Multiple Choice QuestionsDuring sewage treatment, biogases are produced, which include
methane, hydrogen sulphide and carbon dioxide
methane, oxygen and hydrogen sulphide
hydrogen sulphide, methane and sulphur dioxide
hydrogen sulphide, nitrogen and methane
Global warming can be controlled by
Reducing deforestation, cutting down use of fossil fuel
Reducing reforestation, increasing the use of fossil fuel
Increasing deforestation, slowing down the growth of human population
Increasing deforestation, reducing efficiency of energy usage
With the rise of water temperature, dissolved oxygen
remains unchanged
increases in amount
decreases in amount
is more available to the aquatic organisms
'Kyoto Protocol' is a multination international treaty for
phasing out green house gases
controlling ozone destroying substances
management of hazardous wastes
conservation of biodiversity
Phenomenon involving increase in concentration of non-degradable pollutants from lower to higher trophic levels is called
biomagnification
bioaccumulation
biodegradation
bioinvasion
During waste water treatment, trickling filter is used for
primary treatment
secondary aerobic treatment
secondary anaerobic treatment
tertiary treatment
B.
secondary aerobic treatment
Trickling filter is a fixed-bed biological reactor that operates under (mostly) aerobic conditions. It is used for secondary aerobic treatment. In this system, pre-settled wastewater is continuously trickled or sprayed over the filter. As the water migrates through the pores of the filter, organics are aerobically degraded by the biofilm covering the filter material.
Relationship between DO and BOD is that they
are directly proportional
are inversely proportional
are not related
always remain equal to each other
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