 Out of the discharge of the Emisor Oriental 23 m3/s would be treated in a planned wastewater treatment plant in El Salto in Hidalgo State to deliver water to the Tula Irrigation District.Almost half of the investment (US$1.28 bn) will be for the construction of 6 wastewater treatment plants, the largest of which by far would be the Atotonilco (El Salto) plant.The US$900m contract to finance, build and operate the plant, allegedly the largest wastewater treatment plant in the world, was awarded in 2010 to a consortium led by the Spanish company Acciona.