Search

Submitted by Ruth Quaresma de Freitas (ruth_quaresma@hotmail.com) on 2019-02-27T16:40:50Z No. of bitstreams: 1 ALOYSIO FERRAZ DE ABREU - DISSERTAÇÃO PPGECA 1989..pdf: 2230269 bytes, checksum: 7696c1f24fc7357ac98bb67375c329c5 (MD5) Made available in DSpace on 2019-02-27T16:40:50Z (GMT). No. of bitstreams: 1 ALOYSIO FERRAZ DE ABREU - DISSERTAÇÃO PPGECA 1989..pdf: 2230269 bytes, checksum: 7696c1f24fc7357ac98bb67375c329c5 (MD5) Previous issue date: 1989-11-10 Na presente pesquisa avalía-se a tratabílidade, por via anaeróbia, de uma agua residuária sintética, com características semelhantes àquelas esperadas para as águas residuárias do Polo Cloroquímico de Alagoas. Nessas aguas espera-se um alto teor de cloreto de cálcio e magnésio (dureza de 25 g.1-1 de CaCO3)e, ocasionaImente, organoclorados, notadamente tricloropropano e cloreto de alila. Correspondentemente a pesquisa se concentra na avaliação da influência dessas substâncias sobre a atividade metanogênica do lodo anaeróbio, Concluiu-se que ambas, alta dureza e a presença de organoclorados , mesmo em teores pequenos (1 mg.1 -1), inibem a atividade metanogênica ao ponto de inviabilizar o tratamento por via anaeróbia. In this research study the anaerobic treatability of a synthetic wastewater with característics similar to those expected in the chlorinechemical complex of Alagoas is evaluated. These waters are expected to contain a high concentration of calciun and magnesiun chloride (hardness of 25 g .1-1 CaCO3) and, ocasionally, chlorinated organics like tricloropropane and allyl chloride. Thus there search work was concentrated on evaluating the influence of these substatices on the methanogenic activity of anaerobic sludge. It was concluded hat both the high hardness and the presence of chlorinated organics even in small concentrations (1mg.1-1 ), inhibited the methanogenic activity so severely that anaerobic treatment is not feasable.

An Aerated Submerged Biological Filter was used to promote biological nitrification of a synthetic saline wastewater. Black PVC corrugated plates were used to make the structured packing of the 6 liter reactor. Nitrate, nitrite, and ammonia concentrations, pH and DO were periodically measured, according to APHA (1985). In spite of the deleterious effect of salinity, it was possible to obtain nitrogen removal efficiencies as high as 95% for a 25 g/L salt concentration after a three-day reaction in the batch reactor. Continuous operation using a NaCl concentration of 25 g/L was tested using three different hydraulic retention times: 7, 15, and 25 hours. An increase in ammonia removal was observed when the retention time was increased from 7 to 15 hours. However, no further notable increase was obtained for a 25 hour retention time, showing that nitrogen removal tends towards a maximum limit of about 80%.

Background: High concentration of salt makes biological treatment impossible due to bacterial plasmolysis. The present research studies the process of electrochemical oxidation efficiency and optimal levels as important factors affecting pH, salt concentration, reaction time and applied voltage. Methods: The sample included graphite electrodes with specifications of 2.5 cm diameter and 15 cm height using a reactor with an optimum capacity of 1 L. Sixty samples were obtained with the aid of the experiments carried out in triplicates for each factor at 5 different levels. The entire experiments were performed based on standard methods for water and waste water treatments. Results: Analysis of variance carried out on effect of pH, salt concentration, reaction time and flow intensity in elimination of chemical oxygen demand (COD) showed that they are significant factors affecting this process and reduce COD with a coefficient interval of 95% and test power of 80%. Scheffe test showed that at optimal level, a reaction time of 1 hour, 10 g/L concentration, pH = 9 and 15 V electrical potential difference were obtained. Conclusion: Waste waters containing salt may contribute to the electro-oxidation process due to its cations and anions. Therefore, the process of electrochemical oxidation with graphite electrodes could be a proper strategy for the treatment of saline wastewater where biological treatment is not possible.

Summarization: Currently, the treatment of aquaculture-origin effluents is mainly performed through land-based recirculating aquaculture systems (RAS). In this study, we evaluate and introduce a novel immobilized/packed bed bioreactor which uses a synthetic textile as the support medium. A marine microbial consortium was developed on the textile by its inoculation with the microalgae Picochlorum sp. The bioreactor was tested with variable loadings of C and N and showed outstanding performance approaching removal rates up to 95% within a few hours (4–5 h) of operation. Pyrosequencing analysis revealed a novel microbial consortium consisting mainly of chitrinomycetes, Pseudomonas sp. and the absence of β-proteobacteria, which is the Class encompassing autotrophic nitrifiers. Quantitative polymerase chain reaction further confirmed these findings suggesting heterotrophic nitrification and aerobic denitrification as the principal mechanisms of N-removal from the bioreactor. Overall our findings reveal the potential of the AdvanTex System for the treatment of marine aquaculture effluents–COD reduction and N-removal, in a single stage. Presented on: Journal of Hazardous Materials