Reverse osmosis treatment system

A reverse osmosis treatment system comprising:

• a reverse osmosis treatment device configured to separate first to-be-treated water into permeate and brine via reverse osmosis;
• a first pump configured to push out a part of second to-be-treated water thereby to feed third to-be-treated water;
• a second pump configured to push out a remaining part of the second to-be-treated water thereby to feed fourth to-be-treated water;
• a third pump configured to pressurize the third to-be-treated water thereby to feed fifth to-be-treated water having a higher pressure than the third to-be-treated water;
• a first energy recovery device configured to exchange pressures between the fourth to-be-treated water and the brine thus separated by the reverse osmosis treatment device, thereby to produce sixth to-be-treated water having a higher pressure than the fourth to-be-treated water;
• a merging portion configured to merge the fifth to-be-treated water and the sixth to-be-treated water, thereby to produce the first to-be-treated water;
• and
• a second energy recovery device configured to raise a pressure of the third to-be-treated water by rotating a turbine or a Pelton wheel with a pressure of the permeate thus separated by the reverse osmosis treatment device.