Extension of the purified water refining and control system at the Cintruénigo WWTP, Navarre

In operation since January 1996, the Cintruénigo wastewater treatment plant (WWTP) discharges its water into the river Alhama. In order to minimise the environmental impact of the discharge, it was proposed to equip the plant with a water refining and control system. The solution adopted is the construction of an artificial wetland under the plant to redirect the final discharge there. 
 
With a capacity of 250 litres per second, the new outlet consists of two siphons: one by means of a cofferdam to cross the river Alhama and the other next to the wetland to reach it as directly as possible

 

In addition, a spillway has been installed at the inlet of the treatment plant with a flow regulating valve and a screening system for the discharged flow. The latter consists of three 600 mm diameter bags which are capable of absorbing a unit flow of 1.16 m³/sec.
 
The wetland has a surface area of 4,972 m² and Phragmites australis is the dominant plant species. Willows and tamarisks are used for revegetation. The infrastructure of the site will be constructed by paving and enclosing the spillway and the wetland.