Novel hybrid technology for the sustainable development of the circular economy in urban agriculture
Climate change and environmental pollution are just some of the main challenges to be addressed. A number of actions have been taken, in particular the circular economy has proved to be among the most effective in overcoming the traditional approach of the linear economy. Circular economy means not only minimizing the waste produced by giving it a new life, but also preserving the use of resources such as energy and water. Among the different technologies developed by a circular economy approach, the use of photobioreactors and aquaponics systems are growing. They are closed systems of cultivation and growth of microalgae, which are the most important microorganisms in aquatic ecosystems for the global carbon balance and are fundamental for the capture and bioconversion of carbon dioxide (CO2) into energy, are widely used. The aim of this study is to highlight the synergistic action that could be provided by the combinated action between a photobioreactor microalgae and an aquaponic system. Specifically, the algal biomass obtained, after being dehydrated, could be partly used to feed the fish species in aquaculture, while the remaining part is treated in order to produce biofuels and biopolymers that are produced with high added value. The aquaculture system, in turn, thanks to the metabolism of the fish species involved and specific treatment, i.e. disinfection with UV + ozone, and biological treatment with self forming dynamic membrane, provides a source of nutrients indispensable for algal and vegetables growth.