Ground Water Applications of Membra nes Ma rch 30, 2011
Presented by: Bill Legge, P.Eng. GE Wa ter & Process Technologies ZENON Membra ne Solutions
...
Ground Water Applications of Membra nes Ma rch 30, 2011
Presented by: Bill Legge, P.Eng. GE Wa ter & Process Technologies ZENON Membra ne Solutions
Outline • • • • •
Overview Common a pplica tions Trea tment requirements Process design Ca se studies
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Membra ne Ba sics
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How do membranes work? Wat er molecules and dissolved salt s pass freely t hrough t he membrane pores
Semi permeable membrane wall wit h microscopic pores
Cont aminant s such as bact eria and viruses can not pass t hrough t he membrane’s pores
Types of Membranes High Pressure
Low Pressure MF & UF Removes:
NF & RO Removes:
Turbidity
Turbidity
Viruses
Inorga nics
Ba cteria
Virus
Protozoa
Ba cteria
• Orga nics
Protozoa Orga nics Smallest Pore Size
Microfiltration (MF)
Ultrafiltration (UF)
Legend
Nanofiltration (NF)
Removal
• Partial Removal
Reverse Osmosis (RO)
Turbidity and Microorganism Removal Nomina l pore size = 0.02 - 0.04 µm Absolute pore size = 0.10 µm Non-specific remova l of: turbidity, ba cteria , viruses by size exclusion
Cryptosporidium Parvum (4-7 µm)
Giardia Lamblia (6-16 µm)
GE Ultrafiltration Membranes 500 Series
Reinforced immersed Challenging raw water quality MBR
1000 Series
1500 Series
Unsupport ed pressurized Unsupport ed immersed Ideal for small scale Ideal for large scale potable, tertiary, and potable, tertiary, desalination pre-treatment desalination preapplications treatment , and media Ideal for industrial process filter retro-fit water, make-up and reuse applications
ZeeWeed ® 1000 – Building Block Design
Membrane Casset t es a re inserted into concrete ta nks to form a Membrane Train Membrane Modules are inserted into frames to form a Membrane Casset t e
Typica l Immersed Configura tion Pla n View
Air Compressors Blowers
5 (6) tra ins 6 x 60 module ca ssettes 16 (20) MGD
Membra ne Ta nks
CIP Pumps
Future Tra in
Air Compressors a nd Air Dryer
Process Pumps Process Pumps
Clea ning Chemica ls
Overall dimensions: ~ 45’ x 155‘
CIP Ta nk Ba ckpulse Ta nk
Immersed Operating Modes PERMEATION MODE • Water passes through the membrane • Particles larger than the pore size of membrane are rejected • Particles accumulate in the tank BACKWASH MODE Performed when recovery reaches setpoint to remove solids from tank • Reverse flow of treated water or ‘backpulse’ • Aeration • Drain the tank and refill
Permeation and Backwashing Ba ckwa sh < 5 minutes
• permea te down • a ir scour
Permea tion ~30-90 minutes
• ba ckpulse • ta nk dra in • refill
Ra w Wa ter
Trea ted Wa ter
Applica tions in Groundwa ter Trea tment
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Common Membra ne Applica tions • Iron a nd ma nga nese remova l • Arsenic remova l • Pre-trea tment to NF/RO
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Membra nes for Iron & Ma nga nese Remova l
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Why remove iron & ma nga nese Iron: produces undesira ble colour & ta ste sta ins la undry a nd plumbing reddish brown promotes growth of iron ba cteria Ma nga nese: produces undesira ble colour & ta ste sta ins la undry a nd plumbing bla ck lea ds to a ccumula tion of microbia l growths 15 / GE Title or job number / 5/24/2011
How much iron & ma nga nese to remove • In most jurisdictions, the following a esthetic objectives a pply for drinking wa ter • Iron ≤ 0.3 mg/L • Ma nga nese ≤ 0.05 mg/L
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Chemistry of Oxida tion • Under reducing conditions such a s GW, both Iron a nd Ma nga nese ca n be present in dissolved form • Dissolved iron a nd ma nga nese ca nnot be removed by a UF/MF membra ne a s they a re sma ller tha n the pore size of the membra ne • Addition of oxida nt converts dissolved Iron a nd Mn into precipita tes which ca n be removed by UF/MF membra nes Fe (II) (soluble) Fe(OH)3 (Insoluble) Mn (II) (soluble) MnO2 (Insoluble)
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Chemistry of Oxida tion • Iron is rela tively ea sier to oxidize a nd ca n be oxidized by a era tion under most circumsta nces • Ma nga nese is more difficult to oxidize a nd requires a stronger oxidizing a gent such a s pota ssium perma nga na te. • Oxida tion efficiency improves with increa se in pH • Wa ters with low pH ma y require some ba se a ddition
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Oxida tion + membra ne filtra tion pH Adjustment (optional)
Oxidant Flash Mixer
Permeate Pump
Feed
Air Contact Chamber (optional)
UF/ MF Membrane
Reject Air
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Ca se Study: Seekonk, MA
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Seekonk, MA – Trea tment objectives Parameters Turbidity
