Method and system for treating cold rolling pickling wastewater

The invention provides a treatment method of cold rolling pickling wastewater, the cold rolling pickling wastewater contains particulate matters, acid radical ions and iron ions, the treatment method of the cold rolling pickling wastewater comprises the following steps: carrying out microfiltration on the cold rolling pickling wastewater, and removing the particulate matters to obtain a first filtrate; carrying out nanofiltration on the first filtrate to separate acid radical ions from iron ions to obtain a first penetrating fluid and a first concentrated solution; carrying out nanofiltration on the first concentrated solution to obtain a second concentrated solution and a second penetrating fluid; adding scrap iron edge wires into the second concentrated solution, and carrying out reduction reaction to obtain a first iron-containing solution with iron ions with a certain concentration; and carrying out acid regeneration reaction on the first iron-containing solution to obtain iron and acid. According to the