Snowate Submerged

MBR Manual

Notice
This user manual illustrates Snowate product series basic information,
design principle, installation, operation and maintenance.
For the sake of safe and appropriate usage of SW product, please read
this manual carefully and keep it properly.
Products covered by this manual are included in Chapter 1 Specifications.
Cautions Technical Terms

This MBR product applies to residential and municipal wastewater treatment, please do not use it for Hollow Fiber Membrane
other purpose without SW approval.
The hollow fiber membrane refers to a membrane that has a shape that is fibrous with sup-
Further notice will not be made if any change with specification and contents in this manual.
porting function, usually outer diameter less than 3mm.
Permeate of this product is not suitable for drinking, shower or bath purpose.
To make sure long term and stable performance of this product, periodic inspection and repair is MBR (Membrane Bio-Reactor)
needed. Membrane Bio-Reactor is a new waste water treatment process that combines membrane
Please use this product within suggested MLSS (5,000-12,000mg/L, min 3,000mg/L, max
separation with biological treatment technology, it consists of biochemical reaction system
15,000mg/L), higher MLSS will cause increase of viscosity, which can affect membrane cleaning
and membrane modules. This technology utilizes a membrane module to retain activated
and sludge will be on surface of hollow fiber, contributing to pressure increase and MBR module
damage. sludge and macro molecular organic matter in an aerobic bio-reactor to increase concentra-
Please make sure TMP less than -0.05MPa, setting a limit value is suggested. tion, hydraulic retention time (HRT) and sludge retention time (SRT) can be controlled sepa-
Please make sure air scour flux for MBR module within 0.25-0.35Nm3/(m2•h), MBR module will be
rately, while refractory substances can be biodegraded constantly in the reactor.
damaged if flux is above 0.5Nm3/(m2•h).
HRT (Hydraulic Retention Time)
MBR module cleaning chemicals are sodium hypochlorite (NaClO), sodium hydroxide (NaOH),
Oxalic acid (H 2 C 2 O 4 ), citric acid (C6 H 8 O 7 ) and hydrochloric acid (HCl). Chemicals need to be Hydraulic Retention Time (HRT) is a measure at an average length of time holding the
rejected after proper usage according to MSDS, which is available from chemical suppliers. waste water in a tank, which is also the average reaction time of waste water and microor-
When moving MBR cassette, please make sure MBR modules are under protection from pipes, me-
ganisms in bio-reactor.
chanical components and other sharp stuff.
SRT (Solids Retention Time)
When lifting the MBR cassette with chain or wire, please make sure they are all in tense condition to
protect membranes. Solids Retention Tim (SRT) is the average time the activated-sludge solids are in the system.
Please hold the bracket or collection pipe of MBR module instead of the membranes, and make sure MLSS (Mixed Liquid Suspended Solids)
all tools, pipes and other mechanical components are away from MBR module.
Mixed Liquid Suspended Solids (MLSS) refers to total weight of activated sludge solids per
Please be careful when cleaning MBR contamination residue and make sure there is no damage to
unit volume mixture within an aeration tank.
the membranes.
Please do NOT use high pressure cleaner for membrane cleaning, which may damage the mem- Flux
branes. Flow of permeate water through the membrane, usually in terms of permeate water flow cer-
Please make sure this product is away from construction site, fire, welding and cutting machines.
tain square meter at certain time, unit L/ m2·h.
Before putting active sludge into MBR tank, please inject water to clean pipes and the pool, plastic
TMP (Trans-Membrane Pressure)
and steel parts can damage the membranes.
Please use 2mm or smaller screen, cylinder filter and wedge wire mesh are recommended. Pressure drop across the membrane.
To protect modules from plastic parts or other things, a cover on the tank is suggested. Fouling
All the storage and transportation should be away from direct sunlight at 0 - 40 , store the mem-
Fouling refers to the phenomenon of membrane permeate flux or filtration performance de-
branes at dry environment, please pay attention to membrane damage under moisture condition.
cline due to smaller membrane pore size or membrane clog caused by physico chemical or
Please make sure hollow fiber (PVDF with PET supporting layer), sealing material (polyurethane)
and water collection pipes (ABS) etc. are away from chemicals that may aging them. mechanical reaction between membrane and macro molecular solute such as small particles,
Please do NOT use this product to filtrate wastewater with solvents or chemicals which may cause colloidal particles, organic matter and microorganisms in waste water to be treated.
membranes expansion, breakage and deterioration (chemical compatibility at the end of this manual).
Framework of the product is SUS304, please do NOT use it under the conditions of high salt concen-
Above technical terms in this user manual may be different from terms used generally.
tration, which will corrode SUS304 and shorten product service life.
Please follow local laws and regional regulations when disposing MBR modules and cassettes.

01 02
 Contents Chapter 3 Installation and Commissioning 20
3.1 Transportation and Installation 20
Chapter 1 Specifications 05
3.1.1 Packaging and Transportation 20
1.1 MBR Module Specifications 05
3.1.2 Membrane Cassette Arrival Inspection 20
1.2 Cassette Specifications 07
3.1.3 Membrane Cassette Pre-installation Inspection 20
Chapter 2 Design of MBR 08 3.1.4 Check List before Installation 21
2.1 MBR System 08 3.1.5 Installation 21
2.1.1 Main Equipments in MBR System 09 3.2 Clean Water and Sludge Test after Installation 22
2.2 Feed Water Quality 10 3.2.1 Clean Water Test 22
2.2.1 Oil & Grease 10 3.2.2 Sludge Test 23
2.2.2 Anti Foaming Agents 10
Chapter 4 Operation & Maintenance 24
2.2.3 Others 10
4.1 MBR Operation & Maintenance 24
2.3 Pre-treatment 11 4.1.1 Abstract 24
2.4 Activated Sludge Conditions 12 4.1.2 Membrane Cassettes Working Parameters 25
2.4.1 MLSS Concentration 12 4.1.3 Inspection Items 25
2.4.2 Sludge Viscosity 12 4.1.4 Additional Information on Inspection Items 26
2.4.3 Others 12 4.1.5 Problems and Solutions 27
2.5 MBR Operation 13 4.1.6 Operation & Maintenance Records 28
2.5.1 Design Flux 13 4.2 MBR Start Up 31

2.5.2 Self-priming Pump 13 4.2.1 Seed Sludge Input 31

2.5.3 Intermittent Suction Setting 14 4.2.2 Start-up 31

2.5.4 Attentions for Equipment Design 14 4.2.3 Operation 31

2.6 Aeration Amount 15 4.2.4 Problems and Solutions 31

2.6.1 Air Flow 4.3 Membrane Repair 32

15
2.7 Chemical Cleaning 4.3.1 Preparation 32
15
4.3.2 Repair Procedure 32
2.7.1 Abstract 15
4.3.3 Attentions 33
2.7.2 Cleaning Procedure 16
4.4 MBR Module Preservation 33
2.7.3 Acid Cleaning 17
2.7.4 Attentions 17 Chapter 5 Chemical Compatibility 34
2.7.5 Attentions for Recovery Cleaning 18 Appendix I: 500 m3/d MBR System Design of Municipal Sewage 35
2.8 Layout of Membrane Element and Cassette 19
Appendix II: 500 m3/d MBR System PID for Municipal Sewage 41

03 04
Chapter 1 Specifications
ITEMS UNIT SPECIFICATION

Module type -
1.1 MBR Module Specifications SWB1V4024-10 SWB1V6024-15 SWB1V7924-20

Membrane area m2 10 15 20
Snowate reinforced hollow fiber PVDF-MBR has pore size 0.1μm, it is made with PET
Hollow fiber direction - Vertical
supporting layer with high strength (tensile strength>150N), anti-peeling off feature (peeling
off strength>0.6MPa), high flux (pure water flow 2,000L/(m2•h•bar)@25 , design flux can Hollow fiber material - PVDF with PET support

be 30 L/m2•h) and excellent chemical resistance. Seal material - Polyurethane (PU)

