Toray MBR
Instruction
Manual“NHP210 Series”
Last updated April 2023
06-G-MB2-NHP210-230430

Toray MBR

NoticeThe data and information contained in this document are based upon rigorous technicaltesting by Toray, and is to the best of our knowledge reliable. Toray cannot control designand operating conditions, and consequently Toray does not assume any liability for results
obtained or damage incurred through the application of the information provided herein.
No liability, warranty or guarantee of final product performance by Toray is implied by the
information provided in this document.
This manual supersedes all previous versions. Technical modification of products or
production technology may necessitate changes to information in this manual without priornotice. Please verify that your version of the manual is the latest version available by either
contacting Toray, or checking online at www.water.toray.

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When using this document, please read the Terms and Conditions of Use below thoroughly and agree to them before using
this document. By using this document, you agree to all of the Terms and Conditions of Use outlined here. The Terms andConditions of Use are subject to change without prior notice, so please check with Toray for the latest Terms and Conditionsof Use before using the document.
1.

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The content in this document is protected by copyright laws in respective countries and relevant treaties. Accordingly,
the document's information may not be reproduced, altered, or distributed without permission in writing from Toray. We
permit downloading this document through Toray's website as a PDF file, stored on a personal computer, and printed
out for customers' personal use. However, we prohibit transferring this document to any other websites or printed media.
The material contained in this document may not be used without permission from the copyright holder for any otherpurpose that exceeds the scope permitted under copyright law.

2.

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The "TORAY" company name used in this document is a trade name, and the names of products manufactured by
Toray are trademarks or registered trademarks. Toray's trade names and trademarks are protected under the JapaneseTrademark Law, the Unfair Competition Prevention Law, and other legislation. The trade name and trademarks may not
be used or reproduced without express permission from Toray.

3.

Disclaimer
Toray takes all reasonable care in updating the information in this document. However, Toray makes no representation
and warranty of any kind, either express or implied, including without limitation, any implied warranties concerning theaccuracy, usefulness, suitability, or fitness for a particular purpose of the information in the document.
Toray shall not be responsible or liable for any losses or damage incurred due to the use of the information in thisdocument. The information in this document is subject to change without prior notice, and Toray reserves the right tosuspend or discontinue the publication of this document.

4.

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The goods and services contained in this document are not available in all countries and regions. Goods and services
may also be supplied under different trademarks in different countries. We ask that you contact your nearest Toray
representative office if you wish to use the goods and services shown or implied in this document.

5.

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This Terms and Conditions of Use shall be governed by and construed according to the laws of Japan. Any and all
disputes arising out of or relating to this document shall be brought to the Tokyo District Court Tokyo, Japan.

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Toray MBR

Contact Information
Toray Industries, Inc. — UF & MBR Membrane Products Department (Global Headquarters)
Nihonbashi Mitsui Tower, 1-1, Nihonbashi-Muromachi 2 chome, Chuo-ku, Tokyo, 103-8666
Japan
Tel: +81-3-3245-4542 Fax: +81-3-3245-4913
Toray Membrane USA, Inc. (TMUS)
13435 Danielson Street, Poway, California 92064 USA
Tel: +1-858-218-2360 Fax: +1-858-218-2380
Toray Membrane Europe AG (TMEU)
Grabenackerstrasse 8b, Muenchenstein 1 CH-4142, Switzerland
Tel: +41-61-415-8710 Fax: +41-61-415-8720 E-mail: info.tmeu.mb@mail.toray
Toray Asia Pte. Ltd. (TAS)
1111 Somerset Road, #14-22-#14-27, Singapore 238164, Republic of Singapore
Tel: +65-6226-0525 Fax: +65-6226-0509
Toray BlueStar Membrane Co., Ltd. (TBMC)
No. 28 Yu An Road, Shunyi District, Beijing 101318, China
Tel: +86-10-8048-5216 Fax: +86-10-8048-5217
Toray Membrane Middle East LLC (TMME)
3515, 3rd Industrial City, 8682, Dammam, 34857, Kingdom of Saudi Arabia
Tel: +966-13-568-0091 Fax: +966-13-568-0093
Toray Advanced Materials Korea Inc. (TAK)
Korea Toray R&D Center 7, Magokdonng-ro 10-gil, Gangseo-gu, Seoul 07790, Republic of
Korea
Tel: +82-22-3279-7389 Fax: +82-2-3279-7088

website: www.water.toray

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TORAY MBRTABLE OF CONTENTSI.

INTRODUCTION .......................................................................................................... 1
1.

Features of MBR ......................................................................................................... 1

2.

Outline of “NHP210 Series” ......................................................................................... 2II.

FOR SAFE OPERATION OF “NHP210 SERIES” ......................................................... 5
1.

Safety Instruction for Unpacking and Installation ......................................................... 52.

Safety Instruction for Operation and Maintenance ....................................................... 6

3.

Safety Instruction for Chemical Cleaning of Element ................................................... 8

III.

SPECIFICATIONS AND PERFORMANCE OF “NHP210 SERIES” .............................10

1.

Specifications of Element ...........................................................................................10

2.

Specifications of Filtrate Tube Assembly ....................................................................10

3.

Specifications and Performance of “NHP210 Series” Module .....................................10IV.

MEMBRANE FILTRATION PROCESS DESIGN FOR “NHP210 SERIES”...................13

1.

Standard Time Chart ..................................................................................................13

2.

Flow Diagram of Membrane Filtration .........................................................................143.

Layout of “NHP210 Series” Modules in Membrane Tank ............................................20

4.

Piping .........................................................................................................................23

V.

INSTALLATION OF “NHP210 SERIES”.......................................................................27
1.

Preparatory Procedure ...............................................................................................27

2.

Unloading/Lifting Products..........................................................................................27

3.

Checking Products .....................................................................................................28

4.

Storing Products.........................................................................................................28

5.

Installing Products ......................................................................................................29

VI.

START OF OPERATION .............................................................................................33

1.

Clean Water Operation...............................................................................................33

2.

Seeding Sludge Injection ............................................................................................34

3.

Actual Filtration Operation ..........................................................................................35

VII. OPERATION CONTROL .............................................................................................37
1.

Standard Operating Conditions ..................................................................................37

2.

Operating Parameters ................................................................................................39

3.

Basic Control Philosophy ...........................................................................................39

4.

Daily Inspection ..........................................................................................................41

VIII. MAINTENANCE OF “NHP210 SERIES” ......................................................................44
1.

Maintenance Items and Maintenance Frequency .......................................................442.

Air Diffuser Cleaning ..................................................................................................45

3.

Chemical Cleaning of Element ...................................................................................47

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4.

Chemical Agents Available for Chemical Cleaning .....................................................47

5.

Handling of Chemical Agents .....................................................................................49

6.

Chemical Cleaning Procedure ....................................................................................52

7.

Lifting Procedure ........................................................................................................57

8.

Storing Products after Use .........................................................................................58

9.

Disposing Procedure ..................................................................................................59

IX.

REPLACEMENT PARTS LIST.....................................................................................60

X.

TROUBLESHOOTING .................................................................................................61XI.

WARRANTY CLAIMS ..................................................................................................62

XII. WARRANTY POLICY ..................................................................................................63
XIII. REFERENCE ..............................................................................................................64

Symbols used in this manual!

DANGER

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which, if not avoided, will result in serious injury or death.

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WARNING

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which, if not avoided, can result in serious injury or death.

!

CAUTION

This symbol is used to indicate a potentially hazardous situation
which, if not avoided, may result in injury or property damage.

“Prohibited”
This symbol indicates that ignoring or violating the instructions is
prohibited to avoid serious hazard or product damage.

“Instruction”
This symbol indicates an important action or procedure which has tobe taken without fail.

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TORAY MBRI.

INTRODUCTION

Toray MBR is the submerged membrane module suitable for the membrane bioreactor (MBR)
that has been developed based on the polymer science and the membrane fabrication
technologies accumulated for a long time in Toray Industries, Inc.
"NHP210 Series" is a new model of MBR module equipped with thin membrane elements
having higher packing density, while reliable performance of Toray PVDF membrane has been
kept unchanged. This manual explains MBR's features and describes the specifications of"NHP210 Series" and its safe operations including installation, operation, maintenanceprocedures and peripheral equipment. Operators should thoroughly read this manual to ensurestable operation.
1.

Features of MBR

The process flow of the conventional activated sludge system (CAS) and MBR are shown in
Fig.I-1 and Fig.I-2, respectively.
Wastewater

Aeration Tank

Sedimentation Tank

Discharge

Fig. I-1
Wastewater

CAS Flow

Submerged Membrane
ModuleDischarge or Reuse

MembraneTankROmembraneFig. I-2

Reuse

MBR Flow

MBR provides the following advantages:(1) Small Footprint
Unlike CAS, MBR separates sludge within an aeration tank using membranes, thus eliminating
the space for the sedimentation tank. Also with membrane, MBR can hold higher concentrationof activated sludge in the aeration tank, so its volume can be reduced. As a result, MBR
requires a smaller footprint compared to CAS.
(2) High Quality of Treated Water
MBR removes suspended solids (SS) from the sludge liquid with membrane much morecertainly than the conventional sedimentation process. MBR also rejects microorganisms suchas Escherichia coli and Cryptosporidium efficiently.

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2.

Outline of “NHP210 Series”“NHP210 Series” is the membrane module composed of the element block and the aeration
block. The element block contains several cassettes and in the cassette the membraneelements, each of which consists of two flat membrane sheets, are arranged at a constantclearance. Each element is connected via plastic tube to the filtrated water manifold. The
aeration block consists of coarse-bubble air diffusers to supply scouring air (see Fig.I-3).
This module is used submerged in sludge liquid.
The following shows the features of “NHP210 Series”.

Frame
NozzleTubes

Filtrate water manifold

Element
block

6 pcs

50 sheets

Aerationblock

Element

Cassette

ModuleCoarsebubblediffuser

Fig. I-3 Components and appearance of “NHP210-300S”

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TORAY MBR(1) Shape of Element
The membrane element is a flat sheet type as shown in Fig.I-4. At the normal filtration
operation, the sludge accumulated on the membrane surface is cleaned up effectively withupward water stream generated with the scouring air supplied from the air diffusers installedat the bottom side (Fig.I-5). This mechanism ensures the stable filtration since the membrane
does not easily admit of sludge adherence to its surface.
In addition, thin membrane element which consists of two membrane sheets and spacers in
between makes it possible to have higher membrane packing density in the module similar tothat of a hollow fiber membrane, and also the vibration of elements by scouring air improves
membrane cleaning efficiency.

480

Fig. I-4 Structure of Element
Element

Air

Filtrated water

Air

Membrane

Activated sludge

Fig. I-5 Filtration Principle of Activated Sludge

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TORAY MBR(2) Membrane Structure
The flat sheet membrane consists of a PVDF (Polyvinylidene Fluoride) functional layer and abase layer of PET (polyester) non-woven fabric. This structure gives the membrane superior
physical strength and high chemical resistance.
(3) Membrane Pore Size
Numerous small-size pores are distributed evenly over the membrane surface with a sharp
pore-size distribution. This structure gives an outstanding high treated water quality andexcellent water permeability, making the membrane highly resistant to clogging (see Fig.I-6
and Fig.I-7) compared to other membranes. The average pore size is 0.08 micrometer.

Number of pore (1012/m2)

1.5

3.0 micrometer

0.08 micrometer

1.0

0.5

0

0

0.2

0.4

0.6

Pore size (micrometer)

Fig. I-6 Membrane Surface

0.8

Fig. I-7 Pore Size Distribution(photo)(4) Cassette Replacement
Membranes can be taken out and exchanged by cassette. It is possible to replace only acassette which contains a damaged membrane.

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II.

FOR SAFE OPERATION OF “NHP210 SERIES”

Before using “NHP210 Series”, please thoroughly read this Instruction Manual and follow the
instructions described in this manual, especially the safety precautions shown below. The
details of each precaution are described in the relevant chapter
1.

