Nour FAWAL, Baghdad OUDDANE, Jalal HALWANI

Huta Marine Works LTD, Huta Group, 1830 Jeddah 21441. E-mail : nourfawal@hotmail.com

1- introduction 2- Key selection for intake factor 3- Types of intake 4- Our selection 5- Intake installation and case study 6- Conclusion

Population + industry new water request tapping the sea and ocean water for desalination

SWRO : intake + treatment + water discharge. The most challenging aspect is the INTAKE: technical strategy, regulatory challenges, & public perception

INTAKE: decision key, general type of intake, our selection and our case study

Intake designs are site specific; (15-20%) of the capital cost.

Sea water intake is the essential process of SWRO since it conditions other processes. The objective is to provide reliable and consistent high-quality feed water.

Improvements in the raw water quality lead to reduction in the complexity of pretreatment systems and increasing the operational reliability of facilities.

1) Required intake capacity 2) Regulatory region 3) Site location types 4) Technical options as a function of installation

location 5) Water sources characteristics 6) Ecology and environment concerns 7) Economic considerations 8) Stakeholder Considerations

Two main families : Surface water intake (open) and subsurface water intake

In general : open intake for the large plant capacity Water quality is variable Recently trend is for the use of the subsurface intake Subsurface intake is limited for the small plant

location parameter sea water well1 Dahab, Egypt DOC (mg/L) 1.6 1.2

UV-254 (m−1) 1.4 0.8

Fuerteventura Island, Spain TOC (mg/l) 0.5 0.7 UV-254 (m−1) 0.36 0.55 Phytoplancton, cell/L 57720 0

Al-Birk, Saudi Arabia Dissolved protein (mg/L) 2.73 0.75 Dissolved carbohydrates (mg/L) 1.57 0.52

SWCC Al-Jubail test sites

TOC (mg/L) 2 1.2-2 Bacteria (CFU/mL), 0 h 1800 1300 Bacteria (CFU/mL), 24 h 1.1 × 105 3.3×105 Bacteria (CFU/mL), 72 h 5.6 × 104 4.0×106

Mediterranean location-spring

Total picophyto-plankton (cells/mL) 1.6 × 103 1.3×102 Synechococcus (cells/mL) 1.3 × 103 1.0×102 Picoeukaryote (cells/mL) 1.1 × 103 1.9×101 Nanoeukaryote (cells/mL) 1.2 × 102 1700

Site 1

TOC (mg/L) 1.2 0.9 Polysaccharides (mg/L) 0.12 0.01 Humic substances + building blocks (mg/L) 0.5 0.4

Low-molar mass acids & neutrals (mg/L) 0.25 0.16

Low molar mass compounds (mg/L) 0.33 0.29

Site 2

TOC (mg/L) 0.9 0.6 Polysaccharides (mg/L) 0.4 ND Humic substances + building blocks (mg/L) 0.26 0.16

Low-molar mass acids & neutrals (mg/L) 0.22 0.13

Low molar mass compounds (mg/L) 0.38 0.3

ADVANTAGE DISADVANTAGE

1. Suitable for most terrains and projects

2. High flow capacity 3. Relatively easy to build

(save time) 4. Low cost 5. Rapid implement solution 6. Smaller footprint and less

visual impact on the seashore

1. Lower and more variable feed water quality

2. Poor water quality 3. Vulnerable to marine

variation conditions 4. Requiring costly pre-

treatment 5. Higher operational cost 6. Significant environmental

impact during operation

ADVANTAGE DISADVANTAGE

1. Water quality improved 2. Stable water quality for

long term 3. Reduce cost of

pretreatment & operation 4. Respect the aquatic life 5. Less vulnerable

1. Limited flow capacity 2. Higher risk of insufficient

flow capacity 3. Additional pretreatment

maybe required 4. Plug of interstitial pore 5. Slow implement solution in

case of problem 6. Environmental impact:

groundwater, coastal beauty and mud

7. High construction cost

Our plant capacity is 20.000 m3/d The cost geology (sandy beach) Stable cost with low wave activity

