Large knife gate valves in stormwater drainage project

The tunnel ends at the terminal pumping station near Jebel Ali Port, where water is drained through a double system, which can drain excess water through pumps connected to lines extending 600 m into the sea with high operational efficiency. This makes the main pumping station highly integrated when it comes to services, buildings, and facilities in the management of stormwater drainage as well as surface water.

Offering protection to the marine environment, the collected stormwater will be discharged into the sea only after climate change and sea level has been considered, therefore, supporting the principles of sustainability and taking into account the safety of the marine environment.

One of UEA’s key sustainability projects

The station measures 150 x 175 x 62.5 (depth) m, and has an overflow structure with shoreline outfall, with 3 x 500 m HDPE pipes, 2,000 mm diameter outfall pipes, hydraulically actuated penstocks and valves, HVAC installation, power supply distribution network, power transformers and switchgears, as well as all associated buildings, including mechanical, electrical, instrumentation and control works and external works.

The deep tunnel stormwater system is considered the first of its kind in the region to drain stormwater and surface groundwater, by collecting water and storing it for the next 100 years.

Finding the right valve solution

After Archirodon was awarded the job, they proposed three different designs to the client, Dubai Municipality, to meet the project requirements. AVK and Orbinox stayed in close contact with Archirodon from the early stages, and were therefore able to bring their expertise within especially engineered big valve solutions to influence the design proposal.

As the specifications for the valve were not clearly defined, and even though the initial requirement was of a metal seated gate valve with hydraulic actuator, the team from AVK Gulf and Orbinox focused on an Orbinox knife gate (DN2200) as the preferred suggestion. The gate was to withstand several challenges due to the collection of highly corrosive groundwater under high-pressure (PN 10), making the knife gate made of super duplex (SA2507) material with hydraulic actuator stood out as the ideal solution.

After several meetings and visits, the knife gate solution was finally proposed as the most convenient solution for the client. In September 2019, the job was awarded to AVK and Orbinox, not only beating tough competition from other European providers but also considering that a DN2200 metal seated gate valve that can be hydraulically operated is actually very difficult to find.

Moreover, Orbinox’ WS model is a cost-effective solution with a proven track record of delivering similar solutions for various dams and reservoirs around the globe.

Challenging dimensions

Due to the size, weight, and dimensions of these huge, heavy valves, installation at the site came with its own set of challenges – not eased by the fact that they were to be installed at a depth of 42 m below ground. The entire process was slow and labour-intensive, enabling accurate and precise installation at the very first attempt for every valve, which each came with a weight of 20 tones. However, the actual fixing of the valves to the pipes was relatively straightforward as they are fixed with bolts.

The hydraulic cylinders operating the valves were also installed with extreme precision and accuracy enabling them to operate smoothly.

Close teamwork, engineering expertise and local support have proved to be our strengths throughout the project, opening an entryway into Dubai Municipalities’ robust project pipeline. The total project had a value of EUR3.4 million.