Submarine Pipelines


Submarine Pipeline of Punta Catalina – Dominican Republic

Submarine pipeline for the seawater cooling circuit of a Thermoelectric Power Plant. The system consists of 3 pipes 350 m long, DN2500, placed in a trench, and a diffuser consisting of 33 risers of DN1000/800/560.

CHARACTERISTICS

Client: ODEBRECHT/TECNIMONT/ESTRELLA Consortium
Completion period: 18 months

Submarine outfall for the seawater cooling system of the Thermoelectric Power Plant, 2x360 MW, of Punta Catalina consisting of 3 pipelines of PEAD DN2500, 350 m long each, and three diffusers consisting of 33 risers each of DN1000, 800 and 560 mm.

The pipelines were made in Norway and towed to the installation location. Each pipeline was ballasted with 72 reinforced concrete rings of 6.40 m3 and weighs 16 tons each. They were placed in parallel in a single trench opened by the Novadragamar dredging pontoon and covered with a layer of riprap.

The diffuser’s smaller orifices (Ø560 mm) are installed closer to land (inner), followed by the intermediate orifices (Ø800 mm) and, lastly, the larger orifices (Ø1,000 mm) are located at the offshore end.

 Details

Submarine Outfall of Sidi - Bernoussi, Casablanca - Morocco

Submarine outfall in a length of 2,200 m, of DN2300, to discharge pre-treated effluents, consisting of a 1,057 m tunnel section built by submarine micro-tunnelling, lined by reinforced concrete piping with a steel core, and a 1,143 m PEAD section placed in a trench, for a maximum debit of 11 m3/s and working pressure of 6 bar.

CHARACTERISTICS

Client: LYDEC – Lyonnaise des Eaux Casablanca
Completion period: 34 months

Outfall for discharging treated effluents, consisting of a tunnel section of reinforced concrete pipe with a steel core and PEAD pipeline, with a maximum debit of 11 m3/s and a working pressure of 6 bar.

Tunnel section:
Construction of the tunnel by a micro-tunnelling machine with an excavation diameter of 2,750 mm for pipes of Ø 2,100 mm inner and Ø 2,670 mm outer diameter, in a length of 1,057 m. The micro-tunnelling machine’s launching shaft was 12 m in internal diameter and 14.5 m deep.  A geotechnical survey was performed at the start of the project (bathymetry, seismic reflection and refraction, exploratory sample boring and mechanical tests) to obtain the land's main parameters which are critically important in this type of marine works.

PEAD section:
Section performed by classic marine works (dredging, rock excavation, immersion of PEAD pipeline and ballasting), 1,343 m long, of which a part was buried in a trench and the final part is laid on the seabed and stabilised by its own weight, concrete ballast rings and by the diffuser that is anchored on the seabed.

 Details

Submarine Outfall of Anza, Agadir - Morocco

Outfall to discharge treated effluents of a mixed human and industrial origin, made of PEAD DN710 mm, 2,867 m long and consisting of three sections:
- Section in a trench, 225 m long.
- Section of Horizontal Directional Drilling, 987 m long.
- Section placed on the natural bottom, 1,655 m long, installed in depths ranging from -13.70 m CD to -31.00 m CD.

Short North Outfall of 630 m x DN1000
Short South Outfall of 165 m x DN710

CHARACTERISTICS

Client: R.A.M.S.A. – Régie Autonome Multiservices Agadir
Completion period: 24 months

Outfall for discharging treated effluents of a mixed human and industrial origin in PEAD Ø 700 piping in a length of 2,867 m, in three distinct sections:

Section in a trench:
Terrestrial section 225 m long installed in a trench, from the discharge chamber to the start of the tunnel. The trench was covered with sand (protection layer) and exaction materials.

Tunnel section:
Construction of the tunnel by Horizontal Directional Drilling in a length of 987 m and 1,016 mm in diameter. Installation of the PEAD pipeline of Ø 710 mm in diameter.

Submersed section:
Section of 1,655 m submersed at a depth between -13.70 m (CD) and -31.00 m (CD). This section was installed on the seabed and stabilised by its own weight, by concrete ballast rings installed in the piping and by the diffuser that was fixed to the seabed.

Diffuser:
Four-riser diffuser to disperse the effluents, built of steel, painted and protected against corrosion by sacrificial anodes.

 Details

Submarine Outfall of Bata – Equatorial Guinea

Outfall for the supply and sanitation project for the city of Bata in PEAD DN1100 PE100, SDR 22, PN 7.7, in a length of 1,280 m.

CHARACTERISTICS

Client: SOMAGEC GE / Ministère des Travaux Publiques de la République de Guinée Equatorial
Completion period: 12 months

Length: 1,280 m
Nominal inner diameter: 1,000 mm
Outer diameter: 1,100 mm
Diffusers: 8 duckbill valves
Pipeline: PEAD, PE100, SDR22, PN7.7

 Details

Submarine Outfall of Ta'Barkat - Malta

Submarine outfall in PEAD PE100 SDR26 PN6.4 in a length of 971 m and DN 1,600 mm, with a diffuser installed at a depth of -40.50 CD.

