Berriatua-Ondarroa interceptor, 1st Phase
Project management:
Execution period:
Bizkaia Provincial Council (DFB)
4,275,760 €
Diputación Foral de Bizkaia (DFB)
October 2007 - March 2009


The work carried out is as follows:

General interceptor

The general interceptor or collector, with a total length of 894 m., which functions under gravity, has two stretches: Gardotza to Ensanche Pumping Station and Kamiñazpi to Ensanche Pumping Station, both emptying at Ensanche Pumping Station. The construction method employed was microtunnel drilling in rock for 1200mm. in diameter with reinforced concrete pipe jacking. The yards used for working and for withdrawing the jacking equipment were executed by means of shafts with retaining walls.

Secondary collectors

In order to conduct the wastewater from the Rentería and Kamiñazpi neighbourhoods into the general interceptor, 2 secondary collectors with a total length of 540 m. and diameters of between 315 mm. and 800 mm. were executed. In general terms the construction system employed was that of a collector in a trench. However, when the depth was considerable, jacking with a steel jacket was employed.

Kamiñazpi spillway

This control device, into which the Kamiñazpi collector empties, consists of a regulating tank housed in the working shaft of the Kamiñazpi-Ensanche  Ø1.200 mm. jacking. The volume of regulation provided by the spillway is approximately 165 m3. Excess flow is discharged into the river by means of a relief collector 800 mm. in diameter, which has a check valve to prevent water from entering when the River Artibai is in spate.

Ensanche pumping station

Ensanche pumping station has been built on the left bank of the River Artibai. Initially this pumping station will receive the flows from the Rentería and Kamiñazpi neighbourhoods of Ondarroa. Later it will also collect the flows from Rentería's new industrial estate, and likewise from the area to be developed in Ondarroa's Aieri neighbourhood. All these flows reach the pumping station via the 2 stretches of the general collector, one of which comes from Gardotza and the other from Kamiñazpi, and they are impelled to line 1 of the new Galtzuaran wastewater treatment works.

The station is equipped with two shredders of solids with a nominal flow of 250 m3/h  situated before the aspiration chambers, and also 4 pumps with a nominal flow of 80 m3/h.

The pumping station also includes a plant built at ground level. This plant houses the electrical switchboards and control panels. Horizontal directional drilling was also carried out beneath the bed of the River Artibai to carry an electricity supply to the pumping station from the opposite riverbank.

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