Águas de Portugal Group
Description of the visit
The Ilhavo and Cacia WWTPs, located in the Ria de Aveiro region, just to the south of Porto, were used as case studies for an R&D project that has been developed by Porto's Higher Institute of Engineering (ISEP). This project, based, amongst other things, on a student's master’s thesis, aims to apply artificial neural networks to the optimization of anaerobic digestions in treatment plants. The overall objective is to maximise the increase in production and/or quality of the biogas generated by these anaerobic digestions and, so, generate more electricity from this fuel. A new approach is underway for 201 and it is hoped that this will result in better advantage being taken of the features of the biogas produced.
The two treatment plants are medium-sized and include, in the solid phase, an anaerobic digestion stage with two digesters each and the respective equipment necessary for the heating of sludge and production of electricity. Together, they have made an outstanding contribution to the marked improvement seen in the Ria de Aveiro since the beginning of the last decade. Today, the lagoon is in a much better condition, thanks to the integrated system of sanitation that is mainly based on these two WWTPs. For all these reasons, the operations teams have been putting a lot of work into the different forms of research and collaboration they do with academic institutions. This work focuses on management efficiency and the reduction of operating costs for these infrastructures. Both WWTPs are near Porto and motorway access is good. Although the Ílhavo WWTP is located a little further away, it has the additional attraction of an innovative biogas treatment system and is, therefore, ideal for a visit focused on innovation.
The Ílhavo WWTP is located in the parish of Gafanha da Encarnação (Ílhavo municipality) and has been designed to treat 39,278 m3 per day of urban wastewater produced in the municipalities of Aveiro, Cantanhede, Ílhavo, Vagos and Mira (159,700 HE).
The plant, which cost around 14 million euros, has been in operation since August 2002 and plays a key role in the treatment of industrial wastewater produced in the region.
The treatment at the Ílhavo WWTP is secondary, and the treated wastewater is discharged into the Atlantic Ocean through the São Jacinto Submarine Pipeline (Aveiro). The plant also includes, as mentioned above, anaerobic digestion of sludge and cogeneration.
The visit includes
What is innovative about it?
Demonstration sites in the area of anaerobic digestion, particularly with regard to:
Biogas treatment through a biological percolation bed;
Optimization of anaerobic digestion by neural networks: Neural AD.
Ferric chloride is added to the mixed sludge (before shipping to digestion) to control the hydrogen sulphide concentration in the biogas. The final treatment of the biogas is carried out in 2 sets of chemical odour treatment scrubbers that have been adapted to act as biological percolation beds. Both the application of scientific knowledge and the efficient use of available resources at the WWTP have meant that out-of-service equipment now has a new use. The facility has been operating since 2013, with excellent hydrogen sulphide removal efficiency rates. This has meant that less ferric chloride needs to be used in the initial stage.
The Neural AD (Neural Networks + Anaerobic Digestion) project, involving ISEP and Águas do Centro Litoral (AdCL) (a subsidiary of AdP), has been in development since 2013. This is applied R&D with artificial neural networks being used to optimise anaerobic sludge digestion. The research has resulted in better prediction of the behaviour of the process under different conditions. This, in turn, has led to maximised energy recovery from the biogas produced in the sludge digestion project generated in the WWTP. The methodology was applied in 3 AdCL WWTPs (Cacia, Espinho and Ílhavo) and is still evolving. Initially designed in 2013 by Águas de Portugal (AdP) and ISEP, in the second year of development the Technical Higher Institute (IST), the Faculty of Science and Technology of Lisbon's Nova University, and the University Minho joined the project, by running case studies at other AdP Group WWTPs.
The Neural AD project won an International WEX Global Awards 2015 award, in the ‘Water and Energy’ category.
Location, time and accessibility
During the visit, participants will be accompanied by technicians from the WWTP operations staff and by the department coordinator responsible for the infrastructure operation, as well as a management representative. They will have the opportunity to see the whole facility from the water inlet to the final effluent, giving them the possibility of networking, at the same time, with the staff. Participants will see the changes in water quality across the water treatment process and the relation between the water treatments and the production of sludge and energy (duration 60-90 minutes).
Moreover, visitors will attend a presentation of the Neural AD project and biogas treatment and the applied results at the Ílhavo WWTP (demo sites visit duration: 60-90 min). The maximum number of attendees is 25, to ensure there is ample opportunity for technical discussion and an exchange of experiences. The facility is not adapted to people with reduced mobility. The participants will get to the WWTP by bus.