CHARACTERISTICS

Client: WSC – Water Services Corporation
Completion period: 12 months

Submarine outfall in PEAD PE100 SDR26 PN6.4 with an outer diameter of 1,600 mm and 971 m in total length, with a diffuser installed at a depth of -40.50 CD.

The outfall is installed in a trench in the first 440 m and laid on the seabed in the remaining 530 m.

The diffuser is 144 m long and consists of 18 risers.

The works included performing all studies and complementary surveys, building the reinforced concrete ballast blocks, anti-corrosion protection, assembly of rings on the piping, installation in the ocean and construction of the load chamber in reinforced concrete.

 Details

Submarine Outfall of El Jadida - Morocco

Outfall for discharging treated effluents of a mixed human and industrial origin in PEAD DN900 mm and in a length of 2,086 m, consisting of three sections:
Section in a trench, of 448 m;
Section installed by Horizontal Directional Drilling, of 918 m, in rocky soil;
Section laid on the natural bottom, 720 m long, installed in depths ranging from -10.20 m CD to -14.00 m CD.

CHARACTERISTICS

Client: R.A.D.E.E.J – Régie Autonome Intercommunale de Distribution d’Eau et d’Électricité et d’Assainissement Liquide de la Province d’El Jadida.

Completion period: 24 months

Outfall for discharging treated effluents of a mixed human and industrial origin in PEAD PN100 Ø 900 mm and in a length of 2,086 m, consisting of three distinct sections:

Section in a trench:
448 m of piping installed in a trench with depths from 2 to 6 m. The trench was covered with sand (protection layer) and excavation materials. At the end, it was covered with a concrete slab to prevent it from being reopened by the force of waves.

Tunnel section:
Installation by Horizontal Directional Drilling in a length of 918 m in a rocky seabed starting at the surf zone.

Submersed section:
Section of 720 m submersed at a depth between -10.20 m (CD) and -14.00 m (CD). This section was installed on the seabed and stabilised by its own weight, by concrete ballast rings installed in the piping and by the diffuser that was fixed to the rocky seabed.

Diffuser:
Four-riser diffuser that disperses the effluents, built of steel, painted and protected against corrosion by sacrificial anodes.

 Details

Seawater Desalination Plant – Fouka - Algeria

Study, design and execution of the marine works for the Fouka desalination plant. Consisting of two seawater intake pipelines (in PEAD Ø1,600 mm), 900 m long, and two seawater intake structures (suction heads), along with a brine outfall in a total length of 370 m (in PEAD Ø1,200 mm) and respective diffuser.

CHARACTERISTICS

Client: MYAH TIPAZA, S.P.A. / SNC - Lavalin International, Inc.
Completion period: 20 months

Study, design and execution of the marine works for the Fouka seawater desalination plant, which included:

- Two seawater intake pipes in PEAD Ø 1,600, in a length of 900 m each – Two seawater intake structures (suction heads). - A brine outfall in PEAD Ø 1,200, of 370 m in length, and one diffuser.

The works included::
- Excavation of the placement trench between -5.50 CD and -9.00 CD. Dredging and rock blasting.

- Pre-casting of 484 reinforced concrete ballast rings of Ø 1,600 mm, 86 stabilisers for the seawater intake pipelines and 65 rings of Ø 1,200 mm for the outfall.

- Supply, preparation (assembly of the rings and connection of the sections) and placing of the pipelines.

- Manufacturing and placing of the seawater intake structures (suction heads).

- Cathodic protection of the metallic parts.

- Protection of the pipelines in the trench section with a layer of sand one meter thick and a layer of riprap of 50 to 500 kg.

- Placing of the 86 stabilisers fastened to the ballast rings.

- Supply and installation of three marine navigation buoys.

- Tests.

 Details

Submarine Outfall of Rabat - Morocco

The outfall has a total length of 2,150 m, with a total of 800 m on land and a total of 1,350 in the ocean.

CHARACTERISTICS

Client: REDAL, S.A
Completion period: 29 months

Outfall on land (from 0 to 800 m):

• Construction of a launching shaft for tunnelling (also a permanent well) 12 m in diameter, about 23 m deep and reaching a depth of -11.40 CD.
• Construction, by micro-tunnelling, of a tunnel of 800 m with reinforced concrete piping with an outer DN of 2,630 mm and inner DN of 2,000 mm.
• Construction of piping, with 2.5 m pipes, coupled as the tunnel boring machine advanced. The pipeline reached 800 m at level -18.00 m CD with a minimum covering of soil above the tunnel’s upper generating line of 4.5 m.

EOutfall in the ocean (from 800 to 2,150 m):

• A trench was opened with a suction dredge to lay the piping of PEAD DN 2,000 mm, thus installed on a natural bottom in its entire length.
• The piping, manufactured in Norway, was towed to the Port of Mohammedia, Morocco, where it was prepared (assembly of the concrete ballast blocks) in two sections of 450 and 900 m, after which they were towed to Rabat for installation.

