NOVELTY - A substrate is produced by forming a precipitated stream of solid components comprising liquid component and a solid component comprising ferric hydroxide precipitate in which organic material, micronutrients, and first population of microbes are enmeshed; and separating the solid and liquid components in the precipitated stream to obtain a solid organic substrate for microbial digestion and an aqueous liquid.    USE - Method of producing a substrate for microbial digestion (claimed).    ADVANTAGE - The method makes retention of the dissolved solids more practicable.    DETAILED DESCRIPTION - A substrate is produced by:    (A) blending a capture solution comprising water, iron (II) ions, micronutrients, a first population of microbes and pH buffer compounds with an organic material to produce a blended stream;    (B) electrolyzing the blended stream with an electric field in a chamber having an anode comprising iron;    (C) forming a precipitated stream of solid components comprising liquid component and a solid component comprising ferric hydroxide precipitate in which organic material, micronutrients and the first population of microbes are enmeshed;    (D) optionally adding a flocculent on the precipitated stream to enhance precipitation; and    (E) separating the solid and liquid components in the precipitated stream to obtain a solid organic substrate for microbial digestion and an aqueous liquid.    INDEPENDENT CLAIMS are included for:    (1) a method of facilitating digestion of untreated organic material comprising blending a solid organic substrate with the untreated organic material, and providing a ratio of the solid organic substrate to the untreated organic material effective for enhancing or facilitating digestion of the untreated organic stream; and    (2) a substrate for microbial digestion comprising a ferric hydroxide lattice having enmeshed organic matter, anaerobes and micronutrients.    DESCRIPTION OF DRAWING(S) - The drawing is a flow chart showing a classification of electrocoagulation reactor systems.