Treatment of wastewater generated during the fast pyrolysis of wood waste

One of the effective methods of processing lignocellulosic biomass is pyrolysis, which allows processing it into the liquid product, regardless of the composition of the feedstock. The liquid product obtained as a result of fast pyrolysis (bio-oil) is gaining popularity worldwide as replacing fossil fuels. In the process of processing pyrolysis condensates for fuel and chemical products, wastewater (wood vinegar) is formed, containing organic acids, furans, and phenols. In a large-scale forest chemical production, this waste is formed in large quantities, and its storage or incineration is extremely expensive. Discharge into centralized sewer systems of this drain is impossible due to its high toxicity and mutagenic effect. In this regard, the purpose of this study is to use a set of methods for cleaning WW for further discharge into centralized sewer systems. On the basis of the analysis carried out, a set of methods was proposed as the main methods for the purification of wood pyrolysis by means of sequential purification stages in the form of adsorption with biochar, oxidation with ozone and hydrogen peroxide, and ultrafiltration of the effluent. A high efficiency of 94% in the course of preliminary tests was achieved by the oxidation method under the conditions of the Fenton reaction due to its greater compliance with the conditions relative to other methods, the acidic environment, and the presence of oxidizing substances in the treated wastewater.