Cultivo de microalgas da espécie Chlorella vulgaris em efluente sanitário sintético, com foco na ficorremediação e na produção de bioprodutos
Data
2022-12-09
Autores
Campos, Marcos Vinicius Pereira Borges de 
Orientadores
Perpetuo, Elen Aquino
Tipo
Dissertação de mestrado
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Resumo
Atualmente, pouco mais da metade da população do Brasil é atendida por redes coletoras de esgoto, o que representa diretamente riscos à saúde ambiental de corpos hídricos visto que efluentes que não recebem tratamento adequado e apresentam excesso de nutrientes inorgânicos e matéria orgânica, ao serem lançados nesses corpos hídricos, podem agravar processos de eutrofização. Uma alternativa para a redução desses compostos de águas residuárias de variados tipos que tem recebido cada vez mais destaque é o emprego de microalgas no tratamento de tais efluentes previamente ao seu lançamento, técnica a qual é denominada de ficorremediação. Nesse sentido, o presente estudo buscou avaliar o crescimento de duas cepas da microalga Chlorella vulgaris, uma de ambiente salobro (SL2C) e outra dulciaquícola (BMAK D1), cultivadas em diferentes concentrações de efluente sanitário sintético (25%, 50%, 75% e 100%), visando conciliar tanto uma produção sustentável de bioprodutos de interesse comercial quanto a remediação do efluente de uma forma eficiente e de baixo custo. Teores de clorofila a, clorofila b, carotenóides, lipídeos, densidade ótica, densidade celular e concentrações de amônia, ortofosfato e demanda química de oxigênio (DQO) dissolvidos foram monitorados por 14 dias durante um período de incubação. Para ambas as cepas foram observadas melhores taxas de crescimento e bons valores de densidade celular e de densidade óptica na concentração de T50% de efluente. Em T50%, BMAK D1 também demonstrou um bom teor de produção de pigmentos fotossintetizantes, como também demonstrou um bom potencial de ficorremediação de DQO. SL2C demonstrou bons teores de produção de pigmentos em T25%, indicando que menores concentrações do efluente beneficiaram o crescimento algal e a produção de pigmentos de ambas as cepas. SL2C, entretanto, apresentou melhores eficiências de redução de DQO em T50% e T75%. Foram também observadas maiores sínteses lipídicas em T75% e T100% para ambas as cepas e em especial para SL2C, a qual possivelmente se encontrou sob um estresse osmótico maior. Ambas as cepas também demonstraram melhores eficiências de redução de amônia e ortofosfato em concentrações mais altas de efluente, em especial BMAK D1. Por fim, vale citar que todos os tratamentos realizados apresentaram concentração final de nitrogênio amoniacal em concordância com a Resolução CONAMA nº 430/2011.
Nowadays, approximately half of the brazilian population is attended by sanitary sewage collection networks, which directly represents risks to the environmental health of water bodies, since effluents that do not receive adequate treatment and have an excess of inorganic nutrients and organic matter, when released in these water bodies, they can aggravate eutrophication processes. An alternative for the removal of these compounds from wastewater of various types that has received increasing attention is the use of microalgae in the treatment of such effluents before their release, a technique which is called phycoremediation. In this sense, the present study sought to evaluate the growth of two strains of the microalgae Chlorella vulgaris, one from a brackish environment (SL2C) and the other from a freshwater environment (BMAK D1), both cultivated in different concentrations of synthetic sanitary effluent (25%, 50%, 75% and 100%), aiming to conciliate both a sustainable production of bioproducts of commercial interest and the remediation of the effluent in an efficient and low-cost way. Chlorophyll a, chlorophyll b, carotenoids, lipids, optical density, cell density and dissolved ammonia, orthophosphate and chemical oxygen demand (COD) concentrations were evaluated during 14 days of an incubation period. For both strains, good growth rates and good cell density and optical density values were observed in the T50% effluent concentration. At T50%, BMAK D1 also showed a good level of photosynthetic pigment production, as well as a good COD phycoremediation potential. SL2C, in turn, showed good levels of pigment production at T25%, indicating that lower effluent concentrations benefited algal growth and pigment production of both strains. SL2C, however, showed better COD removal efficiencies at T50% and T75%. Higher lipid syntheses were also observed at T75% and T100% for both strains and especially for SL2C, which possibly was under greater osmotic stress. Both strains also demonstrated good ammonia and orthophosphate removal efficiencies at higher effluent concentrations, especially BMAK D1. Finally, it is worth mentioning that all treatments carried out in this study presented a final concentration of ammoniacal nitrogen in accordance with CONAMA Resolution Nº. 430/2011.
Nowadays, approximately half of the brazilian population is attended by sanitary sewage collection networks, which directly represents risks to the environmental health of water bodies, since effluents that do not receive adequate treatment and have an excess of inorganic nutrients and organic matter, when released in these water bodies, they can aggravate eutrophication processes. An alternative for the removal of these compounds from wastewater of various types that has received increasing attention is the use of microalgae in the treatment of such effluents before their release, a technique which is called phycoremediation. In this sense, the present study sought to evaluate the growth of two strains of the microalgae Chlorella vulgaris, one from a brackish environment (SL2C) and the other from a freshwater environment (BMAK D1), both cultivated in different concentrations of synthetic sanitary effluent (25%, 50%, 75% and 100%), aiming to conciliate both a sustainable production of bioproducts of commercial interest and the remediation of the effluent in an efficient and low-cost way. Chlorophyll a, chlorophyll b, carotenoids, lipids, optical density, cell density and dissolved ammonia, orthophosphate and chemical oxygen demand (COD) concentrations were evaluated during 14 days of an incubation period. For both strains, good growth rates and good cell density and optical density values were observed in the T50% effluent concentration. At T50%, BMAK D1 also showed a good level of photosynthetic pigment production, as well as a good COD phycoremediation potential. SL2C, in turn, showed good levels of pigment production at T25%, indicating that lower effluent concentrations benefited algal growth and pigment production of both strains. SL2C, however, showed better COD removal efficiencies at T50% and T75%. Higher lipid syntheses were also observed at T75% and T100% for both strains and especially for SL2C, which possibly was under greater osmotic stress. Both strains also demonstrated good ammonia and orthophosphate removal efficiencies at higher effluent concentrations, especially BMAK D1. Finally, it is worth mentioning that all treatments carried out in this study presented a final concentration of ammoniacal nitrogen in accordance with CONAMA Resolution Nº. 430/2011.
Descrição
Citação
CAMPOS, Marcos Vinicius Pereira Borges de. Cultivo de microalgas da espécie Chlorella vulgaris em efluente sanitário sintético, com foco na ficorremediação e na produção de bioprodutos. 2022. 100 f. Dissertação (Mestrado Interdisciplinar em Ciência e Tecnologia do Mar) – Instituto do Mar, Universidade Federal de São Paulo, Santos. 2022.