Since 2005, the La Gavia Wastewater Treatment Plant (WWTP)in Madrid has had the capacity to treat an average flow of 2 m3/s (172,800 m3/day), representing a 950,000 population equivalent.
The current facilities include a water reuse system with a total capacity of 1,800 m3/h (43,200 m3/day). This tertiary treatment stage is made up of settling and sand filtration. It also includes microfiltration and final ultraviolet disinfection for the entire flow.
The quality standards imposed by the Tagus River Basin Management Authority resulted in analysis of the upgrading needs of the La Gavia WWTP in order to adapt the facility to the new effluent requirements. As a result of these studies, a tertiary treatment facility was designed and built to treat an average flow of 3,600 m3/h (1 m3/s) and a maximum flow, in exceptional cases, of 5,400 m3/h (1.5 m3/s).
In addition, the capacity of the existing pumping station from the South interceptor sewer to the La Gavia WWTP was increased from 500 l/s to 1,500 l/s to enable.
The flow enters the WWTP from the La Gavia interceptor sewers I and II, which carry wastewater from the districts of Vallecas, and a large portion of the inflow also comes from the South interceptor sewer. Because planned urban development in the districts of Vallecas have not as yet been completed, the full treatment capacity of the WWTP is not currently being used.
For this reason, the current initiaitve also includes the construction of a bypass between the interceptor sewers on the Right Bank and the existing South interceptor sewer on the two banks of the Manzanares River for the purpose of redirecting, in very specific operating circumstances, a flow of up to 2 m3/s of wastewater from the first interceptor sewer to the second, thereby providing a higher inflow to the La Gavia WWTP (in combination with the pumping station).
Finally, part of the La Gavia tributory was restored. This involved cleaning, excavation and the addition of a breakwater layer for the purpose of solving the current problem of flooding of the lower part of the WWTP.
The contract for the work, valued at €9,449,593.35, was awarded to the ERAR de la Gavia consortium, made up of Sacyr Construcción and SADYT.