Skip to main content
Sign in Register
Sarkari MCQs Government Exam Question Bank
Question no. 17019

Wastewater containing grease and floating oils requires treatment in what type of unit_________________?

Select your answer for: Wastewater containing grease and floating oils requires treatment in what type of unit_________________?
Show answer

Answer: C. skimming tanks

Explanation

Skimming tanks are specialized wastewater treatment units specifically designed to remove grease, oil, and floating scum. They operate by slowing water velocity and allowing lighter-than-water hydrocarbons to float to the surface. Mechanical skimmers then sweep the accumulated surface layer away before it reaches downstream biological units. Grease and floating oils interfere with biological wastewater treatment by coating microbial cell walls. Skimming tanks are typically placed ahead of primary sedimentation basins to protect downstream mechanical equipment. Air injection is sometimes used in conjunction with skimming to enhance floatation of fine grease droplets.

Municipalities require restaurants and industrial food processors to install grease traps before discharging to sewers. Wastewater treatment plants rely on skimming units to prevent unsightly scum accumulation in settling tanks. Effective oil removal protects pumps, pipes, and aeration equipment from clogging and operational failure. Grit chambers are designed to remove heavy inorganic sand and gravel particles rather than floating oils. Detritus tanks capture heavy grit and organic debris rather than specialized grease and floating scum. Sedimentation tanks settle out suspended solids but do not effectively skim floating oils from the surface.

Subject
Engineering
Category
Civil Engineering
Topic
—
Difficulty
medium

Related questions

Engineering Civil Engineering
medium

Q1. If Biochemical oxygen demand (BOD) of a town is 20000 kg/day and BOD per capita per day is 0.05 kg, then population equivalent of town is_________________?

Select your answer for: If Biochemical oxygen demand (BOD) of a town is 20000 kg/day and BOD per capita per day is 0.05 kg, then population equivalent of town is_________________?
Save
Show answer

Answer: D. 400000

Population equivalent is calculated by dividing total municipal biological oxygen demand per day by per capita demand. Dividing twenty thousand kilograms per day by zero point zero five kilograms per capita yields four h...

Engineering Civil Engineering
medium

Q2. When coliform bacteria are detected in a water specimen, which confirmatory test must be administered_____________?

Select your answer for: When coliform bacteria are detected in a water specimen, which confirmatory test must be administered_____________?
Save
Show answer

Answer: A. presumptive coliform test

Detecting coliform bacteria triggers the presumptive coliform test initially. This first step uses lactose broth fermentation tubes to detect gas production. Positive presumptive results must then undergo further confirm...

Engineering Civil Engineering
medium

Q3. Under Indian operational conditions, what is the typical sludge volume index for normal sludge________________?

Select your answer for: Under Indian operational conditions, what is the typical sludge volume index for normal sludge________________?
Save
Show answer

Answer: C. 150 to 350

Under Indian operational conditions, normal activated sludge exhibits a sludge volume index ranging between 150 and 350. This empirical range reflects the settling characteristics of biomass typical in regional wastewate...

Engineering Civil Engineering
medium

Q4. The principle stating that increasing variable inputs while holding one production factor fixed leads to less-than-proportional output gains is known as______________?

Select your answer for: The principle stating that increasing variable inputs while holding one production factor fixed leads to less-than-proportional output gains is known as______________?
Save
Show answer

Answer: A. Law of diminishing return

The law of diminishing returns states that adding variable inputs while holding one factor constant yields smaller gains. Initially, output may rise rapidly, but successive additions of the variable input eventually prod...

Engineering Civil Engineering
medium

Q5. When total water hardness exceeds total alkalinity, carbonate hardness is calculated as being equal to________________?

Select your answer for: When total water hardness exceeds total alkalinity, carbonate hardness is calculated as being equal to________________?
Save
Show answer

Answer: A. total alkalinity

Carbonate hardness is limited by and equal to total alkalinity when hardness exceeds it. Any hardness remaining beyond total alkalinity is classified as non-carbonate hardness. This chemical relationship simplifies water...

Engineering Civil Engineering
medium

Q6. Treatment of sewage within a facultative stabilization pond is accomplished via________________?

Select your answer for: Treatment of sewage within a facultative stabilization pond is accomplished via________________?
Save
Show answer

Answer: C. dual action of aerobic bacteria and anaerobic bacteria

Aerobic bacteria break down complex organic pollutants in the upper pond layers efficiently. Anaerobic bacteria stabilize settled sludge at the bottom through rigorous fermentation processes. Algae produce essential oxyg...