NOVELTY - The system (10A) has a biomass solid content extraction unit which extracts biomass solid content (24) processed by a biomass process unit. A slurrying tank (21) is provided for injecting water (19) and slurries extracted biomass solid content while connecting with the biomass solid content extraction unit. A settling tank (31) is provided in the downstream side of the slurrying tank. A screw conveyor or belt conveyor is provided for carrying out water separation scooping up the biomass solid content that settled to the bottom side of the settling tank.    USE - Biomass processing system for use in production of organic raw material such as alcohol, petroleum substitute items, and amino acids (all claimed).    ADVANTAGE - The slurry-like biomass solid content is made to settle in the settling tank. The water is removed and made as the concentration slurry-like biomass solid content by separating the biomass solid content using the screw conveyor. The content of reaction inhibition substance is reduced with the removal of water, when the reaction inhibition substance is included in slurry-like biomass solid content.    DETAILED DESCRIPTION - A saccharification tank is provided for saccharifying biomass solid content separated with a solid-liquid separator (30). The biomass process unit is selected from hydrothermal decomposition process unit (17), an alkali decomposition process unit, or an acidolysis process unit. INDEPENDENT CLAIMS are included for the following:    (1) a method for producing sugar liquid using biomass feedstock (11) involves supplying biomass feedstock containing cellulose, hemicellulose, and lignin to under-pressurization from under a normal pressure. The biomass feedstock is decomposed on high temperature, high pressure conditions by the biomass process unit. The sugar liquid is produced after carrying out of enzyme saccharification of biomass solid content from which water is removed;    (2) a method for producing alcohol by performing alcoholic fermentation using the sugar liquid obtained by the sugar liquid production process using the biomass feedstock; and    (3) a method for producing organic raw material including alcohol, petroleum substitute items, or amino acids by fermentation process using the sugar liquid and the biomass feedstock.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of the biomass processing system. (Drawing includes non-English language text)    Biomass processing system (10A)    Biomass feedstock (11)    Hydrothermal decomposition process unit (17)    Water (19)    Slurrying tank (21)    Biomass solid content (24)    Solid-liquid separator (30)    Settling tank (31)