Wetland construído para tratamento de efluente secundário de condomínio empresarial, Uberlândia - MG

Abstract

In this study, we evaluated the efficiency of two wetlands units constructed of vertical flow in pilot field scale for the treatment of secondary effluent of a business condominium of the municipality of Uberlândia-MG. The WC-FV units differed in their configurations - the filter material and the emergent macrophyte species. The unit named Treatment 1 was constructed with partial filtering material, ceramic and macrophyte residue from the cerrado (Eleocharis acutangula), while Treatment 2 was partially filled with crushed and macrophyte Typha. The operation was divided in three phases, varying the organic load in: (1) 1,59; (2) 6.56; (3) 35.57 (gDBO, M-2d-1) and the type of alimentation, batelada (1) and intermittent in predetermined pulses (2 and 3). Samples were collected at the entrance and the exit of treatment units to determine the parameters: pH, chemical oxygen demand (COD), biochemical oxygen demand (BOD), turbidity, total dissolved solids (SDT), total nitrogen (total N), total phosphorus (total P), and total coliforms. The WC’s performance was marked by high removals of total P, above 89%, with a mean residual concentration of less than 0.75 mg.L-1. In the batelada type of alimentation, the treatments reached satisfactory total N removal with 61% in T1 and 77% in T2, which resulted in residual concentrations of 24 mg.L-1 and 16 mg.L-1. The total result of WC T 1, with cerrado macrophyte, showed statistically equal removal efficiencies for all evaluated parameters, with percentages and mean concentrations of BOD of 71% (18 mg L -1), COD 78% (48 mg L -1), 95% CT (1.31E + 05), turbidity 77% (6 NTU), SDT 429 mg. L-1 and pH 7.0. The cerrado macrophyte system planted in filter alternative material showed the same nutrient removal capacity compared to the widely used system.