Features of MBR: Bottom protection - Polyurethane (PU)
Material
a. High flux and quality permeate: MBR modules are made with hydrophilic modified PVDF
Collection pipe - ABS resin
material, PET support can greatly reinforce hollow fibers, high porosity and 0.1μm pore
Frame - SUS 304
size contributes to high permeate flux and permeate water turbidity < 0.2NTU (On-line tur-
Nominal rating μm 0.1
bidity meter).
b. High peeling off strength of the membrane, which can resist instantaneous high pressure ID/OD mm 0.9 / 2.2

back washing, burst pressure > 0.6MPa. Module size D×W1×L1 mm 48×620×1,000 48×620×1,500 48×620×2,000
c. Flexible in module types. Dry weight kg 4.7 5.8 6.6
d. High loading density saves space, joint connection makes installation and dismantle very
Permeate at both ends permeate port size G1/2”
convenient. A variety of cleaning methods are available, which can be customized, suitable Connection mm
Plug φ24
for medium and large water treatment project.
Negative pressure suction, filtration
Figure 1.1 shows SWB module size, table 1.1 shows membrane module specification . Filtration Method -
+ stop (continuous aeration)

Suction Pressure MPa Recommended: -0.01 ~ -0.05, Best value: -0.01~ -0.03

Working Temp. Recommended: 5 - 40, Best value: 15 - 30

Feed Water pH - 6-9

Operational
Feed Water Oil & Grease mg/L Animal and vegetable oil<50, Mineral oil<1
Conditions
End
Cap Cleaning pH - 1 - 11

MLSS mg/L Suggested: 3,000 - 15,000, Best: 5,000-12,000

Permeate Design Flux L/m2•h 10 - 30

Collector Tube
Permeate Turbidity NTU < 0.2 (On-line turbidity meter)
Hollow Fiber Groove
Others - Silicone anti-foaming agents not allowed

* W:480mm L1:1,000 / 1,500 / 2,000mm Table 1.1 SWB Membrane Module Specification
W1:620mm L: 1,025 / 1,525 / 2,025mm
W2:592mm

Figure 1.1 SWB Module

05 06
1.2 Cassette Specifications Chapter 2 Design of MBR
MBR cassette is consisted of frame (SUS 304 material), water collecting pipe (ABS material)
and MBR module, every standard cassette is made of different quantity of modules. Table 1.2 SWB series hollow fiber membrane cassettes are submerged membrane units for MBR wa
shows the membrane assembly parameters of 40 pcs modules. stewater treatment.
This product is placed in membrane separation tank, which can be used in liquid solid separa-
tion of activated sludge.
Number of modules (n) 15m /pcs×40pcs
2
This product needs to be adjusted to meet below design criteria, otherwise it can NOT work
Membrane area (m2) 600 properly as specification sheet declared, product aging and damage may occur.
Membrane cassette dimensions L×W×H (mm) 2,100×1,390×1,800
2.1 MBR System
Dry weight (kg) 490

Wet weight (kg) 1,000

MBR system includes pretreatment systems, bio-reactors, aeration systems, membrane equip-
ment and chemical cleaning system.
Table 1.2 SW SWB Membrane Cassette Specification MBR process flow as below figure 2.1.

Membrane cassettes with different quantity of membrane modules are available upon request,
as figure 1.2 shows:
Blower LLS
LLS
Permeate pump

Dosing
Screen

Equalization tank Lifting pump MBR tank MBR module Backwash pump Produce water tank

Figure 2.1 MBR Process Flow

Figure 1. 2 SW SWB Membrane Cassette

07 08
2.1.1 Main Equipments in MBR System 2.2 Feed Water Quality
1. Screens 2.2.1 Oil & Grease
MBR system using hollow-fiber membrane are more sensitive to fouling from hairy materials
NOTICE: Please make sure N-hexane extraction in feed water within a limit 50mg/L.
and therefore require fine screens to protect membrane from clogging, a fine screen typically 1. If there is oil (vegetable or animal oil) on the filter, it will clog the membranes, so please
range from 1.0 to 2.0 mm. do NOT let feed water with high oil content flow into activated sludge tank. Once N-
2. Flow Equalization Tank hexane extract exceeds 50 mg/L, pretreatment is necessary to control the limit under
MBR is basically constant flow operation, installing a flow equalization tank can dampen the 50mg/L, which can be oil separator, DAF (Dissolved Air Flotation) or other technology.
flow variation. The volume of the flow equalization tank is designed based on the fluctuating 2. If it is degradable oil, such as vegetable or animal oil, to some extent, membrane fouling
flows volume that can be determined based on a hydrogragh recording
规格the flow rate distribu-
can be controlled with high MLSS. However, once N-hexane extract exceeds 50 mg/L, oil
tion over a time period, and feed water flux, as well as the processing capacity of membrane will attach on membrane surface and cause clog, so pretreatment is necessary.
cassettes. 3. Mineral oil is very difficult to degrade, which is more likely to clog the membrane than
3. Membrane Separation Tank animal and vegetable oil. Therefore, once the mineral oil is mixed into the raw water and
Tank for submerged membrane modules is called membrane separation tank, it can also be the mineral oil content is more than 1mg /L, paying special attention to pretreatment to
used with an aerobic tank in a package MBR system. The membrane separation tank has the control the limit under 1mg/L.
highest sludge concentration, which is the best tank for discharge of excess sludge. 4. Surfactants in feed water can generate foam in the aeration tank, causing problems such as
4. Permeate Water Tank sludge overflow.
Storage for permeate water, also acting as backwash tank. Permeate can be discharged or
reused after dosing sodium hypochlorite (NaClO) as disinfection.
2.2.2 Anti Foaming Agents
5. Dosing Tank NOTICE:
Storage for sodium hypochlorite (NaClO) and acid cleaning chemicals for membrane cassette, 1. Please do NOT use silicon anti foaming agents.
NaClO can resolve under high temperature and release chlorine, so please keep it away from 2. If anti foaming agents needed, please use agents with high quality alcohol, ether or ester.
sunlight. a. Activated sludge can generate foam, if anti foaming agents are necessary, please use
6. Water Tank for Dilution agents with high quality alcohol, ether or ester.
Used to dilute NaClO and acid cleaning solvents, it can be municipal tap water or MBR per- b. If silicon anti foaming agent is used, it will adsorb on the membrane surface, which accel-
meate. erates the increase of membrane pressure drop, making membrane cleaning very difficult
7. Self-priming Pump/ Suction Pump and sometimes it may be necessary to replace the membrane.
Used to pump permeate, a suction device may be needed when start up, such as vacuum pump c. If sludge generates foam, please use physical defoaming method to keep anti foaming
that sucks up air in the pipe, a flow valve is placed on the drainage side of the self-priming agents within limit.
pump to control the flux automatically.
8. Backwash Pump 2.2.3 Others
Backwash pump supports MBR modules backwash to recover flux, pump specification de- 1. Membrane cassette can only work after feed water being properly treated in biological
pends on backwash flux and pressure, backwash pressure 0.1-0.2MPa, backwash flux is 1-2 tank, otherwise untreated organic substances dissolved in the feed water can adhere to the
times of permeate flux, backwash time 1min per 2-4 hours. 2. membrane surface and affect membrane performance.
9. Air Blower The coagulant (used for sludge dewatering) may adsorb on the membrane surface and
Air blower produces air for biological process and membrane air cleaning, air blower capacity affect membrane performance, so do NOT dosing too much coagulant. Please also make
depends on air flux needed of biological reaction and membrane area. sure liquid of the dehydrator will NOT flow directly into the membrane separation tank.

