ON THE ESTIMATION OF BIOLOGICAL OXYGEN-DEMAND OF COLLECTED WATER SAMPLES WITH SPECIAL REFERENCE TO THAT OF THE GANGES WATER

A procedure for measuring BOD of collected Rater samples using a Karub e type microbial BOD sensor is described, BOD of water samples collect ed from the Ganges at Calcutta, decreases on standing. This phenomenon has been attributed to consumption of the organic matter present in t he collected sample due to microbial growth and cut-off the source of the organic matter from the sample. The water samples should therefore be sterilised at collection point so that BOD can be measured later o n in test laboratories either by the 5-day BOD or by the 30-minute sen sor method.