Population equivalent

The biggest water treatment project in Argentina in the last 70 years.

The system consists of a pretreatment plant, an input lifting station and an output pumping station.

The joint venture consisting of ACCIONA and FISIA ITALIMPIANTI (WeBuild Group) was awarded the EPC contract by AySA for the Sistema de Riachuelo project in Argentina. The aim is to create an integrated solution to respond to capacity limitations and service level quality of sewerage systems in the metropolitan area of Buenos Aires, providing a service to a population of 4.3 million.

The system offers benefits to 12 municipalities in Buenos Aires and will incorporate a further 1.5 million people into the sanitation network in the future. The project also generates great social benefits in terms of public health, the environment and social development. Overall, more than 30 kilometres of tunnels will mean better service quality and the avoidance of pollution from wastewater effluent in the Riachuelo area.

General information

  • Entity: AySA
  • Location: Buenos Aires, Argentina.
  • Population supplied: 4,300,000
  • Flow rate: Intake and output pumping: 36 m3/second, pretreatment plant 27 m3/second,
  • Type of contract: EPC

Key features

The Riachuelo System project consists of three contracts:


  • Mega-collector
    • More than 30 kilometres of tunnels
    • Removal of coarse solids (4 u x 100 mm)
    • 8 vertical-shaft dry chamber electric pumps with a capacity of 4.5 m3/second each and an overall pump head of 23 metres


  • Pretreatment Plant
    • Treatment capacity: 27 m3/sec
    • Removal of coarse solids
    • Medium and fine mechanical screening
    • Separation of sands and floating bodies: 32 desanders


  • Output pumping station
    • Vertical-shaft dry chamber electric pumps with a capacity of 4.5 m3/second each and an overall pump head of 19 metres.

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