The plant of case study 1 is installed in the UPC Agrópolis campus, located at the municipality of Viladecans (Barcelona). The plant is composed of 3 horizontal photobioreactors (PBRs) of 10m3 each. PBRs are daily fed with 6.9m3 of urban wastewater and agricultural runoff. The plant produces around 2kg per day of microlagae biomass dominated by cyanobacteria, that is harvested in a lamella settler. The biomass harvested is treated together with secondary sewage sludge in an anaerobic digester of 450m3 that currently produces around 80 L of biogas per day. The sludge from the anaerobic digester (22.5 L/d) is subsequently treated in a sludge treatment wetland, while the water coming from the settler (6m3/d) is treated in nutrients recovery columns based in sol-gel coating and then disinfected by a solar-driven system based on ultrafiltration. Resulting effluent is applied for irrigation in an 80m2 field planted with rapeseed.
In the following months the operation of the PBRs will be modified in order to enhance the accumulation of polyhydroxybutyrate by cyanobacteria.