Regulation of the organic pollution level in anaerobic digesters by using off-line COD measurements

• Published in: Bioresource technology 2011-09, Vol.102 (17), p.7666-7672
• Main Authors: Méndez-Acosta, H.O., García-Sandoval, J.P., González-Álvarez, V., Alcaraz-González, V., Jáuregui-Jáuregui, J.A.
• Format: Article
• Language: English
• Subjects: Anaerobic digestion; Anaerobiosis; Applied sciences; Attenuation; Biological and medical sciences; Biological treatment of sewage sludges and wastes; Bioprocess optimization; Biotechnology; Control; Crack opening displacement; Digesters; Disturbances; Environment and pollution; Environmental Pollutants; Estimators; Exact sciences and technology; Food industries; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; Pollution; Pollution levels; Sampled delayed control; Steady state; Tequila vinasses; Use and upgrading of agricultural and food by-products. Biotechnology; Wastewater treatment; Wastewaters; Water treatment and pollution
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2011.05.053

► A control scheme to optimize anaerobic digestion processes was designed and experimentally validated. ► The control scheme can be easily implemented by using standard COD measurements. ► No expensive on-line analyzers are required. ► The organic pollution level is effectively regulated in spite of parametric uncertainties and load disturbances. ► The real-life industrial application of this control scheme is particularly encouraging. A sampled delayed scheme is proposed to regulate the organic pollution level in anaerobic digestion processes by using off-line COD measurements. The proposed scheme is obtained by combining an error feedback control with a steady state estimator to track constant references and attenuate process load disturbances. The controller performance is tested experimentally for the treatment of tequila vinasses over a period of 68days under different set-point values and several uncertain scenarios which include badly known kinetic parameters and load disturbances. Experimental results show that the COD concentration can be effectively regulated under the influence of set-point changes and high load disturbances by using only a daily off-line COD measurement, which makes the industrial application of the proposed control scheme feasible.