Safety Instruction for Unpacking and Installation

Attach chains or slings to the lifting lugs when lifting element deck, an element
block or aeration block of “NHP210 Series”. Slowly raise the module straight
up. Avoid sudden changes in movement to minimize shaking the module.
Never allow personnel to stand under the “NHP210 Series” during lifting.
Never lift or operate the module with worn or damaged parts. Use chains orslings rated for the weight being lifted. Check the condition of each part before
lifting.

Do not lift upper element block and lower element block at once as one unit
when lifting NHP210-600D. Lift the upper and lower element block separately.
Make provisions, in advance, to access the upper portions of the membrane
module via a scaffold or ladder when installing “NHP210 Series” module. Do
not climb on the module structure. Never step on the air diffuser and filtratewater manifold. Use protective equipment to ensure the safety of workers.

Wear the appropriate personal protective equipment (e.g. safety gloves) inorder not to cut one’s hand on the edge of the module frame.
During transportation, storage, and installation, take appropriate measures toprotect "NHP210 Series" or associated components from damage. Do not put
any heavy objects directly on the module. Store the module in an area thatwill minimize the risk of damage from moving equipment like forklifts etc.
Exposing the “NHP210 Series” and membrane elements to temperatures
above 40 deg C or direct sunlight should be avoided. Exposure to direct
sunlight/UV radiation will cause the polypropylene air diffuser and filtrate water
manifold to deteriorate.

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Take adequate measures, during the installation process, to protect the“NHP210 Series” from: sparks emitted from welding equipment, fusion cutting,or grinding.

Avoid pressurizing the filtrate side of "NHP210 Series”.

Install the screen with openings of 3.0 mm or under before the membranetank. In case of receiving wastewater with fibrous debris such as raw sewage
without primary clarifier, select mesh type for the screen device. Overflow or
waste carryover must be avoided at all the time.
Connect the flanges of air diffuser and filtrate water manifold to the piping withthe tightening torque of 20 N.m, in order to avoid distortion, leakage, or
breakage of the air diffuser and filtrate water manifold.
Consider piping materials and regulate the load to the flange connection
points at less than 20 kg per flange in order to avoid distortion, leakage, or
breakage of the air diffuser and filtrate water manifold. If the load exceeds thelimit shown above, put some supports on the piping to reduce the load.
2.

Safety Instruction for Operation and MaintenanceFiltrated water is not for potable uses. Do not directly drink the MBR filtrate.

Before discharging the treated water to the environment or reusing it, makesure to analyze its quality and confirm that the water quality meets theintended purpose.
Do not burn the membranes without appropriate facilities since harmful
Hydrogen fluoride (HF) gas will be generated. Hire a professional solid waste
disposal company to perform the task when disposing of the membraneelements.

Make certain the air discharge valve is in the open position to assure any
accumulated air is released when first filling the membrane tank with cleanwater or sludge. After the tank is filled with clean water or sludge, close theair discharge valve before starting operation.

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Do not use ground water for the initial filling of the membrane tank. Groundwater may contain considerable concentrations of iron, manganese, calcium,or silica. Naturally occurring compounds of these elements can clog themembrane pores.
White foaming may occur in the membrane tank during clean water operation.
The foaming is caused by the leaching of residual biodegradable hydrophiliccomponents contained in the membrane after the manufacturing process.
Foaming is normal and does not adversely affect the membrane filtration
process but if you want to remove this, do not use silicone-based anti-foaming
agent which may cause choking of membrane pores.
Do not operate the membranes longer than necessary to purge the system ofentrained air when using clean water in the MBR tank. Prolonged clean water
operation can clog the membrane pores.
Keep the membranes wet once they get wet. If the membranes are allowed
to dry out, the permeability of the membranes may be permanently reduced.

Prior to introduction of any seeding sludge into the membrane tank pass all
sludge through a 3 mm or less mesh screen device.
Make certain sufficient air is being supplied to the membrane module air
diffuser before operating in the filtration mode. Failure to do so will result inthe membrane becoming clogged.
Do not allow contamination of chemicals, toxic agents, oils, or othersubstances into the MBR tank or wastewater that can adversely affect thecondition of the activated sludge.
If anti-foaming agents are to be added to the membrane tank, use only alcohol
based anti-foaming products. Do not use silicone-based anti-foaming agent
which may cause choking of membrane pores.
Avoid abrupt changes to especially pH, temperature, salinity, and suction
pressure, when operating in the filtration mode, even if these changes arewithin acceptable operating guidelines.
When it is obvious that a module part is worn and potential for failure is high,promptly replace that part with approved replacement parts.

Protect “NHP210 Series” from freezing at any time.

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Take measures to keep the membrane elements wet when removing the“NHP210 Series” module from the activated sludge for inspection or
maintenance. Allowing the membrane elements to dry out will adversely affectthe membrane’s permeability.
The air scour should be stopped when the filtration process is suspended.
There are two exceptions:
1) Do not stop the air scour during the normal relaxation period.
2) Do not stop the air scour that is required for normal metabolic processes of
the activated sludge or for prevention of sludge sedimentation. However,under these conditions the amount of air flow directed to the diffuser should
be reduced to just the amount required to maintain sludge viability or agitate
sludge.
Once a filtrate tube has been removed or disconnected from either theelement nozzle or filtrate manifold, it should be replaced with a Toray
approved replacement part. Old filtrate tubes lose their elasticity, and theintegrity of the seal can be compromised
Never use a pressure washer machine when washing the membrane moduleand element which can cause fatal delamination of membrane element edge.

Hold the grip and do not hold the other portion of the cassette suchas outer ribs when handling the cassette for maintenancepurpose.
grip

3.

Safety Instruction for Chemical Cleaning of Element

Chemical agents used for chemical cleaning can be harmful to one’s health.
Wear protective goggles, protective gloves, and other safety gear whenhandling chemicals. Make sure to check the details of its material safety data
sheet (SDS) beforehand.
If chemicals come in contact with your skin or clothes, immediately wash thecontacted area with a large volume of running water.

If chemicals splash into your eyes, immediately flush with large volumes ofrunning water and contact a doctor.

Immediately stop the chemical cleaning operation if any of the associatedcleaning equipment appears to be malfunctioning.

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Do not inject any chemical into the membrane directly from the chemical pumpdischarge. Excessive membrane element internal pressure will damage theelement. Be sure to inject chemicals at a pressure less than 10 kPa (100mbar).
Before starting injecting chemical to elements, confirm that the membranetank liquid level is more than 500 mm above the top of the module.

Store chemicals in a dark, cold place free from direct sunlight.

Use chemical storage tanks constructed of chemically compatible materials toprevent corrosion.

Never mix sodium hypochlorite with heavy metals or acids. The resulting
chemical reaction will generate toxic chlorine gas.

To avoid scattering of chemical solution turn off the air scour during a chemicalcleaning.

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III.
1.

SPECIFICATIONS AND PERFORMANCE OF “NHP210 SERIES”
Specifications of Element

TableIII-1 and Fig.III-1 show the specifications and the physical dimensions for the NHP210
Series element.
Table III-1 Specifications of Element (TSP-50080)
Model name

TSP-50080

Membrane configuration
Application

Flat sheet
Filtration of activated sludge

Filtration method

Suction filtration
0.08

Nominal pore diameter (µm)
Effective membrane area (m2)Dimensions (mm)Weight (kg)Main material

0.7

Total width

480

Total height800

Thickness

1.8

Dry

0.25

Wet (Reference)

0.5

Membrane

PVDF and PET non-woven fiber

NozzlePE

Nozzle480

Fig.III-1 Element Appearance (mm)2.

Specifications of Filtrate Tube Assembly

Table III-2 and Fig. III-2 show the specifications and appearance of Tube
Assembly.
Table III-2 Specifications of Filtrate Tube Assembly
Material
Tube Inside diameter (mm)Tube outside diameter (mm)Dimensions (mm)Thermoplastic polyether-polyurethane (tube)
Polypropylene (connector)
810
Approx. 125 x 155

Fig.III-2 Tube Assembly Appearance*Two elements are connected to one manifold nozzle via tubes and connector

Connector

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3. Specifications and Performance of “NHP210 Series” Module
Table III-3 shows the specifications of “NHP210 Series” cassette and module.
Table III-3 Specifications of Cassette and Module
Model name
Number of membrane elements

ECS035(Cassette)
50

Cassette structure

WidthOveralldimensions (mm)LengthDimensions

HeightWidthexcluding filtrate header
pipes and air diffuser
pipe

(mm)

LengthHeightFrame
Material

Manifold
Connection

Air diffuser
Temperature
pH*2 of liquid
MLSS
Trans-membranepressure

Operating range

*3

*1
*2
*3
*4
*5

Scouring Air Flow rate
(NL/min/Module) *4
Scouring Air Flow rate
(Cubic feet/min/Module) *4

3 cassettes x 4 decks
770

1,635

1,635

820

2,175

3,845

-

565
1,460

565
1,460

-

2,090

3,760

N/A
N/A

240
40

440
40

18

200

400

146

975

1,950

-

304SS (316LSS is available as option)
Polypropylene-

Polypropylene (SS is available as option)

ANSI 1 1/2 inch flange using M12 bolts/nuts
One flange per each deck (300S: 2 pcs per module, 600D: 4 pcs per module)
ANSI 1 1/2 inch flange
Using M12 bolts/nuts
Two flanges per Aeration block
5-40 deg C
5-10
Not higher than 18,000 mg/L
Cleaning: Until 5 kPa (50 mbar) from the initially recorded TMP (assuming thefiltrate flow rate is the same value)
Maximum allowable TMP: Not higher than 20 kPa (200 mbar)

Cleaning chemicals feed
pressure
Cleaning chemicals andchemicals concentration

3 cassettes x 2 decks
770

Filtrate water manifold
Air diffuser,

NHP210-600D(Double-decker)
600

485(excluding nozzle&hose)440

Module (dry)Aeration block (dry)Cassette/Element block(dry)Cassette/Element block(sludge clogging)*1

Weight(kg)

NHP210-300S(Standard module)300

Not higher than 10 kPa (100 mbar)
Sodium hypochlorite (effective chlorine concentration)： 2,000-6,000 mg/L(10<pH<12)
Oxalic acid： 0.5-1.0wt%
Citric acid： 1.0-3.0wt%- *5

1,000 - 2,000

1,300 - 2,000-*535 - 71

46 - 71

The weight assumed in the case of sludge clogging between elements.
Except when the chemical cleaning with the designated chemical agents.
For the standard operating condition, refer Table VII-1.
Air volume as being 0 deg C and 101.325 kPa (1 atm).
MBR operation only by Cassette is not assumed.

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Table III-4 and III-5 shows the performance of ”NHP210 Series” modules.
Table III-4 Filtrate water quality (Reference value)
Model name
Filtrate
water
quality*1

*1
*2
*3

All models
TSS (mg/L) *2

Not higher than 3.0

Turbidity (NTU) *3

Not higher than 1.0

This value can be attained when operated under the standard operating conditions as specified in thisInstruction Manua during a period specified separately by Toray.
Measuring method of TSS is complied with Standard Method of Examination of Water and Wastewater
20th Edition (1998), Section 2540D, Total Suspended Solids Dried at 103-105 deg C or ISO 11923.
Measuring method of NTU is complied with Standard Method of Examination of Water and Wastewater
20th Edition (1998), Section 2130, Turbidity or ISO 7027.

Table III-5 Flow capacity (Reference value)
Model name
Filtration
Flow (m3/d)*4*4

NHP210-300S

NHP210-600D

Sewage20 - 150

40 - 300

Industrial wastewater

20 - 100

40 - 200

This value is just a reference value and not a guaranteed value of Toray. Sustainable operating filtration
flow capacity varies among the plant depending on the type of wastewater, total process design, andoperating condition. In case of industrial wastewater application, it is strongly recommended to conduct
a pilot test before membrane tank designing.

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TORAY MBRIV.

MEMBRANE FILTRATION PROCESS DESIGN FOR “NHP210 SERIES”

This section will address the following for the Toray “NHP210 Series”: Standard sequence of
operation/time chart, illustrated piping, flow schema, and module(s) layout in the membrane
tank.
1.

