We optimise the energy recovery from sludge through two-phase anaerobic digestion at different temperatures

EDAR de Alcoy: first implementation in Spain of thermal double phase that reduces sludge by 25.5%% and increases biogas by 20%%.

We have implemented an innovative two-stage anaerobic digestion technology that improves the efficiency of sludge treatment at wastewater treatment plants, increasing renewable energy production and reducing the volume of waste generated.

At the Alcoy Wastewater Treatment Plant, we are developing a new model based on two thermal stages: a first phase at 55°C which enhances sludge hydrolysis, and a second at 35°C which optimises its stabilisation. This approach allows us to accelerate the biological process and maximise the energy recovery from the organic matter.

The results reflect a significant improvement in performance: sludge production has been reduced by 25.5 % and biogas generation has increased by 20 %, reinforcing the facility's energy self-sufficiency. In addition, the process contributes to sludge sanitisation, with a 90 % reduction in the microbiological load.

This advancement, developed alongside EPSAR and supported by R&D&I projects, consolidates a more efficient and sustainable model for sludge management, aligned with circular economy principles and aimed at maximising resource recovery.