One of the most significant sectors of forest industry in Latvia is the production of wood boards, especially plywood. One of the stages of raw material preparation for plywood producing is hydrothermal treatment of birch wood. Wastewater from plywood hydrothermal basin is characterized by the high degree of contamination. The basic contaminating component of wastewater from plywood industry are lignin matters which are accountable for a rather high level of chemical oxyden demand (COD) and color of water. The aim of the work was the choice of parameters of model hydrolysis of birch wood, simulating the conditions of its treatment in the hydrothermal basin in plywood industry. The formed hydrolysate and the industrial wastewater were characterized by the pH value, density, the content of dry substances, the elemental and functional composition as well as by spectroscopy methods. The surface active and viscosimetric properties were studied. The elemental and functional composition of the samples is similar that confirm the authenticity of the choice of parameters of model hydrolysis, simulating birch wood treatment in the hydrothermal basin. Fourier Transform InfraRed (FTIR) spectroscopic, UV-visible light absorption, reduced viscosity and surface tension methods are analytical methods that are commonly used to determine the lignin in samples. FTIR spectroscopy showed that the dry residues of the model birch wood hydrolysis and wastewater from plywood industry are not structurally different The UV-visible light absorptance range at 270-280 nm help to determine the birch wood lignin in samples. This is connected with the aromatic nature of lignin, which is determined by the phenyl propanol elemental units entering into its composition. Reduced viscosity and surface active properties of solutions are compatible. It gives proof, that the dry matter of solutions contains the active high-molecular compound – lignin, which is characterized by properties of polyelectrolyte.