Abstract:

Microbial pollution is one of the main types of reverse osmosis membrane pollution in seawater desalination system. In the spring of 2016, frequent and rapid increasing of pressure difference, constant desalting rate and decreased water yield happened in the first-order reverse osmosis membrane of the seawater desalination system in Hongyanhe nuclear power plant. After dissection analysis of reverse osmosis membrane, the main reason was microbial contamination. The microbial growth caused by incomplete sterilization lead to an increasing of pressure difference and decreasing of water yield. By increasing the amount of sodium hypochlorite added to the pretreatment fungicide of seawater, the amount of residual chlorine at the outlet of the ultrafiltration water tank was increased in order to decrease the breeding of microorganisms in the sea water. And in different seasons, different concentrations of dosage would be controlled. It is verified that this measure can control the inlet microorganism of the reverse osmosis system at a low level, reduce the increasing frequency of pressure difference, and improve the operation reliability of the equipment of the sea water desalination system of Hongyanhe nuclear power plant.

Key words: seawater desalination, microbes, residual chlorine