09 10
 2.3 Pre-treatment 2.4 Activated Sludge Conditions
To prevent contaminants in feed water damage the MBR modules, proper pre-treatment is 2.4.1 MLSS Concentration
necessary.
Suggested: 5,000 - 12,000mg/L (Min. 3,000mg/L, Max. 15,000mg/L).
1. Contaminants Retention
1. Unlike conventional sedimentation treatment, MBR system is using membrane for liquid
Contaminants such as fibers, hairs and plastic fragments etc. in feed water may become the
and solid separation, it can work at high MLSS during wastewater treatment.
cause of the entanglement of the hollow fiber membranes and need to be removed by screen
2. As MLSS concentration increases, sludge viscosity will go up, membrane air cleaning effi-
(cylinder filter or wedge wire mesh 1-2mm suggested).
2. pH ciency will be affected. Especially when MLSS exceeds 12,000 mg/L, sludge viscosity will
Adjust pH to neutral value (6-8) if the feed water is acidic or alkaline, neutralizing agent can increase sharply, so please make sure MBR modules are used at proper MLSS concentra-
be sulfuric acid and sodium hydroxide, use pH meter and dosing pump to control chemical tion. However, even with same MLSS, sludge viscosity differs depending on the nature of
concentration. the feed water and sludge, so it is recommended to manage the MLSS together the sludge
3. Oil & Grease viscosity.
Oil & grease can attach to the membrane, cover membrane surface and block membrane pore 3. The lowest concentration of MLSS is 3,000 mg/L, if lower than this value, the degradation
size, which will affect membrane modules performance. Oil &grease can be quantitatively
of organic substances will be insufficient, TMP will increase rapidly.
analyzed by extracting N-hexane, and can be quantitatively separated into animal and veg-
4. During commissioning, MLSS concentration may be less than 3,000mg/L, membrane
etable oils or mineral oils. Natural floating and pressurized air floating method can remove oil
actual flux should be lower than the design flux, then MLSS concentration can be
& grease, contributing to animal and vegetable oils less than 50 mg/L and mineral oil less
increased gradually.
than1 mg/L.
Acid Alkali Flocculant Coagulant
5. At pilot stage, Membrane Flux reference = Design Flux × Current MLSS /
Scraper
Influent Design MLSS
Effluent

Basin Basin Flotation tank 2.4.2 Sludge Viscosity

PH
dosing tank A tank B
NOTICE: Recommended sludge viscosity should be less than 30mPa•s.
Compressed air For industrial wastewater treatment, MLSS and sludge viscosity should be managed together.
If viscosity exceeds the recommended range of 30 mPa•s, membrane cleaning efficiency will
Dissolving tank be reduced, sludge viscosity needs to be controlled in limit range by MLSS.
Reflux pump
Figure 2.2 Oily Water Treatment By Dissolved Air Flotation
2.4.3 Others
4. Water Temperature
The nitrification reaction by nitrifying bacteria can easily be affected by water temperature, 1. Proper biological treatment by activated sludge is very important, temperature in aeration
low temperature will reduce reaction rate, and high temperature will easily kill nitrifying bac- tank is best at 15-35 .
teria. If temperature exceeds 40 , cooling equipments are necessary before biological reac- 2. If the activated sludge treatment is not good or MLSS concentration is lower than limit
tion tank. (3,000mg/L), the untreated organic substances will attach to membrane surface and affect
5. Others its performance, membrane actual running flux should be lower than design flux.
If there are substances that may affect biochemical treatment, it is suggested to be removed. 3. To make sure membrane running flux same as design flux, it is necessary to improve acti-
Such substances include cyanide, heavy metals such as hexavalent chromium, etc., which
vated sludge treatment to good condition.
needs to be verified in advance.

11 12
2.5 MBR Operation 2.5.3 Intermittent Suction Setting
2.5.1 Design Flux 1. To achieve the purpose of stable processing in MBR system, the intermittent suction opera
Reference design flux typically range from 10 to 30 L/m2•h. tion must be implemented at the following time intervals.
1. Filtration with constant flow. 2. Recommended intermittent filtration setting: Pump for 8 minutes, stop for 2 minutes.
2. Filtration flux: 10-30L/m2•h. Notice:
Notice: a. Continuous suction without stopping time will accumulate sludge and fine particles on the

a. Membrane flux should be verified after taking into consideration of feed water type, tem- membrane surface, and attach sludge particles, which will affect the flux and stability of

perature and operation. the membrane.

规格
b. Usually MBR system runs at constant flow. b. The suction time should be set within 9 minutes and the stopping time should be more than

c. TMP will increase with long operation time, monitoring TMP change is very important 1 minute. The normal running interval is 8 minutes of suction and 2 minutes of stopping.

during daily man agement. As shown in figure 2.3.

d. Here membrane flux refers to daily mean value, actually MBR systems are usually inter-
2-4hr
mittent suction operation, instantaneous flow is higher than this average value.

2.5.2 Self-priming Pump

Filtrate Stop Filtrate Stop Backwash
8min 2min 8min 2min 1min
The operating pressure of MBR is usually about -0.01~ -0.03MPa (also TMP 0.01 ~
Continuous Aeration
0.03MPa). The operating pressure indicates the difference between the pressure during opera-
tion and shutdown. Figure 2.3 Running Time Process

1. A self-priming pump is usually used. The specification of the pump depends on flow rate,
position of the pump, lift and pipe resistance.
2.5.4 Attentions for Equipment Design
2. The constant flow valve is set on the drainage side of the pump, the flow rate of pump de-
pends on automatic control unit. 1. The emergency suction stop function should be programmed in the system.
3. Based on the condition of pump and piping, air may be trapped in the piping, which may 2. The pipe is designed that no siphon phenomenon occurs after stop.
affect system stable operation. In particular, large-diameter piping sometimes requires a so- Notice:
lution. Air retention can be prevented by placing the pump at the highest position of the a. Due to some problem, if air blower stops, please make sure filtration automatic stop
production line. function is working, otherwise the sludge will stick on membranes and TMP will
Notice: increase. At this moment, should check air flow or pressure of air blower, alarm or stop
a. Self-priming pump ensures suction pressure, air in the piping can be easily discharged filtration system.
when the system stops and runs again. b. During the intermittent suction operation, even if the suction stopped, because of siphon
b. When start up, air in the pipes can be drained by vacuum pump or other pumps besides and gravity, sometimes filtration is still going on, so an automatic stop valve is set on
self-priming type. the pipe, or siphon switch is set after the suction pump to make sure filtration is stopped
c. When pump working pressure exceeds design pressure, high pressure alarm and unusual when system is shut down.
breakdown alarm should be set up, once alarm starts, please clean the membranes as soon
as possible.

