Avaliação da eficiência da biorremediação por perifíton em rio urbano

Abstract

A large part of domestic and industrial effluents are discharged directly into rivers, increasingly reducing the availability of water resources for most uses, especially human uses, as it causes eutrophication, these effects are negative for the aquatic environment, especially in the aquatic macrophytes proliferation; consumption and depletion of dissolved oxygen; release of gases and production of bad odors; and the decrease in local biodiversity, among others. Bioindication uses organisms that characterize a certain environment to use quantitative and qualitative knowledge from biological communities, and these can indicate the presence, or not, of pollution in the environment. The general objective was to evaluate the effectiveness of the use of biotreatment by periphyton in an urban river with a high degree of pollution with the support of the perception of the riverside residents, through; a) to analyze the water quality of the Jaguaribe River, João PessoaPB, in relation to biological parameters, physical and chemical properties of water and sediment; b) Assess the use of biotreatment to improve the water quality of the Jaguaribe River; c) Assess the perception of social actors about the water quality and uses of the Jaguaribe River before and after biotreatment. In the first, biomonitoring was carried out using benthic macroinvertebrates, from September 2017 to October 2018, at six collection points. The Calcination Method was used to evaluate the organic matter content of the Jaguaribe River sediment samples. Physical and chemical analyzes were performed with a multiparameter probe and water samples were collected for the analysis of Nitrogen compounds and dissolved phosphorus. For benthic macroinvertebrates, quantitative collections were made with a van Veen dredge and the animals collected expressed in density and relative abundance. From this, the BMWP index was used together with the diversity, dominance and equitability indices, in addition to wealth’s species. The studies show the predominance of animals more resistant to pollution (larvae of chironomids and oligoquetes), indicating that the Jaguaribe River is classified as Terrible (Except in P3, where the classification was “Bad”, even with a higher concentration of Dissolved Oxygen (maximum 10.1 mg O2.L-1) and the greatest diversity (H = 1.27 of Shannon) was recorded in relation to the other points. In the sequence, the second part of this thesis, aiming to contribute to the improvement of water quality from the Jaguaribe River, biotreatment by bioremediation was applied, using the periphyton as a solution, three points were selected for the implementation of the Bioremediation modules: P1, in Oitizeiro; P3, in São Rafael and P4 in Tito Silva. Each module is formed by a square frame of PVC pipes 50 mm, which serve as floats, with dimensions of 1.5 mx 1.5 m, containing 15 mm crystal plastic curtains that were arranged in 05 rows 1.4 m x 0.5 m, side by side, parallel and following the direction of the river current. In P1, with 9 modules in the rainy season, 16 and 08 modules, respectively, in P4 and P3, in the dry season, also in 2019. To assess the effect of biotreatment, physical and chemical parameters of the water collected were analyzed upstream and downstream of the bioremediation modules. The results obtained showed, significantly, downstream differences at the three points, that there was a significant increase in Dissolved Oxygen and a reduction in the values of Electrical Conductivity and Phosphorus. There was also a reduction in the values of Nitrate, Orthophosphate and Ammonia, however, they were not significant. For the third part of the thesis, the perception of the residents was analyzed, followed by a semi-structured questionnaire and the interview was recorded, with prior authorization, about the performance of the Biotreatment modules in the quality of the river water. In all, 23 interviews were conducted. After biotreatment, the interviewees revealed that there was an improvement in the transparency of the water, a decrease in the odor, the appearance of more animals (birds and fish), scientifically corroborated by statistical tests that revealed significant differences in the reduction of odor and in the approval of bioremediation for improvement of water quality.