Standard Time Chart

Usually intermittent filtration (filtration with relaxation) is recommended. The most common
mode of filtration operation is nine (9) minutes of filtration followed by one (1) minuteof suspended membrane filtration (membrane relaxation) with continued air scour, as
shown in Fig.IV-1. This period of relaxation, with no filtration, allows the continued air scour to
be more effective at removing solids that may have accumulated on the surface of themembrane. Intermittent filtration followed by a relaxation period is recommended for stableand efficient membrane filtration.
The air scour should be suspended when the filtration process is stopped except for thefollowing conditions:1) During normal membrane relaxation periods.
2) During suspended filtration operation unless aeration is required for mixing or biologicaldemand requirements. For the latter the air flow should be reduced to minimum flow rates
to prevent membrane damage.
* During low wastewater supply period, basically all modules should be in operation at lower
flux rate, considering maintaining viable activated sludge. In case operation of some or all
modules will be shut down, the air scour for those modules should be suspended or appliedintermittently following the above description. For long-term shutdown please refer to thefollowing Section 8, chapter VIII “Storage Products after Use”. F1: Average flow rate for treatment capacityand membrane area calculation
F2: Filtration flow rate for suction pumpcapacity calculation

Cycle of 10 minutes
F2
F1
Filtration
Filtration: 9 min.
Air diffusion

Relaxation: 1 min.
Continuous Operation

Fig.IV-1 Recommended Time Chart for Intermittent Filtration

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2.

Flow Diagram of Membrane Filtration

Two (2) flow diagrams of the membrane filtration process are shown below. One is for gravity
filtration (when site conditions permit) and the other using a suction pump. Also depicted aremajor ancillary devices required for the membrane filtration process.
To reduce the risk of membrane clogging, all activated sludge should pass through afine mesh screen having openings of 3 mm or less prior to being introduced into themembrane tank. Failure to incorporate the screen device may result in large solids clogging
or causing physical damage to the membrane surfaces.
In order to equalize BOD load and filtration flow capacity it is recommended that abuffer/equalization tank be installed to help stabilize operation of the biological treatment andmembrane filtration process.
(1) Gravity filtration configuration
The filtration process can be accomplished by using elevation differences between the liquid

L:OPEN
H:CLOSElevel of the membrane tank and the level of the filtrate outlet (see Fig. IV-2).

Wastewater

Feed
ChemicalAir Outlet

FI

Fine Screen

MembraneLS

ManifoldH

Lower Limit Alarm

L

Tank

PIA
PIA

FIC: Flow Rate Indicator/Controller

FIC

LS: Level Switch
PIA: Pressure Indicator/Alarm

L:CLOSE
H:OPEN
Filtrate Water Outlet

FI: Flow Meter

Air Diffuser

Membrane Module“U-shape”

Fig. IV-2 Schematic Flow Diagram for Gravity Filtration

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In order to obtain enough suction pressure for the filtration process, consider friction loss of allpipes and valves. In addition, the filtrate water outlet should be located at least 3 m below thesurface of membrane tank water level.
It is recommended that the piping from the filtrate water manifold to the filtrate wateroutlet should directly penetrate the tank wall, as shown in Fig.IV-2. In addition, if the filtratewater outlet is an open air discharge, it is recommended that a U-shaped “trap” be constructed
to seal the filtrate piping with water.
The filtrate water flow rate is controlled with the automatic control valve (filtrate control valve).
When the liquid level of the membrane tank gets to the designed lower limit, the filtrate control
valve fully closes to effectively stop the filtration process. When the liquid level of themembrane tank reaches the designed upper limit, the automatic shut-off valve on the raw water
influent line closes to stop the raw water flow to the membrane tank.
In the gravity filtration mode, air may accumulate in the filtrate water lines. To prevent
reduction or loss of suction, the air in the filtrate line should be periodically purged toatmosphere at least once per day. The air purge nozzle should be installed at the highest
position of the filtrate water line. The line should also be fitted with an automatic shut-off valve(the air purge valve) just upstream of the air purge nozzle (As shown in Fig.IV-2). The filtration
process should be suspended for a few minutes while purging any entrained air from the filtrateline. Close the filtrate control valve and open the air purge valve. After all air has been purged,
return the air purge valve to the closed position and open the filtrate control valve.

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TORAY MBR(2) Pump suction configuration

L:OPEN
H:CLOSE

Fig. IV-3 illustrates the general configuration for pump suction filtration.

Air Outlet

Raw

L:CLOSE
H:OPEN

FIC

Feed
ChemicalFiltrate Water

VFD or Auto Valve
Fine Screen

FI

LS
H

PIA

Manifold

Lower Limit Alarm

L
FIC: Flow Rate Indicator/Controller
LS: Level Switch
PIA: Pressure indicator/Alarm
FI: Flow Indicator
PIA
Air diffuser

Membrane Module
Fig.IV-3 Schematic Flow Diagram for Pump Suction Operation
When incorporating a suction pump to facilitate water flow through the membrane, the filtratewater flow rate should be controlled using a flow meter fitted with control output signals and asuction pump fitted with a VFD device or an automatic control valve. In the event the membranetank water level reaches the designed lower limit, the filtration mode should be stopped. As
with the gravity filtration mode previously discussed, should the membrane tank water level
reach the designed upper limit, the upper limit controller will close the raw water inlet control
valve.
Since the liquid in the tank contains a significant amount of dissolved air, some of that dissolved
air will accumulate in the filtrate pump suction line. It would be necessary to periodicallypurge the filtrate line of any accumulated air and in this context, it is quite beneficial tolocate the pump at the top of filtrate piping. A range of methods can be used to remove airfrom the filtrate line: vacuum pump, ejector, or manual water injection. Contact Toray or referto the engineering manual for the additional details.

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TORAY MBR(3) Required ancillary devices for membrane filtration process are listed below. In someinstances additional components may be required.
a.

Fine screen
To treat contents like foreign substance, fibers or etc. in raw wastewater, suitable
pretreatment system including fine screen’s selection is needed to design MBR.
Failure to incorporate a screening device will result in clogging or permeant damage
to the membrane. Incoming wastewater to the membrane tank should pass through ascreen having 3.0 mm or less openings. In case of receiving wastewater with fibrousdebris such as raw sewage without primary clarifier, select a mesh type for the screen
device. Overflow or waste carryover into the submerge membrane tank must be
avoided at all times.

b.

Flow control device
A flow rate controller, a flow meter combined with an automatic control valve, or a flow
meter combined with VFD controlled suction pump should be installed on the filtratewater line to control the flow rate of filtrate water. It is recommended that each train
be fitted with its own discreet filtrate flow rate controller when operating more than
one “NHP210 Series” module simultaneously.

c.

Trans-membrane pressure (TMP) measurement & calculation
For trans-membrane pressure (TMP) determination, the differential pressure (in thefiltrate line and water level) needs to be measured and calculated. This can beaccomplished by either installing two pressure sensors with an accuracy of 0.1kPa
and calculating the difference in the readings in the PLC or using a differential
pressure gauge.
When using two pressure gauges, one pressure gauge should be installed on thefiltrate water line and the other on the membrane tank, to monitor the trans-membranepressure. When operating several “NHP210 Series” modules simultaneously in one
train, it is advised installing one differential pressure measuring instrument for eachtrain.

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TORAY MBR[Example]
P2
PIA

a mm

b mm

P1

PIA

Fig.IV-4 Trans-Membrane Pressure Measurement & Calculation

a = 1,000 mm (= 10 kPa, 100 mbar), b = 3,000 mm (= 30 kPa, 300 mbar)

PIA readings;
Filtration (pump ON)

Relaxation (pump OFF)P1 (kPa)

29

30

P2 (kPa)-15-10

In this case, TMP is calculated as follows;
TMP= (P1Filtration - P1Relaxation) - (P2Filtration - P2Relaxation)= (29) - (30) - [(-15)-(-10)]= 4 kPa* In case water level is stable, P1Filtration is equal to P1Relaxation. Then TMP is;
TMP = P2Relaxation - P2Filtration = -a - P2Filtrationd.

Air supply unit (such as a blower)
This unit supplies air to the air diffusers of "NHP210 Series" module. The air flow rate
supplied to the module should be always within the range of "Scouring Air Flow Rate"
indicated in Table III-3.

e.

Air flow meter.
An air flow meter is recommended to be installed to check the flow rate of the scouring
air supplied to the module. In case of operating several “NHP210 Series” modules
simultaneously in a train, it is advised installing, at a minimum, one air flow meter foreach train.

f.

Suction pump
A suction pump is required in the case of pump suction configuration. To achieve an
accurate designed filtrate flow rate, the suction pump should be fitted with a VFD
controller. The use of a volute pump (centrifugal pump) or volumetric pump (screwpump) with self-priming functions is recommended.

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g.

Level sensor
Level sensors are required to be installed in the membrane tank to monitor and control
the liquid level of the membrane tank and to facilitate calculating TMP via the PLC.

h.

Siphon breaking device on filtrate piping
When using a suction pump, it may be necessary to have a means to break the filtrate
siphon if the filtrate discharge point is lower than water level of the membrane tank.
This siphon flow has to be avoided and the filtrate flow has to be stopped whenever
the pump stops.

!

CAUTIONInstall the screen with openings of 3.0 mm or under before themembrane tank. In case of receiving wastewater with fibrous debris
such as raw sewage without primary clarifier, select a mesh type forthe screen device. Overflow or waste carryover must be avoided at
all the time.

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3. Layout of “NHP210 Series” Modules in Membrane Tank
(1)

Layout of Modules in Membrane Tank

Fig.IV-5a shows how the liquid circulates in the membrane tank. An upward flow of liquid isgenerated as the air is supplied from the air diffuser located at the bottom of the membrane
modules. This flow circulates downward along both sides of the element block.
This circulation flow serves to scour the membrane element surfaces and at the same time to
mix the activated sludge. It is very important to arrange the membrane modules withappropriate distances between each module to obtain an effective activated sludge
circulation, as well as not having excessive space around the modules which allows
sludge sedimentation (installing sludge agitation if necessary).
Fig.IV-5a and Fig.IV-5b illustrate a side view and a top view of the membrane tank containing
three membrane modules. It is required to adhere to the dimensions of W1, W2, W3, and L1
listed below.

Liquid level

L1
ModuleW1

W2

Top of elements

ModuleModuleW1

W2

Fig.IV-5a Membrane Module Layout in Membrane Tank (side view)
W3
W1
ModuleW1

W2

W2
ModuleTank Wall

ModuleW3

Fig.IV-5b Membrane Module Layout in Membrane Tank (top view)

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(i)

W1 :

380 to 680 mm(ii) W2 :430 to 730 mm(iii) W3 :W3 should be as short as possible (normally about 400 mm) within the range
allowing piping and maintenance work.

(iv) L1 :L1, the distance between the top of the element and the liquid level of the tank,should be 500 mm or over at any time of the operation.

*

Refer to the “Dimensions” on the Table III-3 for layout design, not “Overall
dimensions”.

*

Contact Toray in the event the recommended layout design is not possible when installingthe membrane modules in an existing aeration tank.

*Contact Toray in the case the existing tank floor is not level l, If the existing tank floor is
not level l, it is recommended that stands be installed as shown in Fig.IV-6.

ModuleStand
Tank bottom
Fig.IV-6 Installation with Stands (side view)(2) Layout of Modules installed with Other Aeration Equipment
In the case that the membrane modules are to be installed in a tank with other oxygensupplying aeration equipment or in an existing tank where there is already other oxygensupplying aeration equipment, take the following precautions in addition to what is mentioned
in the above section.
The membrane modules should be kept at least twice the W3 dimension noted in Fig. IV-7
from any other oxygen-supplying equipment.

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W1

W2

W1

W2
ModuleModuleTank wall

Module2 X W3OxygenSupplying
Aeration
Equipment

Fig.IV-7 Membrane Module Layout in Membrane Tank with Other Aeration Equipment(top view)
Alternatively keep twice the W1 distance between the modules and other aeration equipmentin the case shown in Fig.IV-8.
W3
2×W1

W2
ModuleW1

W2
ModuleTank wall

ModuleW3

Oxygen Supplying
Aeration Equipment

Fig.IV-8 Membrane Module Layout in Membrane Tank with Other Aeration Equipment(top view)

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4.

