Across
- 7. The process of maintaining a safe water supply
- 9. Water that contains less salts than hard water
- 10. Sensitive or important species whose numbers can show the health of an ecosystem
- 12. A process which may be used to desalinate water by pumping water through filters
Down
- 1. Safe to drink
- 2. Wastewater from a septic tank; liquid industrial waste
- 3. A method of separating the parts of a liquid mixture
- 4. Large underground container that stores sewage
- 5. Poisonous substances
- 6. Water that contains large amounts of dissolved salts
- 8. Waste materials that pass through sewers
- 11. The diffusion of a solvent, usually water, through a selectively permeable membrane