Abstract

GARCIA, William Vilar et al. Miscible displacement of an explosive industry effluent on soil columns. Bragantia [online]. 2012, vol.71, n.1, pp. 98-105. ISSN 0006-8705.  http://dx.doi.org/10.1590/S0006-87052012000100015.

This study evaluated some impacts due to the miscible displacement of an explosive industry effluent applied to a B horizon of an Udox soil (LA-B) under the following treatments: additions of carbonate (BASE), acid (ACID), phosphate (FOSF), carbonate and phosphate (BASE-FOSF) and acid and phosphate (ACID-FOSF). Nitrogen recovery compared with the total amount applied varies from 10.1% (ACID) to 65.5% (BASE). There is correlation between experimental and fitted breakthrough curves for the most columns (p<0.001). The unique exception occurs to ACID-FOSF (p=0.202). There is no correlation between soil net electrostatic charge (NEC) and the model adjusted variables: retardation factor (FR), dispersion-diffusion coefficient (D) and first-order decaying rate (µ). Phosphate adding (FOSF) favors nitrogen movement, since reduces FR (2.35±0.05) and µ (0.498±0.050 h^-1) and increases D (41.8±5.5 cm² h^-1), compared to LA-B column (2.51±0.03; 1.697±0.084 h^-1 and 2.85±1.26 cm² h^-1, respectively). Adding carbonate and/or phosphate (BASE, BASE/FOSF e FOSF) results in the highest values for maximum chemical oxygen demand (COD_MAX). The small DNA amount extracted from soil bacterial cells suggests that the N adsorption and movement have non biological nature, or that the high leachate liquid COD is prejudicial to soil microorganisms.

Keywords : miscible displacement; nitrogen; breaktrough curves; PCR-DGGE.