Presented byPresented by

Haleimah MohamedHaleimah Mohamed 199903922199903922

Tamadher Ali MohamedTamadher Ali Mohamed 199902261199902261

Reem KhalifaReem Khalifa 199902241199902241

Fatima Al-ZarouniFatima Al-Zarouni 199903949199903949

Under the supervision ofUnder the supervision ofDr. Mohamed AbdulkarimDr. Mohamed Abdulkarim

HCl Al2(SO4)3.14.3H2O

SBS

Disinfection pH adjustment

Anti-scalant addition

Media Filter

Coagulation unit

CartridgeFilter

Disinfection(Chlorination)

De-Chlorination unit

Neutralization pH adjustment

Storage Tank

RO

Membr

ane

NaOCl

Hypersperse AS110

HPP

NaOHNaOCl

Pump

Used to prevent reverse osmosis membrane from fouling by removing large percentage of suspended solid from feed water

SDI measurement commonly used to indicate the effectiveness of media filter

Almost, all RO membrane manufacture recommends SDI to be less than 3

[Ksp] =2.44 x10-5

[Ksp] =1.05 x10-4

93.176 L/day

[Ca+2] x [SO4-2]= 4.23 x 10-4 mol/L

Ksp= 2.44 x 10-5

The equation of calulating the dose rate

Antiscalant (Hypersperse AS110)

Plant SDI before cartridge

SDI after cartridge

Al Jubail, Saudi Arabia RO desalination plant

3 2.8

Singapore pilot plant 6.5 6.1

desalination plant at Larnaca, Cyprus

3 2.8

in

outin

SDI

SDISDIremoval

%

%6removal

%6removal

Normally, the available free chlorine concentration before RO membrane is 0.5 – 1 ppm.

The maximum allowable chlorine concentration before RO membrane is 0.05 ppm.

Residual free chlorine can be removed by:

adsorption onto activated carbon media filter

chemical reducing agent (SBS)

Sodium Bisulfite can be formed by dissolving Sodium Metabisulfite (SMBS) in water

In practice, designers used to add 3 mg/L of SMBS of chlorine

Total amount of free chlorine in water = 503 * 106 mg /day

32522 2NaHSOOHOSNa

In theory, 1.34 mg of SMBS will remove 1 mg of free chlorine.

The amount of SMBS needed to remove free chlorine = 7968.22 mole/day

The dosage rate of SBS needed to remove residual chlorine = 205.58 gal/day

The amount of moles of Sodium Bisulfite needed to remove the free chlorine = 15,936.13 mole/day

SMBS

H2O SBS

Q6

Stage 1 Stage 2

Q1 Q2 Q4

Q5Q3

RO membrane

Parameters Value

Overall Recovery% 30%

Recovery for second stage 85%

Salt rejection % 95%

Total product 40MGD

Total dissolved solid for total product 170 ppm

Total dissolved solid for feed 43153ppm

100%covRe rateflowfeed

rateflowPermeateery

Q2 =47 MGD

Q6

Q1 Q2 Q4

Q5Q3

ionconcentratsaltfeed

ionconcentratsaltpermeaterejectionsalt 1

TDS2 = 2156.79 ppm

Material balance on first stage:

ppmTDS

QTDSQTDSQTDS

654883

321

Q6

Q1 Q2 Q4

Q5Q3

554422 TDSQTDSQTDSQ

TDS5 =13415 ppm

Material balance on second stage:

664411 TDSQTDSQTDSQ

The overall salt balance for the system

TDS6= 61550.46 ppm

Added for pH adjustment to minimize the corrosion in the product water pipes

The calculation was based on

The required pH for drinking and potable water is in the range of 6.5 – 9.5

Neutralization of acid

Adjust pH from 7 to 8

Capacity of each filter = 600L/min

number of filter = 582 filter

349 x 103 L/minFeed flow rate =

feed water flow rate / filter capacity = Number of filter element

Filter cartridge/ vessel = 26Number of vessel = 25 ( 23 in operate + 2 standby)

ΔP = 4 psi per 1 m3/min

The feed flowrate inter each vessel= 15 m3/min

Total ΔP = 15 x 4 = 60 psi = 4 bar

number of module =

min19mod

GallonQ ule

min92361

GallonQ feed

4861mod

ule

feed

Q

Q module

number of configuration = 203 configuration

ions C (mg/l) C (mol/L)

Mg+2 829.35 0.03412

Ca+2 488 0.0122

Na+ 13160.22 0.572

HCO3

_ 115.9 0.0019

SO4-2 3473 0.03617

Cl- 23811 0.6726

32899.1 im

iosm mTP 27319.1

psiPosm 28.471

For feed

elementAreaelementmembranefluxQ vesselper #,

vesselsper

stageper

Q

QvesselsofNumber

,

1,

6 vesselsofNumberelementofNumber

properties Stage #1 Stage#2

Permeate flow 47 MGD 40 MGD

Qper,vessel 2755 L/h 2755 L/h

# of vessels 2690 2290

# of element 16140 13740

One vesselsFeed

Permeate

7.101.0 fcfc qnq

2

floweconcentratflowfeedq fc

The calculations of pressure drop in RO membrane

vesselsoneperpsiq fc 7.1738.28601.0 7.1

1. Chemicals• Sodium Hypochlorite • Antiscalent • Hydrochloric acid (HCL) • Sodium bio-sulphate • Coagulant (Aluminum sulphate) • NaOH

2. Process • MMF• Membrane • Desalination plant Intake

3. Products• Brine

1. Chemicals

2. Process

• Sand filter

Advantage: Sand work as a filter

Disadvantages: Need higher pressure Limits on flow rate Cost

1) Mix brine with seawater before discharge.

3. Products

2) More than one discharge.These are located a way of each other at a

distance.

RO plant

Feed seawater

To seawater

5) Deep well disposal

3) Mixing brine water with cooling water coming from adjacent power plant.

4) Evaporation ponds

PID Before HAZOP

HAZOP analysis on water feed entering multi media filter. (Line no. 2)

Guide Word

Deviation Causes Consequences & Action

NO FLOW Pump failure Ruptured (broken) pipeValve (V2) shut

No productoCheck valveoCheck & Repair pump and pipeoPut flow indicator (FI 2)

LESS FLOW Pipe leakagePump failure

Low production qualityLess feed pressureSlow operationoCheck & Repair pump and pipe

MORE FLOW Damage pump The multi media will be shutdown.The ratio between feed water and coagulant is not the same Need to fix coagulant dosingThe efficiency of media filter will decrease.The suspended solid will not be removedLower the product quality Over flowLower removal capacityoCheck & Repair V2

PID After Hazop