The construction of the wastewater treatment plant in Viladecans (Barcelona) continues. This plant designed and built for case study 1 is devoted to biomass production and its further energetic valorization and added-value products recovery. Urban wastewater and agricultural runoff are fed to three PhotoBioReactors (PBRs) for cyanobacteria cultivation. The biomass collected from the three PBRs is harvested in a lamella settler followed by a thickener and then used for polyhydroxybutyrate (PHB) extraction and biogas production via anaerobic digestion. The biogas produced is upgrated in a adsorption column fed with PBR biomass in order to obtain biomethane, whereas the sludge from the anaerobic digester is treated in sludge treatment wetlands to produce bio-fertilizer. The water effluent from the harvesting unit (lamella settler) is in turn submitted to a tertiary treatement (solar-driven ultra filtration) and eventually used for crop irrigation.
The construction and implementation of the biomass production and harvesting units was completed in April 2017. The three PBRs were inoculated with a mixed culture of microalgae in mid April and, since then, the plant has been operative, treating 3m3/d of wastewater. Subsequently, an operation technician has started the corresponding maintenance and well-functioning tasks.
In the coming weeks, the anaerobic digester and tertiary water treatement will be installed. Additionally, the biogas upgrade column, irrigation system, and sludge treatment wetlands have been designed and will be built shortly for them to become operative in autumn 2017.
Hybrid photobioreactors and harvesting unit of site 1