Which one of the following is not a nitrogen-fixing organism?
Anabaena
Nostoc
Azotobacter
Pseudomonas
Big holes in Swiss cheese are made by a
a machine
a bacterium that produces methane gas
a bacterium producing a large amount of carbon dioxide
a fungus that releases a lot of gases during its metabolic activities
The residue left after methane production from cattle dung is
burnt
burried in land fills
used as manure
used in civil construction
Methanogens do not produce
oxygen
methane
hydrogen sulphide
carbon dioxide
Activated sludge should have the ability to settle quickly so that it can
be rapidly pumped back from sedimentation tank to aeration tank
absorb pathogenic bacteria present in waste water while sinking to the bottom of the settling tank
be discarded and anaerobically digested
absorb colloidal organic matter