Coliform removal in a constructed wetland system used in post-swine effluent treatment

  • Fabiana de Amorim Departamento de Recursos Hídricos e Saneamento (DRS), Universidade Federal de Lavras (UFLA), Câmpus Universitário, Caixa Postal 3037, CEP 37200-000, Lavras, MG, Brazil.
  • Jaíza Ribeiro Mota e Silva Departamento de Recursos Hídricos e Saneamento (DRS), Universidade Federal de Lavras (UFLA), Câmpus Universitário, Caixa Postal 3037, CEP 37200-000, Lavras, MG, Brazil.
  • Ronaldo Fia Departamento de Recursos Hídricos e Saneamento (DRS), Universidade Federal de Lavras (UFLA), Câmpus Universitário, Caixa Postal 3037, CEP 37200-000, Lavras, MG, Brazil.
  • Luiz Fernando Coutinho de Oliveira Departamento de Recursos Hídricos e Saneamento (DRS), Universidade Federal de Lavras (UFLA), Câmpus Universitário, Caixa Postal 3037, CEP 37200-000, Lavras, MG, Brazil.
  • Cláudio Milton Montenegro Campos Departamento de Recursos Hídricos e Saneamento (DRS), Universidade Federal de Lavras (UFLA), Câmpus Universitário, Caixa Postal 3037, CEP 37200-000, Lavras, MG, Brazil.
Keywords: agricultural reuse, Cynodon spp., sanitary risk, tertiary treatment, Typha sp.

Abstract

This study evaluated the efficiency of a constructed wetland system (CWS) in removing total coliforms (TC) and thermotolerant coliforms (ThC) of swine wastewater, as a complementary treatment to an anaerobic system. At Stage 1, the experimental system was combined using a vertical flow constructed wetland system (VFCWS) cultivated with Tifton 85 grass in series with a horizontal subsurface flow constructed wetland system (HFCWS1) cultivated with Taboa. In HFCWS1, the hydraulic detention times (HDT) were 4.7, 3.1 and 2.3 days and the surface application rates (SAR) were 294, 319 and 397 kg ha-1 d-1 of COD, in Phases I, II and III, respectively. At Stage 2, the experimental system was combined using a horizontal subsurface flow constructed wetland system (HFCWS2) cultivated with Tifton 85 grass, HDT were 6.1, 2.0 and 0.5 days and the SAR were 850, 656 and 6.34 kg ha-1 d-1 of COD, in Phases I, II and III, respectively. In Stage 1, it was verified that the VFCWS was more efficient in coliform removal when compared to HFCWS1. When only HFCWS were compared, coliform removal in Stage 1 was between 1 and 2 log units in HFCWS1. In the stage 2, the HFCWS2 was more limited, with the highest removal efficiencies during Phase I of 1.6 and 0.8 log units for TC and ThC, respectively. In general, the association resulted in efficiencies that ranged from 96.4 to 99.0% for TC, 94.2 and 97.6% for ThC, equivalent to the average removal of 1.2 to 2 log units, considered satisfactory.


Published
10/09/2019
Section
Papers