Life cycle assessment of an integrated system UASB/anaerobic biofilter with constructed wetlands and filter mixed with reactive support in the treatment of urban effluents

ABSTRACT

This research studied the environmental impact of the UASB/anaerobic biofilter system (anaerobic sludge blanket reactor — UASB/ABF) + floating-type constructed wetland (FCW) + vertical flow constructed wetland — microbial fuel cell (FVCW-MFC) + mixed filter with reactive support (MFRS), applied for pilot-scale remediation of urban effluents on a university campus. Scenarios for proposed changes to the settings of the wastewater treatment plant (WTP) were made (Scenarios 2 and 3). The Scenario 1 system was operated in pulses, with the application of 2.9 m³ of university campus effluent per week. Energy required for pumping in the pilot scale unit (Scenario 1) and for potential application with runoff flow (Scenario 2) were inventoried, considering materials for construction and processing, especially with the control of pollutant load in liquid and atmospheric effluents. The SimaPro 8.0.4 software was used, with a functional unit of 2.9 m³ week^-1 of effluent and a reference flow of 20 years. The results showed a contribution of 84.8% (in single score — Pt) for the system's construction materials, as well as 15.2% for the operation of the Scenario 2 system, without the use of electricity for pumping. Scenario 3, on the other hand, showed that replacing fiberglass tanks with fiber cement tanks could help reduce environmental impacts during the construction phase of the system by up to 58.6% in terms of energy use and up to 80% in emissions of carcinogenic pollutants.

Keywords: life cycle assessment; constructed wetlands; sustainability