Instruction Manual for
Submerged Flat Sheet Membrane
( DF Type)
江苏碧诺环保科技有限公司 Jiangsu Benenv Environmental Technology Co.,Ltd 江苏省宜兴市环科园岳东路 28 号谢桥创业园 C 座 Block C,Xieqiao Park,No.28 Yuedong
Tel：+86-510－80798888 RD.Yixing,214205,jiangsu,China
■ Introduction
Thank you for selecting Benenv Submerged Membrane Module. This manual overview of the Benenv MBR Module and describes in detail how to handle, install, operate and maintain the MBR water treatment process.
Please note that it is important to read this manual carefully in order to use this product safely and properly. Additionally, it is important to retain a copy of this manual for the future reference.
■ Table of Contents
1. Introduction of Membrane Bioreactor………..4
2. Production Descriptions………..5
[1] DF Flat Sheet Element………5
[2] DF flat sheet Membrane Module………..6
[3] DF Integrated Membrane Bioreactor………..7
3. DF Submerged MBR Membrane Module Instillation Guide……….10
[1] Usage Condition……….10
[2] Storage Condition……….11
[3] Membrane Module Installation……….…….12
[4] “Clean Water” Test and Actual Operation………17
4. Maintenance………20
[1] Periodic Membrane Elements and Diffuser Cleaning……….20
[2] Periodic Inspection……….20
[3] Periodic Replacement Parts………..20
[4] Removing Module………20
[5] In‐Situ Chemical Cleaning Method………..21
[6] Chemical Handling Instructions……….23
[7] Diffuser Cleaning Method………..25
[8] Trouble Shooting………..26
1. Introduction of Membrane Bioreactor
Membrane Bioreactor is a kind of efficient wastewater treatment technology which combines activated sludge process and membrane solid ‐ liquid separation process.
As shown in Fig. 1‐1, membrane separation technology replaced settling separation process of secondary sedimentation tank in conventional activated sludge process, greatly improved activity sludge concentration to ensure outlet water quality and improve volumetric loading. Water extracted from MBR bioreactor can be used as reclaimed water directly.
Fig. 1‐1 Treatment process comparison of MBR and conventional activated sludge treatment (CAS)
Due to the filtration function of membrane, microbe will be held back in the bioreactor, well solved the sludge bulking problem in conventional activated sludge process.
With advantages such as high pollutant removal efficiency, high nitrification ability, stable effluent water quality, low excess sludge production, neat construction and easy for operation, MBR has been widely used in organic wastewater treatment, and has great potential for wastewater utilization.
At present, MBR can be divided into two parts as per working condition, the built‐in structural type (also been called immersive type) and external type. Built‐in structural MBR module can be put into biochemical reaction tank directly, and extract clean water from module. The external type MBR membrane can be placed externally for filtration. The mud mixture is pumped into MBR module and the filtrates are clean water. The built‐in MBR is energy consumption due to low pressure pumping.
2. Product Description
[1] DF Flat Sheet membrane element
The submerged flat sheet membrane element is a kind of built‐in structural MBR, it is composed of
Ultra filter membrane, guiding cloth and guide plate. There’s a suction nozzle at the top of guide plate, water after treatment will be extracted from the suction nozzle, see to Fig. 2‐1
Fig. 2‐1 Schematics of Membrane element
(1) Model of membrane element DF—□
DF：Benenv brand
□: Effective membrane area (dm2), 10, 20, 80, 150
(2) Technical Specification
Main performance parameters of Submerged Membrane Element see to sheet 2‐1.
Table 2‐1 Specification of Benenv Membrane Element
Item DF‐150 DF‐80 DF‐30 DF‐10
Effective membrane area (m2/pc)
1.5 0.8 0.3 0.1
Dimension L x W x H(mm)
510 x 1800 x 7 490 x 1000 x 7 380 x 500 x 7 220 x 325 x 6
Weight (kg) 5.5 3.5 1.2 0.4
Pore size(μm) 0.1
Filter membrane material
PVDF
Water yield (L/pc*day) 600‐900 320‐480 120‐180 40‐60 Diffuser Air Supply Rate:
(L/pc*min)
≥12 ≥12 ≥9 ≥5
pH 3‐12
Effluent turbidity(NTU) ＜1.0
Effluent suspended Solid (SS mg/L)
≤1
*Different water quality will cause different water yield of MBR membrane, the above water & air flux is the initial flux of MBR membrane under temperature of 25℃ and suction vacuum pressure ‐10KPa while treating municipal wastewater. (Unit：l/ pc*day).
