OTT MAGNUM User manual

Assembly, Operation, Maintenance of
MAGNUM
®
Membrane Tube Diffusers
and Membranes
7-2006
OTT GmbH Tel: +49 (0)511 / 78631 0
Frankenring 21 Fax: +49 (0)511 / 78631 40
D 30855 Langenhagen Email: [email protected]
Germany www.ott-system.com
page 1 of 6
Memb
rane T
ube
D
iffuser
low buoyancy
1. support pipe PP
2. membrane
3. flooded compartment
4. air distribution
5. locking bolt
6. air header
Content:
technical data page 1
assembly of diffusers page 2
test run page 3
operation page 4
assembly (changing) of diffuser membranes page 5
maintenance and cleaning page 6
Technical Data
MAGNUM
®
Membrane Tube Diffuser on square pipe
MAGNUM
®
Membrane Tube Diffuser on round pipe
A
1000 1500 2000 effective membrane length
B
1200 1700 2200 total length of diffuser
C
Ø 67 Ø 67 Ø 67 outer diameter
D1
D2
80 or 100 or 120 outer dimension (width x heigth)
88.9 or 114.3 or 139.7 outer diameter (round pipe)
= DN80 or DN100 or DN125
dimension in mm
all diffuser dimensions are subject to normal fabrication tolerances
contact OTT if wallthickness of ss pipes is more than 3mm or if plastic pipes shall be used

Assembly, Operation, Maintenance of
MAGNUM
®
Membrane Tube Diffusers
and Membranes
7-2006
OTT GmbH Tel: +49 (0)511 / 78631 0
Frankenring 21 Fax: +49 (0)511 / 78631 40
D 30855 Langenhagen Email: [email protected]
Germany www.ott-system.com
page 2 of 6
1. Introduction
1.1 Control of delivered goods
Each diffuser, particularly the membrane tube, is to
be checked for damage that may have occurred
during shipping. Damage has to be reported to the
freight forwarding company and the seller
immediately.
1.2 Storage
The MAGNUM
®
diffusers are to be stored in their
original packaging in a dry and well-ventilated
place in accordance to DIN 7716. Do not store in
the open! Measures have to be taken to keep the
diffusers away from UV-radiation (sunshine), frost,
dust and works (e.g. welding) close to the storage-
place. The diffusers should be installed and
operated not later than six months after delivery to
avoid possibly harmful environmental influences.
Longtime-Storage of some spare parts for
replacement is possible but due to fast response of
our service not necessary in large numbers.
1.3 Layout / flow pattern
The diffusers and the air headers must be
arranged as specified in the layout of the plant.
The design of the aeration system, e.g. immersion
depth, or the distances between the diffusers and
the headers must comply with the specifications
and the technical presetting of OTT. When using
floating or retrievable systems avoid buoyancy,
and extreme swinging. Any contact of the diffusers
with internals (other diffusers, headers or racks)
will damage the membranes and must be avoided.
Strong waterflow can cause diffuser vibrations,
especially with the MAGNUM
®
2000. This could be
harmful to the whole diffuser unit. Therefore, the
water flow should be along the longitudinal axis
(+/- 45
o
) of the diffuser. Please do not install
diffusers under or very close to mixers. Contact
your OTT representative for detailed installation
advice with regard to the flow regime and mixers.
2. Assembly of diffusers
2.1 General instructions
The installation of the diffusers should be the final
step of all necessary installation works in the area
of the basin. Avoid damages by finishing concrete
works, welding, painting, or any other activities
before you take the diffusers out of their boxes.
Remove all impurities or loose parts from the basin
floor, walkways and side walls.
Before installing the diffuser, all impurities, such as
dust, stones, pieces of wood, etc. must be
removed from the inside of the pipes and headers.
For the correct installation of the diffuser the
following requirement must be fulfilled:
diameter of connection hole: 38 +0.5 mm
the hole must be exactly centred on top of
the air header.
the holes must not be located in the
welded area of the air header
the holes must be free of burrs, particularly
on the inner edge
the surface of the header has to be free of
buckles. Deformations in the area of the
holes cause leakages.
the air headers must be height adjustable.
hole Ø 38 mm + 0.5 mm
hole placed in the centre,
+/
-
0.2 mm of the header
For a proper installation the diffuser and
header have to be dry. Wet parts falsify
the required torque.
The ambient temperature should be above
0°C.
Change both gaskets (spare parts) if the
diffuser is installed for a second time (e.g.
after changing the membranes).
If a (cordless) drill is used, the drill must
not exceed 60 rpm. The assembly has to
be finished using a reliable torque
controlled wrench as described above.
45°
45°
Streaming

