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Environmental Engineering Practice Test: Sewage Filtration and Activated Sludge Process
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Sewage treatment, also known as wastewater treatment, aims to remove contaminants from sewage. This produces an effluent that can be discharged into the environment or reused. The activated sludge process for removing carbonaceous pollution begins with an aeration tank where air (or oxygen) is injected into the waste water. This is followed by a settling tank to allow the biological flocs (the sludge blanket) to settle, thus separating the biological sludge from the clear treated water.   Topics include: Types of Sewage Filter, Conventional Trickling Filter, High Rate Trickling Filter and... Show more
Environmental Engineering Practice Test: Sewage Filtration and Activated Sludge Process
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25 Questions

1. 7% of solids concentration of thickened sludge is obtained from gravity thickener. What is the type of sludge?
2. Recirculation increases the efficiency of high rate trickling filters.
3. Which gas evolves the most in the sludge digestion process?
4. The depth of the filter media of intermittent filter is ___________
5. The recirculation factor in a low rate trickling filter is ___________
6. The size of filter media in a high rate trickling filter is ___________
7. The form of sludge which is free from pathogenic bacteria is ___________
8. With which device, the air is introduced in the aeration tank?
9. The organic loading in low rate trickling filter is 900 kg/hectare-meter/day. What is the efficiency of the filter?
10. The maximum depth of aeration tank used in activated sludge process is ___________
11. The range of temperature at which mesophilic microorganism becomes active in sludge digester is ___________
12. Which of the following plant nutrient is not found in municipal sewage?
13. Which of the following is correct regarding pH in different stages of the sludge digestion process?
14. The sludge digestion process is independent of which of the following?
15. Which of the following is not a drying bed?
16. The minimum size of sludge digestion tank is ___________
17. The detention period of a secondary clarifier is ___________
18. The color of the secondary sludge produced from the high rate trickling filter is ___________
19. In which of the following, both primary and secondary tanks are used?
20. The removal of BOD is independent of the loading conditions in infiltration process.
21. Which of the following is correct regarding anaerobic digestion in the sludge digestion process?
22. Which of the following filter is used in the anaerobic treatment of sewage?
23. The minimum weir loading rate of primary clarifier is ____m3/m/day.
24. The intermittent sand filters have better BOD removal efficiency than trickling filters.
25. The dewatered sludge cannot be disposed by ___________