Model development and application for surfactant biodegradation in an acclimatising activated sludge system

• Published in: Chemosphere (Oxford) Vol. 54; no. 10; pp. 1495 - 1502
• Main Authors: Carvalho, G., Novais, J.M., Pinheiro, H.M., Vanrolleghem, P.A.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-03-2004; Elsevier
• Subjects: Acclimatisation; Applied sciences; Biodegradation, Environmental; Biological and medical sciences; Biological treatment of waters; Biotechnology; Environment and pollution; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; Industrial wastewaters; Model development; Models, Chemical; Non-ionic surfactants; Optimisation; Pollution; Sewage - microbiology; Surface-Active Agents - metabolism; Textile Industry; Textile industry wastewater; Transient state; Wastewaters; Water Pollution, Chemical - prevention & control; Water treatment and pollution; Acclimatisation; Transient state; Optimisation; Non-ionic surfactants; Model development; Textile industry wastewater; Biodegradation; Activated sludge; Costs; Non ionic surfactant; Unsteady state; Modeling; Optimization; Operating conditions; Biological purification; Bioreactor; Sequencing batch reactor; Industrial waste water; Economic aspect; Waste water purification; Dynamic model; Textile industry
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2003.08.028

A model for the biodegradation of non-ionic surfactants in an activated sludge system during acclimatisation was developed, based on respirometric and titrimetric experimental data. The data were obtained in a sequencing batch reactor (SBR) using a non-ionic surfactant as sole carbon source and sludge previously acclimatised to a different surfactant. The model was successfully applied to successive SBR-cycles of sludge acclimatisation processes subjected to two ethoxylated surfactants. The model was validated using the corresponding total organic carbon data. The evolution of the model parameters along the acclimatisation process was examined. An acclimatisation model was developed using the evolution of two of these parameters (affinity constant and inhibition constant), supported by two independently calculated acclimatisation indicators. This acclimatisation model was then applied to determine an optimal surfactant concentration sequence to feed non-acclimatised sludge during a period of 41 days, in order to induce pre-acclimatisation to this surfactant before it replaces another one in the wastewater. The model was also useful in the economical assessment of this and alternative procedures to cope with frequent changes in activated sludge feed composition.