Sea Water & Brackish Water

Reverse Osmosis System

Technology for Sea Water

Desalination

Process &

Maintenance

Reliability

Costs-

CAPEX &

OPEX

Product

Recovery

THERMAL (MSF)

• Simple Pretreatment

• Product quality: TDS = 5~25 ppm

• Medium maintenance (Potential

problem: scaling & corrosion)

• Feed quality flexible

• High installation cost

• Typical production cost (1.71 USD/m3)

Low conversion

(10 ~ 20 % recovery)

MEMBRANE (REVERSE OSMOSIS)

• Complex Pretreatment

• Product quality:

o 1st stage RO: TDS max. 400 ppm

o 2nd stage RO: TDS max. 15 ppm

• High maintenance (Potential problem:

cleaning/replace membrane)

• Feed quality fixed

• Lower installation cost

• Typical production cost (1.01 USD/m3)

Medium conversion

(30 ~ 45 % recovery)

Desalination Advantages- Reverse Osmosis Technology

Desalination is a process that involves reduction of salt from sea

water using membranes by applying external energy in order to be

used as fresh water.

Desalination using Seawater Reverse Osmosis technology when

compared to thermal technologies is widely accepted and popular

due to certain significant factors such as:

Efficiency in producing higher volume of output water

Lower Energy Consumption

High modular and scalable in plant configuration

Lower capital and operating cost

Integration of Technology Water Technologies Made Simple

Commercial & Industrial Use

Sea Water Open

Intake/ Beachwell

MATTEN’s Water

Treatment Systems

Simplified Project PFD

SWRO BWRO

To Polisher

Brine

TDS = 36000 ppm

TDS = <20 ppm

Feed Sea Water

TDS = 500 ppm

1st Stage 2ndStage

Pretreatment

Recovery Unit SWRO adalah ±36% (1st stage = 45%, 2nd stage = 80%).

Sea Water Intake Systems

Beach wells are usually located on the seashore in close vicinity to

the ocean. These intake facilities are relatively simple to build and

the seawater they collect is pretreated via slow filtration through

the subsurface sand/seabed formations in the area of source water

extraction. Raw seawater collected using beach wells is often of

better quality in terms of solids, silt, oil and grease, natural

organic

contamination and aquatic

microorganisms, compared to

open seawater intakes.

Sometimes, beach intakes

may also yield source water of

lower salinity.

Sea Water Intake Systems

Open intake for large seawater desalination plants are typically

complex facilities, including intake piping that extends several

hundred to several thousand metres into the ocean. Source

water collected through open intakes usually requires

pretreatment prior to reverse osmosis desalination. New open

ocean intakes could potentially entrain more aquatic organisms

than beach wells because they take

raw seawater directly from the ocean rather than

source water pre-filtered

through coastal sand

formations.

Process Design Pre-treatment & Chemical Dosage

Ferric Chloride (FeCl3)- will

destabilize the suspended solids

rapidly and increases the removal

efficiency of Dual media filtration

Sodium Hypochlorite (NaOCl)-

will cease the growth of

microorganism on the inner pipe

walls

The raw seawater is supplied to an appropriate pre-treatment

system by RO feed pump. In order to facilitate a good SDI

reduction, strong anti-microbial agent and a coagulant will be

dosed upstream.

Process Design Pre-treatment & Chemical Dosage

The pretreatment system will depend on

the seawater quality.

Common pretreatment system :

- Multimedia Fitration

- Dissolved Air Floatation + Multimedia

Filtration

- Clarifier + Multimedia Filtration

- Ultrafiltration Membrane System

Process Design Pre-treatment & Chemical Dosage

Process Design Pre-treatment & Chemical Dosage

Important parameter on the pretreatment : SDI (Silt Density

Index)

Suspended solids and colloidal materials in feed water are

one of the biggest problems in reverse osmosis systems.

Even though most systems have some pretreatment

including 5 micron prefilters, these fine particles are

responsible for fouling of reverse osmosis membranes.

An SDI of less than 5 is considered acceptable for the

reverse osmosis systems. This means that at values of SDI

of less than 5, the membranes should foul at a very low

rate.

Process Design Sea Water Reverse Osmosis

Main Components :

- Feedwater Pump

- Cartridge Filter

- High Pressure Pump,

Duplex 2205

- Energy Recovery Device

: Turbo or Pressure

Exchanger

- SWRO Membrane &

Housing

- Piping Duplex 2205,

Instrumentation &

Control

Process Design RO Operation

RO separation is a pressure driven process, being said that

the external pressure shall be provided by RO high

pressure pump.

The pressure transmitters are located at critical upstream

and downstream points of the pump to constantly monitor

the pressure and send back the real time data to the data

logging unit.

The pressurized water will flow through

spirally wound RO membranes, the

place of actual separation process.

An online conductivity transmitter will be used to monitor the

conductivity of “permeate” and “offspec”, as the latter being a

water with higher conductivity than a specified range.

Process Design RO Operation

SEA WATER REVERSE OSMOSIS PROJECT REFERENCE

Project Name : Sea Water Reverse Osmosis 4 x 20 m3/hour

End User : CNOOC SES Ltd.

Location : Pabelokan Island

5. Sea Water RO

6. Brackish Water RO

THANK YOU