PHA production will be made through a two stage anaerobic-photosynthetic HRAP system. In the first stage, a mixture of municipal wastewater and agricultural wastes like molasses, will be anaerobically pre-treated in a 20 m3 anaerobic UASB reactor. The effluent from the anaerobic stage will be sent to two 32 m2 HRAPs system. Biomass separation will be done by two clarifiers, including biomass recycled to the system. After PHA production, the remaining biomass will be transformed into biogas using thermal pre-treatment and an anaerobic co-digestion process. Agro wastes and sewage sludge will be used as co-substrates. Biomethane will also be produced by an innovative biogas upgrading system through photosynthetic fixation of CO2 as algal biomass using digestates as a source of nutrients. An evaporative system will be used for digestate stabilization. All these tasks will be installed and operated at El Torno WWT plant, Chiclana de la Frontera in Spain (figure 1).
A demo scale 3000 m2 HRAP will be installed at El Toyo wastewater treatment plant (Almería, Spain) to obtain irrigation quality water. After harvesting by flotation, the effluent will be treated using a planted filter with natural material for enhancing P and N recovery. Irrigation water will be obtained and reused with solar anodic oxidation disinfection and a smart irrigation system. A flow diagram of this installation as shown in figure 2.