Wastewater characteristics MCQs Civil

1. Wastewater is primarily classified as:
(A) Domestic and industrial
(B) Surface and groundwater
(C) Potable and non-potable
(D) Runoff and stormwater

2. The major component of domestic wastewater is:
(A) Suspended solids
(B) Water
(C) Heavy metals
(D) Nutrients

3. The measure of organic matter in wastewater is expressed as:
(A) BOD (Biochemical Oxygen Demand)
(B) COD (Chemical Oxygen Demand)
(C) TDS (Total Dissolved Solids)
(D) pH

4. COD measures:
(A) Oxygen required by microbes to decompose organic matter
(B) Oxygen required to chemically oxidize organic and inorganic matter
(C) Total solids in wastewater
(D) Nutrient content

5. Typical pH of domestic wastewater is:
(A) 4–5
(B) 6–9
(C) 9–11
(D) 2–3

6. Suspended solids in wastewater are:
(A) Dissolved salts
(B) Particles that settle by gravity
(C) Microorganisms only
(D) Oils and grease

7. Total dissolved solids (TDS) in wastewater are mainly:
(A) Suspended organic matter
(B) Dissolved inorganic salts
(C) Fats and oils
(D) Sediments

8. The nitrogen content in wastewater is mostly in the form of:
(A) Ammonia, nitrate, and organic nitrogen
(B) Nitrogen gas only
(C) Nitrite only
(D) Nitrogen oxides

9. The C:N:P ratio in domestic wastewater for microbial growth is approximately:
(A) 100:5:1
(B) 100:10:1
(C) 50:5:1
(D) 100:1:1

10. The color of wastewater is primarily due to:
(A) Dissolved organic matter and industrial dyes
(B) Suspended sand
(C) Microorganisms
(D) Temperature

11. Grease and oils in wastewater are measured by:
(A) COD
(B) Fat, Oil, and Grease (FOG) test
(C) BOD
(D) pH

12. The smell of wastewater is usually caused by:
(A) Dissolved solids
(B) Temperature
(C) Heavy metals
(D) Hydrogen sulfide (H2S) and ammonia

13. Total solids in wastewater consist of:
(A) Suspended solids + dissolved solids
(B) Only dissolved solids
(C) Only suspended solids
(D) Oils and fats only

14. Settleable solids in wastewater are determined using:
(A) BOD test
(B) Imhoff cone
(C) pH meter
(D) COD test

15. BOD5 refers to:
(A) Oxygen demand in 1 day
(B) Total solids in 5 days
(C) COD in 5 days
(D) Oxygen demand in 5 days at 20°C

16. The average BOD of domestic wastewater is typically:
(A) 5–10 mg/L
(B) 150–300 mg/L
(C) 1000–1500 mg/L
(D) 10–20 mg/L

17. COD of domestic wastewater is usually:
(A) 250–600 mg/L
(B) 100–200 mg/L
(C) 1000–2000 mg/L
(D) 50–100 mg/L

18. Ammonia nitrogen in wastewater mainly comes from:
(A) Industrial dyes
(B) Oil and grease
(C) Urine and protein degradation
(D) Sand and grit

19. Wastewater temperature affects:
(A) Solubility of solids
(B) Rate of microbial activity
(C) Odor only
(D) All of the above

20. Heavy metals in wastewater are mostly:
(A) Copper, lead, zinc, chromium
(B) Sodium and potassium
(C) Nitrogen compounds
(D) Carbonates

21. Conductivity of wastewater indicates:
(A) Amount of solids
(B) Amount of dissolved salts
(C) Microbial activity
(D) Oxygen content

22. Fecal coliforms in wastewater indicate:
(A) Organic content
(B) pH
(C) Dissolved oxygen
(D) Presence of pathogens

23. The standard unit of BOD measurement is:
(A) mg/L
(B) ppm
(C) m3/s
(D) kg/day

24. Oil and grease in wastewater can cause:
(A) Blockage in sewers
(B) Interference with biological treatment
(C) Floating scum
(D) All of the above

25. Settling velocity of solids is affected by:
(A) Particle size and density
(B) Temperature only
(C) BOD
(D) pH

26. The main reason for testing wastewater characteristics is to:
(A) Design sewer pipes
(B) Design treatment plants and processes
(C) Estimate rainfall
(D) Determine soil type

27. Turbidity in wastewater is due to:
(A) Dissolved salts
(B) Heavy metals
(C) Suspended solids and colloids
(D) Oils

28. Industrial wastewater is usually:
(A) Homogeneous and consistent
(B) Highly variable and may contain toxic substances
(C) Pure water
(D) Free from suspended solids

29. Alkalinity in wastewater is mainly caused by:
(A) Carbonates, bicarbonates, and hydroxides
(B) Suspended solids
(C) Oils
(D) Heavy metals

30. The main purpose of wastewater characterization is to:
(A) Reduce construction cost of sewers
(B) Determine appropriate treatment and disposal methods
(C) Increase rainfall runoff
(D) Measure soil type