Across
- 1. gas used to sterilise water; kills bacteria
- 4. infrastructure that conveys sewage including drains, manholes and pumping stations
- 5. produced during sedimentation; includes organic matter such as human waste
- 7. the digestion of sludge does not required oxygen so is ...........
- 8. second step in sewage treatment, where solid sediments are allowed to settle out
- 10. first step in sewage treatment, which involves the removal of large objects using a metal grid
- 11. use product from the breakdown of sludge
Down
- 2. dried sludge can be used to generate electricity; it can be replaced easily so if ..................
- 3. wastewater from homes, businesses and industry
- 6. use of sludge
- 9. type of bacterial digestion that occurs in the presence of oxygen