<prompt> Strength of sewage is expressed in terms of all EXCEPT:Biological Oxygen DemandChemical oxygen demandSuspended solidsColiform count  <response>: Ans. d Coliform count. Ref. Park PSM 22ndpg. 708SEWAGE It is wastewater from community containing solid and liquid excreta, derived from houses, street and yard washing, factories and industries. It resembles dirt water with unpleasant smell. Composition of sewage is 99.9 water. Average adult person excretes daily some 100 gm of faeces. Strength of sewage is expressed in terms of - BOD, COD and suspended solids.Biological Oxygen Demand BOD It is most imp. Test done on sewage. It is a std test indicating organic content of the sewage. It is defined as the amount of 02 absorbed by a sample of sewage during a specified temperature, generally 20 deg C for aerobic destruction or use of organic matter by living organisms. BOD values range from about 1 mg per litre for natural waters to about 300 mgL for unRxed domestic sewage.Chemical oxygen demand CODMeasures the O2 equivalent of that portion of the organic matter in a sample which is susceptible to oxidation by strong chemical oxidizer.Suspended solidsIf the amount of SS is 100 mgL, the sewage is said to be weak; if the amount is 500 mgL the sewage is said to be strong. 