Method of dewatering

A method of dewatering solid byproduct comprising:

• a. fermenting syngas to produce solid byproduct containing water and solid particles;
• b. treating the solid byproduct with alkaline material effective to increase pH of the solid byproduct to a value of from about 7 to about 8.5,
• C. adding coagulant to the alkaline-treated solid byproduct, the coagulant effective to reduce net charge of the particles;
• d. adding polymer to the solid byproduct having particles with reduced net charge, the polymer effective to agglomerate the particles so they have an average particle size of at least about 1 mm;
• e. dewatering the agglomerated solid byproduct particles using a filter press to form a cake separated from a clarified stream filtrate, the cake containing the solid byproduct, wherein the filter press operates at a pressure that increases in step sequence from about 0 psi to about 100 psi, with the pressure being increased from about 0 psi to about 20 psi, then to about 40 psi, then to about 60 psi, then to about 80 psi, and then to about 100 psi, and wherein the pressure is applied in total for about 1 to about 3 hours per 33 pounds solid byproduct in 1.7 square feet of filtration area.

A method of dewatering solid byproduct comprising:

• a. fermenting syngas to produce solid byproduct containing water and solid particles;
• b. treating the solid byproduct with alkaline material effective to increase pH of the solid byproduct to a value of from about 7 to about 8.5, wherein the alkaline material comprises spent sodium hydroxide from sanitization for clean in place (CIP) cleaning of equipment used in the fermenting;
• c. adding coagulant to the alkaline-treated solid byproduct, the coagulant effective to reduce net charge of the particles;
• d. adding polymer to the solid byproduct having particles with reduced net charge, the polymer effective to agglomerate the particles so they have an average particle size of at least about 1 mm;
• e. dewatering the agglomerated solid byproduct particles to form a cake separated from a clarified stream filtrate, the cake containing the solid byproduct.