Membrane bioreactor for treatment of pharmaceutical wastewater containing acetaminophen ☆ Farshid Pajoum Shariati a , Mohammad Reza Mehrnia a, ⁎, Bahreh Madadkhah Salmasi a , Marc Heran b , Christelle Wisniewski b , Mohammad Hossein Sarrafzadeh a a School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran, Iran b Laboratoire de Génie des Procédés, Eau et Bioproduits, Université Montpellier 2, F-34095 Montpellier, France abstract article info Article history: Accepted 5 November 2008 Available online 9 October 2009 Keywords: External loop airlift membrane bioreactor Acetaminophen Activated sludge process Pharmaceutical wastewater Treatment of pharmaceutical wastewater is a real challenge for wastewater engineers. In this study, a pilot- scale system including an external loop airlift membrane bioreactor (ELAMBR) was applied for treatment of a synthetic pharmaceutical wastewater. The performance of this system was evaluated in removal of acetaminophen as the main pollutant of a pharmaceutical wastewater. A conventional activated sludge (CAS process) laboratory system was used in parallel with this system to compare both systems in regard to their ability for acetaminophen removal. The performance of the ELAMBR system was monitored for approximately one month to investigate the long-term operational stability of the system and possible effects of solids retention time on the efficiency of removal of acetaminophen. The removal efficiency was significantly higher in the ELAMBR system than the CAS process. 100% of the acetaminophen was removed after 2 days in this system. The results also showed that initial concentration of acetaminophen, chemical oxygen demand (COD) and mixed liquid suspended solids (MLSS) are the most effective parameters in removal of a pollutant such as acetaminophen. This study demonstrates the usefulness of ELAMBR system for pharmaceutical wastewater treatment with the advantages such as: (i) simple operation and maintenance, (ii) efficient removal of pharmaceutical pollutant and COD and (iii) low-energy consumption. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Increasing population, its impact on water quality and increasing expectations for water use based on lifestyle changes lead to increasing demands on water supplies. The demands are for more quantity and better quality of water. Quantity demands may only be met by re-use and quality demands by advanced treatment, in both cases indicating a potential role for membrane technologies [1,2]. Pharmaceutical industry produces a wide variety of products. This industry uses both inorganic and organics as raw materials the latter being either of synthetic or of vegetable and animal origin [3,4]. New compounds are continually being manufactured and released to the environment. Environmental contamination by pharmaceuticals and personal care products (PPCPs) has recently gained widespread public attention as a pervasive problem. These effluents are loaded with pathogenic microorganisms, pharmaceutical partially metabolized, radioactive elements and other toxic chemical substances. So, these products are being released to the environment during manufacturing. Further, more than 70 different compounds have been detected in surface and groundwater in a country such as U.S., often at concentra- tions in the 0.01–1 μg/L range [5,6]. Membrane bioreactors (MBR) are commonly understood as the combination of membrane filtration and biological treatment using conventional activated sludge (CAS) where the membrane primarily serves to replace the clarifier in the wastewater treatment system [1,2]. With more serious environmental pollution, MBR's application in wastewater treatment is receiving more and more attention. The membrane bioreactor is operated similar to a conventional activated sludge process but without the need for secondary clarification and tertiary steps like sand filtration. Low-pressure membrane filtration, either microfiltration or ultrafiltration is used to separate effluent from activated sludge. Due to the absence of a secondary clarifier, the overall MBR plant size can be remarkably reduced in comparison with that of the conventional activated sludge process. MBR provides not only complete retention of all microorganisms and an increase of sludge concentration but also a complete disinfection of treated water. As a consequence, MBR makes hydraulic retention time independent from sludge retention time, which facilitates a more flexible control of operation parameters. High sludge concentration maintained in the bioreactor of the MBR makes it possible to treat high strength wastewater efficiently. The entire retention of activated sludge Desalination 250 (2010) 798–800 ☆ Presented at the Conference on Membranes in Drinking and Industrial Water Production, 20–24 October 2008, Toulouse, France. ⁎ Corresponding author. E-mail address: mmehrnia@ut.ac.ir (M.R. Mehrnia). 0011-9164/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.desal.2008.11.044 Contents lists available at ScienceDirect Desalination journal homepage: www.elsevier.com/locate/desal