break up clumped solids in the reactor. In another aspect of the invention, packing media for use in an anaerobic digester is provided.