Palencia WWTP becomes first in Europe to implement pioneering biological wastewater treatment technology

Palencia is the first European city with a population of over 10,000 to use the new technology in full-scale biological wastewater treatment. The innovative technology will maximise the sustainability, capacity, efficiency and resilience of the treatment process. This breakthrough for the city has materialised thanks to collaboration between Palencia City Council, SUEZ, Aquona – the group’s water service concessionaire in Castilla La Mancha and Castilla y León – and the CETAQUA Water Technology Center in this pioneering project at worldwide level. The project forms part of Aquona’s Strategic Plan to ensure that the WWTP closes the loop in accordance with the principles of the circular economy.

Until now, the InDense technology recently implemented in Palencia had previously only been partially installed in a WWTP in Dijon in France. The installation work at the Palencia facility took almost a year, during which time plant operation was not affected at any time. It is now envisaged that the operation of the WWTP will be monitored for a complete year for the purpose of rolling the model out to other cities, not only in Spain but worldwide.
This innovative project is based on the installation of cutting-edge technology that enables the mechanical separation of activated sludge in the bioreactor, for more effective elimination of nitrogen, phosphorus and carbon in the water. This will increase the treatment capacity of the plant without the need for additional reactor volume. It will also lead to enhanced process efficiency in adverse weather conditions and a substantial improvement to the quality of the water returned to the environment. Similarly, thanks to DENMASS, the treatment process in Palencia will be far more sustainable in terms of reducing waste production and the consumption of chemicals.

«Palencia is to delighted to have been chosen to initiate this revolutionary project in terms of improving environmental quality. This has much to do with the firm commitment that Aquona has made to ensure that, beyond having the cheapest and amongst the highest quality drinking water in the country, the people of Palencia can boast that the water cycle in our city is a pioneer at international level and that we are capable of returning the water to the river in better condition than when it was collected,” said City Councillor for the Environment, Juan Antonio Marcos.


DENMASS is the latest technological enhancement associated with the ambitious Strategic Plan that Aquona has been implementing for several years in the capital. This plan encompasses all the infrastructures associated with the municipal water service, including the Wastewater Treatment Plant (WWTP), the Drinking Water Treatment Plant (DWTP) and the supply network, “which is also the subject of an important project to improve and diversify its capacity”, said the manager of the company in Palencia, Javier del Sol. He also spoke of “pipe renewal, which involves a significant annual investment”.

The ultimate goal of this Strategic Plan is to make the entire service capable of recovering biowaste, to be self-sufficient in terms of energy and to generate zero waste. In other words, to create what is known as a ‘biofactory’.

In this sense, and as in the case now with DENMASS, Aquona has invested in the implementation of the most cutting-edge technology in the sector, such as organic filters, a CHP plant and solar panels. More recently the company has participated in the ECOVAL initiative, also led by CETAQUA.  The goal is to obtain resources or products of high added value rich in organic carbon, such as volatile fatty acids, through the recovery of organic waste generated in municipal environments. In other words, to drive waste reduction and environmental protection through the conversion of waste into resources that are in high demand in the plastics, lubricants and agrochemical industries.