Welcome to the AECOM Water Webinar Series Membrane Bioreactors for Wastewater Treatment Please stay tuned. We will begin shortly
Welcome to the AECOM Water Webinar Series •
“Membrane Bioreactors for Wastewater Treatment” will be delivered by Nick Cooper
•
Duration 1 hour with Q&A
•
We hope you find todays session informative and that it contributes to your knowledge and skills. Our goal is that after today’s session you should be able to begin planning an appropriate sequence of asset management activities designed to ensure long range infrastructure sustainability in the most cost effective manner possible.
•
Your questions are important. The protocol for asking questions during the webinar is that the instructor will stop to ask for questions but you can also enter questions electronically in the “chat” or “Q&A” box usually located in the lower right corner of the screen.
To receive accreditation:
record your attendance complete the learning assessment (Quiz) obtain a score of 80% or higher complete the course evaluation form
REMEMBER: Be careful of spelling when you register, as the text typed is what is used on certificates. REMEMBER: All certificates will be distributed electronically. Please watch for the e-mail in your inbox and junk mail. You must retain this information for your records.
This event has been evaluated and approved by AECOM under the following continuing education Authorized Provider Certifications. Continuing Education Credit for this course is as follows: per IACET (International) you have earned 0.1 CEU per PIE (NY state) you have earned 1 PDH per FBPE (FL state) you have earned 1 PDH Thank You Please note: AECOM holds the copyright for this presentation, 2013.
Membranes in Your Future? Membrane Bioreactors: Process and Design Nick Cooper Vice President, AECOM Water
February 2014
Presentation 1. Terminology 2. Membrane Concepts 3. Membrane Process Configurations 4. Satellite Treatment 5. Membrane Suppliers 6. How Large MBRs? 7. MBR Plant Layouts 8. Immersed Membrane Technologies 9. Design Considerations 10. Design and Operational issues 11. Design Parameters 12. Future Trends
Nick Cooper
[email protected] Vice President, Wastewater Technical Practice Leader Project Manager – Wastewater Treatment, Biosolids, Water Reuse 35 years - Treatment Plant Planning and Design Experience – USA, Canada, Middle East, UK, Southeast Asia, South America Contributing Author and Editor: Metcalf & Eddy - Water Reuse MOP 32 – Energy Conservation MOP 34 – Membrane Bioreactors Metcalf & Eddy - Wastewater Engineering, 5th Edition
Reference Projects – Nick Cooper Forsyth County WRF, Atlanta, Georgia – 10 MLD (Hollow Fiber) Johns Creek Environmental Campus, Roswell, GA – 60 MLD (Hollow Fiber) Al Ansab STP, Muscat, Oman – Phase 1 – 55 MLD (Flat sheet) Al Ansab STP, Muscat, Oman – Phase 2 – 125 MLD (Flat sheet) Advisor: Evan Thomas STP, Calgary, Alberta – 10 MLD (Hollow Fiber) Davie STP, Broward County, FL – 15 MLD (Flat sheet) Woodward Avenue, Hamilton, ON – 500 MLD (Hollow Fiber) Shek Wu Hui STP, Hong Kong – 190 MLD 8
References
On-line Resource: The MBR Site www.thembrsite.com Simon Judd, Cranfield University 9
Terminology
Terminology Cross-Flow Membranes
Maintenance Cleaning
Ultrafiltration
Recovery Cleaning
Microfiltration
Fine Screening
Hollow Fiber Membranes
Peak Daily Flow (PDF)
Flat Plate Membranes
Average Daily Flow (ADF)
Flux Rate
Peak Hour Flow (PHF)
Permeability
Submerged Membrane Unit (SMU)
Clean-in-Place Cassette Scour Air 11
Membrane Concepts
Membrane Bioreactors • A membrane bioreactor is not a biological process. It is a process configuration that allows conventional processes to work more efficiently and in a smaller footprint. • A MBR membrane is a high class filter • Microfiltration and ultrafiltration membranes restrict the movement of solids and bacteria across the membrane. • MF and UF do not remove soluble material.
