Process modeling and analysis of biological nutrients removal in an integrated RBC-AS system using response surface methodology

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 168; no. 1; pp. 269 - 279
• Main Authors: Akhbari, A., Zinatizadeh, A.A.L., Mohammadi, P., Irandoust, M., Mansouri, Y.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 15.03.2011; Elsevier
• Subjects: Applied sciences; Biological nutrients removal; Chemical engineering; Disks rotating speed; Exact sciences and technology; General purification processes; Integrated RBC and AS; Internal recirculation; Pollution; Response surface methodology (RSM); Wastewaters; Water treatment and pollution; Biological nutrients removal; Internal recirculation; Disks rotating speed; Response surface methodology (RSM); Integrated RBC and AS; Activated sludge; Recirculation; Aerobe; Retention; Modeling; Composite material; Waste water; Design; Chemical oxygen demand; Rotating biological contactor
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2011.01.003

In this study, the removal of carbon, nitrogen and phosphorus from a synthetic wastewater in an integrated rotating biological contactor (RBC) and activated sludge (AS) system was investigated. The experiments were conducted based on a central composite design (CCD) and analyzed using response surface methodology (RSM). In order to analyze the process, four significant independent variables viz. hydraulic retention time (HRT), chemical oxygen demand (COD) to nitrogen ratio (COD/N), internal recirculation from aerobic to anoxic zone ( R) and disks rotating speed ( r) and six dependent process and quality parameters as the process responses were studied. The region of the exploration for the process was taken as the area enclosed by hydraulic retention times (9.7, 18.7 h), COD/N ratios (4, 20), R (1, 4), and r (5, 15 rpm) boundaries. The most effective factors on the process performance were found to be HRT and R in terms of COD and TN removal. The optimal region was enclosed by the entire HRT (18, 18.7 h) and r (5, 15 rpm) boundaries, at the medians of the COD:N:P (1000:83:30) and R (2.5). The present study provides valuable information about interrelations of quality and process parameters at different values of the studied variables.