MIDESPolymeric and ceramic membranes filtration as ...iwaresa.com/.../presentations-pdf/IWARESA-2018_Aqualia_Jose-M-Vinas.pdf · Presenter: Jose Mª Viñas ([email protected])

MIcrobial DESalination for low energy drinking water MIDES Polymeric and ceramic membranes filtration as pretreatment for brackish surface water desalination

J. Viñas J. Arévalo M. Burgos V. Monsalvo F. Rogalla Aqualia Innovation and Technology Department. Presenter: Jose Mª Viñas ([email protected])

Polymeric and ceramic membranes filtration as pretreatment for brackish surface water desalination

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Current Water Stress

Worsening of the

situation

Higher number of drinking

water production

plants

Source: World Resources Institute


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Reverse osmosis (RO) desalination plant is considereded as one of the best option to mitigate water stress

Brackish surface water

Seawater

Raw water Desalination plant

Microfiltration (MF) and Ultrafitration (UF) membranes

as pretreatment alternative RO desalination plant

Ineffective pretreatments

cause membrane

fouling

4



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Mediterranean area: Dry and hot summer season Low precipitation High temperature Water scarcity Important coastal tourism in summer season Significant increase of the population in summer

season

Spain: 75.3 millions of international tourists

48.5 millions of tourist to the Mediterranean coast

Supposing a amount of 77,000 millions €

Water scarcity

Top water stress ranking: from position 39 (current) to 33 in 2040

(Source: World Resources Institute)

(Source: Minetad report 2017)




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Location of the study was Denia, a Spanish city located in the Mediterranean coast

Low precipitation

and high temperatures

Denia (Alicante, Spain)

Huge increase of

the population High pressure on

water sources!!!

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R&D Area

BWDP Racons (Denia)

Brackish Water Desalination Plant

Reverse osmosis technology

Brackish river water. Racons River

16,000 m3/d

Potable use

Pilot plant container



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Water sources. Racons River River water composition

Parameter Units Minimum Maximum Average

Calcium mg/L 56.0 264.0 169.9

Magnesium mg/L 55.2 248.0 113.7

Sulfate mg/L 152.0 640.0 322.7

Chloride mg/L 862.0 3522.0 1745.4

Total hardness mg/L 480.0 1680.0 908.5

Temperature ºC 11.0 27.0 19.5

pH Ud 7.2 8.0 7.7

Turbidity NTU 2.0 69.7 9.5

Conductivity µS/cm 5.1 12380.0 6160.9

Organic matter mg/L 1.9 10.1 4.8

Effective pre-treatment methods are required!!

Complex feed water

Very variable composition


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Membrane characteristics

Pilot plant production 1-3.5 m3/h

Membrane material PVDF

Membrane area 49 m2

Membrane form Out-in pressure membrane

Nominal aperture 0.03μm

Temperature Range: 5 - 40°C

Maximum Filtration Transmembrane

Pressure:

0.8 bar

Maximum Backflush Transmembrane

Pressure:

0.6 bar

Allowable pH Range for Cleaning 2.0 – 10.5

Polymeric submerged membrane

Experimental plan

Operation with coagulant reagent Different permeate fluxes were tested in order to check the influence of the flux over:

Membrane fouling kinetics Membrane recovery capacity

Flux was gradually increase until process turn into unstable Fluxes tested: from 30 to 70 LMH Filtration time: 45 minutes

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Membrane characteristics

Pilot plant production 1-12 m3/h

Membrane material Ceramic membrane (AL2O3)

Membrane surface 25 m2

Membrane form Inner pressure monolithic

Nominal pore size 0.1μm

Ceramic membrane

Experimental plan

Different permeate fluxes were tested in order to check the influence of the flux over: Membrane fouling kinetics Membrane recovery capacity

Flux was gradually increase until process turn into unstable Fluxes tested: 60, 80, 120 and 160 LMH Filtration time: 30, 45 and 90 minutes


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S.S. Turbidity pH Conductivity COD Alkalinity Hardness Sulphate Silica SDI

Permeate 0.04 0.14 21.04 258.75 2.21

% removal 99.69 99.06 26.93 5.94

Permeate quality

High permeate quality obtained Permeate turbidity value below 0.14

NTU Reduction of the concentration of

substances presented in the river water


Polymeric membrane:

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Permeate quality

High permeate quality obtained Permeate turbidity value below

0.15 NTU

Ceramic membrane:

S.S. Turbidity pH Conductivity COD Alkalinity Hardness Sulphate Silica SDI

Permeate 0.01 0.08 7,37 5,42 6.90 210,50 1191,55 258.75 10,46 1,75

% removal 99.62 97.65 61.3 15.28


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Membrane performance

High permeability reached (about 600 LMH) Strong relation between feed

water turbidity and permeability

Polymeric membrane:


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Considerable decrease of permeability treating high quality water

Poor permeability with high

feed water quality

Ceramic membrane:

Higher permeability in UF membranes

than MF


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Strong relation between turbidity and fouling kinetics

Low fouling kinetics treating

complex water

Membrane cleaning could restore to initial permeability values

Polymeric membrane:


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Fouling kinetics was higher than expected

Fouling kinetics reached high

values (7 mbar/min) Membrane cleaning could not

restore to initial permeability values

Ceramic membrane:

Better performance of UF membrane

than MF


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Stable operation at 70 LMH and 45 minutes of filtration cycle

Higher permeability than MF membranes

Lower flux than MF membrane

Good membrane recovery capacity

Polymeric membrane:

45 min


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Stable operation at 160 LMH and

90 minutes of filtration cycle Fouling kinetics were higher than

expected

Capable to be operated at high flux and long duration time

Poor membrane recovery

capacity

Ceramic membrane:


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Particle size distribution of river water

Smaller particles can reach the pores, causing pore blocking and a more notable permeability decline.

Particles in a range 10 times bigger than the pore size can cause this blocking problems

Small particles can be

mitigated by coagulant


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Membrane cleanings

Mechanical cleanings Backwash Air scouring

Chemical cleanings Oxidant cleanings

• Hypochlorite cleanings • Hydrogen peroxide cleanings

Acid cleanings

Mechanical cleanings: Backwash Air flash

Chemical cleanings: CEB:

Hypochlorite cleanings Hydrogen peroxide and hydrochloric

acid cleanings

Ceramic membrane:

Polymeric membrane:


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Conclusions

• Polymeric membranes are a viable option in extremely complex brackish natural waters treatment in RO pretreatment

• Ceramic membranes reached higher flux value operating at 160 LMH

• Permeate quality is assured in any case • Suspended solids associated to turbidity was the main factor in membrane

fouling rate, being more important than membrane flux in the specific tested conditions.

• Oxidant chemical cleanings the most effective in permeability recovery for

polymeric membrane

• NaOCl and HCl + H2O2 have similar effectiveness in ceramic membrane recovery capacity


MIcrobial DESalination for low energy drinking water MIDES

Thank you!!


Documents

MIDESPolymeric and ceramic membranes filtration as ...iwaresa.com/.../presentations-pdf/IWARESA-2018_Aqualia_Jose-M-Vinas.pdf · Presenter: Jose Mª Viñas ([email protected])