13
Filtration Spectrum
0.001μ
0.1μ
0.01μ
1.0μ
10μ
100μ
Aqueous Salt
Bacteria
Virus
Metal Ion
Colloidal Silica
REVERSE OSMOSIS
PARTICLE FILTRATION
ULTRAFILTRATION
NANOFILTRATION
MICROFILTRATION
14
1000μ
Membrane Bioreactor – Immersed Membranes
15
Immersed Membranes
Membrane
TSS = 15,000 mg/L TSS = 0 mg/L Air
Solids
Treated effluent Air
Virus
TN = 15 mg/L
Air
TP = 5 Air mg/L
Air
Bacteria BOD5 = 10 mg/L
Air
16
Cross-flow Membranes
• Extracts Reuse quality water • Thickens Sludge to 5+ percent • Reduced air requirements • Package Systems
Cross-Flow Membranes
Reactor
Permeate
Cross-flow Membranes Permeate Mixed Liquor from Reactor Basin
Concentrated Mixed Liquor Return to Reactor Permeate
• Ultrafiltration Membranes • Hollow Tubes • Low Pressure • Self-scouring • Robust and Long lasting
Membrane Bioreactor •
Compact System
•
No Clarifiers or Filters
•
High Mixed Liquor Concentrations Possible
•
No TSS or bacteria in effluent
•
Limits passage of viruses
•
Small Footprint (0.3 ha/10 MLD)
•
Highly automated
•
Requires close monitoring
19
Membrane Bioreactor - Benefits When do you consider MBR:
• • • •
Small sites Near residential areas High quality treatment (low phosphorus, virus control) Satellite Plants
Benefits of MBR:
• • • • • • • •
Can be totally enclosed Simple Common Wall Construction Excellent for fast-track implementation Modular system Fully automated Low operator attention to physical systems Creates its own hydraulics – fits any site Waste sludge has high concentration, reducing sludge storage
Membrane Bioreactors - Caution Caution in considering MBR
•
High level pre-treatment needed
•
Can be impacted by industrial wastewater
•
High energy requirements
•
High chemical requirements
•
Maintenance Cleaning – weekly or monthly
•
Recovery cleaning – 2 – 6 times annually
•
Membrane replacement costs every 7 to 10 years
•
Need for relief pond or tank
•
Supplemental screening is desired and probably needed
•
Oil and grease must be limited to 150 mg/L or less
Membrane Process Configurations
Process Flow Diagram – Conventional Activated Sludge with Tertiary Treatment Grit/Grease Removal
Screening
Screenings
Primary Settling
Biological Treatment
Secondary Settling
Grease
Grit Primary Sludge
Influent Pumping
Return Activated Sludge
Secondary Sludge
23
Filtration
Disinfection
Process Flow Diagram – Hollow Fiber MBR
Grit/Grease Removal
Screening
Screening s
Aeration Tank
Ultraviolet Disinfection
Grease
TSE
Grit
Influent Pumping
Hollow Fiber Membrane Bioreactor
Return Sludge
24
Process Flow Diagram – Flat Sheet MBR
Screening
Grit/Grease Removal
Aeration Tank
Grease
Screenings
Flat Plate Membrane Bioreactor
Ultraviolet Disinfection
TSE
Grit Return Sludge
Influent Pumping
25
Process Flow Diagram – External Cross-Flow MBR
Grit/Grease Removal
Screening
Screenings
Aeration Tank
Grease
Cross-Flow Membranes
Ultraviolet Disinfection
TSE
Grit Return Sludge
Influent Pumping
26
Example MBR Treatment Plants
