Chemistry of the environment

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Across
  1. 4. Separation method used in water treatment to remove insoluble solids.
  2. 6. Greenhouse gas released by animal waste
Down
  1. 1. Process used in water treatment to kill microbes.
  2. 2. Gas responsible for global warming produced by complete combustion.
  3. 3. Type of water used in practical chemistry because it contains fewer impurities.
  4. 5. Element represented by the symbol O.
  5. 7. Rain made acidic mainly by sulfur dioxide and nitrogen oxides.