 Details

Submarine Outfall of Azla – Tétouan - Morocco

Submarine outfall in PEAD Ø 1,200 mm in a length of 3,124 m. The diffuser consists of 11 risers, of 250 mm in diameter, at 12 m intervals and placed to a maximum depth of -37.50 m (CD).

CHARACTERISTICS

Client: AMENDIS - Société des Eaux et d’Électricité du Nord, S.A.

Completion period: 19 months


Design and construction of a 3,124 m submarine outfall in PEAD Ø 1,200 m piping, consisting of the following works:
 - Opening of a trench on land and in the sea to install the pipeline
 - Supply, preparation and installation of the piping
 - Pipeline protection
 - Pipeline cathodic protection
 - Placing of a navigation buoy
 - Installation of a cleaning chamber

The PEAD piping, manufactured in Norway, was towed to the port of Tangier Med for preparation (assembly of the concrete ballast blocks and of the diffuser’s risers).
The diffuser consists of 11 risers, of 250 mm, at 12 m intervals and placed to a maximum depth of -37.50 m (CD).

 Details

Submarine Outfall of Tangier-Port - Morocco

The outfall, in PEAD piping, has a diameter of 1,400 mm and a total length of 2,155 m. The end of the diffuser is at a depth of -42.00 m CD.
Since the natural bottom is rocky until -22.00 m CD, it was necessary to open a trench with drilling equipment and by using explosives to blast the rock.
The diffuser consists of 14 risers in diameters of 240 and 280 mm.

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CHARACTERISTICS

Client: AMENDIS- Société des Eaux et d’Électricité du Nord, S.A.
Completion period: 26 months

The outfall, in PEAD piping, has a diameter of 1,400 mm and a total length of 2,155 m. The end of the diffuser is at a depth of -42.00 m CD.

The Outfall was installed in a trench until the depth of -22.00 m CD of natural bottom and, as of this point, laid over the bottom. Its stability is ensured by concrete ballast blocks installed on the piping in advance at the Port of TANGIER MED.

Since the natural bottom is rocky to a depth of -22.00 m CD, it was necessary to open a trench with drilling equipment and by using explosives to blast the rock.

The piping was manufactured by Pipelife in Norway and towed, floating, to Morocco by an offshore tugboat in sections of approximately 300 m. In Morocco, it was coupled on the surface forming larger sections of 600 m and 900 m and afterwards installed in a single sinking operation per section.

The diffuser consists of 14 risers in diameters of 240 and 280 mm.

 Details

Submarine Outfall of Vale de Faro – Albufeira - Portugal

Terrestrial outfall 900 m long in PEAD Ø 1,000 mm, and a Submarine Outfall, in PEAD Ø 1,000 mm PN 6.3 in a length of 1,020 m and a diffusor placed at a maximum depth of -10.20 m (CD). Together with the pre-existing outfall of Ø 400 mm, a maximum flow of 4,232 m3/h into the ocean was ensured.

CHARACTERISTICS

Client: Águas do Algarve, S.A.
Completion period: 12 months

The Vale de Faro waste water treatment plant, with a maximum effluent flow of raw waste water of 4,250 m3/h, is designed for a population of 130,000 inhabitants.

The works contract called “Design and construction of the disinfection stage of the waste water treatment plant of Vale de Faro, Albufeira, and of the corresponding infrastructures for conveying treated waste water into the ocean", including the following works:

 - Construction of the disinfection stage consisting of UV equipment at the Vale de Faro waste water treatment plan.

 - Construction of two contiguous outfalls, a Terrestrial Outfall 900 m long in PEAD Ø 1,000 mm, and a Submarine Outfall in PEAD Ø 1,000 mm PN 6.3, in a length of 1,020 m and with a diffusor placed at a maximum depth of -10.20 m (CD).

Together with the pre-existing Ø 400 mm outfall, a maximum flow of 4,232 m3/h into the ocean was ensured.

 Details

Submarine Outfall of Foz do Arelho - Portugal

Construction of a Submarine Outfall in PEAD Ø 710 piping, in a total length of 2,150 m, placed at a depth of -33.00 m CD.

Red valves were assembled on the diffuser to diminish the intake of sand.

CHARACTERISTICS

Client: Associação de Municípios do Oeste
Completion period: 21 months


Construction of a Submarine Outfall in PEAD Ø 710 piping, in a total length of 2,150 m, placed at a depth of -33.00 m CD.

In the area next to the coast, the piping was placed, in a single section, in a trench previously dredged by suction.

Construction of a provisional riprap jetty in the surf zone, which made it possible to use a large crane and sheet piling to lay the piping in a trench.

Degasification chamber built of reinforced concrete in the beach area, using a cofferdam of sheet piling.

Red valves were assembled on the diffuser to diminish the intake of sand.

The Atlantic coast is subject to large waves requiring effective construction solutions and large capacity equipment to make the most of the short periods of calm ocean conditions.

 Details