Treatment in small spaces
20 MLD Membrane Bioreactor STP
60 MLD Membrane Bioreactor STP
10 MLD Membrane Bioreactor STP
28
Crescent STP (FilmTec CrossFlow Membranes)
Palm Water STP (Kubota Flat Sheet)
Palm Jumeirah
21 MLD Palm Jumeirah WRF
Below-ground MBR
Palm Water STP - 18 MLD (Kubota Flat Sheet Membranes)
Palm Water STP (Kubota Flat Sheet)
Anoxic Tanks
EQTanks
Anoxic Tanks
32
Cassette Tanks
Palm Water STP (Kubota Flat Sheet)
Aeration Tanks
Aeration Tanks
Aeration Tanks
33
Aeration and Anoxic Tanks
Permeate Room
34
Crescent STP - 15 MLD (FilmTec Cross-Flow Membranes)
Crescent STP (Cross-Flow Membranes)
Piping Gallery
Mixed Liquor Feed Pumps
Mixed Liquor Feed Pumps
36
Piping Gallery
Crescent STP (Cross-Flow Membranes)
CIP Booster Pumps
Permeate Pumps
CIP Piping
FilmTec Cross Flow Membranes
Crescent STP (Cross-Flow Membranes)
30 Membranes per skid 20 skids at 750 m3/d
Permeate Pipe (75 mm)
Return Pipe (200 mm)
39
Satellite Treatment: Sewer mining, Scalping plants
Satellite Treatment for Reuse Package Treatment Building
Existing Park Maintenance Building
Extraction Pump Station
Reclaimed Water Distribution
Return Flow to Sewer
System used for the treatment and reclamation of wastewater located close to the point of reuse Solids discharged back to a centralized collection system
Membrane Suppliers
Membrane Suppliers 1 Membrane
Type
Membrane
Type
GE ZeeWeed D500
Hollow Fiber
Econity – CF Series
Hollow Fiber
Leap MBR – GE Water
Hollow Fiber
Econity - Ecologix
Flat Sheet
Pentair X-Flow
Multi-tube
Evac MBR
Flat Sheet
Kubota RW-400
Flat Sheet
Tianjin Motimo
Flat Sheet
Kubota MicroBlox
Flat Sheet - blocks
Shanghai MegaVision
Flat Sheet
Xylem A-Series
Tubular
Gemini Hainan Litree
Hollow Fiber
MicroDyn-NADIR
Flat Sheet
LG – Green MBR
Flat Sheet
Huber BioMem
Flat Sheet
Hina MBR
Hollow Fiber
Alfa Laval
Flat Sheet
Berghof HyperFlux
Multi-tube
Likuid CBR
Multi-tube Ceramic
Hangzhou H Filtration
Hollow Fiber
Beijing Origin MBRU
Hollow Fiber
Toray - Membray
Flat Sheet
FLI Water - Membright
Flat Sheet
Memos – MEMCROSS
Multitube
Siemens Mempulse
Hollow Fiber
Microclear – newterra
Flat Sheet
1 The MBR Site, S. Judd 2014
43
Membrane Suppliers 1 Membrane
Type
Membrane
Type
Micronet
Hollow Fiber
MMM MaxFlow
Flat Sheet
Asahi Kasei Microsa
Hollow Fiber
Zena Membranes
Hollow Fiber
China Lantian PEIER
Flat Sheet
Econity PF 90M
Hollow Fiber
Hyflux PetFlex
Flat Sheet
Koch Puron
Hollow Fiber
Philosep Philos
Hollow Fiber
Canpure - Saveyor
Hollow Fiber
Sumitomo Poreflon
Hollow Fiber
Senuo Senufil
Hollow Fiber
HyFlux PoroCep
Hollow Fiber
Liqtech SIC Ceramic
Ceramic Flat Sheet
Anua PuraM
Flat Sheet
Shanghai SINAP
Flat Sheet
Huber SmartMBR
Flat Sheet
Mitsubushi Rayon Sterapore
Hollow Fiber
Colloid SubSnake
Flat Sheet
ENE SuperMAK
Hollow Fiber
Superstring SuperUF
Hollow Fiber
Suzhou VINAP
Flat Sheet
Huber VRM
Flat Sheet
Dynatec
Multitube
1 The MBR Site, S. Judd 2014
44
How Large Can you go with MBRs?
