Application of Systems Thinking to the assessment of an institutional development project of river restoration at a campus university in Southern Brazil.

Rapid urban growth and high population density have become a problem for urban water resources, especially in developing countries. In general, the pollution of rivers and degradation of ecosystems are the result of both management failures and lack of sewage treatment. River restoration appears as a solution to improve this scenario, but it is common for there to be an absence of a systemic vision in these projects. Thus, this work analysed one of these projects as an initial approach to create coherent (qualitative) shared perspectives on the same problem. This project was developed in a Brazilian university territory in response to a Public Civil Action. Rivers within the university surroundings are degraded due to sewage disposal and wastewater pollution from external and internal sources within the university, but the programme actions contemplate only interventions within the perimeter of the university while excluding the other parts of its watershed. We analyse this problem under a Systems Thinking approach by using causal loop diagrams, being clear that ecosystems cannot be reduced to territorial limits only. The systemic map shows many actions that contribute to the water quality degradation, with emphasis on illegal dumping of wastewater (sewage) and land use change in the upstream areas prior to the university. Point measures are palliative and do not guarantee the quality of river water. Regulation of impervious surfaces and correct disposal of wastewater can improve the current panorama, but greater integration between stakeholders and other key actors is required.

Use of shrimp shell for adsorption of metals present in surface runoff.

This research analyzes the use of natural shrimp shell and commercial chitin for biosorption of metal ions in surface runoff. Investigation of the use of these biosorbent materials in drainage systems becomes a management measure for two extremely important issues in Brazil, fish waste management and the surface runoff quality. Methodological procedures involved treatments with different amounts of unprocessed shrimp shell and commercial chitin (5g and 10g) for 200mL of a compensatory drainage mechanism (infiltration swale). The contact time of biosorbent and runoff was 24h and removal of metal ions Fe, Mn, Zn, Cu, Ni, Pb, and Cr was studied. Tests with unprocessed shrimp shell showed high concentrations of metallic ions (Pb, Ni, and Cu) causing contamination of the environment. However, the two biosorbents presented good removal of specific metallic ions (Fe, Mn, Zn, and Cr). These results indicate the need for a biosorbent pre-treatment prior to full-scale use. We indicate the need for a more detailed investigation of water quality in the environment used for shrimp farming. Tests with commercial chitin presented satisfactory results for two concentrations tested. Tests with 10g of commercial chitin allowed removal of all tested metal ions (Fe, Mn, Zn, Cu, Ni, Pb, Cr) with removal percentage between 6.7% and 84.4%. This efficiency may be related to the chitin's composition (shrimp, crustaceans, and crab) and to the chemical process applied to the product prior to commercialization.