Evaporator array for a water treatment system

1. An evaporator array for a water treatment system, the evaporator array comprising;

a produced water feed and a first evaporator to receive produced water from the produced water feed,

a makeup water feed and a second evaporator to receive makeup water from the makeup water feed,

an output distillate feed to receive distillate from the first evaporator and the second evaporator, and, a blowdown feed to receive blowdown from the first evaporator and the second evaporator,

wherein the first evaporator and the second evaporator each have a working pH, the working pH of the first evaporator being higher than that of the second evaporator, and

wherein the blowdown feed is separate from the produced water feed.

2. An evaporator array according to claim 1 comprising a plurality of first evaporators, each of the first evaporators receiving the produced water from the produced water feed.

3. An evaporator array according to claim 1 wherein the makeup water feed supplies at least one of brackish makeup water and fresh makeup water.

4. An evaporator according to claim 3 wherein the makeup water feed further supplies blowdown water from a steam generator.

5. An evaporator array according to claim 2 wherein the makeup water feed supplies at least one of brackish makeup water and fresh makeup water.

6. An evaporator according to claim 5 wherein the makeup water feed further supplies blowdown water from a steam generator.

7. An evaporator array for a water treatment system, the evaporator array comprising:

a produced water feed and a first evaporator to receive produced water from the produced water feed;

a makeup water feed and a second evaporator to receive makeup water from the makeup water feed;

an output distillate feed to receive distillate from the first evaporator and the second evaporator; and

a blowdown feed to receive blowdown from the first evaporator and the second evaporator, wherein

the first evaporator and the second evaporator each have a working pH, the working pH of the first evaporator being higher than that of the second evaporator,

the output distillate feed receives a first distillate directly from the first evaporator and the output distillate feed receives a second distillate directly from the second evaporator, and

the blowdown feed receives a first blowdown directly from the first evaporator and the blowdown feed receives a second blowdown directly from the second evaporator.

8. A method of treating water by evaporation, comprising the steps of; supplying produced water to a first evaporator from a produced water feed,

supplying makeup water to a second evaporator,

controlling a first working pH of the first evaporator and a second working pH of the second evaporator such that the first pH is higher than the second pH,

purifying the produced water at the first evaporator, and supplying a first distillate to an output distillate stream and a first blowdown to a blowdown stream, and

purifying the makeup water at the second evaporator, and supplying a second distillate to the output distillate stream and a second blowdown to the blowdown stream,

wherein the blowdown stream is separate from the produced water feed.

9. A method according to claim 8 comprising supplying the produced water to a plurality of first evaporators.

10. A method according to claim 8 comprising supplying makeup water comprising at least one of brackish makeup water and fresh makeup water.

11. A method according to 9 further comprising supplying makeup water comprising blowdown water from a steam generator.

12. A method according to claim 9 comprising supplying makeup water comprising at least one of brackish makeup water and fresh makeup water.