13 14
2.6 Aeration Amount
methods are based on that membrane cassette is submerged in the tank, by injecting chemicals
2.6.1 Air Flow from the side of the suction pump.
1. Standard cleaning air volume for membrane cassette is 0.25-0.35Nm3/(m2•h), please select Organic contamination is main problem for MBR system, so usually it is suggested to use
blower according to the capacity of 0.35Nm3/(m2•h) , the area is the projection area of the NaClO as cleaning chemical. While with long time operation, the system will also be con-
membrane cassette. taminated by inorganic substances, so acid cleaning is also necessary.
2. Continuous aeration above 0.5Nm3/(m2•h) may damage the hollow fiber, so please operate
2.7.2 Cleaning Procedure
within standard range.
3. If single hole SUS aeration pipe works after long time, the sludge will enter the aeration 1. CEB Cleaning
pipe. Once the sludge dries, the aeration port may be blocked, thus the aeration port should CEB cleaning removes clogs on the membrane surface and control the increase of TMP, so as
be cleaned regularly. to achieve membrane system stable operation.
Notice: Cleaning cycle three times a week, injecting NaClO with effective chlorine concentration
a. The air volume is the amount needed for aeration of membrane cassette, and the area of the 200-500mg/L for 15-30 minutes from permeate side (inject 30 sec, stop 5 min), dosing
membrane is taken as the standard calculation. amount of 2L/m2+ piping volume cleaning agent, soaking time is 30-45 minutes. During
b. The value of air flow is only used as the basis of design. During operation, please adjust the cleaning process, aeration should be stopped. This operation is basically controlled by PLC.
air flow after confirming TMP change, dissolved oxygen of activated sludge and the condi- 2. Maintenance Cleaning
tion of rotating flow. Maintenance cleaning needs to be done every month or when the suction pressure exceeds the
c. In integrated MBR system, the air flux needed in the whole process includes the air needed set point, in order to remove contaminants from the membrane surface and make sure TMP
for membrane cleaning and biochemical treatment, higher value will be taken. recover to initial value.
d. During general industrial water treatment, compared to the air needed for membrane clean- Stop aeration, injecting NaClO with effective chlorine concentration 2,000mg/L for 30 min-
ing, biochemical treatment needs more. In this case, the air for membrane cleaning is aer- utes from permeate side, dosing amount of 2L/m2+ piping volume cleaning agent. Maintain
ated from the bottom of membrane cassette. If BOD in feed water is high, it is recom- 30-90 minutes after injection.
mended to use separated MBR system. If TMP is still high after recovery cleaning by NaClO, it can be considered as inorganic con-
e. When the air amount required for membrane cleaning is large, aeration is carried out from tamination, which can be cleaned in place by acid (1wt% oxalic acid or 1wt% citric acid or
the bottom of the membrane module. 0.2wt% HC1).
3. Recovery Cleaning
2.7 Chemical Cleaning When the maintenance cleaning can, t restore the TMP, or when the membrane surface is
Chemical cleaning procedure and attentions for membrane cassette are as bellowing. The attached to the sludge due to the failure of machinery and equipment, soak the whole mem-
usage of chemicals should be based on MSDS. brane cassette in the cleaning tank to remove the contaminants so as to restore TMP to initial
value. Recovery cleaning is better than maintenance cleaning.
2.7.1 Abstract The membrane cassette or membrane element is soaked in solvents (2,000mg/L NaClO or
When monitoring and managing the suction pressure of membrane cassette, suction pressure 1wt% oxalic acid or 1wt% citric acid or 0.2wt% HCl) soaking time for NaClO is 6-24 h, acid
should not exceed the set value (the initial value of suction pressure +0.015MPa), when it ex- for 2-4 h.
ceeds the set value, alarm should be issued, recovery chemical cleaning should be carried out Recovery cleaning can be performed in two ways: lifting the membrane cassette from the tank
quickly, and the pressure difference should be restored. and soak membrane cassette in clean water tank (for integrated MBR system), or keeping the
Chemical cleaning is divided into three types: CEB, maintenance cleaning and recovery membrane cassette in the tank and replacing raw water with cleaning chemicals (separated
cleaning. MBR system).
CEB: three times a week combined with a maintenance cleaning every month (or when the For first operation, membrane cassette should be flushed with clean water before soaking in
suction pressure exceeds the set value) to maintain performance of the system. Both cleaning the tank.
15 16
2.7.3 Acid Cleaning
Acid can lead to decrease of pH in membrane separation tank, but it has little effect on perme-
Cleaning with NaClO is effective for organic contamination, but not for inorganic contamina- ate.
tion, because inorganic contamination can gradually accumulate on membrane surface, under At the beginning of filtration, residual cleaning chemicals in the piping and hollow fiber
such circumstance, acid cleaning can be used to remove inorganic contamination. Acid cleaning membrane are collected as permeate, it has great impact on the permeate quality for a short
is suggested once every 6-12 months for domestic wastewater. time. As the filtration goes on, its concentration drops sharply, when treated water quality be-
Chemical cleaning conditions are shown in table 2.1 and 2.2. comes worse, following measures can be adopted.

Cleaning Cleaning frequency Effective chlorine Injection volume Injection and soaking time a. NaClO Cleaning. NaClO solvent and diluted water are mixed in certain proportion and
method concentration
then supplied to membrane cassette, after cleaning, dosing pump stops, the dilution pump
Backwash pressure
Backwashing 1min / 2 - 4 hours With permeate 0.03-0.075MPa 25-35L/m2·h continues working, residual NaClO in the piping is squeezed into the membrane separation
tank and inactivated, then residual NaClO mixed into permeate can be greatly reduced
2L/m2 15-30min Injection for 30s,
CEB Cleaning 3-5 times a week 200 - 500mg/L
+ piping volume stop 5min, then circulation. which is mixed into permeate. The amount of diluted water varies according to the treat-
Once every month 2L/m2 Injection for 30min,
ment capacity and pipe-laying conditions and needs to be calculated separately.
Maintenance or pressure reaches 2,000mg/L
Cleaning + piping volume soaking for 30-90min. b. Acid Cleaning. Emptying the tank and fill with water, acid in the pipe is transported to the
limit (+0.015MPa)
membrane separation tank through membrane cassette by dilution pump,replace cleaning
1-2 times every year NaClO: 6 - 24 h chemicals in the pipe with water. The amount of input varies according to the treatment ca-
Recovery or when pressure drop Acid: 2 - 4 h
2,000mg/L Soaking
Cleaning can not be recovered Intermittent aeration.
pacity and pipe-laying conditions, and needs to be calculated separately.
after CIP
2.7.5 Attentions for Recovery Cleaning
Table 2.1 Types of Cleaning
During recovery cleaning operation, please make sure that sludge does not contaminate inside
Acid Type Concentration of the suction pipe. The connection part of the suction hose and the suction pipe is fully
Citric Acid 1wt% washed and then dismantled, a plastic bag and tape can be used to seal the opening.
After lifting the membrane cassette, flush the membrane cassette with shower, rinse the
Oxalic Acid 1wt%
sludge attached to the membrane cassette and then soak it. When cleaning the membrane
Hydrochloric Acid 0.2wt%
modules, do NOT use high-pressure cleaning machine, which may damage the membrane.
Table 2.2 Acid Cleaning Concentration (select one) Drainage of membrane cassette and module cleaning shall NOT be discharged to the ground
directly, can be discharged into the raw water tank and MBR membrane tank.When running
2.7.4 Attentions again, make sure the blower is running before starting suction pump.
1. Chemical Usage The chemicals used for recovery cleaning should be properly handled according to related
During chemical cleaning process, NaClO, oxalic acid, citric acid and HC1 etc., can be used, laws and regulations. NaClO can be neutralized by sodium hyposulfide, acids can be neutral-
sometimes also NaOH for pH adjustment, please refer to MSDS, wear goggles and gloves and ized by NaOH before discharge.
use it properly. When continuously cleaning with NaClO and acid, membrane modules, related equipments
and water tank should be thoroughly washed between NaClO washing and acid cleaning
2. Treatment for Residual Free Chlorine and Acid after CEB and Maintenance Cleaning
switch. NaClO and acid mixing can produce toxic chlorine gas, please pay attention to that.
Most chemicals used for CEB and maintenance cleaning can be directly discharged into the
membrane separation tank. Because activated sludge reduces residual chlorine activity, it has
little influence on permeate.

17 18
2.8 Layout of Membrane Element and Cassette Chapter 3 Installation and Commissioning
1. The membrane cassette should be kept at proper distance from the wall of the membrane
tank and bottom of the tank, aeration pipe should be under the membrane cassette, using 3.1 Transportation and Installation
aeration volume required for biological treatment to make sure water and activated sludge This chapter explains instructions about transportation, storage, handling and installation of
flow up and down, clean membrane surface with air and water. the membrane element and membrane cassette.
2. During installation, please pay attention to below distance requirements.
3.1.1 Transportation and Installation
a. Space between membrane modules ≥ 40mm.
SWB membrane elements are individual packed with plastic bag, sealed into a shock-
b. In order to ensure a good relaxation of hollow fiber, the distance between the upper and
规格
proof carton, please do not hit and throw modules during installation.
lower ends of the collection pipe of cassette is 15-30mm shorter than the natural length of
Storage temperature for membrane element and cassette is 0 - 40 , once over this tempera-
the hollow fiber.
ture range, please use thermal insulation or air-conditioned transport vehicle.
c. The distance from the cassette to the tank walls on both sides is D1 ≥ 250mm, D2 ≥
When transporting membrane element separately, our specification is 5pcs /carton. Please
150mm.
make sure number of overlapping boxes less than 5 cartons.
d. The distance between cassettes is W1 ≥ 200mm, W2 ≥ 300mm.
The membrane cassette should not be transported overlapped.
e. Distance from the bottom of the cassette to the bottom of the MBR tank is H3 = 125mm
(the center of the aeration tube to the bottom of the tank). 3.1.2 Membrane Cassette Arrival Inspection
f. Distance from the top of cassette to water surface in MBR tank is H2 ≥ 300mm.
SWB products have been strictly inspected before shipment to ensure that they meet SW
g. Distance from the top of membrane cassette to the bottom of the MBR tank is H1 ≥
quality standard. However, they might be damaged during shipment, please check and make
500mm.
sure they are in good condition.
Suggested inspection items:
1. Check delivery list, product model and quantity.
2. Check product package and product itself in good condition.
3. Check quantity and models of membrane elements and accessories must be identical.
4. If there is any abnormality, please contact our sales person in time.

