OPERATORS MANUAL
ORION II
Orion II 500-10000 Operators
Page 83 of 95
Manual Part no: DOMAON0100 Issue A
April 2008
8 RO MEMBRANE CLEANING
8.1 GENERAL
The RO membranes fitted to the ORION unit should be cleaned if they become fouled or scaled and
the permeate flow from the RO system falls.
The flow of permeate from an RO system is dependent on a number of operating parameters
principally, applied pressure, temperature and the osmotic pressure of the water being purified.
These factors need to be taken into account when assessing whether membranes require cleaning
and this is achieved
by calculating the “corrected flux” for the plant which takes these factors into
account.
Corrected Flux is the flow of permeate per square meter of membrane area corrected for
temperature, pressure and osmotic pressure.
The ORION PLC calculates corrected flux on a continuous basis and advises when cleaning is
required, i.e. when the corrected flux falls below 90% of the previously accepted “clean flux”. This is
indicated by a non fatal alarm and the HMI RO screen.
The following chemicals are recommended for use with ORION systems.
Solution (A) - Acid Cleaning Solution
Properly operated RO systems should not require acid cleaning. Precipitation can, however,
occur when the plant is operated at high recovery or on pre-treatment failure.
In such cases Elgalite RU3, which is an acidic cleaner, will remove calcium and magnesium scale
from the membrane. It is also effective in removing iron which can be present in feed water.
Elgalite RU3 is available in boxes containing 12 x 1.5kg bottles (Veolia Water part number
CHEGRO0083) and is used at the rate of 1.5kg, ORION 500
– 2000 and 3kg, ORION 4000 -
6000.
It is also available in 8kg drums Veolia part number CHEGRO0084 and is used at the rate of 8kg
for Orion 8000 - 10000
Solution (B) - Alkaline Cleaning Solution
An alkaline detergent is recommended for the removal of biological material, colloids, silica etc,
from the surface of the membranes. Elgalite LF12 is a combined alkaline powder detergent
formulated to remove the majority of foulants normally encountered in water treatment systems.
Elgalite LF12 is available in boxes containing 10 x 1kg pails (Veolia Water part number
CHEGRO0058) and is used at the rate of 2kg, ORION 500
– 2000 and 4kg, ORION 3000 – 5000
and 8kg Orion 8000
– 10000.
