Location: Sellafield, Cumbria, England Client: British Nuclear Group Engineering, Submarine Outfall, Construction and Decommissioning Pipeline Decommissioning and Sealine Recovery Project. Removal of three redundant pipelines. Two 250mm diameter steel lines. (SL1 - 750m and SL2 - 2400m) and one 203mm diameter HDPE line (TESL - 2400m). SL2 and TESL were fitted with diffusers. Location: Helensburgh, Scotland Client: Mowlem Johnston /Mackenzie JV for Scottish Water Solutions Submarine Outfalls Sewerage Upgrade Scheme. The supply and installation of main and relief outfalls varying from 315mm to 800mm dia x 45m to 215m long at three locations and repairs to an existing 450mm dia outfall. The work was carried out between the seawall and up to 70m past the low water mark. Location: Holyhead, Anglesey, Wales Client: Welsh Water / GallifordTry Engineering, Submarine Outfall and Direcrtional Drilling Construction of a 1100m x 560mm OD PE outfall. Installation into dredged trench. Cliff crossing completed by a 300m long HDD through rock. Location: Gullane, Firth of Forth, Scotland Client: Scottish Water / ABV East Engineering, Submarine Outfall, Construction and Flowlay Construction of 1186m long x 273mm dia and 645m x 610mm dia concrete weight coated steel pipelines. A trench was dredged on the south bank of the Firth of Forth, but due to a lack of a construction site, the pipelines were built several km away on the north bank and launched directly into the sea. Using L&M’s Flowlay® surface towing and installation technique, the pipelines were towed to the site, positioned and then flooded down into the dredged trench. Location: Gailes, Ayr, Scotland Client: West of Scotland Water Authority Submarine Outfall Design and construction of 650m x 1200mm internal dia polyethylene outfall extension and diffuser. Dredged trench within Irvine Bay. Water depth 12m. Installation by the float and flood method. Location: Levenmouth, Firth of Forth, Scotland Client: East of Scotland Water Authority (s/c to AMEC/ Degremont) Submarine Outfall and Construction Levenmouth Purification Scheme. Design and construction of 1000m x 1.6m dia HDPE outfall as part of a PFI scheme. Pipeline installed within a dredged trench through the seawall which was crossed using a tunnel and shaft. Dispersion modelling undertaken by Kirk McClure Morton. Location: Inverclyde, Glasgow, Scotland Client: West of Scotland Water Authority (s/c to Amec/ Degremont JV) Submarine Outfall Design and construction of 1000mm x 900m dia polythene outfall pipeline. Dredged trench in Firth of Clyde to 40m water depth. Installation by the float and lower method. Location: Bangor, North Wales Client: Welsh Water Submarine Outfalls Four individual contracts in the Menai Straits: 1. Beach Road Pumping Station Outfall - MDPE pipe – 620m long x 1400mm diameter completed with concrete weight collars and a diffuser system consisting of Bifuration pipe work with massiv mesh protection. Installed in one length by the float and sink method. 2. Gorad Road Outfall – 340m long x 630mm diameter MDPE pipe complete with concrete weight collars. 3. Treborth STW marine Outfall – 100m long x 800mm diameter HPPE pipe installed by bottom pull. 4. Beach Road Transfer Main – Marine Section – 1800m of 800mm diameter HPPE pipeline installed along the foreshore, by the float and sink method. Location: East Worthing, Sussex, England Client: Southern Water Services Submarine Outfalls and Construction The construction and installation of two concrete coated epoxy lined steel pipeline outfalls, pulled into a pre-dredged chalk trench, including the installation of 30 No. 35 tonne pre cast concrete diffuser chambers, 5 pre cast hatch box chambers and the construction of a pile marker beacon. Twin 2.7m diameter steel pipejack culverts were also constructed to carry the pipes under the main Worthing to Brighton Coast Road, with sheet piled trench supported each side. In addition the two pipes were backlayed 500m through the fabrication area to the existing treatment works. Location: Teignmouth, Devon, England Client: South West Water Services Engineering, Submarine Outfall and Construction Installation of a 2.35km x 965mm dia long sea outfall. The steel pipeline was internally protected with a cement mortar lining and externally with a reinforced bitumen wrap and concrete weight coating. The pipes were fabricated into strings on a temporary trestle structure and pulled (along with the diffuser section) into a pre-dredged trench by barge mounted winches. The trench was later backfilled with selected stone backfill. Location: Rhyl, North Wales Client: Welsh Water Submarine Outfall and Construction The construction and installation of a concrete weight coated steel pipeline into a pre-dredged clay/ sand trench by the bottom pull method, including 15 diffuser risers and 6 hatch boxes. The existing concrete sea defence wall was removed to allow pipe installation and was temporarily replaced with a sheet piled cofferdam. Location: Charmouth, Dorest, England Client: Wessex Water Authority Submarine Outfall and Construction Installation of a 1.3km x 450mm dia long sea outfall. The steel pipeline was epoxy lined and coated with a bitumen enamel and a reinforced concrete weight coat. Pipeline pulled into pre-dredged trench by barge mounted winches on the LM Njord. The trench was later backfilled and the surf zone section protected with flexible concrete block mattresses and armour stone. A 900m ductile iron land line was laid to the pumping station and extensive mechanical and electrical works were carried out to upgrade the facility along with modifications to the treatment works. Location: Barmouth, West Wales Client: Welsh Water Authority Submarine Outfall, Trenching and Construction Construction of a long sea sewage outfall. Work included the fabrication on the beach of a 1.75km long x 325mm dia concrete weight coated pipe in 35 no. strings, pulling the pipe out to sea, post-burial using LM trenching machine SL4, and finally placing the 45m long diffuser section by diver. All marine work was supported by LME's barge, Njord Location: Baglan Bay Neath, South Wales Client: Neath BC/Port Talbot BC/Neath Submarine Outfall, Trenching and Construction 1220mm dia sewage outfall 4.42km long with 40 diffusers. Mild steel pipe, epoxy lined, coated and butt welded; continuous concrete weight coating. Pulled onto seabed by winch mounted on L&M pullbarge Odin, and jetted into seabed with TM III trenching machine to provide 600mm of cover. |