TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The siliceous material is silica based particles, colloidal silica, cationic silica, aluminosilicate, borosilicate, zeolite or swellable clays. The siliceous material is an anionic microparticulate material (preferably a bentonite type clay, especially hectorite, smectites, montmorillonite, nontronite, saponite, sauconite, hormite, attapulgite or sepiolite).    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The anionic polymer is formed from anionic monomer selected from (meth)acrylic acid, maleic acid, itaconic acid, fumaric acid, vinyl sulfonic acid, allyl sulfonic acid or 2-acrylamido-2-methyl sulfonic acid or their respective salts. The treatment system further comprises addition of a cation polymer and a siliceous material.Preferred Method: The fermentation liquor is distilled where the fermentation product is recovered and the liquor is recovered from the distillation stage as a stillage stream and then subjected to the solid-liquid separation stage. The fermentation liquor containing the fermentation product is subjected to the solids-liquid separation stage and then passed to a distillation stage where the fermentation product is recovered. The anionic polymer and the cationic polymer are added sequentially (preferably the anionic polymer is added first).The fermentation liquor is subjected to a mechanic dewatering stage during or subsequent to application of the treatment system. The mechanical dewatering step is a centrifuge, a screw press, a filter press, a belt filter press, a horizontal belt filter and a pressure filter. The treated liquor from which suspended solids have been removed are recycled and used as washed water. The separated solids are dewatered and then dried to provide a dry solid material and the dry solid material is used as a solid fuel. The fermentation liquor had not been subjected to a temperature of at least 50degreesC.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The siliceous material is silica based particles, colloidal silica, cationic silica, aluminosilicate, borosilicate, zeolite or swellable clays. The siliceous material is an anionic microparticulate material (preferably a bentonite type clay, especially hectorite, smectites, montmorillonite, nontronite, saponite, sauconite, hormite, attapulgite or sepiolite).    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The anionic polymer is a natural polymer or modified natural polymer having a high anionic charge such that the equivalent weight is below 250 and synthetic polymers formed from anionic monomer units (at least 50 (preferably at least 65) wt.%). The anionic polymer exhibits an intrinsic viscosity of at least 4 dl/g (measured in 1 M NaCl at 25degreesC).The cationic polymer exhibits an intrinsic viscosity of below 4 dl/g (measured in 1 M NaCl at 25degreesC) and a charge density of at least 3 milliequivalents/g. The cationic polymer is polyamine, amine/epihalohydrin addition polymer, polymer of dicyandiamide with formaldehyde, polymer of diallyldimethyl ammonium chloride (DADMAC), cationic starch and cationic inulin, polymer of dialkyl amino alkyl(meth)acrylate or its salt and dialkyl aminoalkyl(meth)acrylamide or its salt. The dose of the anionic polymer and the cationic polymer is at least 50 g/tone each (based on the dry weight of the fermentation liquor). The siliceous material is silica microgels, silica sols, silica gels, polysilicates, polyaluminosilicate or polyborosilicate.