3.1.3 Membrane Cassette Pre-installation Inspection

1. Before installing the membrane cassette, check piping tank and pump are clean and in good
condition. After installation, please flush pipes, raw water pumps, suction pumps, blowers
and chemical dosing pipes.
2. 2mm fine screen is suggested before membrane separation tank to protect the membrane
cassette from damage, for wastewater containing fibers and hairs, hair collecting device is
needed.
3. A plastic cover is suggested to prevent the tank from contamination.
Figure 2.4 Layout of the MBR Membrane Cassette in Reaction Tank 4. In addition to the construction process, it is also necessary to ensure that no foreign matters
of more than 2mm are mixed in at other times. The mixing of foreign matters may cause
damage to the membrane.
19 20
Stuff that may damage the membrane as below 4. Bonding union: lay ABS glue on inner wall of the union and outer wall of permeate collect-
a. The water contains foreign matter larger than the screen. ing pipe, then insert the union into permeate collecting pipe and rotate one turn. Please note
b. Foreign matter (leaf branches, plastic bags, etc.) blown or dropped during maintenance and that the union should be inserted completely. Then install another union on second perme-
repair of membrane cassette. ate water collection pipe. Please make sure that the unions need to be on the same side.
c. Residual from piping and machinery. 5.Install the union inner thread: Remove the union inner thread. Check again if the inner seal
d. Others such as wire rope, baler, bolt, nut, ruler, metal sheet, steel wire, cuttings, tape, weld- of the union is in good condition and replace it if it is defective. A few turns of PTFE tape
ing slag, fish, shells, etc. are wound on the outer thread of the membrane cassette, generally 3 to 4 turns. Screw the

3.1.4 Check List before Installation 规格 union wire into the frame one by one. This step requires the use of a belt wrench and a spe-
cial wrench for the outer wire.
Before installation, the contents that need to be checked and confirmed are as follows:
6.Install the membrane element: Insert the membrane element plug into the hole in the upper
1. The membrane tank has been cleaned to ensure that there are no large particles that can
end of the frame. Check that the union seal is in good condition and tighten the upper end.
cause membrane scratches and other contaminants.
Then insert the other plug of the membrane element into the hole at the lower end of the
2. The membrane guide rod has been installed correctly.
frame. Check if the union seal is in good condition and finally tighten the lower end.
3. A fine screen of 2mm or smaller.
7.Follow step 6 to install the remaining membrane element until all installation is completed.
4. Hair collecting device is needed for wastewater with fibers and hairs.
8.Use blind or plastic film to seal the flange of frame.
5. The liquid level needs to higher than membrane cassette and lower than the guide rod.
9.Use a lifting device to hoist the membrane cassette above the membrane tank. Unseal the
6. Aeration system is working, including source, pipeline and valve.
flange of the membrane cassette, connect the corresponding pipe, and slowly lower the
7. Pipeline connected to the membrane rack is installed, including water production pipeline
membrane cassette along the guide rod after completion. The entire installation is complete.
and backwash pipeline.
8. Membrane cassette lifting equipment is available. 3.2 Clean Water and Sludge Test after Installation
9. Membrane cassette installation tool is ready, including belt wrenches, special wrenches for
3.2.1 Clean Water Test
outer wire joints, herringbone ladders, scissors, brushes. Installation materials include
1.Water storage tank: fill water (tap water or clean river water) into the water level specified
ABS glue, raw material belt.
by the tank.
10.Membrane cassette installation site needs to be leveled.
2.Water level indicator and alarm check: When storing water, please record actual water level
3.1.5 Installation and adjust according to water level indicator, and make sure alarm can work.
When above preparation is finished, the membrane cassette can be installed. Installation step 3.Water tank leakage check: After filling water to required level, mark and keep it for 24
instructions: hours to confirm whether the water level has declined. Please also check whether there are

1. Open the membrane product and take out of the membrane element. dissolved ingredients from concrete.

2. Place the membrane element on the wrapper and cut the film with scissors. Be careful not 4.If the tank is leaking, it needs to be repaired after emptying the water. Therefore, it is rec-

to scratch the hollow fiber. ommended to install membrane cassette after inspection of this item.

3. Bonding plug: lay ABS glue on inner wall of the plug and outer wall of permeate collecting 5.Test run of equipment: please make sure all equipments operated according to user manual,

pipe, then insert the plug into permeate collecting pipe and rotate one turn. Please note that record the main indicators such as speed and current.

the plug should be inserted completely. Then install another plug on second permeate water 6.Pumps, blowers and other fluids need to meet performance curve, flow, pressure, speed and

collection pipe. Please make sure that the plugs need to be on the same side. current, etc. should be recorded.

21 22
 Chapter 4 Operation & Maintenance
7. Monitor and record the flow in the tank caused by aeration.
8. Adjust the flow meter, dissolved oxygen and other test instruments.
At the beginning of filtration, hydrophilic agent from the hollow fiber will flow into per-
4.1 MBR Operation & Maintenance
meate, which may cause turbidity and bubbles in permeate. Generally, it will become 4.1.1 Abstract
clear after 10 minutes of filtration. MBR is a solid-liquid separation system by replacing the sedimentation tank in conventional
9. Comprehensive water test run. activated sludge process, so the MBR system does not require a sedimentation tank and
The water is pumped from the raw water tank or equalization tank to implement commis- adapts to high concentration of MLSS with almost 100% SS removal. A typical activated
sludge process and MBR system is shown in figure 4.1 and figure 4.2. Compared to the con-
sioning of the overall system. 规格
ventional activated sludge process, the advantages of MBR are as following.
The filtration flow rate will change at 5-30L/m •h, successively check and record TMP.
2

a. No sedimentation tank is required, small footprint.

3.2.2 Sludge Test b. MLSS concentration can be increased to 5,000-12,000mg/L, biological reaction tank be-
comes much smaller.
1. Input sludge.
c. MBR cassettes submerged in aeration tank can produce high quality permeate with self-
2. Once filtration starts, please confirm whether there are SS or bubbles in permeate.
priming pump, permeate can be used as feed water of RO membrane.
If there is SS leakage or mixed bubble, it may be caused by membrane or piping leakage, d. Chemical dosing can greatly improve the phosphorus removal efficiency.
please check one by one.
The MBR system can be an integrated MBR system in which membrane cassettes are in
3. Increase filtration rate from 5 L/m2•h to the design flow rate, confirm and record TMP.
membrane separation tank, or a separated MBR system in which the membrane cassettes are
disposed outside the membrane separation tank, just as figure 4.3 shows.

