Environmental Engineering — Part 2 MCQs with Explanations

15 cm and 300 cm is the correct answer to “The minimum and maximum diameters of sewers shall preferably be”. This question is standard in competitive examination syllabi for Environmental Engineering.

Oxidation is the correct answer to “The biochemical treatment of sewage effluents is essentially a process of”. This question is standard in competitive examination syllabi for Environmental Engineering.

25 years is the correct answer to “Sewerage system is usually designed for”. This question is standard in competitive examination syllabi for Environmental Engineering.

15 - 20 years is the correct answer to “Sewage treatment units are normally designed for”. This question is standard in competitive examination syllabi for Environmental Engineering.

1 minute is the correct answer to “Generally the detention period for grit chambers is kept as”. This question is standard in competitive examination syllabi for Environmental Engineering.

Removing odours is the correct answer to “Activated carbon is used for”. This question is standard in competitive examination syllabi for Environmental Engineering.

Consists of undesirable substances rendering it unfit for drinking and domestic use is the correct answer to “The polluted water is one which”. This question is standard in competitive examination syllabi for Environmental Engineering.

200 ppm is the correct answer to “In a BOD test, 1.0 ml of raw sewage was diluted to 100 ml and the dissolved oxygen concentration of diluted sample at the beginning was 6 ppm and it was 4 ppm at the end of 5 day incubation at 20°C. The BOD of raw sewage will be”. This question is standard in competitive examination syllabi for Environmental Engineering.

0.05 to 0.5 ppm is the correct answer to “The amount of residual chlorine left in public water supply for safety against pathogenic bacteria is about”. This question is standard in competitive examination syllabi for Environmental Engineering.

None of the above is the correct answer to “Which of the following retards the self purification of stream”. This question is standard in competitive examination syllabi for Environmental Engineering.

(i) and (iv) is the correct answer to “As compared to rapid sand filters, slow sand filters give (i) Slower filtration rate (ii) Higher filtration rate (iii) Lesser efficiency in removal of bacteria (iv) Higher efficiency in removal of bacteria The correct answer is”. This question is standard in competitive examination syllabi for Environmental Engineering.

(i) and (iv) is the correct answer to “The amount of coagulant needed for coagulation of water increases with (i) Increase in turbidity of water (ii) Decrease in turbidity of water (iii) Increase in temperature of water (iv) Decrease in temperature of water The correct answer is”. This question is standard in competitive examination syllabi for Environmental Engineering.

(i) and (iv) is the correct answer to “Cleaning is done by (i) Scraping and removal in filters slow sand (ii) Back washing in slow sand filters (iii) Scraping and removal in filters rapid sand (iv) Back washing in rapid sand filters The correct answer is”. This question is standard in competitive examination syllabi for Environmental Engineering.

Percentage of sludge by volume to percentage of suspended solids by weight is the correct answer to “Sludge volume index is defined as the ratio of”. This question is standard in competitive examination syllabi for Environmental Engineering.

1.5 mg/liter is the correct answer to “The maximum permissible limit for fluoride in drinking water is”. This question is standard in competitive examination syllabi for Environmental Engineering.

Presence as well as in absence of oxygen is the correct answer to “Facultative bacteria are able to work in”. This question is standard in competitive examination syllabi for Environmental Engineering.

4 ppm is the correct answer to “The minimum dissolved oxygen which should always be present in water in order to save the aquatic life is”. This question is standard in competitive examination syllabi for Environmental Engineering.

10 mg/liter is the correct answer to “The dissolved oxygen level in natural unpolluted waters at normal temperature is found to be of the order of”. This question is standard in competitive examination syllabi for Environmental Engineering.

Lesser value is the correct answer to “As compared to geometrical increase method of forecasting population, arithmetical increase method gives”. This question is standard in competitive examination syllabi for Environmental Engineering.

Directly proportional to BOD remaining is the correct answer to “The rate of BOD exerted at any time is”. This question is standard in competitive examination syllabi for Environmental Engineering.

All (i), (ii) and (iii) is the correct answer to “If the coli form bacteria is present in a sample of water, then the coli-form test to be conducted is (i) Presumptive coli-form test (ii) Confirmed coli-form test (iii) Completed coli-form test”. This question is standard in competitive examination syllabi for Environmental Engineering.

75 is the correct answer to “Percentage of bacterial load that can be removed from water by the process of plain sedimentation is about”. This question is standard in competitive examination syllabi for Environmental Engineering.

Egg shaped sewer is the correct answer to “The type of sewer which is suitable for both combined and separate system is”. This question is standard in competitive examination syllabi for Environmental Engineering.

Malaria is the correct answer to “Which of the following is not a water borne disease”. This question is standard in competitive examination syllabi for Environmental Engineering.

Reflux valve is the correct answer to “The type of valve which allows water to flow in one direction but prevents its flow in the reverse direction is”. This question is standard in competitive examination syllabi for Environmental Engineering.

Greater than that of rapid sand filters is the correct answer to “The rate of Alteration of pressure filters is”. This question is standard in competitive examination syllabi for Environmental Engineering.

Anti-siphonage pipe is the correct answer to “A pipe which is installed in the house drainage to preserve the water seal of traps is called”. This question is standard in competitive examination syllabi for Environmental Engineering.

N = y + R is the correct answer to “Select the correct relationship between porosity (N), specific yield (y) and specific retention (R)”. This question is standard in competitive examination syllabi for Environmental Engineering.

2 to 4 is the correct answer to “The percentage of filtered water, which is used for backwashing in rapid sand filters, is about”. This question is standard in competitive examination syllabi for Environmental Engineering.

30 to 35 is the correct answer to “The percentage of chlorine in fresh bleaching powder is about”. This question is standard in competitive examination syllabi for Environmental Engineering.

Separate system is the correct answer to “For a country like India, where rainfall is mainly confined to one season, the suitable sewerage system will be”. This question is standard in competitive examination syllabi for Environmental Engineering.

40 mm/hr is the correct answer to “If the time of concentration is 9 minutes, then the intensity of rainfall according to British Ministry of Health formula will be”. This question is standard in competitive examination syllabi for Environmental Engineering.

150 to 350 is the correct answer to “For normal sludge, the value of sludge index for Indian conditions is”. This question is standard in competitive examination syllabi for Environmental Engineering.

Carbon dioxide is the correct answer to “The most common cause of acidity in water is”. This question is standard in competitive examination syllabi for Environmental Engineering.

4B is the correct answer to “The length of rectangular sedimentation tank should not be more than (Where ‘B’ is the width of the tank)”. This question is standard in competitive examination syllabi for Environmental Engineering.

(i) and (ii) is the correct answer to “Septic tank is a (i) Settling tank (ii) Digestion tank (iii) Aeration tank”. This question is standard in competitive examination syllabi for Environmental Engineering.

To increase the filtration slow sand filters capacity of is the correct answer to “Double filtration is used”. This question is standard in competitive examination syllabi for Environmental Engineering.

Sulphur dioxide is the correct answer to “Which of the following chemical compounds can be used for de-chlorination of water”. This question is standard in competitive examination syllabi for Environmental Engineering.

Sluice valve is the correct answer to “The type of valve which is provided to control the flow of water in the distribution system at street corners and where the pipe lines intersect is”. This question is standard in competitive examination syllabi for Environmental Engineering.

More and less is the correct answer to “The detention period and overflow rate respectively for plain sedimentation as compared to sedimentation with coagulation are generally”. This question is standard in competitive examination syllabi for Environmental Engineering.