The Earth's resources

12345678910111213141516171819202122
Across
  1. 4. Water that is fit to drink
  2. 6. The most abundant gas in our atmosphere today
  3. 9. The type of digestion that breaks down sewage sludge
  4. 11. The first step in sewage treatment, removing large solids
  5. 13. A finite resource used to make cement and concrete
  6. 14. A rock containing a bound metal
  7. 15. A resource that we can get more of is called _________
  8. 17. The evidence collected from ancient ice or soil layers to 'read' the past
  9. 18. The method used to purify water from any source
  10. 19. Rubber, wood and wool are all examples of _________ resources
  11. 21. The scientific name for thermal radiation
  12. 22. A by-product of the sewage industry
Down
  1. 1. A gas given off from power stations that causes acid rain
  2. 2. the inability of the Earth to re-radiate heat energy causes this effect
  3. 3. A consequence of a rise in sea level
  4. 5. The conversion of salty water to useable water
  5. 7. The greenhouse gases let short ___________ radiation pass through
  6. 8. Gas we rely on that wasn't in the Earth's original atmosphere
  7. 10. The name given to tiny solid particles that are carried into the air
  8. 12. Coal is an example of this type of rock
  9. 16. The copper extraction process where plants are grown
  10. 20. __________ assessment: process used to assess environmental impact of a manufactured item