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12. In a paper industry, the wastewater generated in the wash unit contain 2% organic matter and 7% salts. If the quantity of washed pulp contains 0.5% organic matter and 3% salts and constitutes 25% of the water used in the process. Answer the following questions: a) How much organic matter did the material have before entering the wash unit? And what about salts? b) Would it be possible to reuse the washing water? 5