Uso combinado de microalgas e Wetland construído para a remoção de carga orgânica, nutrientes e fármacos de águas residuárias urbanas.

Abstract

The increase in population and the increasing occupation of urban spaces makes the treatment of urban wastewater a challenge on a global scale. In Brazil, practically 50% of the population does not have access to the sewage network and many of the existing treatment systems are archaic and inefficient. In this sense, nature-based systems (SBN) can be an alternative capable of providing good efficiency in removing the main pollutants present in urban effluents and with lower implementation and operation costs. In this context, the production of microalgae (PM) in wastewater and constructed wetlands (CW) are included. This doctoral work aimed to evaluate the combined use of PM, together with WC, for the removal of organic load, nutrients and emerging contaminants, from urban wastewater, originating from the University of Santa Cruz do Sul. It was evaluated in the laboratory the action of microalgae of the species Scenedesmus subspicatus for the removal of drugs. Furthermore, an experimental Effluent Treatment Station (ETS) was implemented containing an anaerobic reactor, a microalgae production system and the constructed wetland, where environmental parameters related to organic load and nutrients were monitored for a year, as well as the efficiency evaluated. of the system to remove drugs found in the raw effluent. The results obtained showed that the microalgae of the species Scenedesmus subspicatus acts directly in the removal of substances such as propranolol and sulfometoxazole and indirectly in the removal of salicylic acid, acetominophen, atenolol and albendazole. Furthermore, the experimental system implemented for the treatment of urban effluents demonstrated na efficiency of 68.5% in the removal of total nitrogen (TN), 70% efficiency in the removal of ammoniacal nitrogen (AN), 68% in the removal of total organic carbon (TOC), 53% efficiency in removing COD, in addition to 95% in removing turbidity. The results also showed the presence of nine pharmacological substances in the raw effluent, and the system was able to completely eliminate eight of these substances and 99% of the drug dipyrone. In this sense, with the results obtained, it is possible to state that the combined MA+CW system is very promising, not only for the removal of organic load and eutrophicating elements, but also for some emerging contaminants, and can contribute to the increase in technology in the area. of sanitation. Future research can be developed to combine other system configurations combined between MA and CW, in addition to deepening knowledge about the mechanisms of action involved in removing emerging contaminants found in raw urban wastewater effluent, which use such a system for their treatment.