Reverse Osmosis SystemPresented by : Ach Farid Wadjdi

3P

Purpose :

To share & discuss Reverse Osmosis (RO) application

Process :

Presentation & discussion

Pay Off :

Better understanding for RO system, Monitoring, Control, and Services.

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AGENDA

Reverse Osmosis Overview Reverse Osmosis Monitoring Membrane Problem Profiling and Probing Membrane Cleaning Activity

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Reverse Osmosis Overview

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U ltra filtra tion

M icro filtra tion

C la rifica tion

F iltra tion C h lo rina tion

S uspended P a rtic lesC o llo d ia l m a tte r

O rg a n ics , F e & M nB io fo rm s

E le c tro d ia lys is

Evapo ra tion

A ctiva ted C a rbon

R eve rse O sm osis

Ion E xchange

D isso lved ionsH a rd n e ssa lk a lin ity

O rg a n ics & R e s .C l2

D ecarbona tion

C hem ica l Scaveng ing

D eaera tion

D isso lved G asesC O 2O 2

H 2 S , N H 3

C ontam inants

Contaminant in Water

RO OVERVIEW

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Osmotic Pressure

High LowSemi-

permeable membrane

OSMOSIS

Applied Pressure

REVERSE OSMOSIS

High Low

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Microfiltration Ultrafiltration Nanofiltration Reverse Osmosis

Range Macro molecular Molecular Sub molecular Ionic

Particle size 1.0 - 0.1 mm 0.1 - 0.01 mm 0.01 - 0.001 mm <0.001 mm

Removes Suspended solids,Large colloids,Bacteria

Proteins,Colloids,Organics

Pyrogens,Divalent ionsVirus

Small Organics,Metals,Salts

MolecularWeight

>100,000 10,000 - 100,000 200 - 20,000 <300

OperatingPressure

10 psig 10 - 100 psig 200 -250 psig 200 - 800 psig

PretreatmentNeeds

Medium Medium High High

Capital Cost Medium Medium High High

Membrane Filtration

Semipermiable Membrane

Thin Film Composite (98% of Industrial market)

Cellulose Acetate Polysulfone

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Celluloseacetate

Thin filmcomposite

Typical pH range 5.0-6.5 2.0-11.0

Average % rejection 95% 99%

Microbio susceptibility Yes No

Temperature limit 35°C 45° C

Chlorine tolerance Excellent Poor

Typical operatingpressure

400 psig 200 psig

Membrane Comparisons

RO System

Train

Pressure Vessel

Stage 2

Stage 1

Reverse Osmosis Monitoring

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Point of Monitoring

RO MEMBRANE

PERMEATE

REJECT

HIGHPRESSUREPUMP

FEEDWATER

SDI, FeedPressure

Feed Flow Rate, pH,Conductivity, Turbidity,Temperature, Oxydants, and Biocide (TFC elements) Reject

Pressure

Reject Flow Rate,Conductivity

Permeate Flow Rate,Conductivity, PermeatePressure, and Biocide (CA and TFC elements)

1. Percent salt rejection & Percent salt passage

2. Normalized permeate flowrate

3. Differential pressure

4. % Recovery

Performance monitoring

1. % Salt Rejection & % Salt Passage

% Rejection = (TDSfeed - TDSProduct) x 100

TDSfeed

% Salt Passage = TDSProduct x 100

TDSfeed

Conductivity Factor

TDSfeed = 0.6 x Conductivityfeed

TDSpermeate = 0.5 x Conductivitypermeate

TDSreject = 0.7 x Conductivityreject

2. Normalized Permeate Flow

The formula used to calculate Normalized Permeate flow is :

Qnorm = Qi * (NDPstart / NDPi) * (TCstart/TCi)

Qnorm = Normalized permeate flowQi = Permeate flow at point iNDPstart = Net Driving Pressure at startup or reference conditionNDPi = Net Driving Pressure at point i.TCstart = Temperature Correction Factor at startup or reference conditionTCi = Temperature Correction Factor at point i.

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= Feed Pressure - Reject Pressure

3. DIFFERENTIAL PRESSURE (∆P)

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4. % RECOVERY

% Recovery = (Permeate Flow) x 100 %

Feed/Inlet Flow

Membrane Problem

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Scaling

The major scalants are calcium carbonate, calcium sulfate, barium sulfate, silica, and Calcium/magnesium silicate

Cause: change in pH, salt concentration, dan temperature.

The best precaution against scaling are optimizing the pre-treatment, maintaining design flow rate & continuously injecting scale inhibitor

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Fouling

Foulants are normally formed from suspended matter found in the feed water.

To RO membrane manufacturers, fouling is considered a normal occurrence that can be controlled with effective monitoring, maintenance and cleaning programs

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Degradation or hydrolysis

RO membranes can degrade or hydrolyze when exposed to oxidants (chlorine; etc.), pH changes, biodegradation, or temperature extremes.

CA membranes are very sensitive to biodegradation, pH ranges outside of 5.0 to 6.5, and temperature higher than 40 0C.

TFC membranes are very sensitive to oxidizers, pH ranges outside of 2.0 to 11.0 and temperature higher than 45 0C.

Profiling and Probing

PROFILLING

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Determined which pressure vessel, has high contribution to increase permeate conductivity.

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Probing : Determines which membrane or interconnector that has high contribution to conductivity

Using : 1/4” Polypropylene Tubing

PROBING

1 2 3 4 5 6 7

Reverse OsmosisCleaning

When to clean the membranes ?

Decreasing normalized permeate flow 10 – 15 % from the last cleaning

Decreasing % Salt Rejection 10 – 15 % from the last cleaning

Increasing ∆P 10 – 15 % from the last cleaning

After 3 month operation

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CLEANING - OPERATIONAL

Alkaline Cleaning Remove organic & inorganic fouling Chemical : PC – 98, PC – 40 & NaOH for pH adjustment (10,5 – 12) Please loading PC – 40 first for dilution Circulate and soak every 15 minutes in interval 4 hours Record flow, pressure & temperature and maintain within the rangeAcid Cleaning Remove scaling Chemical : PC – 77 & HCl for pH adjustment Circulate for 2 hours, soak for 30 minutes and then circulate for 1 hour (Pressure max. 4 bar) Maintain pH during acid cleaning Record flow, pressure & temperature and maintain within the rangeSanitation Remove microbiological Chemical PC – 11 Circulate the solution for 60 minutes

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Before cleaning, please do flushing RO (15 minutes) & circulate (30 minutes) tocleaning tank with permeate water.

Cleaning Skid

Volume Cleaning : 40-55 m3/membrane

THANK YOU

TERIMA KASIH

MATUR NUWUN