Banca de DEFESA: Sarah da Silva Brito

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : Sarah da Silva Brito
DATE: 28/03/2024
TIME: 09:00
LOCAL: Sala de Informatica do PPGTARH Plataforma MS Teams
TITLE:

CYANOBACTERIA AND THEIR RISKS IN A STABILIZATION POND SYSTEM AND THE RECEIVING WATER BODY OF THE PARANOÁ WASTEWATER TREATMENT PLANT - FEDERAL DISTRICT

KEY WORDS:

Wastewater Treatment Plants (WWTPs), High-Rate Algal Ponds (HRAPs), Geitlerinema amphibium, cyanobacteria, stabilization ponds.

PAGES: 112
BIG AREA: Engenharias
AREA: Engenharia Sanitária
SUBÁREA: Recursos Hídricos
SUMMARY:

Population growth, especially in urban areas, implies an increase in water consumption and a greater generation of domestic sewage. These impacts have environmental, social and public health consequences. Some domestic effluent is discharged directly into nature, while some goes through Wastewater Treatment Plants (WWTPs). However, the effectiveness of these treatments can vary, which can lead to degradation of the receiving water bodies. In Brazil, sewage treatment plants often use stabilization ponds due to their ease of operation and relatively low implementation costs. Although effective at removing organic matter, these ponds can contribute to the eutrophication of the receiving water body, due to the high nutrient loads present in the treated effluent. Likewise, stabilization ponds can pose a problem for human health if the treated effluent is discharged into the receiving water body containing some type of cyanotoxin or other persistent toxic substances.

Thus, this research sought to analyze the stabilization ponds of the Paranoá WWTP, as well as the water body receiving the treated effluent (Paranoá River), with regard to physical, chemical and biological parameters. The focus of the research was to analyze the dynamics of cyanobacteria in the high-rate algal ponds (HRAPs) in the dry and rainy periods, as well as to identify isolates and cyanobacteria and evaluate the production of cyanotoxins. In addition, we sought to investigate the influence of different N/P ratios on the growth of the isolated cyanobacterial strain Geitlerinema amphibium.

The results indicated that the density of cyanobacteria in various ponds of the WWTP showed a positive correlation with different parameters, such as DO, chlorophyll-a, temperature and pH. High densities of cyanobacteria cells were observed in the final effluent and in the Paranoá River after the effluent was discharged. In addition, high concentrations of nutrients discharged into the river generated supereutrophic conditions at the point of discharge. Although the stabilization ponds are similar in terms of their design parameters, there was great variability between them, since the effluent leaving the UASB reactor is not divided equally between the ponds. In the samples collected, the presence of Geitlerinema amphibium and Phormidium sp. was detected in the ponds and in the final effluent, both species of cyanobacteria potentially producing cyanotoxins. However, no cyanotoxins were detected in the isolated strain of G. amphibium or in the final effluent. In the experimental study, the growth of Geitlerinema amphibium was more favorable in the N/P = 40/1 ratio treatment, indicating the strain's affinity with nitrogen-rich environments. However, the responses of this species to the N/P ratios in situ in the HRAPs were different. The results obtained can contribute to the optimization of treatment conditions in WWTPs and provide important information for the development of water quality management policies. As a result, this work highlights the importance of implementing appropriate technologies to efficiently treat domestic sewage and, in stabilization ponds, monitor and control cyanobacteria in these systems to guarantee water quality, protect public health and the environment.

COMMITTEE MEMBERS:
Externa à Instituição - ANDREIA MARIA DA ANUNCIAÇÃO GOMES - IFRJ
Interna - 1512988 - ARIUSKA KARLA BARBOSA AMORIM
Presidente - 1509161 - RAQUEL MORAES SOARES
Interna - 1646057 - YOVANKA PEREZ GINORIS