activities WORLDWIDE

Consulting ENGINEERS since 1963

Cotonou is the economic capital of the Republic of Benin and its surrounding areas with a population of 1,000,000 inhabitants and a drinking water system that partially covers Cotonou and its suburbs. Given the saturation of the current well fields and the limited extension of the network, SONEB launched a project in 2005 to improve the DWSS network in Cotonou to ensure the availability of drinking water over the medium to long-term. In 2005, SONEB conducted a diagnostic study of the DWSS system which revealed the need to carry out major works at a cost of around € 70 million. The works were divided into three phases:

  • Phase 1: urgent work - now completed
  • Phase 2: 1st stage of the development (2008-2012): reinforcement of the water infrastructure to produce and treat at least an additional 30,000 m3/day and the construction of a 4th distribution network - current contract, which consists of:
    • Extension of well field (16 new wells, 61,000 m³/day)
    • Construction of a new raw water transmission system with a 25.7 km (DN 200 - DN 800) forcemain
    • Rehabilitation and extension of raw water treatment:
      • Godemey water treatment plant: Rehabilitation of existing facilities (capacity 18,400 m3/d, i.e. 800 m3/h); extension works to increase the total capacity to 41,662 m3/d, i.e. 1,811 m3/h: Construction of additional degassing towers, construction of a 2,000 m³ treated water tank, extension of the reagent dosing installations (calcium hydroxide and calcium hypochlorite)
      • Védoko water plant (total capacity of 52,931 m3/d, i.e. 2,301 m3/h: Extension of the dosing installations, adaptation of the switching cabinets
    • Rehabilitation and extension of the pumping system:
      • Godemey water plant: Extension of the pumping station to pump towards to two distribution zones (Védoko and Godomey); installation of new variable delivery pumps ready for the future extension with the installation of an additional pump to meet demand in 2025, total capacity: towards Védoko: 2015: 2 +1 pumps 21,850 m3/d; 2025: with 1 additional pump of 24,200 m3/d; pump characteristics: towards Védoko: 330 – 550 m3/h at 60 – 36 m ; 132 kW ; towards Godomey: 2015: 2+1 pumps, 19,812m3/d; 2025: with an additional pump 30,875 m3/d; pump characteristics: 300 – 640 m3/h at 73 – 47 m; 132kW
      • Védoko water plant: installation of additional pumps with the following characteristics: towards the Maro Military network: 350 m3/h at 55m; 132 kW ; towards the Akpakpa network: 450 m3/h at 65m; 160 kW
    • The construction of a new water tower (1,750 m³)
    • Rehabilitation of 16.5 km of the DWSS network (DN 200)
      • 90.9 km extension of the DWSS network (DN 60 - DN 600)
      • Improved operating conditions by installing a remote control system
      • Supply and installation of approximately 7,000 private connections
  • Phase 3: 2nd stage of development: reinforcing Phase 2 actions, treatment/pumping and distribution of an additional 20,000 m3/day

The project management concerns works of Phase 2 which include the following objectives:

  • Improving the profitability of SONEB
  • Mobilisation of additional resources and improved operating conditions
  • Reinforcing the water supply, treatment, pumping and distribution system

Investment Phase 2: Euro 32,000,000

Services Provided

IGIP delivers full project management, preparation of design and supervision of Works within this project:

  • Preparation of the detailed design for the necessary extension works.
  • Preparation of tender documents for works and supply contracts.
  • Assistance in the awarding of construction and supply contracts, including tender analysis and the preparation of the evaluation report.
  • Contract Management and supervision of Works in accordance with the Technical Specifications, including the validation of construction documents, progress reports and the coordination between the various parties.