[2] DF flat sheet membrane module
Fig. 2‐2 Module structural diagram
Flat sheet membrane module is composed of aeration system and supporting frames.
The aeration system delivers air from blower to each membrane unit to ensure average air flushing. The collecting pipes collect effluents from each piece of membrane unit. The membrane unit can be easily withdrawn for check and replacement from the membrane unit.
Table 2‐2 Specification of Benenv Membrane Module
Item DF80‐50 DF80‐100 DF150‐100 DF150‐150
Water yield(m3/d) 16‐24 32‐48 60‐90 90‐135
Membrane unit(pcs)
50 100 100 150
Membrane area(m2)
40 80 150
225 Outer dimension
L x W x H(mm)
850x620x1800 1600x620x1800 1600x650x2700 2350x650x2700
Weight(kg) 250 450 700 1000
Frame material SS 304
Aeration pipe material
SS304/UPVC/ABS Collecting pipe
material
UPVC
[3] DF Integrated membrane reactor
(1) Diagram of integrated membrane bioreactor
(2) Integrated Bioreactor Reactor Components
Integrated wastewater treatment units is consisted of (a) Pretreatment facility
(b) MBR membrane bioreactor tank (c) Sludge tank
(d) Disinfection tank (e) Control cabinet
(a) Pretreatment treatment facility
The pre‐treating tank is the anoxic tank. The water inlet, weir tank, water charging system in the anoxic system ensured sewage self‐flow into the MBR membrane bioreactor tank.
The anoxic tank is filled with elastic packing, floating filler and anoxic sludge. The retention time for wastewater (here we refer to domestic sewage) in the anoxic tank is 2‐5 hours. Intermittently given oxygen, organic matter gradually transformed into inorganic substances after oxidization, nitration and denitrification.
(b) MBR membrane bioreactor tank
The module frames include guide rail, aeration system which is connected with blower, and water collection system which connected with self‐priming pump.
The immersive flat sheet membrane was set in the tank to accommodate activated sludge, sewage retention time in the reaction pond is 4‐5 hours. Clean water enters into disinfection tank through the outlet of MBR module after degradation of activated sludge, parts of the excess sludge are pumped back to the sludge digestion pond whereas overflow port was set in the upper part of reaction tank to allow sewage flows into regulating tank, venting port in the bottom for maintaining and cleaning of the tank
(c) Sludge tank
Sludge collecting hopper is set at the bottom of sludge tank for sludge concentration. Supernatant liquid can flow back to MBR bioreactor tank through weir tank in the upper part, automatic sludge discharge can be achieved at the bottom of sludge tank by static pressure.
(d) Disinfection tank
Physical disinfection method is adopted in the disinfection tank to purify water quality by the release function of active ion, and at the same time heavy metal in the water gets reacted and sedimented.
(e) Equipment control room
There are two sets of blowers, two self‐priming pumps, 1 set of cleaning system, and the other set of control system. Blowers get alternatively running for every 12 hours. Noise reduction & Glissando measures are taken to the blower, air
filtration system is set in the air vent of the equipment control room.
All the above units are controlled by PLC and installed in the box.
(3) Technical parameters of integrated membrane bioreactor
Spec. capacity (m3/d)
Membra ne spec.
