Abstract: The water treatment system includes: an aluminate ion addition part for adding an aluminate ion additive to water to be treated containing at least salt content and silica; a first precipitation part provided on the downstream side of the aluminate ion addition part; a first pH adjustment part provided on the downstream side of the first precipitation part; a first solid/liquid separation part for separating the solid content in the water to be treated; a second pH adjustment part for adjusting the pH of the water to be treated from the first solid/liquid separation part to a second pH level; and a first separation membrane (desalination treatment) apparatus provided on the downstream side of the second pH adjustment part so as to separate the water to be treated into first permeated water and first non-permeated water by removing the salt content in the water to be treated.

Abstract: The water treatment system includes: an aluminate ion addition part for adding an aluminate ion additive to water to be treated containing at least salt content and silica; a first precipitation part provided on the downstream side of the aluminate ion addition part; a first pH adjustment part provided on the downstream side of the first precipitation part; a first solid/liquid separation part for separating the solid content in the water to be treated; a second pH adjustment part for adjusting the pH of the water to be treated from the first solid/liquid separation part to a second pH level; and a first separation membrane (desalination treatment) apparatus provided on the downstream side of the second pH adjustment part so as to separate the water to be treated into first permeated water and first non-permeated water by removing the salt content in the water to be treated.

Abstract: A water treatment device 1 includes: a soluble silica deposition section 13 that deposits soluble silica dissolved in water to be treated W1, the water to be treated W1 having a concentration of aluminate ion represented by general formula (1) below and a pH that are in predetermined ranges; a solid-liquid separating section 14 that separates the deposited soluble silica from the water to be treated W1 to obtain water to be treated W1 in which the soluble silica has been removed from the water to be treated W1; and a reverse osmosis membrane filtration section 30 that filtrates, by using a reverse osmosis membrane 30a, the water to be treated W1 in which the soluble silica has been removed in the solid-liquid separating section 14.

Abstract: The present invention is to provide a water treatment device and a water treatment method that can efficiently remove soluble silica in water to be treated. A water treatment device 1 of the present invention comprises: a soluble silica deposition section 13 that deposits soluble silica dissolved in water to be treated W1, the water to be treated W1 having a concentration of aluminate ion represented by general formula (1) below and a pH that are in predetermined ranges; and a solid-liquid separating section 14 that separates the deposited soluble silica from the water to be treated W1 to obtain treated water W2 formed by removing the soluble silica from the water to be treated W1.