Alagados construídos para tratamento de águas cinzas com meio suporte de resíduos de construção e demolição

Abstract

The increase in population and the mismanagement of natural resources cause the scarcity of drinkable water and increase in solid waste in urban areas. These problems can be mitigated with the reutilization of greywater and construction and demolition waste. In this work, the constructed wetlands was considered as an alternative for solid waste use ad wastewater reutilization, due to its quality of treatment, low maintenance, simplified operation and employment of solid waste. Thus, this work aimed to assess the technical feasibility of a pilot-scale horizontal subsurface flow constructed wetlands system with solid waste as substrate for the treatment of synthetic greywater using the ornamental plant Zantedeschia Aethiopica. The experiment presented two main studys (static system and dynamic system) with the alteration of the hydraulic retention time – two, four and six days for the static system; one and two days for the dynamic system. Results showed that the constructed wetlands obtained, for the static system, a reduction of 86% in COD and 20% in total phosphorus, but an increase of 117% in total solids and 112% in conductivity as well as a maximum pH of 9.6. For the dynamic system, there was a reduction of 86% in COD and 8% in total phosphorus, and an increase of 1100% in total solids and 327% in conductivity as well as a maximum pH of 7.7. The ornamental plant resisted well to the experiment. It presented a high density of roots, which involved the whole system, what shows its efficiency in the removal of organic matter besides esthetically enhancing the system and increasing the public’s acceptance. Therefore, it can be concluded that the constructed wetlands studied is feasible for the reutilization of greywater for non-drinkable purposes, however, the use of construction and demolition waste as support medium is not the most suitable due to the interferences on wastewater. It is recommended to find another destination for this material.