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PURO: reverse osmosis in a well

Department of Water ManagementSection Sanitary engineering

Bas Heijman

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Content

• Introduction reverse osmosis• Brackish water: sustainable source for drinking

water• Energy aspect of reverse osmosis• Is infiltration of concentrate sustainable?• Conclusions

• Other research into sustainable drinking water production

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Introduction reverse osmosis

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Content

• Introduction reverse osmosis• Brackish water: sustainable source for drinking

water• Energy aspect of reverse osmosis• Is infiltration of concentrate sustainable?• Conclusions

• Other research into sustainable drinking water production

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Brackish water: sustainable source for drinking water

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Brackish water: sustainable source for drinking water Nieuwe

Maas

-20

NAP

-10

-30

-40

-50

-60

-70

-80

-90

250m

deklaag

WVP ondiep

scheidende laag

WVP diep

<150 mg/l

150 – 300 mg/l

300 – 500 mg/l

500 – 1.000 mg/l

>1.000 mg/l

huidige RO-puttenReijerpark putten rivierzijde

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Brackish water: sustainable source for drinking water Nieuwe

Maas

-20

NAP

-10

-30

-40

-50

-60

-70

-80

-90

250m

deklaag

WVP ondiep

scheidende laag

WVP diep

<150 mg/l

150 – 300 mg/l

300 – 500 mg/l

500 – 1.000 mg/l

>1.000 mg/l

huidige RO-puttenReijerpark putten rivierzijde

Micropollutants

Water > 100 years in sub surface

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Brackish water: sustainable source for drinking water

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Brackish water: sustainable source for drinking water

• Option 1: discharge to channel

• Option 2: discharge to sea

• Option 3: infiltrate in the subsurface

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Brackish water: sustainable source for drinking water• RO submerged in a well• Hydrostatic pressure about 7 bar• No feed pump needed• Cross flow pump: about 1 bar• Permeate pump: about 7 bar• Extraction brackish water above RO• Infiltration concentrate (2x) beneath RO

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Energy aspect of reverse osmosis

Feed 50 m³/h8 bar

Permeate 25 m³/h0 bar

Concentrate 25 m³/h7 bar>>0 bar

Normal RO

+8 bar Sub-murged RO

+1 bar + 7 bar

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Energy aspect of reverse osmosis

• PURO 40% energy savings compared to normal brackish water RO

• Both RO’s calculated with 50% recovery• Substantial energy savings!

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Is infiltration of concentrate sustainable?

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Is infiltration of concentrate sustainable?

• In “Westland” about 1000 RO installations for farmers with infiltration of concentrate

• Province of South-Holland: no permits for farmers after 1013

• No alternative at this moment

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Is infiltration of concentrate sustainable?

• Decreasing fresh water reserve?• What is the water balans?• Faith of all the ions in the subsurface. Not only

NaCl but also ions like As, Pb, Hg etc.• How does the concept fit into regulations?

Province, Netherlands, Europe • How does the concept fit into future

regulations?

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Is infiltration of concentrate sustainable?

• At the same time: problems with salt intrusion:

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Is infiltration of concentrate sustainable? Nieuwe

Maas

-20

NAP

-10

-30

-40

-50

-60

-70

-80

-90

250m

deklaag

WVP ondiep

scheidende laag

WVP diep

<150 mg/l

150 – 300 mg/l

300 – 500 mg/l

500 – 1.000 mg/l

>1.000 mg/l

huidige RO-puttenReijerpark putten rivierzijde

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Conclusions

• Brackish water is a sustainable source for drinking water because of the absence of micro-pollutants

• PURO: 40% less energy consumption compared to conventional brackish water RO

• Concentrate infiltration is necessary within the PURO concept

• Concerns of concentrate infiltration important research topic

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Content

• Introduction reverse osmosis• Brackish water sustainable source for drinking

water• Energy aspect of reverse osmosis• Is infiltration of concentrate sustainable?• Conclusions

• Other research into sustainable drinking water production

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Drinking with the wind

• Several prototypes • Seawater: pressure 60 bar• Brackish water:

pressure 15 bar

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Drinking with the wind

• 3th windmill/RO combi• Cheap drink water for

10.000 people in Somaliland

• Drinkwater from brackish groundwater with RO

• Direct use of wind energy (no electricity)

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Ceramic filter pots• Desinfection • Point-of-use• Cheap• Local production • 22 factories

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Ceramic filter Pots

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Clostridium spores

E.coli K12

MS2 bacteriophages