Regulation of petrochemical waster at an activated sludge system via a simple robust feedback control aproach
Regulación de aguas residuales petroquímicas en un sistema de lodos activados vía una propuesta simple de control retroalimentado robusto
A. Velasco-Pérez1*, H. Puebla2, S. Martinez-Delgadillo3, M.A. Morales4 and R. Solar-González5
1 Facultad de Ciencias Químicas, Universidad Veracruzana. Orizaba, México. * Corresponding author. E-mail: alvelasco@uv.mx.
2 Departamento de Energía.
]]> 3 Departamento de Ciencias Básicas, Universidad Autónoma Metropolitana, Azcapotzalco, México D.F.4 Subgerencia de Calidad y Protección Ambiental, PEMEX Petroquímica, Coatzacoalcos, Veracruz.
5 Universidad del Istmo. Tehuantepec, Oaxaca.
Received June 25, 2013.
Accepted February 24, 2014.
Abstract
In this paper the regulation of petrochemical wastewater from an activated sludge system is addressed via a simple robust feedback control approach. The control approach is based on simple step response models and a favorable choice of the discharge flow-rate from the settler as the manipulable variable. Based on simple first order model and first order model plus input delay to account for dead-times induced by the measurement of COD two controllers are derived. The proposed controllers are composed by two parts: (i) an uncertainty observer to compensate uncertainties and neglected terms in the input-output models, and (ii) an inverse dynamics feedback controller. Numerical simulations show good closed-loop performance and robustness properties.
Keywords: petrochemical wastewater, wastewater treatment, activated sludge system, robust control, modeling error compensation.
]]>Resumen
En este trabajo se aborda la regulación de aguas residuales de la industria petroquímica en un sistema de lodos activados por medio de un diseño simple de control robusto retroalimentado. La propuesta de control se basa en modelos de respuesta escalón simple y una elección favorable del flujo de descarga del sedimentador como la variable manipulable. Con base a modelos de primer orden y primer orden más tiempo muerto, que considera el tiempo de retardo en la medición de DQO, se derivan dos controladores robustos. Los controladores propuestos se componen por dos partes: (i) un estimador de incertidumbres para compensar incertidumbres y términos despreciados en los modelos aproximados entrada-salida, y (ii) un control retroalimentado por inversión dinámica. Las simulaciones numéricas, sobre un modelo validado de un sistema de lodos activados tratando aguas residuales de la industria petroquímica, muestran un buen desempeño a lazo cerrado y buenas propiedades de robustez.
Palabras clave: aguas residuales petroquímicas, tratamiento biológico de aguas residuales, sistema de lodos activados, control robusto, compensación de error de modelado.
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