| abstract |
According to the present invention, in an RO membrane treatment system provided with an energy recovery device that recovers energy from concentrated water in an RO membrane device, biofouling is suppressed not only in the RO membrane device, but also in the energy recovery device and, to improve system-wide energy efficiency and for stable operation, at least one of a combined chlorine-based slime control additive and a stabilized bromine-based slime control additive is added to an RO water supply so as to render the residual halogen concentration in the concentrated water in the RO membrane device introduced into the energy recovery device 0.1-10000 mg/L in terms of the total chlorine concentration. |