Qty (pcs)
Module size L x B x H(mm)
Qty of module
Outer dimension (mm)
Box Qty DFZH‐25 25 DF80 110 1750x600x1650 1 7000x2400x2500 1 DFZH‐40 40 DF80 180 1450x600x1650 2 7500x2400x2500 1 DFZH‐50 50 DF80 220 1750x600x1650 2 8500x2400x2500 1 DFZH‐80 80 DF80 330 1750x600x1650 3 10000x2400x2500 1 DFZH‐100 100 DF80 400 1600x600x1650 4 12000x2400x2500 1 DFZH‐120 120 DF80 480 1900x600x1650 4 12000x2400x 2500 1 DFZH‐160 160 DF80 660 1750x600x1650 6 7000x2400x2500 2 DFZH‐200 200 DF80 840 1900x600x1650 7 7500x2400x 2500 2 DFZH‐240 240 DF80 960 1900x600x1650 8 8500x2400x2500 2 DFZH‐320 320 DF80 1200 1900x600x1650 10 10500x2400x 2500 DFZH‐400 400 DF80 1680 1900x600x1650 14 7500x2400x2500 3 DFZH‐480 480 DF80 2160 1900x600x1650 18 9500x2400x2500 3 DFZH‐560 560 DF80 2400 1900x600x1650 20 10500x2400x2500 3 DFZH‐640 640 DF80 2640 1900x600x1650 22 11500x2400x2500 3 DFZH‐720 720 DF80 2880 1900x600x1650 24 12500x2400x2500 3
3. DF Submerged MBR Membrane Module Installation Guide [1] Usage Condition
(1) Application: Solid‐liquid separation of activated sludge
Filtration method: Gravity filtration method or suction filtration method
(2) Diffuser Air Supply Rate: Table 2‐1
(3) Filtration Pressure: 20 [kPa] or lower
(4) Chemical Injection Pressure for Chemical Cleaning of Membrane Module
Continuous: 10 [kPa] or lower (1m by gravity)
Maximum Instantaneous: 20 [kPa] or lower
(5) Chemical for Chemical Cleaning of Membrane Module
Effective chlorine concentration of sodium hypochlorite: 1.0[%] or less
→ It is recommended that 0.5% of effective chlorine concentration of sodium
hypochlorite be used for in‐situ chemical cleaning Oxalic acid: 1.0[%] or less
(6) Water temperature: 5 to 40[°C]
(7) pH: 5 to 10
* The water temperature and pH described above do not represent the operational condition of activated sludge process.
* It is recommended to pour chemical solution by gravity for in‐situ chemical cleaning of membranes. If it is injected by pump, the pressure may cause a sudden increase in pressure in membrane module, which leads to damage membrane elements and module.
[2] Storage Condition
(1) Benenv Membrane Module must be stored on a level surface.
(2) Always cover the Membrane Module with a plastic sheet during the storage.
Please avoid an exposure to direct sunlight, and store MODULE(s) indoors with the room temperature ranges between 5 and 40℃.
(3) Spare membrane elements for a replacement should also be stored indoors.
(4) Keep Membrane Module and membrane elements away from heat or flame.
(5) Never expose Module to welder or grinder sparks during engineering work.
(6) Never leave out Module for a long time where there will be an exposure to direct sunlight, especially during summer when it is intensively hot.
(7) Do not wet the membrane element before use.
(8) Do not damage the membrane surface. Fundamentally it is not possible to repair damaged membrane element.
[3] Membrane Module Installation
Install an Module in the following steps:
1. Diffuser Case Installation
2. Membrane Case Installation
3. Permeate Piping Connection
4. Air Supply System Connection
5.Ancillary Equipment (Customer's Provision)
(1) Diffuser Case Installation
(a) Check the arrangement of Membrane module with an equipment layout
drawing for the facility, and install it/them within the deviations described in the following sections.
(b) Install a diffuser case so that the upper surface is leveled within 5 mm
deviation. When installing multiple diffuser cases, install them such that upper surfaces of any and all the cases are leveled within 10 mm
difference.
(c) Make sure to fix the diffuser case(s) to the MBR using chemical anchor
bolts.
(2) Membrane Case Installation
(a) Do not remove the plastic sheet for packing until operation starts.
(b) Extreme care must be taken not to expose membrane case to welder or
grinder sparks.
Fig. 2-3 Membrane Module Installation Deviation
(3) Permeate Piping Connection
(a) Size the main permeate header piping and install the header piping. Make sure that the header pipes are level.
