DISEÑO, CONSTRUCCIÓN Y EVALUACIÓN DE UN SISTEMA DE CONTACTOR BIOLÓGICO ROTATORIO (CBR) PARA EL TRATAMIENTO DE AGUAS RESIDUALES MUNICIPALES A ESCALA PILOTO
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Inv. y Des.
Abstract
En este estudio se diseñó, implementó y evaluó el desempeño de una planta piloto de tratamiento de aguas residuales domésticas, basada en contactores biológicos rotatorios (CBR). La demanda de fuentes de agua en zonas semi- áridas ocasiona que se reutilicen aguas residuales en agricultura, aunque no tengan ningún grado de tratamiento. Los CBR son sistemas de tratamiento aerobio llevado a cabo por microorganismos adheridos sobre discos que rotan lentamente a través de un flujo de agua residual. Entre las ventajas del sistema se puede mencionar, los niveles potencialmente altos de eficiencia, que ocupan poco espacio y se pueden ampliar modularmente; sin embargo, son sistemas costosos de implementar, debido a que se requiere de la importación de los discos. En este estudio se escogió el poliestireno por su disponibilidad local y se verificó que es un medio de adherencia adecuado para los microorganismos. Las eficiencias máximas alcanzadas por el CBR una vez concluido el periodo de aclimatación fueron: 81%, 75% y 85% para la remoción de DQO total, DQO soluble y SST. La eficiencia global del sistema constituido por un sedimentador primario, un CBR de 3 etapas y un sedimentador secundario, alcanzó niveles de 68-79% para DQO total, 68-77% de DQO soluble y 81-99% de SST. Los niveles de tratamiento alcanzan valores dentro de los límites establecidos en la legislación boliviana para descarga de aguas residuales, por lo que es recomendable su escalamiento en condiciones climáticas similares a las del estudio.
In this study, a pilot scale domestic wastewater treatment plant based on rotating biological contactors (RBC), was designed, built, and evaluated. The demand of sources of water in semi-arid zones causes wastewater reuse in agriculture even without any treatment. RBC is an aerobic treatment system carried out by microorganisms attached to discs that rotate slowly through a stream of wastewater. Among the advantages of the system it can be mentioned, the potentially high levels of efficiency, the small footprint, and that can be expanded modularly; however, they are expensive systems to implement, due to the high cost of imported discs. In this study, one side rough polystyrene was chosen due to its local availability and it was verified that it is a suitable means for microorganisms to adhere. The maximum efficiencies reached by the RBC once acclimatization period was concluded, were: 81%, 75% and 85% for the removal of TCOD, SCOD and TSS. The overall efficiency of the system consisting of a primary settler, a 3-stage RBC and a secondary settler, reached levels of 68-79% for total COD, 68-77% of dissolved COD and 81-99% of TSS. Treatment levels are within the limits established in Bolivian legislation for wastewater discharge, so scaling up of this technology in climatic conditions similar to those of this study is recommended.
In this study, a pilot scale domestic wastewater treatment plant based on rotating biological contactors (RBC), was designed, built, and evaluated. The demand of sources of water in semi-arid zones causes wastewater reuse in agriculture even without any treatment. RBC is an aerobic treatment system carried out by microorganisms attached to discs that rotate slowly through a stream of wastewater. Among the advantages of the system it can be mentioned, the potentially high levels of efficiency, the small footprint, and that can be expanded modularly; however, they are expensive systems to implement, due to the high cost of imported discs. In this study, one side rough polystyrene was chosen due to its local availability and it was verified that it is a suitable means for microorganisms to adhere. The maximum efficiencies reached by the RBC once acclimatization period was concluded, were: 81%, 75% and 85% for the removal of TCOD, SCOD and TSS. The overall efficiency of the system consisting of a primary settler, a 3-stage RBC and a secondary settler, reached levels of 68-79% for total COD, 68-77% of dissolved COD and 81-99% of TSS. Treatment levels are within the limits established in Bolivian legislation for wastewater discharge, so scaling up of this technology in climatic conditions similar to those of this study is recommended.
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Vol. 20, No. 1