The GATE Grind

GATE 2022 ES – Question 29

Water and Wastewater Treatment and Management · Industrial Effluents and Reuse · 1 mark · Multiple select

For molasses-distillery and wood-based pulp/paper effluents, which statements are NOT correct?

  1. Both have dark colour
  2. Both have high toxicity
  3. Both generally have BOD>15000 ppm
  4. Both have high pH

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Correct answer: (B) Both have high toxicity; (C) Both generally have BOD>15000 ppm; (D) Both have high pH

Explanation

Both streams can be strongly coloured. Their toxicity, BOD and pH depend on process and treatment; a blanket BOD above 15000 ppm and high pH for both are not appropriate, particularly since distillery spent wash is typically acidic. The official selection is **B, C, D**. Rejecting B as universal does not imply that either effluent is harmless.

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