The Barcelos City Hall opened a public tender, worth 35.4 million euros, for the construction of the municipality’s new Wastewater Treatment Plant (ETAR), according to an announcement published today in the Official Journal.
Interested companies must submit their proposals by October 23, after which the project has an execution period of 910 days, counted from the date of award.
The Barcelos municipality has already stressed that this is the “biggest investment of all time” in depolluting the Cávado River.
The new ETAR, to be built in the Barcelos parish, will replace the current one, in operation since 1999 and “technically obsolete, with a limited capacity to respond to the demographic, urban and industrial evolution of the municipality.”
“The technical limitations that the current equipment presents translate into inadequate treatment of the wastewater and, consequently, the pollution of local water bodies, compromising biodiversity and public health,” the municipality states.
Therefore, the investment in building a new ETAR is identified in the Strategic Plan for Water Supply and Sanitation of Wastewater and Rainwater (PENSAARP 2030) “as a first-line priority to resolve serious environmental liabilities.”
The new ETAR will have capacity to treat not only the wastewater from homes, but also the pollution generated by the textile industries in the municipality.
After it becomes operational, it is estimated that more than 73 thousand people will actually be connected to the network and benefiting from the service.
The Braga district municipality notes that one of the major technical challenges of the project lies in the fact that around 35% of inflows are of industrial origin, mainly from the textile sector (dyeing works), presenting dyes and difficult-to-degrade organic compounds and requiring advanced technologies.
“The chosen technology uses beneficial microorganisms to eliminate the pollution present in the wastewater, in a prolonged process that ensures a more efficient treatment. This system can remove harmful compounds, such as nitrogen, without the need for additional equipment,” explains the municipality.
After this biological phase, the water will undergo a supplementary treatment, which includes very fine filters and the application of ozone, to remove color and the most resistant pollutants, typical of effluents from the textile industry.
“Thus, ensuring compliance with the legal water quality parameters of the Cávado River,” underlines the municipality.
In addition, the new ETAR was designed to consume less electricity, with efficient aerators and motors that only operate when necessary.
To gain autonomy, it will produce its own energy through solar panels and a small hydroelectric plant at the outlet of the treated water.
The treated water will be reused within the plant, the sands removed from the residues will be reused and the demolition materials will have new life.
The clean water will be returned to the Cávado River, in an area integrated into the Northern Littoral Natural Park, a sensitive ecosystem that shelters protected species such as the otter.
“By significantly reducing the pollutant load discharged into the river, the new ETAR will contribute to the improvement of the water quality and, indirectly, to the preservation of habitats and biodiversity of the region,” the municipality also notes.