Piping

The procedures of the pipe arrangement for the air diffusers and the filtrate water manifold aredescribed in this section. For connection specifications of the air diffuser and the filtrate water
manifold, please refer to the reference document (XIII Reference).
(1) Pipe Arrangement for the air diffusers
The pipe from the air supply device (blower) is connected to the two flanges (A) locatedon the air diffuser (see Fig.IV-9). When using polypropylene diffuser, heat tolerant plastic
pipe and/or use of flexible pipe/joint is recommended for the pipe for easy flange connection
without putting stress to the air diffuser. Also, it is recommended that the air supply flange (B)be installed above the tank liquid level to lift the module from the tank if necessary.
To facilitate cleaning of the air diffuser, install branch pipes and valves as illustrated in Fig. IV9. It is recommended that these valves be located within 500 mm above the liquid surface. It
is also highly recommended that these valves be automatically actuated valves with associated
PLC control circuits for automatically controlled air diffuser maintenance cleaning. Refer to VIII2 for the procedure recommended for cleaning the air diffusers.
B
Header pipe

BB

500mm or lessLiquid level

Discharge valve
Branch pipeAA

Air diffuser

Fig.IV-9 Example of Piping to Air Diffuser

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TORAY MBR!

CAUTION

Consider piping materials and regulate the load to the flange
connection points at less than 20 kg per flange, in order to avoid
distortion, leakage, or breakage of the air diffuser and filtrate water
manifold. If the load exceeds the limit shown above, put some
supports on the piping to reduce the load.

(2) Piping to the manifold
Fig.IV-10 and Fig.IV-11 illustrate two approaches of the filtrated water piping from the
Membrane Tank. Fig.IV-10 shows downward piping and Fig.IV-11 shows upward piping.
The downward piping is incorporated when sufficient suction can be developed via siphon (thefiltrate discharge lower than the tank level). The upward piping is for operation when a suction
pump is required (the pump is above the membrane tank).
In both upward and downward piping, the chemical injection valve and the air discharge valve
should be installed on a pipe tee between the pipe from the filtrate water manifold to the filtratewater control valve. These devices are necessary for chemical cleaning and are detailed in
sections VIII-3 to VIII-6.
It is advised that you prepare and attach a “riser pipe” to connect two filtrate manifolds
of one element block for ease of piping and handling (out of Toray’s scope of supply).
Fig.IV-12 shows example of the riser pipe.
In case of NHP210-600D, prepare separate riser pipes for the lower element block andthe upper element block, and do not connect both blocks to one single riser pipe.
It is also advised confirming that the diameter of filtrate piping is suitable for the assumablemaximum flow velocity at each point, especially after aggregating filtrate flow from several
manifolds such as header pipes.

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Air discharge valve
Chemical feed line
Chemicalinjection valve
Filtrated water valve

Filtrated water outlet

Fig.IV-10 Downward Piping from Membrane Tank

Air discharge valve

Chemical injection valve
Chemical feed line
Suction pump
Filtrated water valve

Fig.IV-11 Upward Piping from Membrane Tank

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Fig.IV-12 Riser Pipe (example)!

CAUTION!

CAUTION

Consider piping materials and regulate the load to the flange
connection points at less than 20 kg per flange, in order to avoid
distortion, leakage, or breakage of the air diffuser and filtrate water
manifold. If the load exceeds the limit shown above, put some
supports on the piping to reduce the load.
Be sure to confirm that the diameter of filtrate piping is suitable forthe assumable maximum flow velocity at each point, especially after
aggregating filtrate flow from several manifolds such as header
pipes.

(3) Maximum number of Modules in a single header
A maximum number of 30 modules per filtrate header with subgroups of max 10
modules for aeration (diffuser cleaning) and chemical cleaning is possible to design.

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V.
1.

INSTALLATION OF “NHP210 SERIES”
Preparatory Procedure(1)

Take precautions to plan the route for the “NHP210 Series” to the membrane tank.
The route should include the unloading area for the “NHP210 Series” to the final
installation site.

(2)

Make arrangements of the necessary equipment to unload the “NHP210 Series” froma truck such as a forklift or pallet jack etc.

(3)

Prior to installation, confirm that all necessary piping components are in place
within the membrane tank. Make certain that all construction waste materials
have been removed from the tank. All loose materials remaining in the tank should
be removed from the tank prior to installation of the “NHP210 Series”. In addition, it
is important to test all water and air lines to confirm that all field assembled
joints are free of leaks.

2.

Unloading/Lifting Products

Unload "NHP210 Series” with suitable equipment such as forklift, crane, or truck mounted
hydraulic lift gate.
Inspect the "NHP210 Series" module for any damage inflicted during transport.
(1)

You will receive two packages with the “NHP210 Series” module. One is the element
block complete with the prescribed number of membrane elements and the other box
an aeration block.

(2)

Do not lift the packages from overhead when unloading the package which contains
multiple element blocks or aeration blocks. Always lift these packages fromunderneath using a forklift or pallet jack.

(3)

To avoid damage, do not stand or sit on the packages.

(4)

A cassette can be handled by manpower only before starting operation. If several
cassettes are installed in an element block frame, do not move it by hand and use
appropriate equipment such as a forklift.

(5)

When lifting an element block, hook a sling or chain at the lifting points on the element
block and lift it with a hanger. When lifting an aeration block, hook a sling or chain at
appropriate lifting points and lift it with a hanger. Take precautions to keep the“NHP210 Series” components upright in their proper orientation.

(6)

Be careful not to damage element nozzles, air diffusers, filtrate manifolds, orother components when lifting.

(7)

Employ good safety practices when unloading the “NHP210 Series” components.

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3.

!

DANGER

Attach chains or slings to the lifting lugs when lifting “NHP210
Series”. Slowly raise the module straight up. Avoid sudden changes
in movement to minimize shaking the module. Never allow
personnel to stand under the “NHP210 Series” during lifting!

DANGER

Never lift or operate the module with worn or damaged parts. Usechains or slings rated for the weight being lifted. Check the conditionof each part before lifting.

!

DANGER

Prior to lifting, make ready a flat area to set the module down. This
will minimize the potential for damage. Damage will occur if themodule is allowed to tip over.

!

DANGER

Do not apply a strong force to polypropylene air diffuser/manifold
when moving the module. Otherwise, the air diffuser/manifold may
get damaged.

Checking Products

Upon arrival of the “NHP210 Series”, immediately check the following:(1)

Make certain all items are delivered as stated on the shipping documents.

(2)

Check to make sure no damage was inflicted during transport.

(3)

Check to confirm that the protective covers remain in their correct position.

(4)

Check to confirm that all the filtrate tubes are surely connecting elements andmanifold.

4.

Storing Products"NHP210 Series" has to be stored indoors under lower than 40 deg C of the temperature. If
the “NHP210 Series” cannot be stored indoors due to prevailing construction site conditions,
try to minimize the time being out of doors. As soon as possible, move the “NHP210 Series”
into a protected area to avoid accidental damage. Always comply with all recommended
storage conditions.
At all times during transportation and installation of the “NHP210 Series”, protect themodule elements and other components from damage. Take special measures toprotect the elements from sparks caused by welding, fusion cutting, or grinding. If anyof these activities are in progress, be sure to protect the elements by using fireproof sheets orother protective materials.
(1) Keep the module upright at all times and do not place any heavy objects on themodule.
(2) Maintain the temperature below 40 deg C.
(3) Prevent from freezing.
(4) Prevent from getting wet. Avoid conditions where condensation may occur on themodule or elements.
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TORAY MBR(5) Do not submerge in water until such time as the “NHP210 Series” is ready for final
installation.
(6) Avoid module exposure to direct sunlight.
(7) Protect from falling objects. Again, avoid exposure to sparks from grinding or welding.

5.

Exposing the “NHP210 Series” and membrane elements totemperatures above 40 deg C or direct sunlight should be avoided.
Exposure to direct sunlight /UV radiation will cause thepolypropylene air diffuser and filtrate water manifold to deteriorate.

!

CAUTION!

CAUTION

Protect “NHP210 Series” from freezing.

!

CAUTION

Take adequate measures to protect “NHP210 Series” from sparks
caused during welding, fusion cutting, or grinding.

!

CAUTION

Take precautions to protect the elements from damage. Do notplace heavy objects on the module. Protect the module frompotential collisions with other moving objects.

!

CAUTIONBe careful not to damage the rubber parts of air diffusers andelement fixing brackets.

Installing Products

Check the followings before module installation:(1) Make sure all necessary work in the membrane tank has been completed.
(2) Make sure the tank and all pipes have been thoroughly cleaned and free of debris.
(3) Confirm that there are no leaks in any of the tank and water or air lines.
(4) Using clean water in the tank, check the operation of major equipment components
such as: pumps, blowers, sensors, and control systems.
Review the drawings in the Reference (XIII) to make certain final tie-ins to the “NHP210 Series”
are as per the drawings. Refer to the information in the Reference (XIII) if you intend to install
the module without anchoring the module to the floor of the tank (e.g., using guide rails instead).
(1) Installation of Aeration Blocks (on the bottom of the membrane tank using anchors)
First install the aeration blocks in the membrane tank using suitable anchors. If multiple
aeration blocks are to be installed, record each block’s serial number and position within thetank.
The air diffusers should be installed in a horizontal position to achieve uniform scouring
aeration. The maximum allowable deviation from the dead level for the air diffusers is 3/1,000
on the top surface of the aeration block in both lateral and vertical directions.

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TORAY MBR(2)Plumbing in Air Diffusers

Prior to plumbing in the air diffusers, flush all pipes out. The air diffuser should be connectedto the pipe from air supply unit with the flanges. When using a polypropylene diffuser, pleaseconsider piping materials and regulate the load to the flange connection points at less than 20
kg per flange, in order to avoid distortion, leakage, or breakage of the plastic air diffuser. If theload exceeds the limit above, put some supports on the piping to reduce the load.
One air diffuser is shipped from the factory with two rubber gaskets. Connect air diffuser to the
air-line using rubber gaskets with the tightening torque of 20 N.m.
After plumbing in the air diffusers, fill the membrane tank with clean water until the aeration
blocks are completely submerged in the clean water. Next turn on the air supply, check tomake certain that the air is being evenly distributed throughout the aeration block.
(3) Guide Rail System
This system makes it possible to lift up/down the element block without draining the sludge inthe membrane tank. For NHP210-300S you can choose the MBR plant design with or without
guide rail, whereas it must be incorporated with NHP210-600D due to its tall. Please note that
Toray will provide reference drawing and the buyer will design, manufacture, and install thesystem considering the site conditions.
(4) Installation of Element Blocks
Connect the hanger which has four sling points at its corners with proper load ranges andelement block with chains or slings. Lift the element block with hanger. For safe lifting ofelement block, slowly raise the module straight up and avoid sudden changes in movement tominimize shaking the module. Reference drawing of hanger is available on your requests.
i) In case of NOT using guide rail system (available for NHP210-300S);
Put the element blocks onto the aeration blocks. Joint both of them using provided bolts.
ii) In case of using guide rail system (NHP210-300S and 600D);
Use guide rails certainly and do not connect upper element block and lower element
block when installing double-decked module NHP210-600D. Also, do not lift and installentire decks at one time. Upper/lower element block must be installed one by one to
avoid distortion or damage to the element block which may cause severe accident.

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The serial number of each aeration block and its position in the tank should be recorded. Afterinstallation, take adequate measures to protect the elements and other components fromdamage by covering with fireproof tarps.
(5) Plumbing in Filtrate Water Manifold
Before making any connections to the filtrate manifolds, the water line should beflushed to remove any residual construction debris and avoid pressurizing the filtrateside of "NHP210 Series” over 10 kPa.
Filtrate manifolds are shipped from the factory with one blind flange furnished and temporarilybolted at one end only.
Connect the filtrate water pipe to the one side of the filtrate manifold flange and attach theblank flange to the opposite side of the manifold. Tightening both connections properly.
The buyer may need to purchase a compatible flange for connecting the filtrate water line tothe supplied filtrate manifold. In case of polypropylene manifold, connect the manifold to thefiltrate water line using rubber gasket with the tightening torque of 20 N.m.
To avoid membrane element damage, never place the filtrate connections to the membraneelements under stressful forces.