(b) Connect the branches off the main header to one side of the manifold, and attach the cap to the other side. Install branches using connections such as a flange so that the membrane case can be easily lifted up during maintenance.
(c) Install chemical solution injection ports on each Membrane Module branch or on the main
Fig. 2-4 Example of Permeate Piping Connection
(4) Air Supply System Connection
(a) For every diffuser, there are two connection points for the air supply system. The supply connection is done on one side and the cleaning connection is on the other side. The piping for cleaning should be extended so the cleaning valve can be installed where it is easily accessible.
(b) Connect piping using specified glue for vinyl chloride pipes.
(c) Because the air supply piping and the cleaning piping tend to vibrate
intensively, provide enough support to the MBR not to damage or wear the pipes.
Fig. 2-5 Air Piping Connection Methods
Fig. 2-6 Piping Configurations for Multiple Modules
(5) Ancillary Equipment (Customer's Provision)
<1> Aeration Blower
(a) Set the airflow rate supplied to a single unit within the range shown in the column labels as "Diffuser Air Supply Rate" in Table 2‐1 " Membrane Unit Parameters”
<2> Diffuser Cleaning Valves and Piping
(a) Use a full bore type ball valve as a diffuser cleaning valve.
(b) Try to minimize the length of diffuser cleaning header to the diffuser cleaning valve so that sludge will not clog up the piping system (Please avoid using U‐shaped or complicated piping configuration).
(c) Mount the cleaning valve at the accessible position in order to manually
open and close the valve.
(c) Use an actuated valve, such as motor valve capable of electrically
checking the closing status of the valve, as a cleaning valve and clean the diffuser for approximately 1 to 5 minute at least once per day.
<3> Permeate Discharge Equipment
(a) When using the suction filtration method to permeate clean water, the
system must have a permeate pump, pressure gauge, and flow control valve (variable type is preferable, or a combination of a flow regulator and a flow meter can be used as a substitute).
* Install a pressure gauge on the suction side of the permeate pump. The measuring range required should depend upon the position where the pressure gauge is installed.
(b) When applying the gravity filtration method, the system must have a
solenoid valve (or motor‐operated valve), flow meter, and water level gauge (for the MBR).
(c) Provide a chemical solution injection port as shown in Figs. 2‐7 and 2‐8.
(d) Use pipes with diameter equal to or larger than that of the manifold as a permeate header pipe.
Fig. 2-7 Piping Configuration for Gravity Filtration System
Fig. 2-8 Piping Configuration for Suction Filtration System
[4] “Clean Water” Test and Actual Operation
(1) Precautions in “Clean Water” Test
It is important to note the following points to effectively use the Benenv
Membrane Module.
(a) Please design the system such that filtration stops when aeration is being suspended or diffuser cleaning takes place.
(b) It is better not to aerate the MBR tank when filtration is suspended.
(c) Please design the system such that it automatically shortens the aeration
time when it operates at a low loading, or when the amount of incoming raw wastewater is not much. (Example: Low‐loading mode: Intermittent aeration [5‐minute aeration and 55‐minute suspension] can be done)
(d) The Module must be fully submerged in “clean water” as it is operated.
The depth of submergence should be more than 300 mm from the top of membrane case.
(2) “Clean Water” Test Preparation
Perform the following inspections and preparation before starting the “clean water” test.
(a) Re‐check the air supply piping connection and the permeate piping connection.
(b) Re‐check to see if all the Module(s) is/are leveled.
(c) Make sure to clean the inside of MBR tank completely before it is filled with “clean water”.
(d) If the test is operated in the MBR tank where sands and debris are not completely cleaned, membrane can be fouled.
(e) Put “clean water” such as tap water or underground water into the MBR
tank up to the level specified for a normal operation.
* At this time, open the chemical injection valves in order to allow the air
trapped in membrane element to escape.
* Close the chemical injection valves immediately after air is released from the membrane element.
* Operation using underground water with high concentration in iron, manganese, calcium, and silicon may also cause a membrane fouling.
(3) “Clean Water” Test Operation
After the MBR tank is filled with “clean water”, perform operation using the
“clean water” according to the following procedure.
