waste water

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Across
  1. 3. the process of adding air into wastewater to allow aerobic biodegradation of the organic materials.
  2. 4. the pipes that carry sewage
  3. 6. process of keeping places clean and healthy
Down
  1. 1. a polluting or poisonous substance that makes something impure.
  2. 2. the impurities present in wastewater
  3. 4. the solid accumulated in wastewater treatment plant
  4. 5. used water