Effluent
Influent Effluent Influent
Setting Permeate pump
tank
Aeration
tank

Blower
MBR tank
Blower
Reflux pump

Figure 4.1 Standard Activated Sludge Treatment System Figure 4.2 Integrated MBR System

Effluent
Influent
Permeate pump

Aeration tank
MBR tank
Blower Reflux pump

Figure 4.3 Separated MBR System

23 24
4.1.2 Membrane Cassettes Working Parameters 4.1.4 Additional Information on Inspection Items

Temperature 5 ~ 40
1. TMP
Check the stability of TMP. A sudden TMP increase means clog of membrane surface, which
pH 6~9
may be caused by abnormal aeration or excessive sludge concentration.
MLSS mg/L 5,000 ~ 12,000 2. Aeration Status
Working pressure MPa -0.01 ~ -0.03 Check whether aeration flux of the membrane module meets requirement and aeration flux is
Data Max. TMP MPa -0.05 uniform, if not, necessary measures need to be taken as follows.
a. Check membrane cassette and pipes installation, check the air blower, adjust aeration flux,
Flux L/m2•h 10 ~ 30
etc.
Backwash pressure MPa 0.030 - 0.075
b. If aeration rate decreases or aeration is stopped, NO suction should be operated, other wise
Air scour flux Nm3/ area m2•h 0.25 ~ 0.35 membrane surface will be fouled.
Dissolved oxygen mg/L ≥2 3. Permeate Flux
Record daily permeate flux of the membrane system, adjust the cleaning frequency and clean-
Table 4.1 Working Conditions
ing scheme of the membrane cassettes according to permeate flux change.
4. MLSS
Typical permeate water quality as below table 4.2 (residential sewage as feed water):
Usually MLSS ranges 5,000-12,000 mg/L, please adjust the MLSS concentration appropri-
ately to ensure that the permeate water quality meets the design requirements, then make sure
COD 30mg/L TSS 1mg/L
MLSS concentration is within the operation range of membrane system. If MLSS is too low,
BOD5 5mg/L TP 0.3mg/L putting in sludge or stopping sludge discharge is suggested. If MLSS is too high, increasing
NH3-N 1.5mg/L TN 15mg/L sludge discharge is suggested.
Turbidity 0.2 NTU 5. Sludge Viscosity
Normal sludge viscosity should be below 100mPa·s, if this condition is not met, the specified
Table 4.2 Typical Residential Wastewater Permeates
performance of membrane cassettes may not be achieved, so please adjust viscosity to the
normal range. If sludge viscosity is too high, measures such as replacing sludge and increas-
4.1.3 Inspection Items ing the sludge discharge may be adopted.
The performance of membrane cassette can vary with the quality of feed water and operating 6. DO (Dissolved Oxygen)
Normally DO of the membrane bioreactor is 2-3mg/L, if not meeting this value, adjusting
conditions. In order to maintain stable operation, it is recommended to record the values of all
aeration is suggested.
operating parameters.
7. pH Value
(1) Biological system air scour flux (8) Feed water BOD, COD, SS pH range for membrane bioreactor is 6-9, if not meeting this value, adding acid or alkali is
(2) Membrane cassette air scour flux (9) Permeate BOD, COD, SS suggested.
(3) Water temperature (10) Excess sludge discharge 8. Water Temperature
Water temperature should be 5-40 , if not meeting this value, please take measures such as
(4) pH in aeration tank (11) MLSS in membrane tank
cooling or heating.
(5) DO (Dissolved oxygen) (12) NH3-N level
9. Water Level
(6) Capacity of membrane system (13) Sludge viscosity Please check water level of the membrane bioreactor to ensure that membrane cassettes are
(7) TMP totally submerged in the lowest water level, any problem please inspect as following.
a. Check whether liquid level meter is normal.
b. Check whether outlet pipe is leaking.

25 26
4.1.5 Problems and Solutions
Items Possible reasons Solutions
Problems can be device malfunction or abnormal feed water quality, details as table 4.3 and
4.4 below.
1.Abnormal feed water quality. 1.Confirm feed water quality.
BOD
COD 2.MLSS decrease. 2.Adjust sludge discharge.
Section Problems Reasons Solutions 3.Low aeration flux. 3. Adjust aeration amount (DO 1mg/L).

Inflow Sewage overflows screen Screen is clogged Clean screen

1.Turbidity meter blocked. 1.Clean the turbidity meter.
SS 2.Permeate collection pipes broken. 2.Repair permeate collection pipes.
Liquid level too high 1.Increased feed water flux. 1.Lower down feed water flux. Turbidity
2.Flow regulation pump is 2.Repair regulation pump. 3.Fiber breakage. 3.Repair broke fibers or replace the membranes.
broken. 3.Increase membrane filtration flux
Equalization 3.Membrane cassettes to certain range, clean or replace
tank performance decreased. the membranes.
1.Low T-N removal 1.Analysis of raw water quality.
a. Abnormal feed water quality. 2.Confirm mixer working condition.
Disabled mixing Mixing device is broken Repair mixing device 3.Reduce sludge discharge, NOTE the lack
b. Low mixing efficiency in
anaerobic tank. of do caused by the increase of MLSS.
Liquid level too high Membrane cassettes Membrane cleaning or replacement 4.Adjust to appropriate range.
performance decreased. c.low MLSS.
Anaerobic 5.Reset circulating pump flow.
d. Increased ORP.
tank
Disabled mixing Mixing device is broken Inspect and repair e. Low aeration efficiency.

T-N
Membrane cassettes Suction pump malfunction 1.Repair suction pump.
performance decreased 2.Adjust to correct flux.
2.Low nitrification efficiency. 1.Analysis of raw water quality.
a. Abnormal feed water quality. 2.Reduce sludge discharge, NOTE the lack
1.Membrane fouling. 1.Clean the membranes.
b.Decreased MLSS. of DO caused by the increase of MLSS.
2. Decreased aeration flux. 2.Adjust membrane aeration flux.
c. Low aeration efficiency. 3.Adjust the aeration rate and set the DO
within the appropriate range.
Start pump but no
Piping leakage Inspect and fix connection parts 4.Reset circulating pump flow.
permeate
Aeration
tank Rapid TMP increase, Design flux too high Adjust flux
MBR frequent chemical 1.Abnormal feed water quality. 1.Confirm feed water quality.
tank cleaning T-P 2.Bad coagulation and flocculation. 2.Repair flocculent pipes, reset flocculent
Adjust membrane aeration,
Membrane fouling
clean the membranes dosing amount.

MLSS too high Increase excessive sludge discharge

N-hexane 1.Abnormal feed water quality. 1.Confirm feed water quality.
No aeration Air blower is broken Repair blower extractable 2.Low MLSS. 2.Decrease sludge discharge
(note: increased MLSS will cause low DO).
Liquid level too high 1.Suction pump 1.Repair suction pump.
malfunction. 2.Adjust aeration, clean membranes.
2. Membrane clog. 3.Repair liquid level meter. 1.Disinfectant not enough. 1.Increase disinfectant.
3. Liquid level meter E. coli 2.Water collection pipes broken. 2.Repair collection pipes.
broken. 3.Fiber breakage. 3.Repair broken fibers or replace membranes.

