ABSTRACT Regarding the Brazilian textile industry, part of the northeast region stands out as the second-largest textile manufacturing hub in the country. Despite its importance, this industrial activity has been bringing relevant environmental concerns regarding the disposal of textile effluents, especially from industrial laundries. This waste contains many chemicals and among them are various types of heavy metals. To assess environmental risks associated with heavy metals, pollutant transfer needs to be investigated. This study evaluated the retention and mobility of heavy metals Cd and Cu in alluvial soil, through soil column tests. The up-flow column percolation tests were performed using a nonreactive tracer (KBr) at a concentration of 0.3 mol L-1 and injecting a metallic solution containing Cu and Cd at 100 and 60 mg L-1, respectively. The injection flow rate was 0.75 mL min-1. The hydro-dispersive parameters were obtained by modeling the observed breakthrough curves with the convection-dispersion equation (CDE) and the two-region model, also referred to as the MIM (Mobile-IMmobile waters) model. The transport parameters were obtained from the two-site model (TSS). All elution curves were fitted to the models with the CXTFIT 2.0 program. The Two-Site Sorption Model was the best for the case studied, with R2 of 0.985 and 0.995 for Cu and Cd, respectively. The values of R were considerably higher than the unit, presenting an average of 2.138 for Cu and 1.907 for Cd. This indicates a delay of these contaminants when leaving the column, which is caused by the interaction of these chemical compounds with the soil. The values obtained for parameter D were 3.469 for Cu and 5.205 for Cd. Thus, the metals in this study present a risk of groundwater contamination for the local alluvial aquifers. The main reason for that is the physicochemical features of the soil, such as high sand content (85 %) and low OM content (2.1 %). The results also indicated greater retention and less mobility for Cu than for Cd, pointing to a greater risk for Cd.

Resumo Este trabalho apresenta um projeto experimental de uma trincheira de infiltração instalada na cidade de Recife, PE, nos primeiros meses de vida útil. Foram avaliadas as funções de armazenamento de água no interior do sistema e a função de infiltração, observando-se o processo de recessão. Em razão dos consequentes eventos de precipitação, a trincheira foi muito solicitada, não tendo suprido, em alguns casos, o grande volume de entrada, o que gerou extravasamento na estrutura. Uma análise de custo foi implementada e avaliaram-se o desempenho e o custo de construção para os tempos de retorno (2, 5, 10 e 25 anos) e durações de chuva de projeto (10, 15, 60 e 120 min). Essa análise revelou que houve subdimensionamento da camada de armazenamento. Apesar disso, a trincheira de infiltração apresentou resultados positivos, com a capacidade de infiltrar no mínimo 63,57% dos volumes de entrada, ou seja, trata-se de uma técnica compensatória no manejo das águas pluviais urbanas.

Abstract The aim of this paper is to present an experimental project of an installed infiltration trench in Recife/PE in the first months of life. Storage functions within the system were evaluated through the monitoring of the water levels and infiltration function, watching for the downward movement behavior level, recession. Because of the consequent events of precipitation, the trench was very requested, not having supplied, in some cases, the large volume of entry, which generated a leakage in the structure. A cost analysis was implemented and evaluated the performance and the cost of construction for the return times (2, 5, 10 and 25 years) and project rainfall durations (10, 15, 60 and 120 min). Despite the storage layer was undersizing, the infiltration trench showed positive results, and found a minimum capacity of infiltrating 63.57% of the input volumes, presenting itself as a compensatory technique in the management of urban rainwater.