El new Montalvo submarine outfall and the Sanxenxo port wastewater pumping station They are now officially in the hands of the Sanxenxo Town Council. These are two key pieces of an ambitious sanitation plan that seeks to significantly improve the water quality of the Pontevedra estuary and strengthen the environmental protection of this coastal area.
The state-owned company Waters of the Basins of Spain (ACUAES) has formalized the transfer of these infrastructures, within a larger project that also involves the Poio City Council and which totals an investment of 24 millones de eurosThe goal is to modernize the entire purification and pumping system, guaranteeing a more efficient and sustainable service for an area strongly linked to tourism and the sea.
Transfer of management to the Sanxenxo Council
With the signing of the agreement, the The Sanxenxo City Council assumes the operation, conservation and maintenance This includes both the Montalvo submarine outfall and the Sanxenxo Port pumping station. The Poio Town Council will participate as a user of the system once the Raxó pumping station, which is integrated into the same sanitation scheme, becomes operational.
The transfer ceremony took place on the beach, in the vicinity of MontalvoThe signing took place with the presence of the president of ACUAES, María Rosa Cobo, and the mayors of Sanxenxo and Poio, Telmo Martín and Ángel Moldes. The agreement represents an administrative and operational milestone, as it marks the start of direct management by Sanxenxo of facilities considered strategic for the estuary.
As detailed in the firm, the transfer of assets will be done in a progressiveAs the remaining elements of the system come into service, they will be added to the municipal inventory, with the expectation of completing the process in autumn with the delivery of the new Paxariñas wastewater treatment plant.
The administrations involved emphasize that this action is part of a comprehensive sanitation improvement plan that affects both Sanxenxo and the western area of Poio, including new collectors, pumping stations and the expansion of the treatment plant, with a view to ensuring the quality of the waters for bathing, fishing and nautical activities.
Financing and distribution of investment
The package of actions represents a total investment of 24 millones de euroswhich are financed through a combination of European funds and local contributions. Half of the budget comes from ERDF funds 2014-2020 and 2021-2027, channeled through the General State Administration, while the rest is covered with resources linked to the municipalities involved.
In the specific case of Sanxenxo, the mayor has stressed that Citizens do not assume an additional direct cost. for these works. The portion that corresponds to the municipality is covered by the annual fee paid by the water service concessionaire, so, in the words of the mayor, "the residents have not had to contribute a single euro" from their own pockets to finance the infrastructure.
The framework agreement signed between ACUAES, Sanxenxo and Poio It establishes the distribution of responsibilities and sets the economic framework for the operation. In this way, the long-term viability of the sanitation system is ensured, both in terms of the amortization of investments and the operating costs of the new pumping and treatment equipment.
The institutions involved also emphasize the nature Sourcing This investment is for tourism in the Rías Baixas, a sector that depends heavily on the state of the waters and the environmental quality of the beaches, coves and marinas of the region.
Technical characteristics of the Montalvo submarine outfall
El Montalvo submarine outfall It is one of the central components of the new system. It consists of a conduit of high density polyethylene (HDPE) 1.304 meters long and 630 millimeters in diameter, designed to discharge the maximum flow from the Paxariñas treatment plant, estimated at 557 liters per second.
During the execution of the project, the land section of the existing emissary, while the first segment of the new route, 251 meters long, was carried out by Horizontal directional drilling (HDD)This technique allows the pipeline to be installed below the surface with less impact on the coastal environment and on public use of the beach.
One of the most outstanding environmental contributions of the work has been the removal from the seabed of an old section of outfall pipeThe pipeline, approximately 900 meters long, was no longer in use. This removal of obsolete infrastructure helps improve the condition of the seabed and reduces risks associated with abandoned pipeline remnants.
The hydraulic design of the outfall takes into account both the maximum flow rate of the treatment plant and the oceanographic conditions of the estuary, so that the dispersion of the treated effluent It is produced under optimal conditions, minimizing any impact on the coastline and complying with European regulations on urban wastewater.
Modernization of the Sanxenxo Port pumping station
Along with the outfall pipe, the other key infrastructure transferred to the City Council is the Sanxenxo Port pumping and boosting stationwhich has undergone a major renovation to increase its capacity and reliability. Following the upgrade, the pumping station can handle a flow rate of up to 200 liters per second.
The intervention has involved the removal of the old equipment, keeping only the deodorization and ventilation systems which were still considered valid. In their place, four new vertical shaft dry-chamber pumps, new boilers and valves, a surge tank to protect the pipeline against overpressure, and a crusher to improve the pretreatment of water entering the system.
In addition, the station has been equipped with a relief control system This allows for safer management of situations involving heavy rainfall or isolated incidents on the network. The existing pumping system is maintained, now supported by higher-performance electromechanical equipment designed to respond more quickly to any contingency.
With these improvements, the port's pumping system is fully integrated into the new sanitation scheme, ensuring that wastewater is conveyed to the Paxariñas Wastewater Treatment Plant under suitable conditions, avoiding uncontrolled spills and reducing the risk of pollution episodes in the port environment and on nearby beaches.
Expansion and operation of the Paxariñas WWTP
The Montalvo submarine outfall is directly connected to the Paxariñas Wastewater Treatment Plant (WWTP)which has undergone a major expansion. The new plant became operational on March 16 and is designed to serve 98.412 equivalent inhabitants, with an average flow rate of 16.042 cubic meters per day.
The expansion works have made it possible to reach a optimal level of purificationadapted to current requirements regarding discharge and environmental quality. The delegation of authorities and technicians who participated in the signing of the transfer of the outfall visited the wastewater treatment plant facilities to verify its operation and the progress of the pending work.
Currently, the work is focused on the demolition of the old facilities that have become obsolete with the new plant configuration, as well as in emptying, cleaning, repair and renewal operations of electromechanical equipment in decanters and biological reactors.
Simultaneously, a new office building and workshop intended for operations and maintenance personnel. Once these works are completed, the surrounding area will be landscaped, a general perimeter fence will be built, and the installation of photovoltaic panels to reinforce the energy efficiency component of the installation.
Network of collectors and complementary pumping stations
The project is not limited to the outfall and the wastewater treatment plant, but includes a network of collectors and pumping stations which allow the collection and conveyance of wastewater from different areas of Sanxenxo and the western part of Poio towards Paxariñas. Among the projects visited by the authorities were the collectors of Raxó, Areas and the Avenida de León, as well as the O Espiñeiro, Areas and Raxó pumping stations.
These complementary infrastructures ensure that the urban and tourist centers of the region are connected to a modern sanitation system, preventing scattered spills and improving the capacity to respond to peak influxes, especially in high season, when the population multiplies due to the arrival of visitors.
As the works progress, it is expected that, in stages, all parts of the system enter service and will be transferred to the Sanxenxo Town Council as they meet the technical and administrative requirements for their final commissioning. ACUAES has set the completion of the process for next autumn.
Overall, the entry into service of Montalvo submarine outfall, the modernization of the port pumping system and the expansion of the Paxariñas WWTP They represent a qualitative leap forward in sanitation management in the Pontevedra estuary. The new infrastructure strengthens environmental protection, supports tourism and fishing, and lays the foundation for a more efficient and sustainable water management model in Sanxenxo and Poio, with investment backed by European funds and the involvement of local authorities.