The CALAGUA group develops control systems and algorithms for the most important processes in wastewater treatment. The algorithm designs are based on numerical simulations and subsequent validation in pilot plants. Most of the controllers developed to date have also been validated in full scale WWTPs.

The currently available control systems developed by the research team include the following:

• Aeration controllers for systems using turbocompressors, blowers and/or turbines
• Control of biological nitrogen removal using low-cost probes (DO, pH and redox potential) or nutrient probes/analysers
• Control of biological phosphorus removal (optimization of primary sludge fermentation in fermenters or primary decanters)
• Sludge age control in the biological process
• Influent controller for dividing the inflow among the different reactor lines
• Sludge line optimisation controller to maximize phosphorus recovery by struvite crystallisation (control of level, flow, crystalliser pH and thickener elutriation)
• MBR membrane fouling control (physical cleaning by regulating biogas/air flow and backwashing stage frequencies

The CALAGUA group has installed aeration and biological nitrogen removal control systems in 14 Spanish WWTPs, achieving considerable improvements in the stability of the biological process, nitrogen removal and reduced power consumption.