Wastewater Treatment: Key Concepts and Processes

Posted on Mar 15, 2025 in Geology

Wastewater Treatment: Key Concepts

  1. As SRT increases: Sbeff decreases and XH increases

  2. What is the right definition of SRT? V/Qw

  3. What is the process that inactivates pathogens in ozone disinfection? Breaking cellular membrane.

  4. What is the coagulation process? Formation of micro-flocs from destabilized colloids.

  5. What cations are responsible for the hardness of water? Mg2+ and Ca2+

  6. If the partial pressure of a gas increases, the solubility in water of the gas: Increases

  7. What type of particles are responsible for turbidity? Particulate non-settleable compounds.

  8. Which of the following is an effect of thermal pollution? Lack of O2 due to lower solubility of gases at high temperature.

  9. Which of the following is an effect of eutrophication? All are correct: Increase of pH of water where there is eutrophication; Plants do not grow to the back of sunlight; Bacteria consume the oxygen in water by degrading dead plants.

  10. What does eutrophication refer to? An excess of algae growth due to inorganic nutrients.

  11. What is the objective of the Water Framework Directive? To guarantee the availability of natural resources.

  12. What is the objective of the urban wastewater treatment directive? To protect the environment from urban wastewater discharges.

  13. What is the objective of the settling process? To remove suspended solids.

  14. What parameter affects the up-flow velocity of the water in a settler? The surface of the settler.

  15. What is the flocculation process? The formation of macro-flocs from destabilized colloids.

  16. Which parameter affects the efficiency of a settler? Particle settling velocity and up-flow velocity of water.

  17. What is the process that inactivates pathogens in chlorine disinfection? Oxidation of the pathogens.

  18. What parameter does not affect the disinfection with ozone? pH

  19. Which is the correct definition of COD? O2 consumed during the chemical oxidation of wastewater.

  20. What is the process that inactivates pathogens in ultraviolet disinfection? Destruction of DNA chains.

  21. What is the objective of the bar screening? To remove inorganic particulate solids.

  22. What is removed in the secondary treatment? Organic matter, nitrogen, and phosphorus.

  23. Which is the correct definition of BOD? O2 consumed during the biological oxidation of wastewater.

  24. Which is the right definition of HRT? V/Qin

  25. What does Sbeff depend on? SRT, bh, Ks, and μH

  26. As Qw decreases: Sbeff decreases and XH increases.

  27. What type of bacteria can degrade NH4? XA atrophic bacteria.

  28. What type of bacteria can degrade COD? XH heterotrophic bacteria.

  29. During the oxidation of NH4: O2 is consumed and NO3 is produced.

  30. During anoxic degradation of organic matter: NO3 is consumed and N2 is produced.

  31. During anoxic oxidation of organic matter: NO3 is consumed.

  32. YA represents: grams of XA generated per gram of NH4 consumed.

  33. Which of the following uses are allowed for regenerated water? Irrigation of golf courses, cleaning of streets, and ponds.

  34. Which are the optimum conditions for struvite recovery? 8 < pH < 10 and low temperatures.

  35. What does the term oxygen sag refer to? The lack of oxygen due to organic matter discharge.