Largest MBR Facilities – Worldwide1 Installation
Location
Technology Provider
Commissioned
PDF (MLD)
ADF (MLD)
Seine Aval
Acheres, France
GEWPT
2016
357
224
Canton WWTP
Ohio, USA
Ovivo USA
Likely 2015-2017
333
159
Shek Wu Hui
Hong Kong
?
2016
250+
190
Macau
China
GEWPT
2014
189
137
Riverside
California, USA
GEWPT
2014
186
124
Al Ansab
Muscat, Oman
Kubota
2016
175
125
Brightwater
Washington, USA
GEWPT
2011
175
122
Visalia
California, USA
GEWPT
2014
171
85
Qinghe
China
OW/MRC
2011
150
150
North Las Vegas
Nevada, USA
GEWPT
2011
136
97
Ballenger McKinney WWTP
Maryland, USA
GEWPT
2013
135
58
Cox Creek WRF
Maryland, USA
GEWPT
2015
116
58
Yellow River
Georgia, USA
GEWPT
2011
114
71
Shiyan Shendinghe
China
OW/MRC
2009
110
110
Aquaviva
Cannes, France
GEWPT
2013
108
60
Busan City
Korea
GEWPT
2012
102
102
Guangzhou
China
Memstar
2010
100
Wenyuhe
Beijing, China
OW/Asahi Kasei
2007
100
1 The MBR Site, S. Judd 2014
PDF: Peak daily flow ADF: Average daily flow, Megalitres per day GEWPT: GE Water and Process Technologies OW: (Beijing) Origin Water MRC: Mitsubishi Rayon Corporation
100
Largest MBR Facilities – Worldwide (Cont’d) Installation
Location
Technology Provider
Commissioned
PDF (MLD)
ADF (MLD)
Johns Creek
Georgia, USA
GEWPT
2009
96
42
Changi
Singapore
GEWPT
2014
92
61
Awaza/Polimeks
Turkmenistan
GEWPT
2011
89
71
Songsan Green City
Korea
Econity
Planned 2015
84
Beixiaohe
China
Siemens
2008
78
-
Al Ansab
Muscat, Oman
Kubota
2010
77
55
Cleveland Bay
Australia
GEWPT
2007
77
29
Broad Run WRF
Virginia USA
GEWPT
2008
73
38
Gongchon
Korea
Econity
2012
65
65
Lusail STP
Doha, Qatar
GEWPT / Degrémont
2013
62
58
La Moree
France
GEWPT
2013
Gaoyang
China
United Envirotech
Expected 2014
60
Cairns North
Australia
GEWPT
2009
59
19
Cairns South
Australia
GEWPT
2009
59
19
Peoria
Arizona, USA
GEWPT
2008
58
38
Aquapolo
Sao Paulo, Brazil
Koch Membrane Systems
June 2013
56
56
Sabadell
Spain
Kubota
2009
55
Jordan Basin WRF
Utah, USA
GEWPT
2010 47
61
54
Membrane Plant Layouts and Configurations
Fowler Water Reclamation Facility – 10 MLD
49
Fowler Water Reclamation Facility – 10 MLD
55 m
10 MLD Process Train
57 m
Al Ansab STP, Muscat, Oman – 55 MLD
Operations Building
Aeration Basin
51
Membranes Basin
Permeate Gallery
Al Ansab STP Muscat, Oman
New Reuse Storage Tanks New Aerated Grit/ Grease Removal New Pre-aeration Tank
New Aeration Tanks
New Membrane Tanks
Expansion from 55 MLD to 125 MLD
Al Ansab STP, Muscat, Oman – 55 MLD
25 m
50 m
155 m
Expansion to 125,000 m3/d)
Johns Creek Environmental Campus, Georgia USA
Johns Creek Environmental Campus (60 MLD)
55
Membrane Bioreactors: Immersed Membrane Technologies
Hollow Fiber Technology Hollow Fiber •
Ultrafiltration membrane 0.04 – 0.07 µ
•
Trans-membrane pressure range 0.14 – 0.55 bar (2 – 8 psi)
•
Suction permeate extraction
•
Backpulsing required
•
External cleaning/in-tank or separate
•
Return flows to process pumped from membrane tanks
57
Membrane Technology - Hollow Fiber GE Zenon ZeeWeed 500- vertically strung membrane fibers, water is filtered by applying a slight vacuum to the end of each fiber which draws the water vertically up through the membranes.
