Abstract: In the field of water treatment, this invention relates to economical methods, processes and apparatus for preparing Class A bio-solids wherein: dewatering costs and energy costs are efficient, the solids product has reduced ammonia and sulfide odor, and the concentration of solids in the aqueous solids may vary from approximately 3 to approximately 90 percent. This invention presents mesMophilic and thermophilic digestion in concert, wherein mesophilic digestion incorporates strains of Thiobacillus with nitrifiers to remove sulfide(s) and ammonia from bio-solids. Chemical dewatering of thermophilic digested bio-solids is accomplished incorporating a cationic, quatemized or an anionic polyacrylamide with at least one selected from a list consisting of: an aluminum salt, an iron salt, an amine comprising a quatemized nitrogen moiety and any combination therein. A quatemized polyacrylamide is presented alone.

Abstract: In the field of water treatment, this invention relates to economical methods, processes and apparatus for preparing Class A bio-solids wherein: dewatering costs and energy costs are efficient, the solids product has reduced ammonia and sulfide odor, and the concentration of solids in the aqueous solids may vary from approximately 3 to approximately 90 percent. This instant invention presents messophilic and thermophilic digestion in concert, wherein messophilic digestion incorporates strains of thiobacillus with nitrifiers to remove sulfide(s) and ammonia from bio-solids. Chemical dewatering of thermophilic digested bio-solids is accomplished incorporating a cationic, quaternized or an anionic polyacrylamide with at least one selected from a list consisting of: an aluminum salt, an iron salt, an amine comprising a quaternized nitrogen moiety and any combination therein. A quaternized polyacrylamide is presented alone.