!

DANGER

Attach chains or slings to the lifting lugs when lifting element deck,
element block, or aeration block of “NHP210 Series”. Slowly raise
the module straight up. Avoid sudden changes in movement tominimize shaking the module. Never allow personnel to stand underthe “NHP210 Series” during lifting.

!

DANGERUse chains or slings with sufficient load rating to lift the weight of the"NHP210 Series" or any of its components.

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DANGER

When installing “NHP210 Series” module, make provisions, inadvance, to access the upper portions of the membrane module via
a scaffold or ladder. Do not climb on the module structure. Neverstep on the air diffuser and filtrate water manifold. Use protective
equipment to ensure the safety of workers.
Use guide rail system and do not connect upper element blocks andlower element blocks when using double-decker module. The
upper/lower element blocks should be lifted separately when lifting
double-decker module.

!

DANGER!

CAUTION

Wear the appropriate personal protective equipment (e.g. work
gloves) in order not to cut hand on the edge of the module frame.

CAUTION

Connect the flanges of air diffuser and filtrate water manifold to thepiping with the tightening torque of 20 N.m, in order to avoid
distortion, leakage, or breakage of the air diffuser and filtrate water
manifold.

!

CAUTION

Consider piping materials and regulate the load to the flange
connection points at less than 20 kg per flange in order to avoid
distortion, leakage, or breakage of the air diffuser and filtrate water
manifold. If the load exceeds the limit shown above, put some
supports on the piping to reduce the load.

!

CAUTION

Avoid pressurizing the filtrate side of "NHP210 Series” over 10kPa.

!

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VI.
1.

START OF OPERATION
Clean Water Operation(1) Check the following items prior to module(s) operation:a.

Check that the air diffusion pipe and the filtrate water pipes are properly connected tothe module(s).

b.

Check that the element block is securely installed on the aeration block.

c.

Remove any protective materials covering the membrane tank. Check that themembrane tank is completely free of dust and debris. The presence of soil and dust
may cause damage to the module.
Open the air discharge valve on the filtrate line to release any air from the filtrated.

side of the elements before introducing clean water into the membrane tank.
e.

Introduce clean water (tap water or filtered water) to the membrane tank. Fill the tankup to the recommended operating liquid level.

f.

Close the air discharge valve located on the filtrate line, after filling the membrane
tank.

!
!

CAUTION

Open the air discharge valve before feeding clean water to themembrane tank. Close the air discharge valve after feeding water.

CAUTION

Do not use natural ground water for clean water operation, as it may
contain much amount of iron, manganese, calcium, and silica which
may cause the clogging of the membrane pore.

(2) Clean water operation
After feeding clean water to the membrane tank, follow the recommended procedures below
to start the clean water operation.
a.

Start the blower to supply air to the air diffusers. Check that the required amount of
air is supplied to the air diffusers and the diffused air is being distributed evenly withineach module.
*

White foaming may occur in the membrane tank during clean water operation.
The foaming is caused by the leaching of residual biodegradable hydrophiliccomponents contained in the membrane after the manufacturing process.
Foaming is normal and does not adversely affect the membrane filtration process
but if you want to remove this, do not use silicone-based anti-foaming agent
which may cause choking of membrane pores.

b.

Check that the recommended amount of air is evenly supplied to each module whenusing one blower to supply air for multiple modules. If the distribution of air is found
not evenly distributed between modules, it may be necessary to modify the air line
header piping inside diameter to achieve uniform air distribution to each module.

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c.

Check the system controls and associated control components for proper operationand proper sequence of operation.

d.

Start the clean water filtration process. At the initial operation of suction pump, priming(filling the suction piping with water) may be needed for proper pump suction and inthat case avoid pressurizing the filtrate side of "NHP210 Series” over 10kPa. Measure
and record the trans-membrane pressure and water temperature at designed filtration
rates (at normal, maximum, and minimum flow rates). It is beneficial to periodicallyrecord flow rates and TMP values.

e.

Stop the clean water filtration process and discontinue the air supply as soon as theabove tests have been satisfactorily completed.

2.

White foaming may occur in the membrane tank during clean water
operation. The foaming is caused by the leaching of residual
biodegradable hydrophilic components contained in the membrane
after the manufacturing process. Foaming is normal and does notadversely affect the membrane filtration process but if you want toremove this, do not use silicone-based anti-foaming agent which
may cause choking of membrane pores.

!

CAUTION!

CAUTION

Do not conduct clean water operation for a long time. Clean water
operation may cause membrane clogging.

!

CAUTION

Keep the membranes wet once they get wet. If the membranes areallowed to dry out, the permeability of the membranes may bepermanently reduced.

!

CAUTION

Avoid pressurizing the filtrate side of "NHP210 Series” over 10 kPa.

Seeding Sludge Injection

Do not attempt to produce filtrate from any wastewater that has not first been seeded withactivated sludge. Failure to do so will result in severe clogging of the membrane pores
Follow these steps when seeding sludge in the membrane tank with activated sludge:(1)

Locate a nearby wastewater treatment facility that treats wastewater similar incomposition to the wastewater to be treated with the new “NHP210 Series”. Makearrangements to transport some of that healthy, activated sludge from the nearby
wastewater facility to the facility needing the seeding sludge. Activated sludge withhigher MLSS concentration and higher MLVSS/MLSS ratio is preferable. Initial
MLSS concentration of the membrane tank should be at least 3,000 mg/L or
higher. Higher than 7,000 mg/L is preferred.

(2)

Drain the clean water if the membrane tank has been filled with it, then supply theseeding sludge through the <3mm screen to the tank.

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Begin feeding the raw wastewater as soon as possible after the activated sludge
has been introduced into the membrane tank.

(4)

Do not use seeding agents.

(5)

Do not use silicone-based anti-foaming agent which may cause choking of
membrane pores.

3.

!

CAUTION

Prior to introduction of any seeding sludge into the membrane tank pass
all sludge through a 3 mm or less mesh screen device.

!

CAUTION

Open the air discharge valve before feeding sludge to the membranetank. Close the air discharge valve after feeding sludge.

Actual Filtration Operation

After successfully seeding the sludge within the membrane tank, start the air supply to the
diffusers, start sludge circulation, and activate the filtration process and the raw wastewaterfeed.
Pay particular attention to the following operational parameters:(1)

The condition of the seeded activated sludge may not be optimal for membrane
filtration until such time as the food to microorganism ratio (F/M) has been optimized.
To avoid fouling the membrane elements while the activated sludge is evolving,
operate the MBR well below the designed flux rate. This is especially important until
the activated sludge MLSS concentration approaches 7,000 mg/L. Gradually
increase the flux rate as the condition of the activated sludge improves.

(2)

At the initial operation of suction pump, priming (filling the suction piping with water)
may be needed for proper pump suction and in that case avoid pressurizing thefiltrate side of "NHP210 Series” over 10kPa.

(3)

Sludge parameters such as MLSS and sludge filterability (see VII. 4. (10)) should
be checked frequently to assess the actual sludge condition.

(4)

Check the air diffuser cleaning procedure and associated automated valves forproper operation. Details for the procedure are given in the chapter VIII.

(5)

Once the filtrate water flow has stabilized, measure and record the trans-membranepressure and the liquid temperature. Details for operation control are given in thenext chapter.

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!

CAUTION

The air scour should be stopped when the filtration process issuspended. There are two exceptions:
1) Do not stop the air scour during the normal relaxation period.
2) Do not stop the air scour if the activated sludge requires air for
normal metabolic processes or preventing sludge sedimentation.
However, under these conditions the amount of air flow directed tothe diffuser should be reduced to just the amount required tomaintain sludge viability or agitate sludge.
Avoid pressurizing the filtrate side of "NHP210 Series” over 10kPa.

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VII.

OPERATION CONTROL

1.

Standard Operating Conditions

Table VII-1 shows standard operating conditions for “NHP210 Series".
To ensure stable operation, operating parameters such as MLSS, sludge viscosity, DO(dissolved oxygen concentration), and pH should be kept in the range of recommended
standard operation conditions listed in Table VII-1 below. All wastewater should pass througha 3mm (or less) screening device before introducing into the membrane tank. Large solids may
damage the membrane surfaces.
If anti-foaming agents are to be added to the membrane tank, use only alcohol based
anti-foaming products. Do not use silicone-based anti-foaming agent which may cause
choking of membrane pores.
* Recommended:

Kurita Water Industries “Kuriless 653”
Schill & Seilacher “Structol SB2032”

The operating conditions may deviate from these standard conditions, depending on conditionof the sludge, raw water quality, and/or other given operating conditions.
Table VII-1 Standard Operating Conditions for “NHP210 Series”
Parameter

Unit

Operating condition

MLSS

mg/L

Sludge viscosity*

mPa⋅s

DO
pH
Liquid temperature

mg/L
deg C
NL/min/Module(Cubic feet/min/
Module)7,000 - 18,000
Not higher than 100 **Not higher than 250 ***1.0 or more
6-8
15 - 40

Scouring air
flow rate

NHP210-300S
NHP210-600D

1,300 (46)1,500 (53)

* Measured by single cylinder rotary viscometer.
** B type viscometer, e.g. VT-03F by Rion Co., Ltd at 62.5 rpm.
*** C type viscometer, e.g. TVC-10 by Toki Sangyo Co., Ltd at 20 rpm.

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!

WARNING

Do not use the filtrate water for directly for drinking.

WARNING

Analyze the quality of the filtrate water to ensure that the water
quality meets the intended purpose before actual use.

CAUTION!

Do not allow contamination of chemicals, toxic agents, oils, or othersubstances into the MBR tank or wastewater that can adversely
affect the condition of activated sludge.

!

CAUTION

Avoid abrupt changes in pH, temperature, trans-membranepressure, or any other conditions even if they are within the standard
operating conditions (Table VII-1).

!

CAUTION

Perform regular inspections of the module. Replace worn parts, as
needed, in a timely fashion.

!

CAUTION

If anti-foaming agents are to be added to the membrane tank, use
only alcohol based anti-foaming products. Do not use silicone-based
anti-foaming agent which may cause choking of membrane pores.

!

CAUTION

Protect the modules from freezing.

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2.

Operating Parameters

The performance of the “NHP210 Series” varies depending on raw water quality and site
specific operating conditions. In order to achieve stable “NHP210 Series” operation, it isrecommended that various operating parameter values be monitored and recorded regularly.
The following operational parameter values should be recorded regularly for more stable
operation and troubleshooting(1)

Scouring air flow rate (blower air flow)(2)

Diffusion pressure (blower discharge pressure)(3)

Filtrate water flow rate

(4)

Trans-membrane pressure (TMP)(5)

Liquid temperature in the membrane tank(6)

DO (dissolved oxygen) concentration in the membrane tank(7)

pH in the membrane tank

(8)

MLSS in the membrane tank(9)

Raw water quality (BOD, COD, turbidity, T-N, T-P, etc.)(10)

Filtrate water quality (BOD, COD, turbidity, T-N, T-P, TSS etc.)(11)

Excess-sludge discharge rate

(12)

Sludge viscosity(13)

Sludge filterability

Preferable recording frequencies are;

Every five (5) minutes for on-line instrumentsEvery day for off-line instruments and sludge propertiesEvery week for water quality analysis

3. Basic Control Philosophy
Presented below is the point of the generic MBR control philosophy. The actual MBR system
control philosophy will be based on the specific site operating conditions.
(1) Suction Pump: The filtrate suction pump should be controlled to operate for intervals ofnine (9) minutes on and one (1) minute off. The filtrate suction pump motor should be fittedwith a VFD drive. A filtrate flow transmitter should be installed to provide a control signal to
the suction pump VFD. The suction pump should be stopped if the liquid level in themembrane tank drops to a predetermined low liquid level. If, at any time, the air supply tothe membrane module or RAS (return activated sludge) is interrupted, the suction pumpshould be stopped. Do not operate the filtrate suction pump on low membrane tank levelor high TMP. Once the air supply has been restored the membrane tank and good RAS
circulation is observed, delay the activation of the suction pump for one minute to makecertain sufficient sludge mixing has taken place prior to restarting the filtration process. The
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suction pump should always be off when performing air diffuser cleaning.
(2) Membrane Scouring Blower: The blower supplying air for membrane scouring should beon continuously. Air flow (and suction pump) should be stopped if the liquid level in themembrane tank falls below the preset low level for a long period or the flow to themembrane tank stops. In such cases the air supply should be applied for five (5) minutes
each hour the system is not producing filtrate. This is required to keep the sludge well
mixed and in good condition for restarting the filtration process while avoiding too muchstress to the membrane elements.
(3) Membrane Tank Water Level: If the liquid level in the membrane tank reaches the lowlevel, the suction pump and membrane scouring air should be stopped. If the membranetank reaches high level the wastewater feed supply should be stopped.
(4) TMP: Two TMP alarms should be incorporated into the MBR control logic. A ”HIGH TMP
ALARM” should be activated before the TMP increases 5 kPa from the initial TMP value.
A ”HIGH-HIGH TMP ALARM” which stops filtration should be activated when the TMP
reaches 20 kPa.
(5) Air Diffuser Cleaning Valves: Install the air diffuser valves, automatic actuated valves arerecommended to facilitate automatically controlled operation of the air diffuser cleaning
cycles. Air diffuser cleaning should take place at least once every 24 hours of operation.
(6) Equalizing/balancing wastewater load in terms of both quality and quantity is quite
important for stable operation of MBR. In this regard having equalization tank with mixing
equipment is recommended.

