FuturEnviro | Junio June 2019 www.futurenviro.es 31 Los flotantes por su parte se bombean al separador de grasas del pretratamiento con dos bombas centrífugas sumergibles ya existentes, una en reserva, de 10 m3/h de caudal unitario. Medida y regulación de caudal a biológico Una vez que el agua ha pasado por la decantación primaria, dada la diferencia de caudales entre el máximo de tratamiento primario y el caudal punta de tratamiento biológico, se realiza una regulación de caudal. Tras la decantación primaria existe un canal Parshall y un vertedero que limita el caudal al tratamiento biológico. El caudal hidráulico máximo admisible en el tratamiento biológico se sitúa en 1.400 m3/h. Este alivio funciona como by-pass del tratamiento biológico cuando sea necesario y lleva el agua decantada a la arqueta de salida de la planta. Posteriormente existe un sistema de distribución del caudal a cada uno de los reactores biológicos mediante vertedero de pared gruesa tipo Neyrpic. Se ha instalado sobre cada uno de los vertederos un medidor rádar por cada línea de reactores biológicos Para la ejecución de las obras se contempló la demolición de los tres reactores biológicos y del digestor aerobio existente y la construcción en su lugar, de tres nuevos reactores con volúmenes anaerobios, anóxicos y aerobios efectivos para la reducción de fósforo y nitrógeno. Se realizaron las obras provisionales necesarias para que la planta actual no se quedase fuera de servicio. Para poder ejecutar los nuevos reactores y su conexión con la arqueta de regulación de caudal, se previó la ejecución de una arqueta anexa desde la que partir una nueva tubería de Ø 1000, aislada con una compuerta, que cuenta con capacidad para poder transportar el caudal punta de 1.400 m3/h. Pasos de remodelación de la arqueta de reparto a biológico Para garantizar que el volumen enviado a los reactores no supera el valor de consigna establecido (1.400 m3/h), dejándolo únicamente en manos de un elemento fijo, se ha procedido a la instalación de un servomotor en la compuerta de by-pass del tratamiento biológico, que en función del medidor Parshall instalado antes del reparto a reactores, sube para derivar parte del caudal de manera que no se supere los 1.400 m3/h en el tratamiento biológico. Reactor biológico Introducción Sometida ya el agua bruta a un pretratamiento y posterior tratamiento primario inicia ahora su recorrido por un tratamiento biolóbiological treatment to be used as a standby in this pumping station, owing to the lack of space in this chamber. Moreover, all the existing pipes were substituted with new stainless steel pipes. The pipe that carries the sludge from the primary sludge chamber to the screening and digestion building is newly installed. The supernatants are pumped to the pretreatment grease separator by two (1+1 standby) existing submersible centrifugal pumps with a unitary flow rate of 10 m3/h. Metering and control of flow to biological treatment Given the difference between the primary treatment maximum flow and biological treatment peak flow, flow control is carried out once the water has undergone primary settling. Subsequent to primary settling a channel equipped with a Parshall flume and a weir limit the flow to biological treatment. The maximum hydraulic flow into biological treatment is set at 1,400 m3/h. This control channel operates as a biological treatment bypass line when necessary and carries the decanted water to the plant outlet chamber. Subsequently, a flow distribution system featuring a Neyrpic broad-crested weir controls the flow to each of the bioreactors. A radar type flowmeter is installed above each weir for each line of bioreactors. The 3 existing bioreactors and aerobic digesters were demolished and 3 new reactors were constructed to replace them. The new reactors have effective anaerobic, anoxic and aerobic zones for phosphorus and nitrogen removal. The necessary provisional construction work was carried out to ensure that the existing plant remained in operation. In order to be able to build the new reactors and connect them to the flow control chamber, an adjoining chamber was built and a new pipe with a diameter of 1,000 mm extend from this chamber. This pipe is isolated by means of a sluice gate and has the capacity to convey the peak flow of 1,400 m3/h. Actions taken to remodel the distribution chamber to biological treatment In order to ensure that the volume sent to the reactors does not exceed the established set point (1,400 m3/h), leaving it solely in the hands of a fixed element, a servomotor was installed in the biological treatment bypass sluice gate. Depending on the reading of the Parshall flume installed prior to distribution to the reactors, the sluice gate is raised to divert part of the flow in such a way that it does not exceed the limit of 1,400 m3/h into biological treatment. Bioreactor Introduction The raw water has now undergone pretreatment followed by primary treatment and is ready to undergo biological treatment, which basically seeks to reduce the organic matter content in the water. The biological treatment implemented envisages nitrogen and phosphorus removal.We shall now give a more detailed description of the basic aspects of this process. The ideal approach is to regulate the sludge concentration in the activated sludge tank to achieve a very high value. In fact, experience shows that final clarification can function correctly and EDAR de Aranjuez (Madrid) | AranjuezWWTP (Madrid)
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