Electrodeposition paint recovery system and method

An electrodeposition paint recovery system comprising:

• an electrodeposition bath in which electrodeposition painting is performed on an object to be painted;
• at least two water washing baths in which the object to be painted after electrodeposition painting is washed stepwise with water;
• a first filtration membrane which is an ultrafiltration membrane or a microfiltration membrane, and which feeds filtrate obtained by filtering an electrodeposition solution that contains an electrodeposition paint within the electrodeposition bath to the water washing bath at a last stage from among the at least two water washing baths, and feeds a concentrated solution to the electrodeposition bath, respectively;
• a third filtration membrane which is an ultrafiltration membrane or a microfiltration membrane, and which feeds filtrate obtained by filtering water in one of the at least two water washing baths after washing to a second filtration membrane which is connected at a later step, and feeds a concentrated solution to a water washing bath located more toward the electrodeposition bath side than the one water washing bath or to the electrodeposition bath;
• the second filtration membrane which is a reverse osmosis membrane, and which feeds filtrate obtained by filtering the filtrate water fed by the third filtration membrane to the water washing bath of the last stage, and feeds a concentrated solution to one of the electrodeposition bath and a water washing bath other than the water washing bath of the last stage, respectively;
• and
• a flow rate adjustment unit that adjusts a feed amount of each of the filtrate obtained by filtration by the first filtration membrane and the filtrate obtained by filtration by the second filtration membrane to the water washing bath of the last stage,
• wherein water after water washing is fed from the water washing bath of the last stage sequentially in order from the water washing bath or baths located more toward the electrodeposition bath than the water washing bath of the last stage to the electrodeposition bath.

An electrodeposition paint recovery method, wherein an electrodeposition bath in which electrodeposition painting is performed on an object to be painted, at least two water washing baths in which the object to be painted after electrodeposition painting is washed stepwise with water, and a first filtration membrane which is an ultrafiltration membrane or a microfiltration membrane, and which feeds filtrate obtained by performing filtration on electrodeposition solution containing electrodeposition paint in the electrodeposition bath to a washing bath at a last stage from among the at least two water washing baths and feeds a concentrated solution to the electrodeposition bath, are used and water after water washing is fed from the water washing bath of the last stage sequentially in order from the water washing bath or baths located more toward the electrodeposition bath than the water washing bath of the last stage to the electrodeposition bath, the method comprising:

• feeding filtrate obtained by filtering by the first filtration membrane to a second filtration membrane which is a reverse osmosis filter;
• feeding filtrate obtained by filtering with the second filtration membrane to the water washing bath of the last stage, and feeding a concentrated solution to a water washing bath other than the water washing bath of the last stage or the electrodeposition bath;
• and
• adjusting a feed amount of each of the filtrate obtained by filtration by the first filtration membrane and the filtrate obtained by filtration by the second filtration membrane to the water washing bath of the last stage.

An electrodeposition paint recovery method, wherein an electrodeposition bath in which electrodeposition painting is performed on an object to be painted, at least two water washing baths in which the object to be painted after electrodeposition painting is washed stepwise with water, and a first filtration membrane which is an ultrafiltration membrane or a microfiltration membrane, and which feeds filtrate obtained by performing filtration on electrodeposition solution containing electrodeposition paint in the electrodeposition bath to a washing bath at a last stage from among the at least two water washing baths and feeds a concentrated solution to the electrodeposition bath, are used, and water after water washing is fed from the water washing bath of the last stage sequentially in order from the water washing bath or baths located more toward the electrodeposition bath than the water washing bath of the last stage to the electrodeposition bath, the method comprising:

• filtering, by a second filtration membrane which is a reverse osmosis membrane, filtrate water obtained by performing ultrafiltration or microfiltration on water after water washing in one of the at least two water washing baths with a third filtration membrane, and feeding a concentrated solution to a water washing bath more toward the electrodeposition bath than the one of the water washing baths or to the electrodeposition bath;
• feeding a filtrate obtained by filtering with the second filtration membrane to the water washing bath of the last stage, and feeding a concentrated solution to a water washing bath other than the water washing bath of the last stage or the electrodeposition bath;
• and
• adjusting a feed amount of each of the filtrate obtained by filtration by the first filtration membrane and the filtrate obtained by filtration by the second filtration membrane to the water washing bath of the last stage.