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4.

Daily Inspection

The above Section 2, Chapter VII lists operating parameters that should be monitored. Daily
recording of the values associated with these parameters will be helpful in determining
the current condition of the MBR system. Failure to control or abnormal values can leadto serious problems and damage to membrane products. Operational data should beanalyzed daily to serve as a guide for preventative maintenance. Take action to correct
any unfavorable operational trends before more serious conditions develop. In addition, it isbeneficial to inspect all system components for correct and smooth operation on a weekly
basis.
(1) Diffused Air Conditions
Check the air flow rate and blower discharge pressure of the air supply line to the MBR air
diffuser. Too low of an air flow rate can result in membrane clogging. Too high of an air flowrate can result in element damage. Try and keep the air flow rate per module between
recommended ranges. If the recommended air flow rate cannot be achieved, stop filtration andcheck the air supply piping for leaks, incorrect valve positions, blower inefficiency, or possible
air line restrictions. In the case where multiple MBR modules are located in the same tank,check that diffused air is being evenly distributed between each MBR module. If uneven air
distribution is observed, conduct an air diffuser cleaning as described in Section 2, Chapter
VIII.

!

CAUTION

If the scouring air flow rate drops or becomes extremely irregular orif air supply is stopped, then immediately stop filtration to prevent
membrane clogging.

(2) Trans-Membrane Pressure
Check the trans-membrane pressure (TMP) frequently. When the TMP increases by 5 kPa (50mbar) at a constant filtrate flow rate, it is time to initiate a membrane element chemical cleaning.
A sudden increase in the trans-membrane pressure suggests that the membrane surfaces are
clogging. Clogging can be caused by abnormal diffused air distribution, too high flux rate, toohigh MLSS concentration or deteriorating sludge properties. If TMP values are increasing,check the MBR operating conditions and the biological condition of the sludge. Take necessary
actions to correct operating conditions and then perform a chemical cleaning of the elements.
It is advised measuring the TMPs at different flow rates, e.g. 100% flow, 50% flow, and 33%
flow, when starting MBR operation after commissioning. This is for checking correct functioningof pressure measurement and head loss at filtrate piping for different flow velocities.

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TORAY MBR(3) Activated Sludge Characteristics
The activated sludge of the membrane bioreactor should be self-cohesive and free from odor.
The color of healthy activated sludge is typically brown, however this color can differ among
plants, depending on wastewater composition, organic load, etc. If an unexpected change isobserved in sludge characteristics, check current operating conditions such as BOD load,
MLSS concentration, DO, pH, temperature, and/or wastewater composition, and takeappropriate corrective actions.
(4) Water Temperature
The desirable water temperature is 15 deg C to 40 deg C. If the temperature is out of this range
and the activated sludge properties are not optimum, it is recommendable to install atemperature control device to cool or heat the liquid.
(5) DO
The aeration tank and the membrane tank should be kept in an aerobic condition. If DO is lessthan 1.0 mg/L, take necessary actions such as increasing the air-flow rate of the biologicalaeration unit, or lowering the sludge concentration by increasing the excess sludge discharge
rate. In the case where the air supply for biological aeration requirements and the air piping formembrane scouring comes from the same blower, do not exceed the recommended range ofmembrane scouring air flow rate to the diffuser. To increase DO concentration of the liquid
within the membrane tank, adjust the separate biological aeration system.
(6) pHThe recommended pH range is 6 to 8. If pH is out of this range and the activated sludge
properties are not optimum for filtration, adjust the pH by gradually adding acid or alkali.
(7) MLSSMLSS concentration in the membrane tank is recommended between 7,000 to 18,000 mg/L.
If the MLSS is too low, increase the MLSS concentration in the membrane tank by reducing
the sludge discharge rate. If the MLSS concentration is too high, check the RAS (return
activated sludge) flow rate. If it is determined that the RAS flow rate is too low, increase the
RAS flow rate to the proper value. If RAS flow rate is correct, increase excess sludge discharge
rate.
(8) Water Levels
Check to confirm that the water levels of the membrane tank are being maintained within therecommended values. If it is determined that the levels are not as per the design, check thefollowings: level control devices, level control circuits, filtrate pump VFD controls, activatedsludge feed control valve, and membrane flux rate. Take corrective action as necessary.
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TORAY MBR(9) Sludge Viscosity
It is recommended that the sludge be no higher than 100 mPa.s (measured by B-type
viscometer) or 250 mPa.s (measured by C-type viscometer). If the sludge viscosity is too high,check MBR operating conditions and biological conditions such as F/M ratio, and takenecessary corrective actions.
(10)

Sludge filterability

Paper filtration method is a simple and reliable method to determine the filtration properties ofthe sludge. See the method described in the attached document. Toray recommends
conducting paper filtration test and measurement of TOC and/or turbidity of filtered waterroutinely. In the case an abrupt decrease in filterability is recorded and/or increase in
TOC/turbidity, check the operating and biological conditions, and take appropriate actions.
(11)

Pretreatment System

In addition to the operating parameters for the “NHP210 Series”, check the status of the
pretreatment systems (particularly the screening device) frequently. At regular intervals
remove any accumulated trash that may accumulate on the screening device.

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VIII.

MAINTENANCE OF “NHP210 SERIES”

1.

Maintenance Items and Maintenance Frequency

It is recommended that the following maintenance tasks be performed on a regular basis tomaintain optimal performance of the “NHP210 Series” module.
(1)

Clean the air diffusers (at least once per 24 hours)(2)

Perform a chemical cleaning if the currently recorded TMP increases by 5 kPa (50mbar) from the initially recorded TMP (assuming the filtrate flow rate is the samevalue) or every six (6) months, whichever comes first.

(3)

Replace filtrate connection tubes connected to the filtrate manifold when they show
some deterioration.

(4)

Replace membrane cassettes or element blocks if, after chemical cleaning, filtrate
flow or quality cannot be restored.

!

CAUTIONBe sure to use Toray approved replacement parts.

!

CAUTION

Contact Toray sales department to obtain information on how toorder Toray approved replacement parts.

!

CAUTION

Make certain the tube is securely attached to the membrane element
nozzle when replacing the individual filtrate tubes to the filtrate
manifold.

!

CAUTION

Do not apply excessive force to the nozzle or membrane element
when replacing filtrate tubes. Excessive force may result inmembrane element/manifold damage.

!

CAUTION

Once a filtrate tube has been removed or disconnected from either
the element nozzle or filtrate manifold it should be replaced with a
Toray approved replacement part. Old filtrate tubes lose theirelasticity, and the integrity of the seal can be compromised.

!

CAUTION

Note that element replacement is admissible only after instruction
from Toray service staff or their trained affiliate personnel.

!

CAUTION

Hold the grip and do not hold the other portion of thecassette such as outer ribs when handling the cassette
for maintenance purpose.
grip

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2.

Air Diffuser Cleaning

A clogged air diffuser cannot evenly distribute air to the membrane elements resulting in, whichcauses that solids build up on the membrane element surface, or, in extreme cases, themembrane element gets damage. It is recommended that the MBR module(s) be equippedwith air diffuser cleaning components/valves that can be automatically controlled from
the MBR system PLC. Cleaning of the air diffusers should be performed at least onceper 24 hours or as needed to maintain even air distribution. To clean the air diffuser holes,
it is necessary to flush the activated sludge through the diffuser holes into the diffuser piping
and finally out from the air/sludge discharge nozzles. This is accomplished by supplying air tothe diffuser piping in the reverse direction (see below). The flow of air through the diffuser andout the discharge nozzle will create a suction drawing off the sludge into the diffuser piping.
This reverse flow of sludge that will remove any accumulated solids clogged in the diffuser
holes. The efficiency of the air diffuser cleaning will improve by the reverse procedure of the
air flow direction indicated above.
Observe the flow coming out of the discharge nozzles (V2 and V4) when performing an air
diffuser cleaning cycle. In some cases, lengthening the duration of the diffuser cleaning cycle
can improve the efficiency of the diffuser cleaning cycle.
(1)

Air diffuser cleaning procedure - Principle(i)

The filtration must be stopped at first.

(ii)

Open V2 discharge nozzle valve.

(iii)

Close V1 valve. These valve settings will resultin liquid sludge flowing through the diffuser holes,
into diffuser piping, and the mix of air and sludge
will be discharged through V2.

(iv)

Keep V2 valve open for 1 to 5 minutes.

(v)

Open V1 valve, and then close V2 valve.

(vi)

Clean the other line in the same manner asfollows.

(vii) Open V4 discharge nozzle valve.
(viii) Close V3 valve. These valve settings will resultin liquid sludge flowing through the diffuser holes,
into diffuser piping, and the mix of air and sludge
will be discharged through V4.
(ix)

Keep V4 valve open for 1 to 5 minutes.

(x)

Open V3 valve, and then close V4 valve.

(xi)

Restart the filtration process.

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Air diffuser cleaning procedure for multiple modules - Practical design

For multiple module operation, the flushing procedure described in the previous section canbe applied for each module, or a more convenient and simple approach is shown in Fig. VIII1. Each inlet point of the air diffuser should be connected to each of the two air headers, andeach header equipped with two valves (automatic valves are strongly recommended) at the
inlet point and end point (both higher than water level). The procedure and standard duration
time of each action are as follows:

Flushing: to clean air diffusers, 1 to 5 minutes for each flushing event.



Purge: to blow out inside header pipes, around 30 seconds for each purge event.

Filtration must be stopped prior to starting the air diffuser cleaning procedure and restarted
one minute after air scouring is started. Please take care not to allow sludge to flow toward theblower.

Air

Air scouring

1) Purge (1/3)

Air

Sludge & Air

2) Flushing (1/2)

3) Purge (2/3)

Sludge & Air

4) Flushing (2/2)Air

5) Purge (3/3)
After 5) back to air scouring.

Fig.VIII-1 Air Diffuser Cleaning Procedure for Multiple Modules

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3. Chemical Cleaning of Element
Continuous filtration of the sludge will eventually result in plugging of the membrane element
pores with trapped solids. Clogging of the membrane pores is indicated by a gradual increasein module TMP. A chemical cleaning is recommended when any of the following
conditions are observed.
(1) Until the trans-membrane pressure rises by 5 kPa (50 mbar) from its initial operatinglevel (assuming the filtrate water flow rate is the same) or every 6 months of operation,
whichever comes first. Preparation for the cleaning should be started when it rises by
3 kPa (30 mbar). For example, if an MBR was operated at 7 kPa (70 mbar) TMP in its
initial period, then 10 kPa (100 mbar) is the trigger for

preparation and chemicalcleaning shall be done before it reaches to 12 kPa (120 mbar).
(2) When a sudden and significant increase of module TMP is observed. Chemicalcleanings are most effective in restoring membrane permeability if the membranes are
not severely fouled. However, if you let the MBR operation continue until TMP reaches
its upper limit, 20 kPa (200 mbar), then membrane fouling may get serious andchemical cleaning effectiveness can be less than expected. Follow the cleaning trigger
described in above (1).
(3) It is recommended that operations personnel record the time interval required for the
TMP to increase by 3 or 5 kPa. Premature TMP increases can be the result of lessthan the optimal operating conditions. In-depth TMP monitoring and control are
effective to prolong the life of membranes.
(4) If the membrane permeability is not recovered by a single chemical cleaning, multiple
chemical cleaning may be necessary to restore membrane performance. Repeat hypocleaning or hypo/acid alternating cleaning, considering the foulant nature and TMP
recovery.
4.