Table 4.3 Device Malfunction and Solutions Table 4.4 Abnormal Feed Water Quality and Solutions

27 28
4.1.6 Operation & Maintenance Records
Section Items ○× Solution Section Inspection items Value
For daily maintenance management, it is suggested to use an O&M record sheet (refer to table
Coarse screen Solids accretion Temperature
4.5).
Fine screen Solids accretion MLSS mg/L
It is recommended to use computer software to manage the O&M data.
Anaerobic tank
Below items are mandatory items which need to be recorded and saved, which should be ob- Pump ORP mV

tained once a week. Liquid level meter pH -

Equalization tank
a. Fine screen, aerobic tank, membrane separation tank (sometimes same as aerobic tank). Mixer DO mg/L

b. Membrane separation tank temperature, TMP, permeate flux, suction/stop cycle, DO, mem- Sludge, scum problems Temperature
规格
brane cassette aeration flux, MLSS. Mixing TMP MPa
c. Feed water and permeate water quality analysis: BOD, COD, N-hexane.
Sludge, scum problem Permeate flux m³/h
d. Chemical cleaning record (chemicals, concentration, TMP before and after cleaning). Anaerobic tank Aerobic tank
Instrument (membrane Suction/stop cycle -
e. Operation & Maintenance record. separation tank)
Water level DO mg/L

Aeration status Aeration flux m³/h

Foam, scum problem MLSS mg/L

Suction pump Circulating sludge flux m³/h

Aerobic tank Circulation pump Water analysis

(membrane
separation tank) Air blower Item Feed water Permeate water

Instrument pH

Water level BOD(mg/L)

Permeate water quality COD(mg/L)

Air blower SS(mg/L)

Water level NO2-N(mg/L)

Sludge storage tank
Scum problem NO3-N(mg/L)

Smell NH3-N(mg/L)

Residual chlorine T-N(mg/L)

Disinfection tank
Permeate water transparency T-P(mg/L)

NaClO tank Residual N-Hex(mg/L)

Flocculent tank Residual Special remarks

Dilution water tank Water level

Table 4.5 Operation & Maintenance Record

29 30
4.2 MBR Start Up
2. pH Drop
4.2.1 Seed Sludge Input pH drop is sometimes caused by insufficient nitrification and nitrogen removal, please con-
Seed sludge is required when MBR units start up, which should be treated by 1mm (or firm and adjust DO in aerobic tank, ORP in anaerobic tank, aeration flux and sludge circula-
smaller) screen to avoid big impurities entering membrane tank. Wastewater, which should be tion amount, and perform intermittent operation. When starting up, please note that the pH
treated by 1mm screen too, should be put into the tank after seed sludge. may change easily.
To shorten MBR units start up time, seed sludge input should make sure MLSS in MBR tank 3. Low Nitrogen Removal
over 3,000mg/L. High concentration of T-N in permeate water may come from two reasons: (A) No effective
Seed sludge amount Q= Q1+Q2 ×n÷n* nitrification; and (B) no effective denitrification. Therefore, it is necessary to monitor NO3-N
规格
Q1 Anaerobic tank volume and NH3-N in permeate water and figure out the reason.
Q2 Aerobic tank volume If NH3-N exists in permeate water, it can be considered that (A) has no effective nitrification
n MLSS concentration reaction. At the initial stage of operation, nitrifying bacterias are not enough for nitrification.
n* Seed sludge concentration n* n If DO in aerobic tank is above 1 mg/L, the nitrification reaction will be accelerated with the
BOD-MLSS loading calculation acclimation of sludge.
BOD-MLSS loading=[Feed water BOD(mg/L)×Capacity(m³/D)]÷[Aerobic tank volume
(m³)×Aerobic tank MLSS(mg/L)]
When activated sludge acclimation is not good, or more sludge input is needed, it is suggested
4.3 Membrane Repair
to record MLSS (MLVSS), pH, filtration quantity by filter paper and viscosity in advance, as During operation, if the hollow fiber membrane is broken
a basic value for investigation. or hollow fiber needs to be sampled for analysis, epoxy
resin can be used for repair.
4.2.2 Start-up

30~50mm
4.3.1 Preparation
Start the anaerobic tank mixer, circulation pump and air blower first, after thorough mixing 1. Epoxy resin (water resistant), recommended to cure
Collection
and BOD decomposition, then start filtration process. Please note that residual BOD will trig- within 1 hour. groove
ger TMP increase and membrane clog. To confirm whether dissolved BOD is decomposed 2. Pliers or scissors.
completely, feed water BOD, sludge concentration and estimated tank capacity should be 3. Absorbent paper or cloth. Epoxy resin glue
taken into consideration, a simple COD test can also be performed. Membrane fiber
4.3.2 Repair Procedure
4.2.3 Operation 1. Wash the sludge which is attached to the membrane.
Figure 4.4 Membrane Repair

Start to discharge excessive sludge after MLSS concentration in aerobic tank reaches 5,000- 2. Cut broken hollow fibers at 30-50mm from potting surface.
6,000mg/L, adjust excessive sludge discharge to meet designed value. 3. Absorb moisture at the end of hollow fiber with absorbent paper or cloth, then hold the
fibers with paper or cloth. Refer to epoxy resin user manual, mix epoxy resin and the
4.2.4 Problems and Solutions curing agent, once viscosity of the adhesive is high, coat the end of hollow fiber with

1. Foaming mixed adhesive, make sure the adhesive does not drip, double coating is suggested if nec-

If foaming occurs, please use anti-foaming agents of ethanol series, ester series and ether essary. Once adhesive is not sticky, remove the holding material and install the membrane

series, and do NOT use silicon series anti-foaming agents to avoid membrane clog. module to the cassette.

31 32
4.3.3 Attentions Chapter 5 Chemical Compatibility
At low temperature, epoxy curing takes a long time. If temperature is less than 10 , it is rec-
ommended to use epoxy resin with a faster curing time or repair indoors. The chemical resistance of this product is shown in Table 5.1. This product is only applicable
When the membrane dries, it needs to be wetted again, so please protect it from drying. to the MBR system of organic wastewater with water as the main component. Do not use
chemicals except chemical cleaning methods.
4.4 MBR Module Preservation
1. Keep this product sealed condition if not to use. Acid Alkali
2. Keep membranes storage temperature 0-40 , no freezing.
规格 Acetic acid 5wt% ○ Sodium hydroxide 1wt% ×
3. Keep used membranes in moisture.
4. If used membranes become dry, membranes will be hydrophobic and TMP will increase a Sulphuric acid 5wt% ○ Sodium hydroxide 0.1wt% ○

lot, cleaning and wetting the membranes with chemicals to use it again. Hydrochloric acid 5wt% ○
Notice: Alcohol
Oxalic acid 2wt% ○
A. Keep unused membranes in a cool place under sealed conditions to keep them moisture. If
Citric acid Alcohol 50wt% ○
the unused membranes are stored under damp condition for a long time, it will get mould 2wt% ○

and water permeability may decrease, so keep unused membranes dry.

B. If membranes need to be stored for a long time, keep them in moisture. Even if after clean- General Solvents Other Liquids
ing, there are still impurities on membrane surface, dry preservation will cause contami-
nants adhering to membrane surface and trigger membrane clog, even worse, contaminants Grease × Sodium hypochlorite 2,000mg/L ○

can be not completed removed. Ketone × Sea water △

Please follow below procedure for long time preservation in moisture:
Halogenated hydrocarbon × Tap water ◎
a. Take out of membranes from aeration (membrane separation) tank, wash with clean water
first, then soak the membranes and clean with chemicals. Kerosene ×

b. After soaking and cleaning, dip membrane modules (or cassettes) in tank which is filled Gasoline ×
with tap water (or higher quality water), keep it away from direct sunlight.
c. Change water 1-4 times per month and make sure no freezing in cold areas. ◎ — Resistant
d. If membranes need to be used again, recovery cleaning with 2,000mg/L NaClO solvents ○ — Resistant in short time (chemical cleaning)

can remove microorganisms on the membranes (procedure same as chapter 2.7.2). △— Depends (please consult SW technical team
)×— Not Resistant
Note: Drying preserved membranes have reduced hydrophilicity, higher TMP and lower
permeate, wetting the membranes for next usage is necessary. For wetting operation, please Table 5.1 Chemical Compatibility of PVDF Membrane
consult our technical staff.
C. In cold areas, unused membranes must be stored in dry condition with a plastic film cover.
Keep the wet membranes from freezing.
D. Insects and mouses may damage the product, please take necessary protection.

33 34
500m³/d MBR System Design of Municipal Sewage
The process is as following

1. Designed Duty of Water Sludge Pump

Handling Capacity Q= 500 m³/d 20.8 m³/h. Raw Water Intake Tank MBR Tank Reflux Channel Reflux Pump
Remark Raw water is domestic sewage and has been biochemical treatment, and the inlet
water is treated by 1mm fine screen. Self-priming Pump Permeate Tank

Vacuum System
2. Membrane Module Selection
规格
Filter Backwashing Pump
For small sized systems with 500 m /d, SW-6015×32 components are recommended. The
3

component information is following.

