waste water engineering MCQs – Page 8

Practise focused waste water engineering questions with marked answers for exam preparation and subject revision.

waste water engineering Mcqs
141. The most dangerous pollutant in vehicular emissions is____________________?
comments icon0

A. O3

B. CO2

C. SO2

D. CO
142. If the pH value of sewage is 7__________________?
comments icon0
A. It is neutral

B. It is alkaline

C. It is acidic

D. None of these

143. pH value of sludge during alkaline regression stage, is__________________?
comments icon0

A. More than 6

B. Less than 6

C. Less than 7

D. More than 7
144. 3.0 ml of raw sewage is diluted to 300 ml. The D.O. concentration of the diluted sample at the beginning of the test was 8 mg/l. After 5 day-incubation at 20C, the D.O. concentration was 5 mg/l. The BOD of raw sewerage is______________________?
comments icon0
A. 300 mg/l

B. 400 mg/l

C. 200 mg/l

D. 100 mg/l

145. The gas evolved in sewers is________________?
comments icon0

A. Carbondioxide

B. Hydrogen sulphide

C. Methane

D. All of these
146. If D is the diameter of a circular sewer and D is the top horizontal diameter of an equivalent egg shaped section, the relationship which holds good, is_______________?
comments icon0

A. D = 0.94 D

B. D = 0.74 D

C. D = 0.64 D

D. D = 0.84 D
147. The screens are fixed___________________?
comments icon0

A. Parallel to the direction of flow

B. None of these

C. Perpendicular to the direction of flow

D. At an angle 30 to 60 to the direction of flow
148. House connections to the laterals is generally made by___________________?
comments icon0
A. Glazed stonewares

B. Cast iron

C. R.C.C.

D. P.C.C.

149. Skimming tanks are__________________?
comments icon0

A. Tanks provided with self- cleansing screens

B. Improved version of grit chambers

C. Used to remove the grease and oil

D. Those from which sludge is skimmed out

150. If the side of a square sewer is 1000 mm, the diameter of a hydraulically equivalent circular section, is___________________?
comments icon0

A. 1065 mm

B. 1095 mm

C. 1075 mm

D. 1045 mm

151. The sewerage system consists of______________________?
comments icon0
A. All of these

B. Branch sewer

C. House sewer

D. Lateral sewer

152. The disintegrating pump in which solid matter is broken up before passing out, is__________________?
comments icon0

A. Pneumatic ejector

B. None of these

C. Reciprocating pump

D. Centrifugal pump
153. In sewers the gas generally found, is_________________?
comments icon0
A. All the above

B. Hydrogen sulphide (H2S)

C. Carbon dioxide (CO2)

D. Methane (CH4)

154. Depletion of ozone layer in the outer atmosphere may cause___________________ ?
comments icon0

A. Heart disorder

B. Skin cancer

C. Bronchitis

D. Lung cancer

155. Dry water flow in a combined sewer, is______________________?
comments icon0

A. Domestic sewage

B. Industrial sewage

C. Storm water

D. Inclusive of domestic and industrial sewage but excludes storm water

156. The presence of free ammonia in sewage, is detected by___________________?
comments icon0

A. Adding potassium permanganate

B. Phenol-di-sulphuric acid

C. Boiling

D. Adding sulphuric acid

157. In septic tanks__________________?
comments icon0

A. The clear space between the baffle top and covering slab is about 7.5 cm

B. The baffles or tees are extended up to top level of scum

C. All the above

D. Free board of 0.3 m may be provided

158. For sewer mains of 0.5 to 1 m diameter, the ratio of maximum daily sewage flow to the average daily sewage flow is assumed__________________?
comments icon0

A. 1.5

B. 3

C. 2.0

D. 2.5

159. Fresh sewage may become stale in_________________?
comments icon0

A. Six hours

B. Three to four hours

C. Two to three hours

D. One hour

160. The formula V = (1/n) r2/3____________________?
comments icon0

A. Kutters formula

B. Bazins formula

C. Mannings formula

D. Chezys formula