Perfect condition to use the subsurface intake

Time Available of pre-treatment facilities Project duration Stable sea water Specific Precautions Stakeholder decision

Sea bed of Rabigh beach characteristic

Available aqua organisms

No boat or ship movement

Sea water stable with turbidity around 0.6 NTU

No permit to be directly near the shoreline: 340 m to reach the shoreline and 90 m inside the sea

False information : sub-contractor install only15m in the sea

Decision: start running EC = 42.840 – 43.356 µS/cm (43.119) pH = 7.7 – 8.3 (7.88) SDI = 7.16 – 8.12 (7.5) Temp. = 28.1 – 35.4 °C (31.9 °C)

GRP pipe is only 15 m inside the sea Laying down along the sea ground level No wet well sump 3 storage tanks (22.000 m3) each Production rate 2*9600 m3/d Delivery 6000-8000 m3/d = 11 working days to stop

Target : to extend the intake GRP pipe to 90m 7 GRP pipes have been damaged 2 options : stop or continue with the available New situation: 40m from the shoreline, 3 m water

column above the intake point & 5 m above the sea ground level

EC = 39.000 – 42.700 µS/cm (41.459) pH = 7.5 – 8.7 (7.96) SDI = 5.7 – 7.1 (6.5) Temp. = 26.8 – 33.8 °C (30.9 °C)

5 GRP pipes arrived, modification started New situation: 90m inside the sea; 8-9 m of water

column above the intake point; 14m above the sea ground level

EC = 38.900 – 41.900 µS/cm (40.502) pH = 7.6 – 8.9 (8.1) SDI = 5.0 – 5.9 (5.5) Temp. = 24.4 – 32.1 °C (29.1 °C)

Coast guard forced the remove of the intake pipe Intake pipe removed & replaced New situation: Water deep around 1m, water quality

deteriorated & high temperature EC = 41.100 – 53.700 µS/cm (47.687) pH = 7.5 – 8.9 (8.2) SDI = 7.7 – 11.7 (10.37) Temp. = 25.3 – 31.2 °C (28.7 °C)

Decision taken to create a natural filtration system Stone and gravel have been used EC = 42.000 – 47.600 µS/cm (45.286) pH = 7.5 – 8.1 (7.8) SDI = 9.1 – 10.8 (10) Temp. = 20.2 – 29.2 °C (26.2 °C)

Researches support to have deep water HUTA is the first dredging company in KSA & have

the needed dredger One dredger was nearby our location Decision has been taken to modify the water deep All the approve and access have been arranged Target: to dredge an intake area of 20*10m with

12m water deep

The New Manhole

New situation: 4 m above the sea ground level, 6 m below the sea level, 2 m away from the shoreline

EC = 41.700 – 48.900 µS/cm (44.979) pH = 7.7 – 8.4 (8) SDI = 6 – 10.6 (8.7) Temp. = 20.1 – 28.3 °C (25.5 °C)

Addition of gravel and stone New situation: same previous condition + natural

filter EC = 39.000 – 44.600 µS/cm (43.164) pH = 7.1 – 8.5 (8.2) SDI = 6.5 – 7.7 (7.3) Temp. = 24.2 – 30.8 °C (27.6 °C)

6- Conclusion

Best working condition with the maximum water deep Better coordination must be applied The open intake helped the quick action to modify the situations during the shorted possible time.

Period Situation of intake

Point depth

Far from cost

Cond. µS/cm

SDI pH T °C

18-25/09 near coast along with seabed

0.8 m 14 m 43119 7.5 7.9 32

5-18/10 In the depth sea water/6m seabed

3 m 40 m 41459 6.5 7.9 31

27/10-27/11

In the depth sea water/12m seabed

9m 90 m 40502 5.5 8.1 29

5-17/12 Near the coast (30 cm from seabed

0 m 2 m 47687 10.4 8.2 29

23/12 – 10/1

Near coast + gravel and stone

0m 2 m 45286 10 7.8 26

1-24/02 Near coast + manhole

8 m 2 m 44979 8.7 8 25

4/3 – 4/5 Near coast+manhole+gravel+stone

8 m 2 m 43164 7.3 8.2 28

THANK YOU