Environmental Engineering Questions

• Pick out the wrong statement.
• The weakest sound that can be heard by a person in a quiet environment is equivalent to __________ decibel.
• Water filtration rate in a slow sand filter ranges from __________ litres/m2/hr.
• Presence of nitrogen in high concentration in contaminated air reduces partial pressure of oxygen in lungs, thereby causing asphyxia (suffocation) leading to death from oxygen deficiency. Concentration of N2 in contaminated air at which it acts as a natural asphyxant is ≥ __________ percent.
• The pH value of potable water should be between
• Maximum permissible residual chlorine in treated water should be __________ mg/litre.
• Disinfection of water is done to destroy pathogenic bacteria and thus prevent water-borne diseases. Disinfection of water may be done by the use of
• Inorganic impurities causing water pollution is
• TLV of ammonia, nitrogen dioxide and phenol vapor in air is __________ ppm.
• Noise level inside a jet air liner in normal flight is about __________ decibels.
• Hydrogen ion concentration in distilled water is
• Sulphur dioxide present in the industrial chimney exhaust gases causes
• __________ content of the phosphate rock is the pollutant of primary interest in a phos-phatic fertiliser plant.
• During sewage treatment, the sewage is subjected to __________ treatment in Imhoff tank.
• __________ is the process of killing organism in water.
• Maximum permissible concentration (i.e. TLV) of DDT in public water supply system is __________ micro gram (μ g)/litre.
• The maximum CO2 is emitted into the atmosphere by
• Pick out the wrong statement.
• Brown spots in fabrics will be caused by washing with water containing large amount of .
• Removal of __________ results from the disinfection of water.