RO concentrated water recovery system

The utility model discloses an RO (reverse osmosis) concentrated water recovery system which comprises a chemical hardness removal device, a concentrated water ultrafiltration device and a concentrated water reverse osmosis device which are sequentially communicated through pipelines and pumps, a UF (ultrafiltration) self-cleaning filter is arranged in front of the concentrated water ultrafiltration device, and an RO security filter is arranged in front of the concentrated water reverse osmosis device; the chemical hardness removal device comprises a front mixing tank, a rear mixing tank, a flocculation reaction tank, a clarification tank and a PH regulating tank which are communicated in sequence, the bottom of the clarification tank is communicated with a sludge discharge pump, and the chemical hardness removal device is communicated with a concentrated water collecting box of the existing RO equipment. The chemical hardness removal device, the concentrated water ultrafiltration device and the secondary con