Method for processing bark press water from sawmills and/or pulp mills
AssigneeSöDra SkogsäGarna Ekonomisk FöRening
InventorsJim Parkås, Narcis Mesic, Fredrik Solhage
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Abstract
A method for processing a bark press water from sawmills and/or pulp mills is disclosed. According to the disclosure, the method comprises a) filtration of the bark press water to provide a bark press water filtrate having a particle size of less than 100 μm, and b) concentrating the bark press water filtrate to a level of at least 10% dry weight and thereby providing a first fraction of concentrated bark press water, comprising tannic compounds; and a second fraction of purified bark press water.
Claims20
A method for processing a bark press water being wastewater from sawmills and/or pulp mills, wherein the method comprises
- a) filtration of the bark press water to provide a bark press water filtrate having a particle size of less than 100 μm;
- b) concentrating at least a part of the bark press water filtrate to a level of at least 10% dry weight and thereby providing a first fraction of concentrated bark press water, comprising tannic compounds;
- and a second fraction of purified bark press water;
- c) adding sulphite salt to the first fraction of concentrated bark press water in a level of 4-25% by weight, based on the dry weight tannic compounds within the concentrated bark press water;
- and
- d) fractionation by distillation of the second fraction of purified bark press water from step b) to thereby provide at least two different distillation fractions;
- wherein the bark press water is obtained by a bark pressing step.
Dependencies are inferred from the claim text.