Assembly, Operation, Maintenance of
MAGNUM
®
Membrane Tube Diffusers
and Membranes
7-2006
OTT GmbH Tel: +49 (0)511 / 78631 0
Frankenring 21 Fax: +49 (0)511 / 78631 40
D 30855 Langenhagen Email: [e-mail]
Germany www.ott-system.com
page 3 of 6
2.2 Diffuser installation in 3 steps
1. Insert the diffuser into the bore hole using
the fastening bolt (Clip-In
®
system). The
symbol (recycling/material PP) on the
middle part of the diffuser must point
towards the installing person. The locking
bolt is turned in line with the pipe (see
picture below).
2. Insert the bolt into the bore hole, away
from the body of the mechanic.
3. After the diffuser is clipped into the hole
tighten down the connection ONCE by
using a torque wrench, with a torque of
27 Nm! Do not retighten the diffuser after
the torque once has been reached!
You can watch an online installation movie on
our website at www.ott-system.com in the
category products and the sub-category
MAGNUM.
2.3 Test Run
In order to avoid any kind of negative impact on
the installed diffusers, keep the period between
installation and trial run (water coverage of
diffusers) as short as possible.
Fill up the basin carefully with clean water (e.g.
from the clarifiers) until the diffusers are covered
with 10 inch of water. Make sure that the inflowing
water does not fall directly on the diffusers or
damages them!
The trial run in the basin should be carried out
directly after installation. The water tightness of the
installed diffusers can be tested, by shutting off the
aeration. While the membranes close up, leaks
would keep putting air through.
Use the test run for starting up the diffusers.
For an optimum performance the diffusers
must have been in operation for at least 24
hours at a maximum possible specific airflow
(see table). This is especially important before
oxygen transfer tests.
2.4 Downtime until start of operation
After the trial run and start up phase the system
can be operated. If the operation cannot be started
directly, the water level should be increased up to
1 meter minimum, and maintained until the system
is put into operation. Pay attention to water
evaporation or ice formation. During periods of
frost, the basin should be filled up to a swd of 3 m
(10 ft).

Assembly, Operation, Maintenance of
MAGNUM
®
Membrane Tube Diffusers
and Membranes
7-2006
OTT GmbH Tel: +49 (0)511 / 78631 0
Frankenring 21 Fax: +49 (0)511 / 78631 40
D 30855 Langenhagen Email: [e-mail]
Germany www.ott-system.com
page 4 of 6
3. Operation
3.1 General instructions
Oil-, dust- and solvent-free air quality as well as air
filtration is required. The intake air must
correspond to the requirements laid out in TA
(Technische Arbeitsanweisungen). Dust filters for
environmental dust are to be designed for a “by
count efficiency” of at least 81% in accordance
with EN 779 (BS 6540, Ashrae 52-76) filter grade
F7 or higher.
The air temperature at diffuser entry may not
exceed 80° C for FLEXNORM or 120° C for
FLEXSIL membranes respectively. The water
temperature should be between 5° and 35°
Celsius. Higher temperatures are possible but
please consult your OTT representative in this
case for additional information.
3.2 Operational airflow of the diffusers
Diffuser Throughput Rates
perforation
types HE micro fine normal medium
[m3/hr/m] [m3/hr/m] [m3/hr/m] [m3/hr/m] [m3/hr/m]
min
0,5 1 1 1,5 2
norm
4 7 8 9 12
max
6 12 16 18 24
daily
stretching
up to
12 16 18 24 30
flushing
up to
18 24 27 36 40
shutt off
possible:
Yes Yes Yes Yes Yes
slot size
0.6 mm 1 mm 1.2 mm 1.4 mm 2 mm
1 m
3
/hr/m = 0.589 scfm
The operational airflow is depending on the
membrane perforation: Bigger membrane pores
allow higher air flow rates as shown in the table
above.
The diffusers should be operated at the maximum
possible air flow rate once a week for about 20
minutes. This way scaling and fouling can be
minimized sufficiently.
Do not exceed the above mentioned maximum air
flow rates.
3.3 Downtime after operation
After pumping out the basin or taking aeration
grids / racks out of the water, take care that
deposits and sludge do not dry on the membrane
tubes. The diffusers should not be placed in the
sun. Dried mineral deposits stick to the membrane,
so that cleaning might become impossible.
In case that the basin is emptied for a longer time,
the diffusers have to be covered with water (see
“Downtime until start of operation”). Further: see
maintenance instructions.

