Abstract: An object of the invention is to reliably prevent the precipitation of scale during a reclamation step in a deionization treatment. A water reclamation system and a deionization treatment device of the present invention each comprises a deionization section, a supply section which supplies a scale inhibitor to a water to be treated, and a control section. The control section acquires a supply start time and a supply stop time for at least one of the scale inhibitor and a low ion concentration water based on the concentration of a scale component in the deionization section, and causes the supply section to supply at least one of the scale inhibitor and the low ion concentration water in the interval between the supply start time and the supply stop time.

Abstract: A de-ionization treatment device includes a capacitive de-ionization treatment unit. In a de-ionization step before a regeneration step, the de-ionization treatment device injects a scale inhibiting agent into supplied water for a period of time that is deduced from a retained water amount of a de-ionization unit and a supplied water flow rate until a predetermined period of time passes or a predetermined ion concentration is reached. The de-ionization treatment device injects the scale inhibiting agent into supplied water at the time of stoppage of the capacitive de-ionization treatment unit until a predetermined period of time passes or a predetermined ion concentration is reached. Alternatively, at the time of stoppage of the capacitive de-ionization treatment unit, the de-ionization treatment device feeds a low ion concentration water in an amount based on the retained water amount of the de-ionization unit to the capacitive de-ionization treatment unit.