(a) Start the aeration blower, and make sure that it operates normally and evenly to provide uniform aeration in the MBR tank.
* Foaming caused by the hydrophilic agent coated on the membrane
elements is a normal phenomenon.
(b) When using only a single blower to provide air to multiple membrane units, check to see that air supply to each unit is balanced. If air supplied to each unit is extremely unbalanced, re‐check the piping configuration (specifically re‐check whether a proper header piping is chosen and whether the pipes are not too small) and operational condition of diffuser.
(c) For the gravity filtration system, open the permeate valve and measure the permeate flow rate, water head, and water temperature. For the suction filtration system, start the suction pump and measure the permeate flow rate, suction pressure, and water temperature.
(d) Stop aeration immediately after “clean water” test operation is completed.
* Please not to perform aeration as much as possible when filtration is suspended. Aeration without filtration for a long time may result in damage on membrane elements
* Because clean water operation may cause a membrane fouling, avoid longer‐term operation than it is necessary.
(4) Sludge Seeding
(a) Direct membrane filtration of raw wastewater may cause a membrane
fouling. Therefore, please seed sludge into the MBR tank immediately before starting the actual operation in order to treat the wastewater biologically.
(b) It is recommended to use fresh activated sludge usually used for
nitrification and denitrification. The more the sludge is seeded, the more stable the initial condition becomes.
(c) Seed proper amount of activated sludge into the MBR tank so that the sludge concentration in the MBR tank (MLSS) will be more than 3,000 mg/L (preferably 5,000 mg/L or more).
* Before seeding activated sludge into the MBR tank, make sure to remove all the debris from the sludge by passing through a fine screen.
* Seed sludge into the tank immediately before the actual operation starts
(wastewater flows into the tank).
* If the seeded sludge has putrefactive odor, perform aeration until the putrefactive odor disappears (for 1 hour at the maximum), and then start filtration.
(5) Actual Operation
(a) The air amount required for each Module differs among unit models. Keep
the supplied air amount per unit within the range described in "Diffuser Air Supply Rate" specified in " Table 2‐1 Specification of Benenv
Membrane Element."
* If the MLSS concentration lowers to 2,000 mg/L or less during the actual operation, seed additional activated sludge into the MBR tank so that the MLSS will be kept at 3,000 mg/L or higher.
(b) When the permeate flow rate becomes stable, measure the permeate
flow rate during the actual operation and additionally measure the water head for the gravity filtration system or measure the suction pressure for the suction filtration system.
* Please not to perform aeration as much as possible when filtration is
suspended. Aeration without filtration for a long time may result in damage on membrane elements.
(c) If using an antifoaming agent is unavoidable due to foaming in the MBR
tank, use petroleum type antifoaming agent. Use of silicone type antifoaming agent may lead to a membrane fouling.
* Never put chemicals that will have an adverse effect on activated sludge, such as toxic substances and large amount of oils, into the tank.
* Avoid abrupt change in temperature, pH, and/or pressure, even if the change is within the normal operational range specified for the Modules
4. Maintenance
[1] Periodic Membrane Elements and Diffuser Cleaning
(1) It is important to perform a periodic in‐situ chemical cleaning of the membrane elements at least once a half‐year.
⇒ Refer to the detailed explanation in [In‐Situ Chemical Cleaning Method]
* If chemical solution is injected by pump, the pressure may cause a sudden
increase in pressure in membrane element, which leads to damage membrane elements and membrane case.
(2) Periodic diffuser cleaning using a cleaning valve is also necessary at least every two weeks.
⇒ Refer to the detailed explanation in [Diffuser Cleaning Method]
[2] Periodic Inspection
It is recommended to have an inspection every three (3) years. However,
customer should regularly inspect and maintain the following items.
(1) SS in the effluent
(2) Suction pressure fluctuations
(3) Unbalanced air supply from diffuser
[3] Periodic Replacement Parts
(1) Retaining Rubber ‐‐‐ To be replaced every three (3) years
(2) Permeate Tube ‐‐‐ To be replaced every three (3) years
(3) Membrane Element ‐‐‐ To be replaced once every three to five (3‐5) years
(depending upon operating conditions)
* Every part must be replaced at its recommended period because if you do not replace it at the proper time, damage of membrane case or membrane element may occur.
