| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 1.5 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
Um dos maiores problemas da indústria de produção de azeite está relacionado com a produção em grandes quantidades de águas ruças, resultantes do processamento do azeite. A produção de azeite a nível mundial encontra-se centralizada na bacia do Mediterrâneo, sendo Portugal um dos dez maiores produtores. As águas ruças representam um problema ambiental onde a sua descarga direta em ambientes aquáticos e terrestes pode originar eutrofização dos cursos de água e solos inférteis, no entanto a nível industrial ainda não foi estabelecido um sistema de tratamento eficiente e economicamente viável. O problema deste efluente deve-se à sua composição química, caracterizada por uma elevada carga orgânica, associada a elevados teores de compostos fenólicos e pH ácido, assim como um cheiro característico e coloração escura. Neste contexto, este trabalho pretende avaliar o potencial das microalgas na diminuição de compostos fenólicos e aumento do pH, nas águas ruças. Para tal, testou-se o efeito da Chlorella vulgaris imobilizada na biorremediação de águas ruças de duas e três fases, em culturas batch. A eficácia do processo foi também avaliada pela fitotoxicidade, em ensaios de germinação e crescimento da Lactuca sativa. Além disso, otimizou-se o processo pela utilização de 2º ciclo e 2º tratamento, pela utilização de inóculos preadaptados, pela redução do tempo de cultura e pela otimização do tipo de reator.
Em função do screening de crescimento em meio sólido, os ensaios em batch foram efetuados com águas ruças de duas fases à diluição de 35%, 50% e 60% e no caso das águas ruças de três fases a diluição de 20%, em meio Walne modificado. Estes ensaios foram desenvolvidos à temperatura ambiente, com iluminação natural e aerificação contínua. A otimização do reator foi feita por utilização de uma coluna de bolhas.
Os resultados obtidos permitiram concluir que a C. vulgaris tem a capacidade de remover os compostos fenólicos e neutralizar o efluente, observando-se uma redução do teor de fenóis entre 20% a 43% no efluente de três fases e de 53% a 73% no efluente duas fases. Em termos fitotóxicos conclui-se que a microalga consegue reduzir a toxicidade das águas ruças, tendo a capacidade de degradar os compostos fenólicos que inibem a germinação e crescimento da L. sativa.
One of the greatest issues in the industry of olive oil production has to do with the massive production of olive mill wastewaters which result from the processing of olive oil. Worldwide production of olive oil is centered in the Mediterranean basin, and Portugal is one of the world’s 10 largest producers. Olive mill wastewaters represent an environmental threat as its direct outflow in aquatic and terrestrial environments may cause the eutrophication of water courses and soils to become infertile. Despite this, an efficient and economically practicable treatment system hasn’t yet been established in the industry. The issues brought by this effluent have to do with its chemical composition which consists of a high organic load, associated with high contents of phenolic compounds and acid pH, as well as a characteristic smell and dark colour. Taking the above into consideration, the aim of this assignment is to assess the potential of microalgae in the decrease of phenolic compounds and increase of pH in olive mill wastewaters. For this purpose, the effect of immobilized Chlorella vulgaris in the bioremediation of phase two and phase three olive mill wastewaters has been tested in batch cultures. The effectiveness of the process has also been assessed by phytotoxicity, in germination trials and growth of Lactuca sativa. Besides that, the process has been optimized through the implementation of a second cycle and second treatment with the usage of preadapted inoculums, with the reduction of culture time and with the optimization of the type of reactor. According to the screening of the growth in solid environment, the batch trials have been performed in two phase olive mill wastewaters on a dilution of 35%, 50% and 60% and for the case of olive mill wastewaters of three phases on a dilution of 20% in modified Walne medium. These trials have been performed in room environment with natural light and continuous aerification. The optimization of the reactor has been accomplished through the use of a bubble column. The results achieved show that the Chlorella vulgaris has the ability of removing phenolic compounds and neutralizing the effluent, and a reduction in the content of phenols from 20% to 43% is observed in the effluent of three phases, while a reduction of 53% to 73% is observed in the effluent of two phases. In what regards to phytotoxicity, we can conclude that the microalgae can reduce the toxicity of olive mill wastewaters having also the ability to degrade the phenolic compounds that inhibit the germination and growth of Lactuca sativa.
One of the greatest issues in the industry of olive oil production has to do with the massive production of olive mill wastewaters which result from the processing of olive oil. Worldwide production of olive oil is centered in the Mediterranean basin, and Portugal is one of the world’s 10 largest producers. Olive mill wastewaters represent an environmental threat as its direct outflow in aquatic and terrestrial environments may cause the eutrophication of water courses and soils to become infertile. Despite this, an efficient and economically practicable treatment system hasn’t yet been established in the industry. The issues brought by this effluent have to do with its chemical composition which consists of a high organic load, associated with high contents of phenolic compounds and acid pH, as well as a characteristic smell and dark colour. Taking the above into consideration, the aim of this assignment is to assess the potential of microalgae in the decrease of phenolic compounds and increase of pH in olive mill wastewaters. For this purpose, the effect of immobilized Chlorella vulgaris in the bioremediation of phase two and phase three olive mill wastewaters has been tested in batch cultures. The effectiveness of the process has also been assessed by phytotoxicity, in germination trials and growth of Lactuca sativa. Besides that, the process has been optimized through the implementation of a second cycle and second treatment with the usage of preadapted inoculums, with the reduction of culture time and with the optimization of the type of reactor. According to the screening of the growth in solid environment, the batch trials have been performed in two phase olive mill wastewaters on a dilution of 35%, 50% and 60% and for the case of olive mill wastewaters of three phases on a dilution of 20% in modified Walne medium. These trials have been performed in room environment with natural light and continuous aerification. The optimization of the reactor has been accomplished through the use of a bubble column. The results achieved show that the Chlorella vulgaris has the ability of removing phenolic compounds and neutralizing the effluent, and a reduction in the content of phenols from 20% to 43% is observed in the effluent of three phases, while a reduction of 53% to 73% is observed in the effluent of two phases. In what regards to phytotoxicity, we can conclude that the microalgae can reduce the toxicity of olive mill wastewaters having also the ability to degrade the phenolic compounds that inhibit the germination and growth of Lactuca sativa.
Description
Keywords
Água ruça Biorremediação Chlorella vulgaris Compostos fenólicos Fitotoxicidade Lactuca sativa