Removal of potentially toxic elements in domestic wastewater treatment stations by wetlands


  • Waldir Nagel Schirmer Universidade Estadual do Centro-oeste do PR - Unicentro
  • Caroline Kozak UNICENTRO
  • Simone Gomes UEPG
  • Larissa Macedo dos Santos UTFPR
  • Adriel Ferreira da Fonseca UEPG



Lack of sewage treatment is amongst the main sanitation problems of Brazil, mainly in low income rural communities. Seeking alternative and low cost technologies to treat such effluents is mandatory. This study aimed to verify the efficacy of a sewage treatment system by root zone stations (constructed wetlands) to remove potentially toxic elements (Cu and Zn) in two wastewater treatment stations (WWTS) (school and single family residence) of small communities in the city of Irati (PR). Three campaigns were carried out between May and September 2011, with two samples each (inlet and outlet), all in replicate, and quantified through atomic absorption spectrometry with flame atomization (AAS-flame). The presence of NH3 in the effluent favored the reduction of pH values, which remained within the neutrality and alkalinity range (from 8.0 to 9.1 for the school effluent and from 6.9 to 7.8 for the single family residence). For this pH range, it was possible to obtain Cu (25% to 75%) and Zn (0 to 100%) precipitation. In general, the constructed wetlands systems were efficient to remove Cu and Zn (between 25% to 75% regarding Cu; and between 67% to 100% regarding Zn), revealing advantages of its use in small communities.