A. The presence of oxygen
B. The absence of oxygen
C. Both cases A. and B.
D. Neither A. nor B.
Correct Answer: C. Both cases A. and B. ✔
Last Updated: August 25, 2020
Related MCQs
- Pick up the incorrect statement from the following?
- Pick up the incorrect statement from the following?
- Pick up the correct statement from the following?
- Pick up the correct statement from the following?
- Pick up the correct statement from the following?
- Pick up the correct statement from the following?
- Pick up the correct statement from the following?
- Pick up the correct statement from the following?
- Pick up the correct statement from the following ?
- The layers of vegetable wastes and night soil alternatively piled above the ground to form a mound, is called__________?
- The gas which may cause explosion in sewers, is__________?
- The discharge per unit plan area of a sedimentation tank, is generally called__________?
- The settling velocity of the particles larger than 0.06 mm in a settling tank of depth 2.4 is 0.33 m per sec. The detention period recommended for the tank, is__________?
- Pick up the incorrect statement from the following for allowing workers to enter sewers__________?
- To prevent settling down of sewage both at the bottom and on the sides of a large sewer, self-cleaning velocity recommended for Indian conditions, is__________?
- The normal values of over flow rates for sedimentation tanks using coagulant, ranges between__________?
- At the junction of sewers__________?
- Sewer pipes are designed for maximum discharge with 25% to 33% vacant cross-sectional area for__________?
- The sewer that unloads the sewage at the point of treatment is called__________?
- For a grit chamber, if the recommended velocity of flow is 0.2 m/sec and detention period is 2 minutes, the length of the tank, is__________?
- If q is the average sewage flow from a city of population P, the maximum sewage flow__________?
- If the depth of flow in a circular sewer is 1/4th of its diameter D, the wetted perimeter is__________?
- If the flame of a miner’s safety lamp in a manhole extinguishes within 5 minutes, the sewer certainly contains__________?
- The sewage treatment units in which anaerobic decomposition of organic matter is used, are called__________?
- If the diameter of a sewer is 150 mm, the gradient required for generating self cleansing velocity, is__________?
- The grit and silt of the grit chambers, may not be used for__________?
- Imhoff cone is used to measure__________?
- Dilution method of disposing of sewage, is not preferred to__________?
- The reduced levels of the string at the consecutive sight rails A and B are 203.575 m, 203.475 m respectively. If the difference of their R.D.s is 10 m, the gradient of the sewer line is__________?
- For the COD test of sewage, organic matter is oxidised by K2Cr2O7 in the presence of__________?
- In sewers the velocity of flow should not be__________?
- In sewers the effect of scouring is more on__________?
- Sewer ventilating columns are generally placed at__________?
- In a sedimentation tank (length L, width B, depth D) the settling velocity of a particle for a discharge Q, is__________?
- The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known__________?
- Water content of sewage is about__________?
- The most efficient cross-section of sewers in a combined sewerage system is__________?
- The factor responsible for purification of sewage in river is__________?
- To maintain aerobic biological activity, the moisture content of the compost mass should be about__________?
- The pH value of sewage is determined with the help of__________?
- The normal value of over flow rates for plain primary sedimentation tanks, ranges between__________?
- Which one of the following statements regarding septic tanks is wrong ?
- In areas where rainy season is limited to a few months, the type of sewerage system recommended is__________?
- Dried sewage after treatment is used as__________?
- In areas where light rains are uniformly distributed throughout the year, the type of sewerage system to be adopted is__________?
- 5 days-biochemical oxygen demand (BOD5) is taken at a temperature of__________?
- Pick up the in-correct statement from the following?
- The moisture content of sludge is reduced from 90% to 80% in a sludge digestion tank. The percentage decrease in the volume of sludge, is__________?
- Bio-chemical oxygen demand (BOD) for the first 20 days in generally referred to__________?
- If is the diameter of upper circular portion, the overall depth of New Egg shaped sewer section, Is__________?
- For evaporation and measurement of settable solids, the apparatus used, is__________?