ULTRAPURE WATER PRODUCTION APPARATUS AND ULTRAPURE WATER PRODUCTION METHOD

摘要

Provided are an ultrapure water production apparatus and ultrapure water production method in an ultrapure water production process configured so that concentrate from a first RO membrane device is processed in a second RO membrane device and permeate is collected. The apparatus and method are advantageous in terms of cost and the decarbonation device for preventing concentration of inorganic carbonic acid in the system is small and space-conserving. The present invention is an ultrapure water production apparatus equipped with: a first RO membrane device (3) for RO membrane treatment of water to be treated; an introduction line (13) for introducing the water to be treated to the first RO membrane device (3); an outflow line (14) for causing permeate from the first RO membrane device (3) to flow out; a second RO membrane device (5) for RO membrane treatment of the concentrate from the first RO membrane device (3); and return lines (19, 20) for returning permeate from the second RO membrane device (5) to the introduction line (13). A decarbonation device (6) for decarbonation of the permeate from the second RO membrane device (5) is provided in the return line.