Q. Water pollution can be stopped best by Treating effluents to remove injurious chemicalsRearing more fishesCultivating useful water plantsSpraying with DDT Answer: Treating effluents to remove injurious chemicals

Q. When Chloride is added to sewage both at the beginning as well as at the end of the treatment process, the phenomenon is called: Post chlorinationSuper chlorinationSplit chlorinationNone of these Answer: Split chlorination

Q. In the treatment of waste water discharge, which treatment stage involves biological treatment Primary treatmentSecondary treatmentTertiary treatmentReverse osmosis stage Answer: Secondary treatment

Q. Thermal pollution of water bodies is due to Discharge of heat (hot water) from power plantsDischarge of chemicals from industriesDischarge of waste from miningDischarges of agricultural run off Answer: Discharge of heat (hot water) from power plants

Q. Water pollution is caused due to Sewage and other wastesIndustrial effluentsAgricultural dischargesAll of these Answer: All of these

Q. The BOD removal in an oxidation pond may be up to 100%97%94%90% Answer: 90%

Q. Sewage water can be purified for recycling with the action of Aquatic plantsPenicillinMicro-organismsFishes Answer: Micro-organisms

Q. Who was the first to recognise the problem of water pollution ? AirstotleTheophrastusHippocratesThales Answer: Hippocrates

Q. Which of the following is a main factor of water pollution? Commercial productionWindmillSmoke and ammoniaDetergents Answer: Detergents

Q. What is the full form of BOD? Biological Ozone DemandBiological Oxygen DemandBiotic Oxygen DemandBiological Oxygen Deficiency Answer: Biological Oxygen Demand

Q. Which of the following is a water polluting factor? SmokeIndustrial wasteDetergentAmmonia Answer: Industrial waste

Q. Biological Oxygen Demand (BOD) is a measure of Industrial wastes poured into water bodiesExtent to which water is polluted with organic compoundsAmount of carbon monoxide inseparably combined with haemoglobinAmount of oxygen needed by green plants during night Answer: Extent to which ...