Interactions Between Organizations Regarding Management of River Water Basins at a Socially Vulnerable Context

The hydrographic basin is the most accepted territorial unit for the integrated management of water resources. The Matanza-Riachuelo (MRB) and Reconquista (RB) basins are located in the most densely populated and industrialized region of Argentina. They are plain basins, with low-flow and low self-purification ability. They present the most serious and oldest urban environmental problems in Argentina in relation to the dumping of domestic and industrial effluents, pipelines, and a lack of land use planning. To improve the management capacities of both basins, two modalities were applied: institutional autarky in the MRB (Matanza-Riachuelo Basin Authority—ACUMAR) and adaptive concertation in the RB (Reconquista Basin Committee—COMIREC). In this context, an interaction was established between government agencies and research institutes that allowed the design and implementation of water remediation strategies applying Chlorella vulgaris immobilized in alginate. This experience demonstrated the potential of this simple and low-cost technology to remove urban-water contaminants, offering as an additional advantage of the possibility of an easy biomass recovery, which may become a source of alternative energy. The first approach was to push for the reduction of several chemical and microbial contaminants present in Cildáñez stream (MRB) using microalgae immobilized in alginate beads. However, these beads had a relatively short shelf life in the natural environment. To overcome this limitation, a second approach was designed: a 3D-printed PLA device to protect the microalgae in alginate matrix. The algae within the PLA devices were protected and able to bioremediate the highly contaminated Bancalari stream (RB).