[4] Removing Module
(1) The membrane case, which is located on top of the diffuser case, can be separated from the Module. Thus, the membrane case can be lifted up by lowering the water level below the permeate manifold and removing the stabilizer pipes.
However, if the guide set is not utilized, the membrane case is fixed to the diffuser case by bolts.
(2) When lifting up the diffuser case, it is necessary to remove the fixing bolts at the bottom of the MBR.
* Be careful the membrane case swing when it is pulled out of the guide pipes.
* Carefully lift the Module up so that the membrane manifold and nozzle of Module will not be damaged.
[5] In-Situ Chemical Cleaning Method
■ Cleaning Procedure
(1) Chemical Solution Preparation
Organic fouling of the membrane micro‐pores can be cleaned by using a dilute solution of bleach (sodium hypochlorite/NaClO). Used chemical (10 to 12%
sodium hypochlorite solution) should be diluted 20 times, and make 3 L of the dilute cleaning solution per element. However, if the sludge concentration is lower than 10,000 mg/L, dilute the chemical 40 times.
If minerals (ex. Hard water, iron, aluminum, others) exist in waste water to be treated by membranes, oxalic or citric acid will be necessary to recover
membrane performance. Prepare about 3 L of 0.5 to 1.0% oxalic acid solution per element. (But if the membrane element is polluted with Ca, NEVER use oxalic acid. Hydrochloric acid or citric acid or etc should be utilized.)
(2) Aeration and Filtration Suspension
Suspend the aeration and filtration of MODULE to be chemically cleaned. Stop the operation of aeration blower(s) and permeate pump(s) and close the permeate valve(s).
(3) Chemical Solution Pouring (The injection port must be previously provided.) Make sure that the liquid level in MBR tank is 300 mm or more above the top of membrane case, or the permeate tubes are completely submerged. Inject the chemical solution prepared into the chemical port to every membrane element.
(Injection time should take between 5 to 10 minutes.) At the time, it is
recommended that chemical injection by pump should be avoided and it should be done by gravity pouring (10kPa or less). The chemical should be poured by, for instance, adjusting the rate with valve in order to prevent a pressure increase within membrane elements. Moreover, the chemical should be injected intermittently in order to release the trapped air from membrane elements.
Especially, a careful attention should be taken as calcium carbonate fouling from treating wastewater with a great amount of Ca contented is cleaned by acid because carbonic acid gas will be generated and may blow out the chemical from the injection port. Finally, if the entire 3L/element chemical cannot be injected, never forcedly inject it all.
(4) Recovery Cleaning
After injecting the chemical solution, keep the membrane elements intact for 1 to 2 hours. As a guide, it should take approximately 2 hours for cleaning organic substances, and 1 hour for cleaning inorganic substances.
(5) Re‐starting Operation After the Recovery Cleaning
First approximately 15 minutes after restarting filtration, return the permeate to the head of the facility (usually equalization tank or anoxic/denitrification tank).
In the case of organic cleaning, after making sure the residual chlorine
concentration in the permeate becomes low enough (10 mg/L or less), restart the normal operation.
Because our recovery cleaning method is such that the chemical solution flows back slowly having a little pressure from the permeate side to activated sludge side, it is effective to clean the membrane before the membrane is fully fouled, or during the period when increase in filtration pressure is still small since the operation started.
[6] Chemical Handling Instructions
When using the following chemicals, please read the Safety Data Sheet (MSDS) carefully beforehand.
■ 12% Sodium Hypochlorite / NaClO (1) Storage Precautions
a) Store in a cool, dark place (refrigerate it). Avoid an exposure to direct sunlight.
b) Never mix the solution with heavy metals because chemical decomposition
can be accelerated.
c) The storage tank should be plasticized or maybe an iron container coated
with corrosion resistant material.
