Impact of the Use of Vinasse Sludge on Agricultural Soil and Surface Waters

Brazil is one of the world's largest sugarcane producers, and the sugar-energy industry generates large volumes of by-products such as vinasse and vinasse sludge, which require appropriate management to minimize environmental impacts. This study evaluated the agricultural disposal of sludge generated during the cleaning of vinasse storage reservoirs and its potential effects on adjacent surface water quality in Costa Rica, Mato Grosso do Sul, Brazil. Surface water quality was monitored at eight sampling points between 2020 and 2023, covering dry and rainy seasons. A total of 34 physicochemical and microbiological parameters were analyzed, and statistical tests were applied to assess spatial and seasonal variations and differences between areas with and without sludge application. The results showed significant spatial differences for calcium, electrical conductivity, dissolved iron, magnesium, manganese, ammoniacal nitrogen, and pH, while seasonal differences were observed for turbidity, total chromium, dissolved iron, and pH. Higher concentrations of several parameters were recorded at points P6 and P7; however, all monitored variables remained within the limits established by CONAMA Resolution No. 357/2005. Comparisons between areas with and without sludge application did not indicate measurable deterioration of surface water quality associated with sludge disposal. These findings suggest that the agricultural use of vinasse sludge, when conducted in accordance with environmental regulations and appropriate management practices, can be environmentally safe. Nevertheless, long-term monitoring remains essential to detect potential cumulative effects and ensure the sustainable management of water resources.