LeapMBR
Koch Puron PSH-500- vertically strung membrane fibers, Water is filtered by applying a vacuum through the fibers.
Flat Sheet Technology Flat Sheet •
Microfiltration membrane 0.4 – 0.7 µ
•
Low trans-membrane pressure 0.02 – 0.04 bar (0.3 – 0.6 psi)
•
Higher flux rates
•
Gravity filtering – no pumps
•
Internal chemical cleaning
•
Forward flow pumping, gravity return flow
59
Membrane Technology - Kubota SP 400
RW 400
EK 400 •
400 panels with tube permeate piping
•
400 panels with tube permeate piping
•
Cartridges in stacked configuration, no tubing
•
Single or double stack
•
Single or double stack
•
Multiple stacks of cartridges or blocks
•
340 m2 area per SMU
•
580 m2 area per SMU •
400 m2 area per SMU
60
Design Considerations
Energy Management – In-Tank Equalization
EQ in Aerobic Tank – Flat plate MBR
EQ in Aerobic Tank – Hollow Fiber MBR
Energy Management – In-Tank Equalization Determining Flow Equalization •
Use Stage Storage Formula
•
Calculate volume for each hour based on the diurnal curve
•
Plot cumulative volume and then determine optimum treatment rate
•
Volume is distance between the target treatment rate and the highest cumulative volume
•
Rough rule of thumb: Dampening peak flows Target PF through plant
EQ Volume, as % of plant capacity
2.0
7 – 8%
1.5
12 – 13%
1.0
20 – 22%
Stage Storage Evaluation
Energy Management Option 1 – Recirculation Pumps in each tank
Flow Distribution Channel - Aerated
Membrane Tanks
Aeration Basins
Recirculation Pumps 64
Energy Management Option 2 – Recirculation Channel Flow Distribution Channel - Aerated
Advantages
Membrane Tanks
Recirculation Channel
•
Creates a deoxygenation and Anoxic zone
•
Centralized Recirculation, WAS and Foam Wasting Pumps
•
Reduced number of pumps, piping
Aeration Basins
Recirculation and Foam Wasting Pumps 65
Return Sludge Channel
Return Sludge Channel
Brescia STP (Italy) Return Sludge Channel
Jurong STP (Singapore) Return Sludge Channel
66
Design and Operation Issues
MBR Design and Operation Issues – Membrane Cleaning
Maintenance Cleaning Hollow fiber •
Weekly
•
Backpulse through membranes – inside to out
•
Maintain Tank in Service
Flat Sheet •
No Maintenance Cleaning
Recovery Cleaning Hollow Fiber
Flat Sheet
•
In situ or in dip tank
•
In situ or in dip tank
•
Drain entire tank with multiple membranes
•
Gravity feed chemicals through membranes – inside to out
•
Backpulse through membranes – inside to out
•
•
Fill tank with plant effluent and chemical (1000 ppm chlorine or 500 ppm citric acid
Individual banks of SMUs can be cleaned without draining the tank
•
Feed dose 6,000 ppm chlorine or 10,000 ppm citric acid
•
Air scour for cleaning
•
No air scour during cleaning
•
Soak for 6 – 8 hours
•
•
Dispose chemicals and return to service
Maintain chemicals in SMU for 1 hours
•
Return to service and permeate chemicals
MBR Design and Operation Issues - Screening
Fine Screening •
All solids getting through the screening will eventually end up on the filters
•
Maximum 2 mm Perforation Required. 1 mm much better.
