Avaliação do processo de tratamento de água utilizando aassociação do coagulante natural Moringa oleifera LAM Ecoagulantes químicos

• Autor(a) principal: Valverde, Karina Cardoso
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/3699
• topic: Água potável; Tratamento de água; Moringa oleifera Lam; Coagulantes químicos; Brasil.; Moringa oleifera Lam; Chemical coagulants; Conventional water treatment; Brazil.; Engenharias; Engenharia Química

The use of natural coagulants, such as Moringa oleifera Lam (M. oleifera) has been largely studied in order to produce a better quality of treated water, also reduce the use of chemical coagulants in the process. This study purpose to evaluate the process of coagulation/ flocculation, sedimentation and filtration using the association of natural and chemical coagulants: M. oleifera and ferric chloride, M. oleifera and aluminum polychloride (PAC), and M. oleifera and aluminum sulphate. In the tests it was used raw water provides from the Pirapo River basin, Maringa, PR, with an initial turbidity of about 70 NTU. Firstly, tests were conducted to evaluate the different methods of preparation of natural coagulant obtained from the M. oleifera seeds. After this, it was evaluated the degradation time of M. oleifera coagulant whole powder. Regarding the association of coagulants, the study of the optimization of operating conditions was performed in terms of coagulation/flocculation and sedimentation, such as: speed and mixing times and sedimentation. In order to build the coagulation diagrams, the pH ranged from clotting and the dosage of standard solution of natural and chemical coagulants. The descending fast filtration step using a double layer filter sand and anthracite were studied to evaluate the possibility to obtain potable water. Ingenerally, it can be considerate that the whole powder seeds of M. oleifera is a suitable natural coagulant and coagulant association, contributing significantly to reduce the quantity of chemical coagulants applied to the process. It has been observed that the mixing parameters affect the removal efficiency of the quality parameters. It has be found that the results obtained for the physical, chemical and microbiological characteristics of treated water were quite significant and consistent with the values required by the legislation (Ordinance no. 2914 of the Ministry of Health), including the trihalomethanes parameter. The association of M. oleifera coagulant and PAC showed better results in terms of residual values of apparent color, turbidity, compounds with absorption at UV254nm and dissolved organic carbon in comparison with other associations studied, which is related to the size of the particles formed and zeta potential. It is pertinent to mention that the use of 80% of M. oleifera with 20% chemical coagulant (ferric chloride, PAC or aluminum sulphate) are suitable for the production of drinking water, the operating conditions studied efficiencies obtained with removing around 99% for apparent color, 96% for turbidity and 89% for compounds with absorption at UV254nm. However, the disinfection step should be added to the process to ensure the absence of microrganisms. It can concluded that the use of M. oleifera as coagulant associated with ferric chloride, PAC or aluminum sulphate, in optimal conditions of the coagulation/flocculation, sedimentation and filtration process ensures removal efficiency of water quality parameters as well as the possibility of producing water with potability standards required by legislation