The type of valve which allows water to flow in one direction but prevents its flow in the reverse direction is Pressure relief valve Sluice valve Air relief valve Reflux valve TRUE ANSWER : ? YOUR ANSWER : ?
The relative stability of a sewage sample, whose dissolved oxygen is same as the total oxygen required to satisfy BOD, is 100 1 Infinite Zero TRUE ANSWER : ? YOUR ANSWER : ?
The self cleansing velocity for all sewers in India is usually 1.0 m/sec to 1.2 m/sec 3.0 m/sec to 3.5 m/sec 1.5 m/sec to 2.0 m/sec Less than 1.0 m/sec TRUE ANSWER : ? YOUR ANSWER : ?
Septic tank is a (i) Settling tank (ii) Digestion tank (iii) Aeration tank Only (iii) (i) and (ii) Only (i) (i) and (iii) TRUE ANSWER : ? YOUR ANSWER : ?
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 400 ppm 100 ppm 200 ppm 300 ppm TRUE ANSWER : ? YOUR ANSWER : ?
Air binding phenomena in rapid sand filters occur due to Higher turbidity in the effluent Low temperature Excessive negative head Mud ball formation TRUE ANSWER : ? YOUR ANSWER : ?
The pathogens can be killed by Nitrification None of these Oxidation Chlorination TRUE ANSWER : ? YOUR ANSWER : ?
As compared to geometrical increase method of forecasting population, arithmetical increase method gives Accurate value Same value Higher value Lesser value TRUE ANSWER : ? YOUR ANSWER : ?
The amount of residual chlorine left in public water supply for safety against pathogenic bacteria is about 0.05 to 0.5 ppm 1.0 to 5.0 ppm 0.01 to 0.05 ppm 0.5 to 1.0 ppm TRUE ANSWER : ? YOUR ANSWER : ?