•
Supplemental screening often needed. Side stream screening or secondary fine screens at entrance to biological process tanks
Side Stream Screening
10 MLD Process Train
Side Stream Screening
Side Stream Screening Side Stream Screens
Aeration Basin 1
Aeration Basin 2
Aeration Basin 3 Mixed Liquor Return Channel Aeration Basin 4
Side Stream Pumps From Pretreatment
Fixed Screen
Fixed screen panel 0.5 – 2.0 mm
Mixed liquor From biological tanks
Reference: Cote, Brink, et Adnan. Pretreatment Requirements for Membrane Bioreactors WEFTEC 2006 73
MBR Design and Operation Issues Oil and Grease •
Limit or prevent Oil and Grease entry into plant that would increase influent O&G above 150 mg/L
•
Aerated grit/grease tank with good skimming required. Target should be 50 mg/L O&G at the biological process.
•
Cleaning with oxalic acid periodically to limit staining of membranes.
Foam Isolation and Removal Foam launder
Benefits Foam Well
• Foam Isolated for removal from each tank • Dedicated Foam Wells
Foam Well
• Improved Plant hydraulics
MBR Design and Operation Issues Foam Accumulation •
With no effluent weirs, need positive foam removal system
•
Full length launder on aeration tanks and other tanks that can trap foam, direct it to a foam pump station
Foam launder, above normal water level
Foam launder, raised water level
12 minutes minute minutes 3169minutes minutes
MBR Design and Operation Issues Air Requirements and Energy Management •
Air scour one of the largest power uses at an MBR plant
•
Need adequate scour to prevent “sludging” – accumulation of thickened mixed liquor against the membrane
•
Scour requirements greater with higher MLSS
•
Savings only marginal and only if MLSS is between 8,000 and 12,000 mg/L in cassette tank
MBR Design and Operation Issues Mixed Liquor Maintenance •
Minimum MLSS for membranes operation is 7,000 mg/L.
•
Optimum range for hollow fiber membranes is 8,000 – 9,000 mg/L MLSS in aeration basins; Maintain MLSS below 11,000 mg/L in cassette tanks
•
Optimum range for flat plate membranes is 9,000 – 12,000 mg/L MLSS in aeration basins; maintain MLSS below 14,000 mg/L in cassette tanks.
•
If MLSS exceeds these levels, system could be subject to sludging. If membranes become filled with sludge, plant capacity will drop dramatically.
•
After sludging, cassettes must be removed from the tank and manually cleaned. Plant could be at reduced capacity for many days.
MBR Design and Operation Issues Mixed Liquor Maintenance (Cont’d) •
Increase recycle to maintain MLSS in optimum range. Supplement with greater air scour at top end of that range.
•
Monitor MLSS daily in each cassette tank. Increase wasting if MLSS increases by more than 1000 mg/L in 7 days.
•
Monitor trans-membrane pressure continuously. Increase sludge wasting if TMP increases by more than 0.1 bar for hollow fiber; 0.25 bar for flat plate.
MBR Design and Operation Issues Sludge Management •
Sludge management design for an MBR is different than for conventional activated sludge process.
•
The danger of excessive MLSS in cassette basins requires rapid response to high MLSS.
•
Minimum sludge management capacity (storage, thickening and dewatering) is 7 days to reduce MLSS in cassette tanks by 1000 mg/L.
•
That may be 2 – 3 times the peak month sludge generation, and excess capacity should be available at all times for this condition.
