🚧 Civil Engineering Solved MCQs with Answers

Practice 1228 approved 🚧 Civil Engineering questions with verified answers from the 🛠️ Engineering Essentials subject for Pakistan exams.

1228 solved MCQs

The rate of accumulation of sludge in septic tanks is recommended asAnswer: 30 litres/person/year If 2% solution of a sewage sample is incubated for 5 days at 20°C and depletion of oxygen was found to be 5 ppm, B.O.D. of the sewage isAnswer: 250 ppm If D is the diameter of upper circular portion, the overall depth of a standard egg shaped section, isAnswer: 1.5 D If the diameter of sewer is 225 mm, the gradient required for generating self cleansing velocity, isAnswer: 1 in 120 Pick up the correct statement from the following :Answer: All the above. The non-clog pump which permits solid matter to pass out with the liquid sewage, isAnswer: centrifugal pump Assertion (A) : Discharging the effluents from the oxidation ponds just up stream of lakes or reservoirs is undesirable. Reason (R) : The discharged algae get settled in the reservoirs and cause anaerobic decomposition and other water qualities.Answer: Both A and R are true and R is the correct explanation of A The width of a rectangular sewer is twice its depth while discharging 1.5 m/sec. The width of the sewer isAnswer: 1.36 m Pick up the correct statement from the following :Answer: All the above. In olden days the type of section adopted in trunk and out fall sewers wasAnswer: horse shoe shaped For the survival of fish in a river stream, the minimum dissolved oxygen is prescribedAnswer: 4 PPm In a fully mechanised composting plant, involvesAnswer: all of these. Self-cleansing velocity isAnswer: velocity at which no accumulation remains in the drains If the over land flow from the critical point to the drain is 8 km and the difference in level is 12.4 m, the inlet time isAnswer: 4 hours An inverted siphon is designed generally forAnswer: three pipes A rainfall may be classified as acidic if its pH value is less or equal toAnswer: 5 When drainage to sewage ratio is 20, the peak dry weather flow isAnswer: slightly less than 5% of the design discharge For treating the sewage of a large city, you will recommendAnswer: a sedimentation tank and an activated sludge treatment plant The dimensions of a rectangular settling tank are : length 24 m, width 6 m and depth 3 m. If 2 hour detention period for tanks is recommended, the rate of flow of sewage per hour, isAnswer: 216 cu m The screens are fixedAnswer: at an angle 30° to 60° to the direction of flow In primary sedimentation, the 0.2 mm inorganic solids get separated if specific gravity isAnswer: 2.65 Pick up the in-correct statement from the following :Answer: Inlets are generally provided in all sewers Clogging of sewers, is caused due toAnswer: all the above. A sewer pipe contains 1 mm sand particles of specific gravity 2.65 and 5 mm organic particles of specific gravity 1.2, the minimum velocity required for removing the sewerage, isAnswer: 0.45 m/sec The coagulant widely used for sewage treatment, isAnswer: ferric chloride House connections to the laterals is generally made byAnswer: Glazed stonewares. The ratio of maximum sewage flow to average sewage flow for mains up to 1 m in diameter, isAnswer: 2.0 Dilution method of disposing off sewage, is not preferred toAnswer: when diluting water is used for water supply near the point of sewage disposed For house drainage minimum gradient isAnswer: 1 in 60 If the side of a square sewer is 1000 mm, the diameter of a hydraulically equivalent circular section, isAnswer: 1095 mm.