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Environmental (301-320)

Updated: Apr 27, 2020


In the plot of residual chlorine versus chlorine dose applied shown in Fig,

the curve will not have any (0, 0) point because chlorine is consumed for disinfection


302.If the methyl orange alkalinity of water equals or exceeds total hardness, all of the hardness is carbonate hardness


303.Some amount of chlorides is allowed in drinking water because

1. it helps in killing bacteria.

2. it is not injurious to human health.

3. it is not economical to remove it completely


304.A commonly used handpump is the reciprocating pump



A.Multistage centrifugal pump of moderate sized impellers-High head and moderate discharge B. Archimedean screw type pump-Low head and low discharge C. Simple reciprocating pump-High head and low discharge D. Axial flow propeller pump-Low head and large discharge


306.Service connection consists of ferrule, stopcock and gooseneck


307.water treatment plant for rural water apply is Coagulation, sedimentation, slow sand filter, chlorination



A.Automobile(per vehicle)-40 B. Leather (per 100 kg)-4 C. Paper (per tonne)-200-400 D. Crude petroleum refinery (per tonne)-1 to 2


309. Consider the following statements : Ventilation of sewer lines is necessary to

1. avoid building up of sewer gases.

2. ensure atmospheric pressure in the waste water surface.

3. ensure the safety of sewer maintenance people


310.For a colony of 10,000 persons having sewage flow rate of 200 litres /capita/day,

BOD of applied sewage of 300 mg/litre and organic loading of 300

kg/day/hectare, the area of an oxidation pond required for treating the sewage of

the colony is 2 hectares



The second stage BOD as shown in Fig is due to nitrification demand


312.The purpose of a proportional weir at the effluent end of a channel type grit removal unit is to maintain constant mean velocity in the channel


313. The trap used for a water closet is called p-trap


314. A circular sewer of diameter 1 m carries storm water to a depth of 0.75 m. The

hydraulic radius is approximately 0.3 m


315. Consider the following statements about waste stabilization ponds

1. The pond has a symbiotic behiaviour of waste stabilization through algae on one hand and bacteria on the other.

2. The oxygen in ponds is provided by algae through photosynthesis.


316 Carbon monoxide-Chemical reaction with haemoglobin in blood Particulate matter-Reduction in visibility and aeroallergens carrier Nitrogen oxides-Photochemical smog in atmosphere Sulfur dioxide-Respiratory distress for living beings



A.Incineration-High open tional & maintenance cost B. Sanitary landfill-Tractor C.Coposting- Requires presorting,grinding and turning D.Salvage by sorting-Limited to special wastes and selected materials


318.The sound pressure level for a jet plane on the ground with sound pressure of 2000 µ bar should be 140 decibel


319.The controlling design parameter in the design of all settling tanks is

overflow rate


320. The F/M ratio is controlled in the activated sludge process by adjusting the

amount of sludge wasting

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