Method for softening sewage and wastewater of power plant by carbon dioxide

The invention discloses a method for softening treatment of sewage and wastewater of a power plant by carbon dioxide. The method comprises the following steps: introducing carbon dioxide into the sewage and wastewater for reaction to adjust the pH value, adding a reagent into the sewage and wastewater to remove calcium ions, adding acid to adjust the pH value to be neutral and then recycling, cleaning and filtering wastes, recycling effluent and recycling limestone. According to the method, the small-particle limestone is used as a calcium carbonate scaling core, the limestone gradually becomes larger after adsorbing calcium carbonate, and the large-particle limestone is reused to a desulfurization system; only sodium hydroxide and limestone are added into the clarification tank, so that discharged wastewater can be completely recovered into the clarification tank, and backwashing water of the filter can be completely recovered into the clarification tank; the method has the advantages of no sludge discharge,