Denitrification of metallurgical wastewater in a novel anaerobic swirling fluidized membrane bioreactor
"The present work was focused on the application of denitrification to a stainless-steel industrial effluent, which contains a high nitrate concentration (~6.8 g N-NO3-), acidic pH (pH=3.3) and a high concentration of Fe=12.5 g/L, Cr=2.9 g/L, Ni=2.2 g/L, and other elements, such as Sn, Mn, Si,...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2019 |
| País: | México |
| Institución: | Instituto Potosino de Investigación Científica y Tecnológica |
| Repositorio: | Repositorio Institucional del IPICYT |
| OAI Identifier: | oai:ipicyt.repositorioinstitucional.mx:1010/2555 |
| Acceso en línea: | http://ipicyt.repositorioinstitucional.mx/jspui/handle/1010/2555 |
| Access Level: | acceso abierto |
| Palabra clave: | info:eu-repo/classification/Autor/Denitrification info:eu-repo/classification/Autor/Stainless-steel effluent info:eu-repo/classification/Autor/Metal bio-recovery info:eu-repo/classification/Autor/Fluidized bed bioreactor info:eu-repo/classification/Autor/Swirling fluidization info:eu-repo/classification/cti/7 info:eu-repo/classification/cti/33 info:eu-repo/classification/cti/3308 info:eu-repo/classification/cti/330810 |
| Sumario: | "The present work was focused on the application of denitrification to a stainless-steel industrial effluent, which contains a high nitrate concentration (~6.8 g N-NO3-), acidic pH (pH=3.3) and a high concentration of Fe=12.5 g/L, Cr=2.9 g/L, Ni=2.2 g/L, and other elements, such as Sn, Mn, Si, Mo, Co, Pb, Cu, V, B and Al, which are present at a concentration lower than 1 g/L. Citrate, which is a chelating agent, can also be present in this type of wastewater. Denitrification applied to this effluent has the challenge to face high nitrate and metals concentrations as well as acidic pH, which could inhibit nitrate removal rate and promote the accumulation of intermediates (NO2- and N2O). The first part of the study was focused on understanding the effects of key metals present in the metallurgic effluent on denitrification performance. This was accomplished by chemical speciation analysis and by monitoring the accumulation of denitrification intermediates. The second step of the project was focused on the development of a novel technology for the treatment of a stainless-steel industrial effluent. This technology was implemented with the aim to remove high content of nitrate in the effluent, neutralize the acidic pH and to achieve metals recovery. The acidic pH can be neutralized by the by-products generated (CO3- and OH-) from the denitrification process. Additionally, these compounds form insoluble species with the metals, promoting their bio-recovery. The project innovation considers the design and test of the process previously described through an Anaerobic Swirling Fluidized Membrane Bioreactor (ASFMBR). Fluidization of granular carbon (GC) through the hydrodynamic conditions established inside the ASFMBR has the objective of promote the collision of GC particles with the microfiltration hollow fiber membranes surface as a mechanical cleaning strategy to prevent membrane fouling. Likewise, a denitrifying biofilm was supported on GC particles to carry out the denitrification process. Swirling fluidization is produced both by the novel reactor geometry (hydrocyclone type) and by a tangential inlet. Membrane module design allows the free GC particles circulation around the membranes. The outlet of the reactor is just composed by the line of permeate flow. This allows the saturation of the chemical species, their precipitation, and rejection by the membranes". |
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