Q.1
Dissolved oxygen in streams is
Q.2
If the time of concentration is 9 minutes, then the intensity of rainfall according to British Ministry of Health formula will be
Q.3
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
Q.4
Percentage of bacterial load that can be removed from water by the process of plain sedimentation is about
Q.5
The type of sewer which is suitable for both combined and separate system is
Q.6
Which of the following is not a water borne disease?
Q.7
The type of valve which allows water to flow in one direction but prevents its flow in the reverse direction is
Q.8
The rate of Alteration of pressure filters is
Q.9
Facultative bacteria are able to work in
Q.10
The minimum dissolved oxygen which should always be present in water in order to save the aquatic life is
Q.11
The dissolved oxygen level in natural unpolluted waters at normal temperature is found to be of the order of
Q.12
The amount of residual chlorine left in public water supply for safety against pathogenic bacteria is about
Q.13
Which of the following retards the self purification of stream?
Q.14
Sewage treatment units are normally designed for
Q.15
Generally the detention period for grit chambers is kept as
Q.16
Activated carbon is used for
Q.17
The gas from sludge digestion tank is mainly composed of
Q.18
The maximum efficiency of BOD removal is achieved in
Q.19
The correct relation between theoretical oxygen demand (TOD), Biochemical oxygen demand (BOD) and Chemical oxygen demand (COD) is given by
Q.20
As compared to shallow wells, deep wells have
Q.21
As compared to cast iron pipes, steel pipes are
Q.22
A pipe which is installed in the house drainage to preserve the water seal of traps is called
Q.23
Select the correct relationship between porosity (N), specific yield (y) and specific retention (R)
Q.24
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
Q.25
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
Q.26
The polluted water is one which
Q.27
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
Q.28
The minimum and maximum diameters of sewers shall preferably be
Q.29
The biochemical treatment of sewage effluents is essentially a process of
Q.30
Sewerage system is usually designed for
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