•
Digesters may have to be bypassed to manage higher sludge processing volume.
MBR Design and Operation Issues Membrane Cleaning •
Membrane cleaning is vital to maintaining membrane value for as long as possible.
•
Cleaning should follow frequency in manufacturer’s requirements, if Fats, Oil and Grease concentration is below 150 mg/L.
•
For greater concentrations of FOG, membranes must be cleaned more frequently, with oxalic acid.
•
Debris should be removed from membranes as soon as it is detected. Membranes should be inspected annually.
•
With normal wear and wastewater conditions, membranes can last up to 10 years. The value of adequate cleaning is extending the life of a membrane by one year or more.
•
Full replacement of membranes is the most expensive OPEX cost in a MBR plant. can cost more than $1.5 million per 10 MLD capacity.
MBR Design and Operation Issues Membrane Replacement •
Membranes are the largest component of Opex, and must be treated as delicate filters.
•
A replacement cost contract should be negotiated that provides a warranty replacement at no cost for the first 3 years
•
A maintenance contract can lock in cassette replacement costs for 20year period at a lower cost than replacing all cassettes at a fixed time period.
Membrane Bioreactor Design Parameters
Typical Design Parameters and Features – Immersed Membranes •
Flow Equalization volume – in-tank to reduce peak hour flows to match peak filtration rate
•
Multiple membrane tanks – Membranes must be capable of handling peak flows with one tank out of service for maintenance or cleaning
•
Aeration requirements for organics and nitrification. Do not accept credit for scour air. Scour air must be added to aeration requirements Parameter
Hollow Fiber
Flat Sheet
Mixed Liquor Concentration in aerobic reactors
8,000 – 10,000 mg/L
9,000 – 12,000 mg/L
Filtration Capacity, average
0.4 m3/m2/day
0.61 m3/m2/day
Filtration capacity, peak hour
0.9 m3/m2/day
1.3 m3/m2/day
Membrane scour requirements
75 – 100 cfm per cassette (2.1 – 2.8 m3/min)
100 cfm per cassette (2.8 m3/min)
Periodic Backpulse
Pumped through membranes minimum every 10 minutes
Relax only, no backpulse pumping
Storage
In glycerine filled bags or submerged in-tank
Stored dry panels
Sizing a Membrane Bioreactor System
•
Determine the plant process configuration and biological process first
•
Note that mixed liquor recycling is critical to maintaining flow across the membrane modules, to prevent sludging. That will define mixed liquor recycle rates, and works well with denitrification schemes
•
Determine level of equalization required based on diurnal flow ranges
•
Determine the optimum range of flux rates
•
Determine the numbers of cassettes (SMUs) required to handle peak future equalized flow
•
Set maximum allowable mixed liquor concentrations and tank volumes
•
Determine the number of membrane tanks required, considering one tank out of service for recovery cleaning or maintenance.
•
Coordinate with vendors and require guarantees on flux rates, chemical consumption and air requirements.
•
Performance guarantees for process performance should be limited to the membrane performance and control systems only. Effluent water quality is defined by the reactors, not the membranes. 86
Future Trends
Future Trends in Membrane Bioreactor Systems Submersible Ceramic Membranes •
High permeability (3.0 m3/m2/hr at 0.04µ pores)
•
Rugged membrane material – silicon carbide
•
Less pretreatment required
•
High solids tolerance
•
Reduced potential for fouling
•
Chemically Inert
•
Cleaning by backwashing
Limitations •
High cost of membranes
•
High pressure requirements
Ref: LiqTech International 88
Future Trends in Membrane Bioreactor Systems Anaerobic Membrane Bioreactor •
Anaerobic conditions treat high strength wastewater
•
No air for scouring
•
Extracts water from septic waste or other anaerobic wastes
Limitations Daniel Yeh, University of South Florida
•
Small scale currently
Anaerobic Cross-Flow MBR 89
Thank you
Nick Cooper
[email protected]
