PROCESS AND SYSTEM FOR TREATING， RECYCLING TREATED DIGESTATE AND FOR OBTAINING FERTILIZER MIXTURE FROM DIGESTATE OBTAINED BY ANANEROBIC DIGESTION OF BIOMAS IN COGENERATIVE BIOGAS PLANT

The present invention relates to a process and system for the treatment and recycling of digestate obtained by anaerobic digestion of input biomass， ie manure， slurry， plant materials and energy crops in a cogeneration biogas plant. A process for treating and recycling digestate and obtaining a fertilizer mixture from organic digestate substrates obtained by anaerobic digestion of biomass in an AD digester (10) under mesophilic conditions where the digestate is the product of a biogas production cycle in a cogeneration biogas plant. potassium salts and ammonium alkalis with constant stirring and measurement of temperature and pH; separating the solid fraction (13; 5) from the liquid fraction (6) in the separator (4); chemical treatment of the solid fraction (5) in the reactor (2) in an acidic aqueous solution with constant measurement of temperature T and pH; drying the acid-treated solid fraction (5) in an oven (7) after which the resulting treated dry matter is fed to an AD digester (10) in which it is mixed with the input biomass; and anaerobic digestion of a mixture of treated dry matter and input biomass in AD digester (10) in mesophilic conditions.The related invention refers to a process and system for treating and recycling of digestate obtained by anaerobic digestion of biomass input， ie manure， slurry， plant material and energy crops in a cogeneration biogas plant. The method of treating and recycling digestate and obtaining a fertilizer mixture from organic substrate of digestate obtained in anaerobic digestion of biomass in an AD digester (10) under mesophilic conditions where digestate is the product of biogas production cycle in a cogeneration biogas plant comprises crystallization of the fertilizer mixture in a reactor (1) by dosing magnesium salt， potassium salt and ammonium hydroxide with constant stirring and temperature and pH value measurement; separation of the solid fraction (13; 5) from the liquid fraction (6) in a separator (4); chemical treatment of solid fraction (5) in a reactor (2) in acidic aqueous solution with constant temperature T and pH value measurement; drying the acid-treated solid fraction (5) in a drier (7)， whereupon the resulting treated dry substance is introduced into an AD digester (10) in which it is mixed with the input biomass; and anaerobic digestion of the treated dry matter mixture and the input biomass in the AD digester (10) under mesophilic conditions.