OPERATORS MANUAL
ORION II
Orion II 500-10000 Operators
Page 34 of 95
Manual Part no: DOMAON0100 Issue A
April 2008
The RO section can be cleaned by system operators, however, CEDI cleaning is more complicated
and should be carried out by a Veolia Water service engineer.
5.10 HOT WATER SANITISATION (HWS)
Hot water sanitisation of the RO feed tank (TK30-01), RO, Degasser (where fitted), CEDI, UV, UF or
MF (where fitted) system is a fully automatic process set via the HMI. It can be either manually
initiated, or run automatically at a pre-set day and time via the PLC.
If Option 11 is chosen then the softeners are also sanitised at the same time.
The procedure for units incorporating Options 10, 12, 13 & 14 is as follows
–
On initiation feed to TK30-01 is isolated and product and concentrate flows (both RO and CEDI) are
recycled to TK30-01 via the relevant automatic valves. Pump pressure is reduced to 7bar and power
is supplied to the electrical heater (HT30-01) fitted to TK30-01 to heat the water in the tank to 85-
87
o
C. HT30-01 is controlled by TT30-01. This temperature is chosen to ensure that the coldest part
of the system (TT30-02) is maintained above 80
o
C. Temperatures around the system are monitored
by TT30-01, TT30-02, TT45-0 and TT80-01.
As soon as any of these temperature sensors reaches 45°C the pump pressure is further reduced to
2.2bar to prevent compaction damage to the RO membranes. When the system temperature, as
recorded by all three sensors, exceeds 80°C a hold timer is started (normally 1 hour). The system
temperature is maintained at >80°C for the duration of the hold period after which the heater is
switched off and the cooling cycle started.
If any of the sensors falls below 79.5
o
C during the hold period the PLC alarms
– sanitisation failed,
and the process steps on to the cooling sequence.
Cooling is a two step process. Starting at the same low pressure used for the hold cycle, automatic
modulating valve VA40-01 or VA42-01 is opened to allow a set flow rate (as monitored by FT45-01)
of hot RO concentrate to drain. At the same time VA10-05, VA12-01, VA13-01 or VA14-01 is
opened to provide a set flow of cold water to drain to prevent damage to the drainage system due to
over heating. TK30-01 is filled with cold softened water to replace that lost through V40-01 or VA42-
01. Water continues to be recirculated and the system temperature falls.
When 45
o
C is reached, the cooling water valve is closed and the pump pressure increased to 7bar.
When the system temperature drops below 25°C the HWS is complete and the unit is returned to
normal service conditions. After a 5 minute delay time (variable) product water can be directed to
service if there is a demand for water and the conductivity and TOC requirements have been met.
