In case of using secondary urban sewage or polluted natural water as makeup water of the circulating water in thermal power plants

the bad influence of nitrification process concerning ammonium nitrogen should be considered. Test and practice show that the high content of ammonium nitrigen in makeup water makes the pH value of circulating water to be abnormally lowered

the corrosinon rate of copper tubes being raised

the total amount of bacterum beinggreatly inereased

and the sterilizing effect of oxidizing bactericide being decreased. In this connection

related remedial measures are given.