Influência da cobertura de pó de coco na lixiviação de solutos em colunas de solo

Abstract

In recent decades, population growth and technological advances have been observed. Hence, it is possible to perceive a greater demand for water, because although it is a renewable natural resource, water is a finite resource. The objective of this work was to evaluate the influence of coconut powder cover on the solutes transport in irrigation with treated sewage reuse in soil columns. Soils used in the study are from the Jatobá Creek experimental basin located in the municipality of Pesqueira-PE and the treated domestic wastewater comes from the Experimental Unit for Treatment and Reuse of Hydro-agriculture (UETRH) located in the Mutuca District, semi-arid region of Pernambuco State. The breakthrough curves for sodium and potassium ions were determined in order to verify the difference between the solutes transport patterns between the soil types, from the application of domestic wastewater treated with the different treatments of coconut powder coating. The experimental design was in a factorial scheme (2x3), whose evaluated factors comprised two types of soil (Litholic Neosol and Yellow Argisol); three treatments (without coconut powder, 1 cm of coconut powder and 2 cm of coconut powder), with five replications, totaling 30 experimental units. The transport parameters of the sodium and potassium ions were obtained by numerical adjustment using the STANMOD software. The transport parameters of the sodium and potassium ions were obtained by numerical adjustment using the STANMOD software. Coverage of coconut powder was efficient in reducing the leaching of ions in the studied soils. There was interaction between solute - sodium and potassium - sandy soil. There was higher interaction between sodium and soil in the cover with 2 cm of coconut powder in relation to the others treatments. For the potassium ion, there was higher interaction in the coconut powder coatings, with the losses associated with the absence of coconut powder. Sodium and potassium ions displaced with transport predominantly by diffusion. The values of the delay factor (R) were higher for the coverage with 2 cm of coconut powder in the sodium ion, whereas for the potassium ion the coverage with 1 cm presented higher R. The values of the diffusion-dispersion coefficient ranged from 0,07 to 1,01 cm².min-1 for the sodium ion and for the potassium ion of 0,15 to 2,04 cm².min-1, and the dispersivity values varied from 1,68 to 4,60 cm and 3,41 to 28.39 cm for the sodium and potassium ions, respectively. The STANMOD model presented excellent numerical adjustment performance for the simulation of solutes transport in the soil.