Production Flow 167 m³/d 4. Calculation of Number of Membrane Modules and Number of
Material Property PVDF - Membrane Racks
Membrane Module SWB1V6024-15 - Number of Components N= 2.99 Set Select 3 Set
Module Area 15 m² Per Rack Size L= 1,700 mm W= 1,440 mm H= 1,800 mm
Number of Membrane Module 32 PCS Outlet Flange DN 65 Aerator Flange DN 50
Instantaneous Flux 18.5 LMH
Average Flux 14.5 LMH
5. Verify Actual Flux
Backwashing Flux 25 LMH
Mode of Operation Negative pressure suction, continuous aeration Number of membrane modules N= 96 pcs Total membrane area A= 1,440 m2
Operating Pressure ≤ -0.05 MPa The actual flux q= 18.6 LMH A single rack permeate flow Q0= 8.9 m³/h
Backwashing Pressure Max 0.2 MPa Water production interface φ= 56 mm Select DN 65
Operating Temperature 5~35 Total flow Q= 26.8 m³/h
Backwashing Time 60~120 s Total water pipeline φ= 79.5 mm Select DN 80
Backwashing Interval 2~12 h

6. Calculate Aeration Flow

3. Operation Mode and Process Flow (The aeration amount is calculated according to 300LMH.)

The MBR system adopts the operation mode of "continuous aeration and intermittent water Aeration flow Qg= 432 Nm³/h 7.2 Nm³/min

production". A single membrane rack Qg0= 144 Nm³/h 2.4 Nm³/min

The typical operation time is: filtration 8min+ pause 2min. Aerator interface φ= 51.1 mm Select DN 50

Backwashing was performed every 4h for 1min. Total aerator pipeline φ= 88.5 mm Select DN 100

Online maintenance cleaning was performed every 7days for the duration 90min.

35 36
7. Main Equipment Selection
7.5 Citric Acid Dosing Pump
7.1 Self-priming Pump
This system sets up a water production system, USE 2 water production pumps, 1 use 1 standby. This system sets up 1 set of pickling system, 2 dosing pumps for each set, one for use and one

System number N'= 1 set Number of racks per set 3 sets for preparation, and the cleaning agent is citric acid.

Single set of permeate flow 26.8 m³/h Single set of backwash flow 36 m³/h Dosing concentration 2,000 ppm

Aeration flow Qg= 7.2 Nm³/min Concentration of dispensing 25%

Dosing pump flow 0.3 m³/H
Selection conditions are following:
Flow Q= 29.52258065 m³/h Head of delivery H= 10 m
Power P= 1.55 kw Select 2.2 kw Efficiency η= 52% 7.6 Sludge Return Pump
Inlet pipe diameter φ= 93.3 mm Select DN 100
The sludge return flow is calculated according to the twice feed flow rate.
Outlet pipe diameter φ= 83.4 mm Select DN 80
The reflux flow Q= 41.6 m³/h
Select two backflow pumps, 1 use and 1 standby. Selection parameters of backflow pump are
7.2 Backwashing Water Pump
following:
This system sets up 1 set of backwash system, each set USES 1 set of backwash pump. Flow Q= 45.8 m³/h
Designed pararmeters selection Head of delivery H= 15 m
Flow Q= 39.6 m³/h Forward 43.56 m³/h Head of delivery H=15 mH Efficiency η= 65%
Power P= 2.74 kw Select 3.0 kw Efficiency η= 65% Power P= 2.9 kw
Inlet pipe diameter φ= 101.3 mm Select DN 100 Inlet pipe diameter φ= 111.6 mm Select DN 125
Outlet pipe diameter φ= 78.5 mm Select DN 80 Outlet pipe diameter φ= 90.0 mm Select DN 100
Total reflux pipeline φ= 85.8 mm Select DN 100
7.3 Air Blower
This system USES the existing air source of the factory. Air source requirements are following: 7.7 Sludge Pump
Flow Q= 7.2 Nm³/min Forward 7.2 Air pressure P= 3 mH20
This system sets up one set of mud drainage system, selects two sets of drainage pumps,
Total Aeration pipeline φ= 88.5 mm Select DN 100
1 standy and 1 backup. Selection parameters are following:
Aeration pipe φ= 88.5 mm Select DN 100
Flow Q= 50.0 m³/h
Head of delivery H= 15 m
7.4 Sodium Hypochlorite Dosing Pump Efficiency η= 65%
This system is equipped with 1 set of sodium hypochlorite dosing system, 2 dosing pumps for Power P= 3.1 kw
each set,one for use and one standby Inlet pipe diameter φ= 121.4 mm Select DN 125
Dosing concentration 500 ppm Outlet pipe diameter φ= 99.1 mm Select DN 100
Concentration of dispensing 10%
Dosing pump flow 0.2 m³/H

37 38
8. Operation Control Instruction 8.3 Time Step Sequence
8.1 Pump and Flow Meter, Variable Frequency Interlock
Water Air Backwashing CEB alkali CEB acid
The water-producing pumps in each group of the system adopt frequency conversion control and production aeration 1min 90min 90min
8min 2min
are interlocked with the water-producing flowmeter. The design parameters of the flowmeter are
the peak flow rate of the system. 4h

PID control chart, as following 7d

15d
Frequency converter Frequency converter

Self-priming pump Flowmeter Reflux pump Flowmeter

8.4 Opening and Closing Status of Each Step Pump Valve

Step Sequence Self-priming Backwashing Produced Backwashing Intake Acid Alkali

8.2 Pump and Level Signal Interlock Pump Pump Water Valve Water Valve Valve Pump Pump

The system is equipped with liquid level record and liquid level switch control. The start and stop Water Production Open Open Open

of the pump is controlled by the level signal. Backwashing Open Open

1.When the MBR level is L, the production pump will stop automatically. CEB Alkali Open Open Open Open
2.When the production tank level L, the backwash pump automatically stops.
CEB Acid Open Open Open Open
3.When the production tank level H, the production pump automatically stops.
4.When the reflux level is L, the reflux pump will stop automatically; when the reflux level is H,
the reflux pump will start automatically.

The PID control diagram is following:

PLC
L Stop H Stop

MBR Liquid level Self-priming pump Water production level

PLC

L Stop
Backwashing pump Water production level

PLC

H Start L Stop
The reflux pump Reflux liquid level

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 500 m3/d MBR System PID for Municipal Sewage

DN100 DN100
DN20

DN20

DN80 DN80 PW-UPVC-80-02

PI FI
101A 101A
DN100
Blower
B01A
Self-priming Pump
DN100 DN100 CA-SS304-100-01 P101A
DN80 DN80 Permeate Tank

DN50

DN50

DN50
PI FI
PW-UPVC-100-01 101B 101B
V104
DN100
NaClO Dosing D01 Citric Acid Dosing D02 Blower PT
101

DN65

DN65

DN65
V=500L V=500L B01B DN100

DN80
Self-priming Pump
Fine Screen

103
LT
P101B
DN125

DN80

102
FI
HCI Dosing

Membrane
DN125

NaClO Dosing
Equalization Tank Anoxic Tank Membrane Cassette
Tank

102
PI
V101 V102 SWB1V6024-15*32 DN80 DN80 DN80
V103
Backwash Tank
DN150 BW-UPVC-80-01 DN100
V105
Filter

Backwash Pump
Lifting Pump
P102
P001

Check Valve Ball Valve Butterfly Valve Cut-off Valve Pneumatic Butterfly Valve

DRAWN
500 m3/d MBR System PID for Municipal Sewage
PI
01
PT
01
FI
01
FT
01
LT
01 CHKD
APPR
Pressure Gauge Pressure Sensor Flowmeter Flow Instrument Liquid Level Meter FAPPR Hengshui Snowate Environmental
PEM Technology CO., LTD
PM
DISC SIGN DESIGN PHASE
DATE
COUNTERSIGNED SCSLE DWG NO.

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