Robust dewatering pumps for continuous operation under tough conditions

Rental of complete dewatering solution simplifies residential construction in Cádiz, Spain

In 2015, the Spanish construction company Obenasa was contracted to build a multi-family residential building in Cádiz. Situated on a plot of just under 6'000 m2, the building was to have two basement levels; one situated a full meter below the phreatic level. Working at this depth would require constant pumping of considerable amounts of water, with any failure posing risks to the foundation’s structural stability.

Construction site in Cadiz Spain

The challenge

Excavation for the two basement levels of the 135-apartment residential building required a maximum digging depth of -9.50 m. Given that the phreatic level was -5.0 to -5.5 meters, this meant fighting both produced and accumulated water. A further challenge was the long-term nature of the project. To protect the structure’s stability, pumping would be required constantly for many months. Also, the location of the pumping wells had to be planned so that they would not interfere with the building work.

The solution

As a first step, a laboratory made tests to determine the water volume to be pumped. Using this information, the location of the wells was planned so that they would not disturb the construction work. Sulzer designed the system with 14 high-capacity drainage wells and pumps, connected by two high-volume water collection pipes surrounding the site. Each pipe passed through a settling tank that safeguarded the pumps by removing sand and fine solids.

Sulzer provided valuable support in achieving a successful pumping operation. They have well-proven solutions and trustworthy experience. Sergio Romanos, Site Manager, Obenasa – Grupo Obras Especiales
Installation of drainage wells and dewatering pumps
Installation of drainage wells and dewatering pumps

Customer benefit

  • The entire system was supplied, run and maintained by Sulzer on a rental basis
  • The Sulzer solution was immediately successful in lowering the phreatic level
  • The dewatering system kept the water away for the entire eight-month building phase.
  • Obenasa was able to work without water-related delays or structural risks to the finished building

Scope of delivery

  • Setup of 14 drainage wells (drilling and sheathing in DN 320 mm)
  • Supply and installation of surrounding collection pipe in HDPE DN160 and DN 200, plus valves and meters
  • Eight-month rental supply of 14 submersible dewatering pumps JC 54 ND and 2 GSM control panels controlling seven pumps each
Sulzer’s people ensured successful pumping with immediate results. Sergio Romanos, Site Manager, Obenasa – Grupo Obras Especiales
Products
  • Submersible drainage center-line pump XJC 50
    The pump is ideal for pumping water and dirty water mixed with light abrasives. 50 Hz: 5.6 kW. Head max 45 meters, flow max 35 l/s. 60 Hz: 6.7 kW (9 Hp). Head max 49 meters (161 feet), flow max 36 l/s (571 gpm).

  • Pump control panels
    A wide range of control panels are available to enable a strong and flexible product offering. New panels are added continuously to match market needs and demands.
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