31) The spacing of bars in coarse screens is generally more than
a) 6 mm
b) 10 mm
c) 25 mm
d) 50 mm
32) The waste stabilization ponds can be
a) aerobic
b) anaerobic
c) facultative
d) any of the above
33) The trap used for a water closet is called
a) gully trap
b) P-trap
c) intercepting trap
d) anti-siphon trap
34) Which is the major pollutant present in photochemical smog ?
a) PAN
b) SO2
c) HC
d) NO2
Good Luck!!