Chemical Agents Available for Chemical Cleaning

Try and select a cleaner that is most appropriate for the suspected foulant when consideringchemical cleaning agents. Selecting an inappropriate cleaner can result in further loss inmembrane performance or possible membrane damage. Table VIII-1 lists suitable cleaningchemicals and standard cleaning conditions.
The buyer is not permitted to use chemical agents which are not described in this Toray MBR
instruction manual and/or to apply excess concentration of chemical agents due to concern of
Toray MBR performance decline. If the buyer takes those actions without prior consultation,
Toray does not take any responsibilities for Toray MBR performance. Toray may be able topropose appropriate procedure and/or suggest alternative measures based on our many
achievements if the buyer contacts with Toray in advance.

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Table VIII-1 Cleaning Chemicals and Standard Cleaning Conditions by ContaminantContaminantChemical

Organic matter

Sodiumhypochlorite

Inorganic matter(either of the two
chemicals)

Solution concentration

Amount used

Hold time(Effective chlorine concentration)(10<pH<12)

0.9 L/element

1 to 3 hours

Oxalic acid*

0.5-1.0 wt%

0.9 L/element

1 to 3 hours

Citric acid

1-3 wt%

0.9 L/element

1 to 3 hours

2,000-6,000 mg/L

* Oxalic acid should not be applied when wastewater contains calcium, since calcium oxalate may form on themembrane surface which can choke membrane pores.

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5.

Handling of Chemical Agents

Follow normal safety precautions when handling potentially harmful chemicals. Avoid
direct contact with skin. Take precautions when handling chemicals and wear safety
goggles, protective gloves, and other suitable safety gear to avoid injuries. Prior tohandling chemicals, read the chemical SDS information to familiarize yourself withdangers and remedies should a chemical spill or contact accident occur.
(1) Sodium hypochlorite solution / NaClO(A) Handling precautions(a) Ventilate well. Avoid heat sources and sparks. Also avoid contact with acids.
(b) Handle the chemical container with great care. Avoid toppling, bumping, or
dragging it.
(c) Take care not to spill liquid chemicals and avoid breathing in vapors. In the caseof dry chemical powders, handle in a manner that minimizes the formation ofchemical dust.
(d) Securely seal all chemical containers after each use.
(e) Thoroughly wash your hands and face and rinse out your mouth after usingchemicals.
(f)

Do not eat or drink anything in the working place except in a designated place.

(g) Do not bring gloves or other contaminated protectors into the rest area.
(h) Forbid unauthorized entry to the place where chemicals are handled.
(i)

Wear appropriate protectors to avoid inhalation, eye or skin contact, and directcontact with your clothes.

(j)Provide local ventilation in the case of handling chemicals indoors.

(B) Storage precautions(a) Store the container in a dark, cold place. Avoid direct sunlight. Firmly seal toprevent direct contact with air.
(b) Use corrosion-resistant containers for storage.
(2) Oxalic acid / (COOH)2(A) Handling precautions(a) Keep away from strong oxidants and bases.
(b) Handle the chemical container with great care. Avoid toppling, bumping, or
dragging it.
(c) Take care not to spill liquid chemicals and avoid breathing in vapors. In the caseof dry chemical powders, handle in a manner that minimizes the formation ofchemical dust.
(d) Securely seal all chemical containers after each use.
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TORAY MBR(e) Thoroughly wash your hands and face and rinse out your mouth after usingchemicals.
(f)

Do not eat or drink anything in the working place except in a designated place.

(g) Do not bring gloves or other contaminated protectors into the rest area.
(h) Forbid unauthorized entry to the place where chemicals are handled.
(i)

Wear appropriate protectors to avoid inhalation, eye or skin contact, and directcontact with your clothes.

(j)Provide local ventilation in the case of handling chemicals indoors.

(B) Storage precautions(a) Store the container in a dark, cold place. Avoid direct sunlight. Firmly seal toprevent direct contact with air.
(b) Use corrosion-resistant containers for storage.
(3) Citric acid / HOOCCH2C(OH)(COOH)CH2COOH(A) Handling precautions(a) Keep away from strong oxidants and bases.
(b) Handle the chemical container with great care. Avoid toppling, bumping or
dragging it.
(c) Take care not to spill liquid chemicals and avoid breathing in vapors. In the caseof dry chemical powders, handle in a manner that minimizes the formation ofchemical dust.
(d) Securely seal all chemical containers after each use.
(e) Thoroughly wash your hands and face and rinse out your mouth after usingchemicals.
(f)

Do not eat or drink anything in the working place except in a designated place.

(g) Do not bring gloves or other contaminated protectors into the rest area.
(h) Forbid unauthorized entry to the place where chemicals are handled.
(i)

Wear appropriate protectors to avoid inhalation, eye or skin contact, and directcontact with your clothes.

(j)Provide local ventilation in the case of handling chemicals indoors.

(B) Storage precautions(a) Store the container in a dark, cold place. Avoid direct sunlight. Firmly seal toprevent direct contact with air.
(b) Use corrosion-resistant containers for storage.

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WARNING

Chemical agents used for chemical cleaning can be harmful to one’s
health. Wear protective goggles, protective gloves, and other safety
gear when handling chemicals. Make sure to check the details of its
material safety data sheet (SDS) beforehand.

!

WARNINGIf chemicals come in contact with your skin or clothes, immediately
wash the contacted area with a large volume of running water.

!

WARNINGIf chemicals splash into your eyes, immediately flush with large
volumes of running water and contact a doctor.

!

WARNINGStore chemicals in a dark, cold place free from direct sunlight.

!

WARNINGUse chemical storage tanks constructed of chemically compatible
materials to prevent corrosion.

!

WARNING

Never mix sodium hypochlorite with heavy metals or acids. The
resulting chemical reaction will generate toxic chlorine gas.

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6.

Chemical Cleaning Procedure(1) Element Chemical Cleaning Procedure
To begin the cleaning process slowly inject the chemical via the filtrate water nozzle into theelements until the cleaning solution flows through the membranes. Do not apply pressure inexcessive of 10 kPa (100 mbar) when injecting the cleaning chemicals. Some
recommended cleaning chemical injection methods are shown below.
a.

Chemical cleaning with the chemical tank located at the bottom (Fig.VIII-2)(i)

Confirm that the chemical injection valve is closed and that the chemical feedpump is in the off position.

(ii)

Using the chemical tank, mix the desired amount of chemical solution.

(iii)

Discontinue the filtration process and associated module aeration. Next close thefiltrate water valve.

(iv)

Start the chemical feed pump and check to make certain the pump is sufficiently
primed, and the chemical is being pumped to the elevated cleaning chemical
injection tank.

(v)

Slowly open the chemical injection valve to start injecting the chemical.

(vi)

After injecting the specified amount of chemicals to the elements, stop thechemical feed pump.

(vii) Allow the membrane elements to soak for 1 to 3 hours.
(viii) After soaking, close the chemical injection valve, open the filtrate valve, and start

the module aeration. Finally, resume normal filtration process.
*

When starting up the MBR after a chemical cleaning, some residual cleaningchemical may be present in the filtrated water for 2 or more filtration cycles. It
is recommended that the filtrate flow be directed back into the raw water tankuntil no residual cleaning chemical is detected. Before directing the filtrate fromthe raw water tank back to the normal filtrate discharge line, test the filtrate pH
and chlorine concentration.
Low water level ofmembrane tank

Vent
Chemicalinjection valve

1,000 mm (=10 kPa) or lessFiltrate water
valve

ModuleChemical tank

Fig.VIII-2

Chemicalfeed pumpChemical Cleaning with Chemical Tank Located at the Bottom

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Chemical cleaning with the chemical tank located above the membrane tank (Fig.VIII3)(i)

Confirm that the chemical injection valve is closed.

(ii)

Using the chemical tank, mix the desired amount of chemical solution.

(iii)

Discontinue the filtration process and associated module aeration. Next close
the filtrate valve.

(iv)

Slowly open the chemical injection valve to inject chemicals.

(v)

After injecting the chemical, soak the elements for 1 to 3 hours.

(vi)

Close the chemical injection valve, open the filtrate valve, and start the module
aeration. Finally resume the filtration process.

*

When starting up the MBR after a chemical cleaning, some residual cleaningchemical may be present in the filtrated water for 2 or more filtration cycles. It
is recommended that the filtrate flow be directed back into the raw water tankuntil no residual cleaning chemical is detected. Before directing the filtrate fromthe raw water tank back to the normal filtrate discharge line, test the filtrate pH
and chlorine concentration.
Chemical tank

Low water level ofMembrane Tank

Chemicalinjection valve

1,000 mm (=10 kPa) or less

Manifold
Filtrated water
valve

ModuleFig.VIII-3 Chemical Cleaning with Chemical Tank Locatedabove Membrane Tankc.

Chemical cleaning with the chemical feed pump and relief piping (Fig.VIII-4)(i)

Confirm that the chemical feed pump is in the off position, both the chemical
feed valve and the chemical injection valve are in the closed position. To makecertain that the filtrate line does not experience too high pressure, confirm thatthe relief piping is located at the height of 1 m or less from the surface of
membrane tank water level.

(ii)

Using the chemical tank, mix the desired amount of chemical solution.

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TORAY MBR(iii)

Stop the filtration process, stop module aeration, and finally close the filtrate
valve.

(iv)

Open the chemical feed valve and start the chemical feed pump.

(v)

Confirm that the outlet of the pressure relief pipe is free of obstructions and thatany cleaning solution being discharged is flowing freely back into the chemicaltank. If the flow from the relief pipe is excessive, make any necessary
adjustments to the chemical pump flow to reduce relief pipe discharge flow.

(vi)

Slowly open the chemical injection valve to start injecting the chemical.

(vii)

After injecting the specified amount of chemicals to the elements, close thechemical injection valve and stop the chemical feed pump.

(viii)

Allow the membrane elements to soak for 1 to 3 hours.

(ix)

After the soaking period close the chemical feed valve, open the filtrate valve,and start aeration. Finally resume the filtration process.

*

When starting up the MBR after a chemical cleaning, some residual cleaningchemical may be present in the filtrated water for 2 or more filtration cycles. It
is recommended that the filtrate flow be directed back into the raw water tankuntil no residual cleaning chemical is detected. Before directing the filtrate fromthe raw water tank back to the normal filtrate discharge line, test the filtrate pH
and chlorine concentration.
Low water level ofmembrane tank

1,000 mm (=10 kPa) or lessAir gap
Filtratewater valve

ModuleChemicalinjection valve
Chemical tankReliefpipingChemicalfeed valve
Chemicalfeed pump

Fig.VIII-4 Chemical Cleaning with the Chemical Feed Pump and Relief Piping!

!

WARNING

Do not attempt to inject chemicals, using a chemical feed pump,without installing a pressure relief pipe and associated air gap.
Excess internal element pressure will damage the membraneelement.

WARNING

If the flow from the relief pipe is excessive, make any necessary
adjustments to the chemical pump discharge flow to reduce relief
pipe discharge flow. Use the safety equipment such as goggles andgloves when inspecting discharge piping and making adjustments.

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TORAY MBR(2) Precautions for Element Chemical Cleaninga.

Keep the injecting pressure below 10 kPa (100 mbar). Avoid direct discharge fromthe chemical pump to the membrane elements. Too high pressure in the membraneelement will cause damage to the membrane. Chemical injection rate is affected bysuch as the membrane fouling status or the amount of chemical already injected. It isadvisable to maintain stable injection rate without entrained air.

b.

