Advanced technologies for the reduction of sludge production in waste water treatment plants

Implementation period

July 2023 – April 2024

Field of work

Digital technology
Resilient infrastructures

Project funded by the Ministry of Industry, Trade and Tourism of the Government of Spain and the European Union – Next Generation EU. Call for grants to support “Agrupaciones Empresariales Innovadoras” for the year 2023, within the framework of the Recovery, Transformation and Resilience Plan.
File number: AEI-010500-2023-303


Since the publication of the RD 1051/2022, of 27 December, which establishes standards for sustainable nutrition in agricultural soils, there is an increasing concern about the final use of sewage sludge due to the limitations established. Effectively addressing this challenge means developing new wastewater treatment processes that minimise the generation of sludge to reduce both the difficulties associated with its management and the operating costs linked to the energy consumption required for its treatment.
LOWDOS proposes developing a technology that integrates two biological processes, anoxic and aerobic, working in series, which will be able to degrade COD according to the discharge limits required by regulations, thereby reducing the sludge generated in the process.


The main goal is to minimise the generation of sludge produced during wastewater treatment processes. For this purpose, LOWDOS focuses on the development of an anoxic biological treatment technology, which reduces sludge production while effectively removing the organic load from the wastewater treatment plants by consuming COD during biological activity. The validation of the technology will also require the monitoring of key parameters for process control and the development of the IoT platform for data processing and visualisation.

Considering that sludge production can be drastically reduced but not decoupled from the purification process, LOWDOS is a two-phase project that will also monitor the sludge generated to analyse alternatives for its use and adapt the bioprocesses to improve its composition.


The main result of LOWDOS is the technological validation and the definition of the working ranges of the main variables that govern the two processes that integrate LOWDOS: the anoxic and the aerobic. Thus, in this first phase, the expected results are as follows:

– Design, construction and start-up of a prototype to be used in the technological validation.
– Design and implementation of the monitoring and control system for the water quality sensors.
– Technological validation and working parameters optimisation of the anoxic and aerobic processes.
– Characterisation of the sludge generated in both processes.