Assembly, Operation, Maintenance of
MAGNUM
®
Membrane Tube Diffusers
and Membranes
7-2006
OTT GmbH Tel: +49 (0)511 / 78631 0
Frankenring 21 Fax: +49 (0)511 / 78631 40
D 30855 Langenhagen Email: [e-mail]
Germany www.ott-system.com
page 5 of 6
4. Assembly / Change of membrane-
tubes
4.1 Preparation / Cleaning
The polypropylene support pipes (bodies) of the
diffusers have to be cleaned and dried carefully
after removing the old membranes and before
starting to assemble the new membranes. Do not
reuse damaged support pipes.
The entire aeration system has to be checked for
dirt in the air headers or racks. All impurities, even
dust and sand, have to be taken (washed or
blown) out of the headers completely.
Depending on the type of aeration system and
local conditions, it could be useful to let air flow
through the system during the works. This might
avoid sludge to enter the open racks / pipes or air
headers. Please contact your OTT representative
for additional information.
OTT recommends taking the diffusers out of the
basin and conduct the replacement at an
appropriate work place.
4.2 Assembly of membrane-tube
Dry the support pipe (body) of the diffuser.
Push membrane onto the support pipe (away from
your body). Avoid using too much force when
assembling the membrane tube.
In case of difficulties, use “support air” by carefully
inserting the blowpipe of a compressor between
sleeve and support pipe.
Never use any lubricant!
Attention, important information
relevant for function and guarantee:
The centre line of the non perforated area of the
membrane has to be adjusted exactly on top of the
ridge. FLEXSIL
®
membranes do have a blue line in
the midst of the non perforated area. This blue line
has to be positioned exactly on top of the ridge.
4.3 Assembly of clamps
After the membrane tube is assembled and
adjusted on the support pipe, the clamps must be
installed on both ends of the membrane. Use only
original OTT GmbH clamps, and fasten the clamps
with the special pincer tool provided by OTT.
Attention, important information:
Clamps have to be closed in a way that there is an
opening of 2,7±0,2 mm (see sketch), this ensures
tight, close fit on the membrane sleeve.
Closed clamps point exactly to the top (12:
00
position). The clamps are covered with the
excess length of the membranes by folding it back.
Both sealings of the diffuser have to been changed
before the diffuser with the new membrane is
assembled again. See the assembly instructions of
the complete diffusers for further information.
4.4 Start up
The membrane tube diffusers are ready for start-
up now. Please read the installation- and
operating- instructions for the completed diffusers
carefully and perform a new bubble pattern test.
closure-up to:
2,7± 0,2 mm
closure of
clamp on
the top
Centre line of the non
perforated area of the
membrane positioned
exactly on 12
00
and 6
00
o’clock position

Assembly, Operation, Maintenance of
MAGNUM
®
Membrane Tube Diffusers
and Membranes
7-2006
OTT GmbH Tel: +49 (0)511 / 78631 0
Frankenring 21 Fax: +49 (0)511 / 78631 40
D 30855 Langenhagen Email: [e-mail]
Germany www.ott-system.com
page 6 of 6
5. Maintenance and cleaning of
membrane tube diffusers
OTT membrane tube diffusers operate reliable and
do not need intensive maintenance. Still regular
control and usual maintenance is strongly
recommended.
Wastewater contains various components which to
a certain extend do settle on the membrane. Some
are mentioned below:
carbonate (water hardness),
precipitants
polymeres (sludge conditioning)
Deposits on the diffuser are usually not harmful to
the membrane but might affect the pressure loss
and bubble pattern.
Certain solvents and oils can have a negative
impact on the membrane. In case of questions
address to you OTT representative.
Biological films are known to reduce the life time
on EPDM rubber membranes. If problems related
to biological films must be expected OTT
recommends using FLEXSIL membranes.
5.1 Lifetime
The lifetime of a diffuser is mainly depending on
the actual process and waste water conditions.
Therefore the suitability and quality of the chosen
membrane material is important. Please discuss
the given situation at the WWTP with the supplier
or your OTT representative to make a sustainable
choice.
OTT membranes are suitable for a waste water
quality as defined in the German „ATV
Arbeitsblattes A 115“ latest edition. This means the
amount of industrial wastewater may not exceed
20 % of the total wastewater flow. In case of
questions please contact your OTT representative.
In order to maintain an economically operation and
a long life cycle follow the assembly, operation and
maintenance instructions for OTT diffusers.
5.2 Performance control
The best indication for layers and crusts on the
membrane is the pressure loss. Monitor the
development of your blower pressure over time.
Define a critical pressure where measures should
be taken.
5.2.1 Flushing with air
First measure should be the flushing with air. This
should be done if possible preemptively on a daily
basis as described in chapter 3.
5.2.2 Cleaning
The diffusers membrane can be cleaned with
water and a high pressure cleaner. The distance
between the membrane and nozzle of the high
pressure cleaner should be at least 0.5 meters.
Alternatively a brush can be used to clean smaller
numbers of membranes. If possible put air through
the diffusers during the cleaning process.
Important: Mechanical or chemical impact can
cause serious damage of the membranes, handle
the diffusers and the cleaning equipment with care!
The membrane may not be damaged, folded or
wrenched while cleaning the diffuser.
Do not use any detergents, solvents, alcohol or
acids for cleaning without having discussed the
case with your OTT representative.
5.2.3 Flushing formic acid
From a certain point on flushing with air may not
be sufficient. The reason can be calcium in the
perforation holes of the diffuser. In this case OTT
recommends flushing with formic acid. Do not use
other acids. The formic acid should be injected into
the air supply or drop pipe. Use an acid
concentration of 80% and 250 ml/hr per meter
installed diffuser length.
Handling acids is dangerous. Wear appropriate
protective clothing. Choose a dosing mechanism
that does not imperil your health. Contact the acid
supplier and follow the prescribed directions for
handling acids.
6. Service
It is possible to send a sample diffuser / membrane
to OTT GmbH. Deposits and the quality of the
membrane will be analysed and an appropriate
advise for cleaning and further measures will be
worked out. Please clean the diffuser before
sending it. Use water (especially clean the flooded
pipe) but do NOT brush or clean away the deposits
on the membrane. Please take care that the
membrane does not dry during transportation - that
would affect the test.