Production of water for injection using reverse osmosis
View Patent ↗A method and system for providing Water for Injection using reverse osmosis. Water for Injection can be produced by reverse osmosis and the reverse osmosis membrane can be kept in a constantly self-sanitizing condition. One way of obtaining a constantly self-sanitizing condition is to maintain the reverse osmosis membrane at an elevated temperature during production of Water for Injection.
1. A method for producing Water for Injection, comprising:
insulating a reverse osmosis membrane unit;
providing the reverse osmosis membrane unit comprising a polyamide thin film composite reverse osmosis membrane;
providing a feed water to a high pressure side of the reverse osmosis membrane;
collecting Water for Injection from a low pressure side of the membrane;
detecting a signal indicative of a temperature of the Water for Injection from on or in the membrane unit;
controlling a temperature of the feed water based upon the signal at a temperature of at least a sanitization temperature at which bacteria of concern do not reproduce and do not produce a measurable level of endotoxin; and
maintaining all wettable components of the reverse osmosis membrane unit at the sanitization temperature while producing the Water for injection.
2. The method of claim 1 wherein the sanitization temperature includes a temperature of greater than 60° C.
3. The method of claim 2 wherein the temperature is greater than 70° C.
4. The method of claim 2 wherein the temperature is greater than 80° C.
5. The method of claim 2 wherein the temperature is greater than 90° C.
6. The method of claim 2 comprising heating the feed water after pre-treating the feed water.
7. The method of claim 1 wherein the Water for Injection meets U.S.P. requirements for Water for Injection.
8. The method of claim 1 wherein the Water for Injection contains not more than 0.25 U.S.P. Endotixin Unit per mL.
9. The method of claim 1 wherein the Water for Injection contains total organic carbon of less than 500 ppb.
10. The method of claim 1 further comprising pre-treating the feed water to a conductivity of less than about 50 μS/cm.
11. The method of claim 1 further comprising pre-treating the feed water to a conductivity of less than about 10 μS/cm.
12. The method of claim 1 further comprising pre-treating the feed water to a conductivity of less than about 1 μS/cm.
13. The method if claim 1 further comprising storing the Water for Injection at a temperature greater than or equal to 65° C.
14. The method of claim 1 further comprising recycling at least a portion of the Water for Injection to the reverse osmosis membrane.
15. The method of claim 14 wherein the portion of the Water for Injection is recycled through a heat exchanger.
16. The method of claim 1 wherein no additional sterilization steps are used after collecting the Water for Injection.
17. The method of claim 1 further comprising the steps of:
providing a solute at a first concentration to the feed water; and
detecting a second solute concentration downstream of the membrane.
18. The method of claim 17 further comprising comparing the second solute concentration with a pre-determined concentration.
19. The method of claim 18 wherein the pre-determined solute concentration is a concentration within a range of a concentration expected when the reverse osmosis membrane is in a properly operating condition.
20. A method for facilitating the production of Water for Injection comprising:
providing a reverse osmosis water purification system, the system comprising:
an insulated reverse osmosis unit comprising a polyamide thin film composite reverse osmosis membrane;
a heat exchanger upstream of and fluidly connected to the reverse osmosis unit;
a temperature sensor positioned in the reverse osmosis unit; and
means for maintaining a temperature of all wettable components of the reverse osmosis unit at greater than 60° C. during production of Water for Injection.
21. The method of claim 20 comprising a means for maintaining the reverse osmosis membrane at a temperature of greater than or equal to 80° C.
22. The method of claim 20 comprising means for maintaining an RO trans-membrane pressure of greater than or equal to 40 psig.