This project involved the design / construction, pre-start and start-up of the Ruães WWTP, where the treatment process includes: preliminary treatment (sieving, sedimentation and degreasing) and tertiary treatment (removal of Nitrogen and Phosphorus) through suspended biomass system at low load. In the solid phase treatment, the mechanical thickening and dewatering of the sludge by band filter was included. The treatment of odours produced in the installation, by biological means was also included. The contract also included the outfall for discharge of treated effluent into in the receiving environment.
While the work was carried out, the maintenance of the existing pond and aeration system was ensured, in order to allow the treatment of the effluent. Upon completion of the construction of the WWTP, the ponds and the remaining buildings were demolished / upgraded.
The main data for the WWTP, for the project horizon, was: equivalent population of 20,000 inhabitants, average flow of 3,000 m3 / day and peak flow of 260 m3 / h.