Make certain the module is completely submerged in the tank prior to injecting any
chemicals. The liquid level above the module should be maintained at 500 mm or
higher.

c.

Elevated chemical cleaning solution temperatures increase the membrane cleaning
effectiveness. However, make certain not to allow the cleaning solution temperatures
to exceed 40 deg C. Conversely, lower cleaning solution temperatures reduce theeffectiveness of the chemical cleaning process. Try to maintain the cleaning solution
temperature as high as possible under 40 deg C.

d.

When starting up the MBR after a chemical cleaning, some residual cleaning chemical
may be present in the filtrated water for 2 or more filtration cycles. It is recommended
that the filtrate flow be directed back into the raw water tank until no residual cleaningchemical is detected. Before directing the filtrate from the raw water tank back to thenormal filtrate discharge line, test the filtrate pH and chlorine concentration.

e.

If a sodium hypochlorite cleaning is immediately followed by acid cleaning orin reverse order, make certain that these chemicals never come in contact with
one another in the cleaning tank or piping. Mixing of the two chemicals will
generate toxic chlorine gas.

f.

If filtrate is used as makeup water for the cleaning solution, there exist the risk of theformation of insoluble calcium compounds when sodium hypochlorite is mixed withthe filtrate. If a high calcium concentration is expected in the makeup water, confirm
the generation of precipitation by performing a bench-scale sodium hypochlorite
addition test. If a whitish precipitate of calcium forms, it is recommended that tap water
be used for the makeup water supply instead of filtrate.

g.

As a result of contacting with hypo solution, some activated sludge nearby membranesurface can be destroyed, which leads to a foaming issue. This sludge damage will
be recovered in the course of time after operation restart and thus not a big trouble.

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TORAY MBR!

WARNING

Immediately stop the chemical cleaning operation if any of theassociated cleaning equipment appears to be malfunctioning.

!

WARNING

Never mix sodium hypochlorite with oxalic acid or citric acid. Suchmixture generates toxic chlorine gas.

!

WARNING

Do not inject any chemical into the membrane directly from thechemical pump discharge. Excessive membrane element internalpressure will damage the element. Be sure to inject chemicals at apressure less than 10 kPa (100 mbar).

!

WARNING

Before starting injecting chemical to elements, confirm that themembrane tank liquid level is more than 500 mm above the top of
the module.

!

CAUTION

To avoid scattering of chemical solution, turn off the air scour during
a chemical cleaning.

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TORAY MBR

7.

Lifting Procedure

Follow these procedures when lifting the “NHP210 Series” modules for maintenance. Lifting
up the module periodically to check its condition and performing maintenance work is effective
for proper operation of the MBR.
(1) If guide rail system is not installed in the membrane tank, drain the activated sludge frommembrane tank.
(2) Disconnect the manifold from the filtrate water line and disjoint the bolts jointing theelement block with the aeration block in case bolts/nuts are applied for connecting both
blocks.
(3) Hook the chain/sling attached with an element block to a hanger.
Connect the hanger which has four proper loading points at its corners and the element
block with chains or slings. Lift the element block with hanger. For safe lifting of theelement block, slowly raise the module straight up and avoid sudden changes inmovement to minimize shaking the module.
(4) Use guide rails certainly and do not connect both element blocks when lifting
double-decked module NHP210-600D. Also do not lift upper element block andlower element block all together. The upper/lower element block has to be lifted one
by one to avoid distortion or damage to the element block which may cause severe
accident. See the instruction below.

!

DANGER

Attach chains or slings to the lifting lugs when lifting element deck,
element block or aeration block of “NHP210 Series”. Slowly raise themodule straight up. Avoid sudden changes in movement to minimize
shaking the module. Never allow personnel to stand under the“NHP210 Series” during lifting!

DANGER

Never lift or operate the module with worn or damaged parts. Usechains or slings rated for the weight being lifted. Check the conditionof each part before lifting.

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8.

!

DANGER!

CAUTION!

CAUTION

Do not lift upper element block and lower element block at once as
one unit when lifting NHP210-600D. Lift the upper and lower
element block separately.
Wear the appropriate personal protective equipment (e.g. work
gloves) in order not to cut hand on the edge of the module frame.
Keep the membranes wet once they get wet. If the membranes areallowed to dry out, the permeability of the membranes may bepermanently reduced.

Storing Products after Use

Take the following steps to preserve and store used “NHP210 Series” modules.
(1) In case of module storage with sludge inside (without sludge drainage), stop
filtration and aeration should be stopped or intermittent e.g. five (5) minutes every
hour to agitate and supply minimal DO to the sludge.
Continuous aeration should not be applied from the viewpoint of membrane protection.
Also, open air discharge valve on filtrate piping during aeration to avoid the possible air
accumulation inside module and subsequent module damage.
(2) For long-term storage of used module (i.e. just for membrane preservation), takefollowing steps.
•

Drain the sludge in the membrane tank.

•

Using a water hose, wash off the sludge from the modules with clean water. In addition,
wash off any remaining sludge on the tank walls. Never use a pressure washer
machine on the membrane module and element.

•

Fill the membrane tank with clean water until the module is completely covered.
Periodically check the water level and add more water if needed to keep the module
covered with water. Open air discharge valve before pouring water and keep it open
during storage.

•

A periodic dosing of the membrane tank storage water to a < 50 ppm concentration of
sodium hypochlorite will help inhibit the growth of algae/microorganism during thestorage period. Maintaining a hypochlorite concentration higher than 50 ppm for along-time interval could cause damage to stainless steel components.

•

If aeration is required during long-term storage, the aeration cycle should be controlled
to aerate only five (5) minutes every hour.

(3) Before re-commissioning of the modules, it is strongly recommended conducting achemical cleaning of the modules to remove any biofilm growth that may havedeveloped on the membrane surface and piping during the storage period.
If used module (after washing off sludge) must be kept out of water, its duration should be
limited within 24 hours and periodic sprinkling of water on the modules (especially membrane
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surfaces) is needed. In that case, it is required to cover the module (especially top and sides)with a tarp or some other plastic sheet that will protect the module from dust, wind, and direct
sunlight.

9.

!

CAUTION

Never use a pressure washer machine when washing themembrane module and element which can cause fatal delaminationof membrane element edge.

!

CAUTION

Keep the membranes wet once they get wet. If the membranes areallowed to dry out, the permeability of the membranes may bepermanently reduced.

Disposing Procedure

Follow these general guidelines when disposing of the membrane after use.
(1) Clean the membrane module with clean water. After the module has been rinsed off allow
the surfaces to dry. Dry surfaces make handling and transport easier.
(2) Dispose of the module or module components according to local waste disposal
regulations. If required, disassemble the module and segregate its components
accordingly (e.g. combustible/incombustible).
(3) Do not incinerate the membrane unless appropriate facilities are available. During theincineration of the membrane materials, harmful Hydrogen Fluoride (HF) gas will be
generated. If the membranes are to be incinerated, it is recommended that a professional
waste disposal company be hired for the disposal.

!

!

WARNINGCAUTION

Do not burn the membranes without appropriate facilities sinceharmful Hydrogen fluoride (HF) gas will be generated. Hire a
professional solid waste disposal company to perform the task when
disposing of the membrane elements.
Hold the grip and do not hold the other portion of thecassette such as outer ribs when handling the cassette
for maintenance purpose.
grip

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REPLACEMENT PARTS LIST

Please contact Toray for the details of the specifications.
(1) NHP210-300S
Name
Filtrate Tube
Cassette or Element Block

Frequency

Type No. of replacement parts

When deterioration
NHP-TUBE-200 (200pcs set)detected.
When filtrate flow or
ECS035 (Cassette)quality cannot be
restored after chemical or ECS210-300S (Element Block)cleaning.

(2) NHP210-600D
Name
Filtrate Tube
Cassette or Element Block

Frequency

Type No. of replacement parts

When deterioration
NHP-TUBE-200 (200pcs set)detected.
When filtrate flow or
ECS035 (Cassette)quality cannot be
restored after chemical or ECS210-300S (Element Block)cleaning.

Instruction Manual

Required Quantity per Module
NHP210-300S(300 pcs/unit)
ECS035 x 6or ECS210-300S x 1

Required Quantity per Module
NHP210-600D(600 pcs/unit)
ECS035 x 12
or ECS210-300S x 2

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TORAY MBRX.

TROUBLESHOOTING

Most of the troubles in the operation of “NHP210 Series” are related to poor membranescouring aeration, chemical cleaning delay, and inappropriate pretreatment. The following
table lists some performance losses, their causes, and possible countermeasures.
Table X-1 Troubleshooting
Problem
1

2

3

The air diffusion flow is below
the required level.
The air diffusion is uneven in
the module or between
modules.

The filtrate water flow rate has
decreased, or the transmembrane pressure has
increased.

Cause
The blower is broken.

Stop the filtration and inspect the blower.

The air diffusers are
clogged.
The air diffusers are
clogged.
The bottom of the element
block is stuck with debris.

Clean the air diffusers.

Membrane clogging has
got severe.
Sludge is accumulated on
the membrane surface
because of uneven air
diffusion
Abnormal properties ofsludge have worsened its
filterability.

Air is accumulated inside
filtrate piping.
4

The concentration ofsuspended solids in the filtratewater has increased.

Element and/or tube has
been broken.
Leakage has occurred in
the filtrate water piping.
Germs are generated on
the membrane or the filtrate
line.

*1:
*2:

ActionClean the air diffusers.
Check the pretreatment system.
Inspect the module.
Correct operation and maintenance worksof the pretreatment system.
Conduct chemical cleaning.
Inspect the blower and clean the air
diffusers to improve air diffusion.
Conduct chemical cleaning.
Remove sludge cake by externalcleaning.
Improve sludge properties.
・ Adjust the excess sludge dischargerate.
・ Prevent entry of abnormalcomponents, such as oils.
・ Adjust the BOD load and oxygen
supply.
・ Adjust the raw water quality (addnitrogen, phosphorous, etc.)
Prime the filtrate piping with water.
Install air removal equipment such as
vacuum pump.
Relocate filtrate piping.
Seal the element and manifold nozzle*1.
Replace the cassette.
Inspect the faulty part*2 and correct thefault.
To clean the filtrated water piping, inject a
sodium hypochlorite solution with aneffective chlorine concentration of 100 to
200 mg/L.

Even if a cause is found in the tube, there is still the possibility of contamination inside the element. Thus, seal
the element and manifold nozzle.
To check the piping joints and welds for leakage with a pressure being applied, be careful not to apply pressure
to the membrane modules.

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WARRANTY CLAIMSMBR modules that are damaged due to improper loading, shipping, handling, or storing shallnot be covered by Toray Industries, Inc.’s warranty. Therefore, it is very important that thecustomer firmly follows instructions of loading, shipping, handling, and storing of the MBR
modules mentioned in this Instruction Manual.
MBR modules which are in their original package can be stored for 12 months from the datethey were shipped from Toray’s factory or warehouse. If they are stored for longer than 12
months, the warranty will become void unless otherwise Toray Industries, Inc. agrees.

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WARRANTY POLICY

Full and proper compliance with this Instruction Manual is a mandatory required thing for theclaims under the warranty. In case of making a warranty claim, the customer automaticallyagrees to provide Toray with the information about operation mode, recording performancedata of MBR systems.
Please kindly contact Toray if the customer wishes to deviate from any of the procedures or
specifications mentioned in this Instruction Manual and request written approval in advance.
Otherwise, the customer has risk of invalidation for any warranty claims that they may make inthe future.

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XIII.

REFERENCE

Following information is provided upon your request:(1) Assembly of Modules(2) Assembly of Guide Rail System(3) Assembly of Hangers.
(4) Procedure of Paper filter test.

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Toray specializes in the development and manufactureof innovative membrane technologies. We offer an
integrated approach using our RO, NF, UF, MBR, andantiscalant products to solve water and process treatment
challenges. Contact us today to find out how Toray canhelp maximize water recovery, achieve high water quality
for water reuse, lower energy requirements, and minimize
life cycle costs. TORAY, experts in RO, NF, UF and MBR.

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