Page | 5
User Manual
2.2 Key Auxiliary Equipment
The key auxiliary equipment for a typical ETUF system includes (but is not limited to) the following:
▪
Feed and filtrate (or dedicated backwash) tanks
When designing for the tanks, make sure that the material chosen (typically: fiber-reinforced
plastic, reinforced concrete or stainless steel) is suitable for type of water it is to contain and
for the type of environment that the system is situated in (i.e. seaside, indoors/ outdoors,
warm/ temperature, dry/ humid, etc).
The size of the tank is dependent on the overall system design, as well as upstream/
downstream requirements. The general principle for the sizing of the tank is:
Size of tank = Downstream design flow x Expected retention time
In addition, care must be taken to keep the tanks (particularly the filtrate/ backwash tanks)
clean with periodic inspection and cleaning. This is especially true for systems located in
tropical/ subtropical countries where biological growth is more rampant. If the bio-organisms
or other types of contaminants are allowed to be back-flushed into the lumen of the hollow
fibers, the fouling will be severe and difficult to remove.
▪
CIP (Clean-In-Place) tank
The CIP tank is used for the preparation and containment of cleaning chemical solutions. Thus,
the tank material(s) must be compatible with the chemical solutions used.
The general principle for the sizing of the tank is:
Size of tank = [No. of modules to be cleaned x Cleaning solution needed per module]
+ Pipe losses & other system considerations
(For cleaning solution needed per module, refer to Section 4.6)
After completing a CIP cleaning, the tank must be thoroughly cleaned. This is especially critical
if new and different chemical cleaning solutions are to be introduced subsequently.
▪
CEB (Chemical Enhanced Backwash) tank
The material of the CEB tank must be suitable for the chemical solutions used.
The general principle for the sizing of the tank(s) is:
Size of tank = [No. of modules to be cleaned x Chemical to be dosed per module] +
Pipe losses & Other system considerations
▪
Feed pump
The feed pump(s) should provide the required feed flow with suitable allowance at a pressure
no greater than the stated feed inlet pressure limit.
If the system is designed, as in most case, to operate at constant flow, then it is recommended
that each feed pump be fitted with and is controlled by a variable frequency drive (VFD) or a
similar control device.
The selection of the pump material is dependent on the conditions of the feed water and the
environment in which it is operating (e.g. duplex or super duplex material pumps are
recommended for seawater applications).
Backup/ standby pumps are generally recommended, especially for large systems or critical
operations.
