1. Sea water Reverse Osmosis
DONE BY: team#4
Suood AlShehhi
Abdullmoen
Mohammed oraiqat

2. Reverse Osmosis overview Maintenance process Conclusion
OUTLINE
Introduction
Reverse Osmosis overview
Maintenance process
Conclusion

3. Introduction Emirates Steel Reverse Osmosis process: Sea Water
Pre-Treatment
Reverse Osmosis
Plant

4. Reverse Osmosis Overview

5. The main purposes of maintenance are:
To reduce corrective maintenance and improve membrane performance.
To reduce machine down time.
To increase the life-time efficiency of the membrane.
To increase the availability of the system.
Efficiency of RO is 90% when all the membranes are online.

6. RO plant main failures
Looking specifically at the RO membranes side when doing corrective maintenance.
There are frequent failures for the membranes:
Fouling
Scaling
High Iron Content (Low water quality)

7. Fouling
Fouling of membranes is due to the suspended or emulsified materials that may be present in the feed water to the reverse osmosis system.
Examples of such materials are:  silica, oil, clay, iron, sulfur and humic acids.
Causes of fouling:
Water hardness
Pre-filter breakdown.
Improper design and maintenance.
Fouling can be minimized by implementing one or more of the below steps:
Reduce operating pressure. (feeding water pressure).
Change filters more frequently (system PPM).

8. Scaling
Scaling means the deposition of particles on a membrane, causing it to plug.
Reverse osmosis membranes and flow passages within membrane elements will scale due to precipitation of sparingly soluble gas, such as 
Example : (calcium carbonate, calcium sulfate, barium sulfate and strontium sulfate).
The surface blockage of the scale results in permeate flux decline, reducing the efficiency of the process and increasing of operation costs. 
There are two methods of scale control commonly employed:
Acidification (acid addiction destroys carbonate ions)
Ion exchange softening (this method utilizes the sodium which is exchanged for magnesium and calcium ions that are concentrated in the RO feed water)

9. High Iron content
Iron, usually presents in groundwater as divalent ion (Fe2+) and is considered as source of membrane scaling. The antiscalant feeding before membranes is effective with respect to precipitation. It reduces iron concentration from 3.8 mg/l to 3.12 mg/l, but this iron level is still the main source of membrane problems. various treatment methods have been employed to enhance water quality by removing iron. Oxidation Processes Depth Filtration Manganese Greensand

10. Maintenance process
According to the risk management matrix, a preventive maintenance schedule should be set to help maintain the plants efficiency.

11. Likelihood of Occurrence
Maintenance Process
(Weighted Impact Rating = Severity of Impact * Likelihood of Occurrence)
Likelihood of Occurrence
Very Low
Low
Medium
High
Very High 1 2 3 4 5
Severity of Impact 6 8 10 9 12 15 16 20 25

12. Maintenance Process Weighted Impact Value Asset Value 1 2 3 4 5 6 8 9
Weighted Impact Value 1 2 3 4 5 6 8 9 10 12 15 16 20 25
Asset Value
Very Low
Low 18 24 30 32 40 50
Medium 27 36 45 48 60 75
High 64 80
100
Very High
125>

13. Risk Rating Impact of Risk Tolerance Level
Very Low
>=1 & <10
Requires to be attended to after low risks as it may have negligible impact on the business
Can be accepted without any or further controls being implemented
Low
>=10 & <20
Requires to be attended to after medium risks as it may have minor impact on the business
Medium
>=20 & <40
Requires to be attended after high risks as it may have an impact on the business
Can be addressed by using a combination or existing controls and some additional controls. May or may not require additional finances
High
>=40 & <64
Requires to be attended after very high risks as this may have a major impact on the business
High risks to be addressed by using a combination of existing controls and some additional controls. May require some finances
Very High
>=64
Requires to attended immediately as it may have a significant impact on business
Very high risks to be addressed by using a combination of existing controls and some additional controls. May require substantial finances

14. Maintenance Process Applying Preventive maintenance:
The efficiency of the RO system very low when any of the failures occurs. This indicates for the operators to increase the frequency of the maintenance to maintain the resource efficiency. By doing so the following will be enhanced:
Efficiency, reliability, and availability of Sea Water RO improved significantly
Efficiency : %
Reliability: %
Availability: %

15. FIND OUTS Preventive maintenance helps in:
Equipment downtime is decreased and the number of major repairs are reduced.
Quality & safety improvement.
Enhances the efficiency of equipment.
Reduces the chance of emergency repair calls.

16. Thank you