Domestic wastewater post-treatment using ornamental plants : Constructed-Wetlands with gravel and bamboo as substrate / Plantas ornamentais no pos-tratamento de efluentes sanitarios : wetlands-construidos utilizando brita e bambu como suporte

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Anaerobic reactor s effluent post-treatment systems make possible the improvement of anaerobic-treated wastewater characteristics in diverse conditions in a simple way. This posttreatment design flexibility will be able to support small communities to have better environmental conditions even if they did not have a traditional wastewater plant previously. The option for a constructed-wetland wastewater treatment system takes in consideration another advantages, as such as the effect on the landscape, that may change the main focus of the treatment plant from the wastewater, decreasing the plant rejection. The vegetal specie may be used to attend commercial and ornamental interests, and they might improve the income of people and create new places of job in the neighborhood as well. Several species with ornamental ar economic al value can be adapted to wastewater post-treatment systems like Zantedeschia aethiopica (calla IiIly), Cyperus papyrus (papyrus), Canna x generalis (canna lilly) and Cyperus isocladus (dwarf papyrus). As it occurs to vegetation, many different materiais can be used as substrates in constructed-wetlands systems like bamboo rings, material that was selected to be compared with a gravei bed constructed-wetland located at UNICAMP in Campinas, SP, Brazil, as an anaerobic baffled reactar post-treatment system. The ornamental species were well adapted to the wastewater post-treatment system. Bamboo rings can be used as substrate, but when gravei is used the system efficiency reached better results. Statistical tests show that, for the conditions imposed to the tested system, the substrate material is more important than the vegetal species to obtain better treatment efficiency. Although the used hydraulic detention time was considerabíy smaller than desirable, the post-treatment system contributed with about 30% of the wastewater treatment system COD and suspended solids removal efficiency results. The best medium total phosphorous removal efficiency value was 27.7% for the gravei and papyrus constructed wetland. The efficiency of total and thermotolerant coliforms removal was about 1 log decay. The use of a vegetated system caused an intense loss of water by evapotranspiration, in average, 44.8%, during research period. This loss covers up the system real capacity in regard to the removal of several parameters, when only compared the affluent and effluent concentrations. The evaluation of the system s efficiency must be verified considering the load removal, instead "of the current methods of analysis based on concentration

ASSUNTO(S)

bambu constructed-wetlands tratamento de efluentes leitos cultivados esgotos bamboo plantas ornamentais saneamento ecological sanitation ornamental plants wastewater post-treatment

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