Use of Bauxite Minerals to Control Pollutant Outflow in Urban Areas

Urban Farm DB summary

This laboratory-scale study tested incorporating bauxite minerals — red waste from alumina refineries — into a specialized soil layer for rooftop gardens, aiming to address the release of pollutants in urban stormwater runoff, a known issue with green roofs, against a backdrop of declining green-planted surfaces in urban areas. Bauxite minerals were noted for their high trapping capacity for trace metals and other soluble species and ease of integration into rooftop garden systems. Based on equilibrium adsorption capacity, an optimum amount of bauxite minerals was proposed, and rainwater runoff characteristics and pollutant release were compared between standard and modified rooftop gardens at laboratory scale. The green roof system with the bauxite layer was found to reduce heavy metal concentrations, and the technique is suggested as applicable to other green surfaces in housing complexes.