Produto da calcinação do lodo de esgoto: caracterização e compartimentos de fósforo
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Data
2025-08-08
Autores
Dolabela, Vinícius Feliciano Gomes
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Universidade Federal do Espírito Santo
Resumo
Phosphorus (P) is an indispensable element for soil fertility and agricultural production. Given the scarcity of its non-renewable sources, it is necessary to adopt alternative sources of P, such as sewage sludge (SS). For its use, the calcination process can be employed, which may render SS more favorable for agricultural purposes. This study aimed to characterize and analyze the forms of P in calcined sludge. The SS samples were obtained from the company BRK Ambiental, collected from three different wastewater treatment plants (WWTP) located in the municipality of Cachoeiro de Itapemirim/ES, and its districts of Itaoca Pedra and Pacotuba. The samples were calcined in muffle furnaces at three different temperatures, 350 °C, 550 °C, and 750 °C, under two different atmospheres (argon and oxygen), in a 3 × 3 × 2 factorial design, with 3 replications. To analyze the fractions of inorganic P, the Hedley sequential extraction method was applied. The quantification of the residual content strongly bound to the mineral matrix was performed through nitric acid (HNO3) digestion. For chemical characterization of the biosolids, infrared spectroscopy and Xray fluorescence analyses were employed. Subsequently, the data were analyzed using ANOVA, followed by Tukey’s HSD test. The inorganic P contents were high for all three locations, with the sludge obtained from Cachoeiro de Itapemirim standing out, although no significant differences were observed regarding the type of atmosphere. The interaction between the SS source and calcination temperature was significant, demonstrating that temperature effects varied according to the origin of the material. The inorganic P fractions were redistributed into labile and moderately labile forms, with higher calcination temperatures favoring less labile forms. Therefore, materials derived from SS present great potential for application in plant nutrition, with possible improvements in P dynamics in the soil, in addition to reducing the environmental impact of SS disposal.
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Material calcinado de lodo de esgoto , Formas de fósforo solúveis , Caracterização de superfície