(2) Handling Precautions
a) Carefully read the handling precautions (such as Material Safety Data
Sheet/MSDS) described in detail attached to the chemical, and handle it properly.
b) Never mix the chemical with heavy metals or acids. Especially, never mix the chemical with acid, since it will generate toxic chlorine gas. If the chemical is accidentally mixed with acid, quickly neutralize it with a basic solution such as sodium hydroxide.
c) Always wear a mask, safety goggles, and rubber gloves when handling.
d) If accidental contact with human body or clothes occurs, immediately rinse
with tap water.
e) If accidental contact with eye by occurs, immediately rinse the eye with a
large amounts of tap water and seek medical attention.
■ Oxalic Acid (Powder) / C2H2O4 (1) Storage Precautions
a) Carefully read the handling precautions (such as Material Safety Data Sheet/MSDS) described in detail attached to the chemical, and handle it properly.
b) Store this chemical at a cool, dark place (refrigerate it). Avoid an exposure to direct sunlight.
c) The storage tank containing dissolved oxalic acid must be a container, which is plasticized or is made of iron coated with corrosion resistant material.
(2) Handling Precautions
a) Never mix oxalic acid with sodium hypochlorite because it will generate toxic chlorine gas. When the chemical is mixed with it by mistake, neutralize it with alkali solution such as sodium hydroxide.
b) Always wear a mask, safety goggles, and rubber gloves when handling.
c) If accidental contact with human body or clothes occurs, immediately rinse with tap water.
d) If accidental contact with eye by occurs, immediately rinse the eye with a large amounts of tap water and seek medical attention.
[7] Diffuser Cleaning Method
■ Cleaning Procedure (1) Stopping filtration
Because membrane surface are not to be scoured by air and MLSS circulation from the bottom during the diffuser cleaning, stop the permeate pump(s) to stop mixed liquor filtration. (At this time, the aeration blower(s) is/are still
operational.)
(2) Opening Cleaning Valve
Open the cleaning valve located above the water surface of the MBR tank, then the MBR mixed liquor will be sucked into the diffusers and be vented to
atmosphere through cleaning valve as cleaning inside the diffusers.
Close the diffuser cleaning valve for 1 to 5 minutes. If diffuser performance is not improved, the procedure should be repeated.
(3) Diffusers Performance Recovery
After the diffuser cleaning valve is closed, inspect MODULE air patterns appear even and equal, and restart the permeate pumps to start the operation again.
(4) For Automated Diffuser Cleaning System:
a) Open the valve for cleaning upon stopping the permeate pump.
b) Clean the diffusers for 1 to 5 minutes at least once a day.
c) In 0.5 to 2 minutes after closing the cleaning valve, operate the permeate pump again. In this case, make sure that the cleaning valve is closed.
[8] Trouble Shooting
Problem Possible Cause Remedies
Damaged blower(s) Repair or replace the blower(s).
1
Aeration rate fails to reach the specified value.
Malfunctioning diffuser(s) Repair the diffuser(s).
Diffuser clogging Clean the diffuser(s).
2
Uneven aeration of an individual Module.
Uneven aeration of multiple Modules.
Membrane unit diffusers are not level.
Adjust operational flux to match the design flux.
Operational flux is higher than design flux.
Adjust operational flux to match the design flux.
Membrane surface is fouled.
Aerate for 30 minutes without filtration. If the flux rate does not recover, then carry out an in‐place chemical cleaning (provided there is not sludge cake on the surface of membrane) or wash membranes by water jet (if there is sludge cake deposition on the membrane surface).
Characteristics of the activated sludge are bad.
(e.g. filterability is low.)
Improve the sludge condition.
3
(Suction filtration system)
High filtration pressure or designed flux cannot be obtained.
(Gravity filtration system)
Water level of MBR tank is too high or designed flux cannot be obtained.
The membrane surface becomes hydrophobic.
Treat the membrane with a hydrophilic agent.
The tube has separated or is damaged.
Repair and replace the tube.
The membrane elements are damaged.
Repair or replace the membrane elements.
Damage on the manifold. Repair or replace the manifold.
4
The permeate is turbid and has not been Properly treated.
Permeate piping connection is loose.
Repair the permeate piping connection.
