Effect of NaClO Addition on Bacteriostasis of Iron Bacteria and Corrosion Control of Pipe Line Steel for Water Distribution Network in Urban Reclaimed Water

Abstract

The effect of the initial dose of NaClO on the bacteriostasis of iron bacteria and the corrosion behavior of the pipeline steel for water distribution network was studied in an urban reclaimed water, which was sampled from a water recycle work in North China. Results show that the iron bacteria can be effectively inhibited by the addition of NaClO; the higher the dose is the longer time needs for the resurrection of the iron bacteria, therefore the better bacteriostasis may be realized; the existence of iron bacteria can significantly promote the corrosion of carbon steel,but with the extension of time, the corrosion of the steel may be suppressed to certain extent due to the formation of biofilms on the steel surface; in fact the addition of NaClO in the initial stage can suppress the corrosion of carbon steel induced by iron bacteria, however NaClO itself is also a corrosive medium to the steel, thus in the meanwhile a higher initial dose of NaClO may enhance the corrosion rate of the steel. Finally an optimal dose of NaClO 7 mg/L is acquired in terms of a compromise between the bacteriostasis in the reclaim water and the corrosion control of the steel.