Environmental Engineering - Study Mode
[#111] 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
Correct Answer
(D) 4,00,000
[#112] The specific gravity of sewage is
Correct Answer
(D) Slightly greater than 1
[#113] The effective size of sand particles used in slow sand filters is
Correct Answer
(A) 0.25 to 0.35 mm
Explanation
Solution: Slow sand filters are a type of water treatment system. They use layers of sand to remove impurities from water. The size of the sand particles is important for how well the filter works. If the sand is too fine, the water will flow too slowly. If the sand is too coarse, it won't trap enough impurities. The effective size refers to the size of the particles where 10% of the sand is finer. For slow sand filters, the effective size needs to be just right for optimal performance. The correct range for effective sand particle size in slow sand filters is 0.25 to 0.35 mm . Therefore, the best option is A .
[#114] Chlorine demand of water is equal to
Correct Answer
(D) Difference of applied and residual chlorine
[#115] Corrosion in concrete sewers is caused by
Correct Answer
(A) Septic conditions