Water and Wastewater Treatment: Key Concepts
Key Concepts in Water and Wastewater Treatment
Flocculation and Coagulation
1. Flocculation requires a mix: From slow and low energy type.
2. Coagulation is: The removal of electric charges, the effect of a reagent.
Decantation
3. The performance of a decanter: Is less the greater the upward speed.
4. Colloids: Influence the turbidity and water color.
5. In a circular static decanter, large sludge scrapers lead to: The central zone.
6. In a pulsed bed decanter: (Missing information, cannot be completed)
Filtration
7. The phenomenon known as “breaking the filter” consists of: Detachment of particles retained.
8. The “career” of a filter: Is the time between two washes.
9. Slow filtration: Provides excellent filtered water quality.
10. In fast filters: Removal of particles is produced only in physical processes.
Disinfection
11. By disinfecting: Pathogens are eliminated.
12. Free chlorine available is: The chlorine in the water as hypochlorous acid, hypochlorite, and chlorine ions molecular.
13. We define “break point” as: The dose required to destroy or oxidize all chloramines.
14. Disinfection by ozonation: Is optimal, but expensive.
15. Active carbon: Is used to eliminate odors, flavors, and other organic contaminants.
Desalination
16. Desalination pretreatment: Reduces operating costs.
17. Ultrafiltration: Removes viruses.
18. Multi-stage flash distillation: The different stages are under pressure.
19. Electrodialysis: Is the recommended treatment of brackish water.
20. Reverse osmosis: Must register sand filters and cartridge before the pump.
21. The membrane of an RO process can be: In spiral.
Pretreatment
22. The purpose of pretreatment is: To avoid problems of obstruction in the subsequent installations.
23. The grids should be cleaned: In both cases.
24. The sand trap: Both are correct.
Wastewater Treatment
25. Primary decanters: In wastewater treatment plants (WWTPs) are static in order to avoid increases in the concentration of organic matter (OM).
26. The process of dissolved air flotation is based: On air into pressurized water flow.
27. The dumping at sea of sewage could be made: With a previous primary treatment.
Biological Treatment
28. The aim of recirculating water in a bacterial bed reactor is: The limiting concentration of organic matter in water.
29. The medium of a bacterial bed support: More is better than the specific surface and the rate of holes.
30. The ventilation of a bacterial bed: Is usually natural through open gaps in the lower deposit.
31. In the activated sludge process: Oxidation of OM occurs in the reactor.
32. Mass load is: Mass of substrate consumed by the mass of microorganisms in the reactor in unit time.
33. The purpose of ventilation systems in an active sludge process is: Both are correct.
34. The purpose of sludge recirculation in an activated sludge process is: To ensure high levels of biomass in the reactor.
Tertiary Treatment
35. Chlorination in a debugging process: Is in itself a tertiary treatment to the treated water.
Sludge Treatment
36. Gravity thickeners: Are used for thickening sludge of all kinds.
37. The stabilization of sludge by heat treatment: Is often combined with anaerobic digestion.
38. In the dehydration of sludge: Drying beds have similar performance to mechanical systems.
39. Septic tanks: Stabilize the sludge by anaerobic digestion.
40. Lagoon systems: Work best in waters with high organic load.