Journal of Water Process Engineering 8 (2015) 136–141 Contents lists available at ScienceDirect Journal of Water Process Engineering journal homepage: www.elsevier.com/locate/jwpe A real petroleum refinery wastewater treatment using hollow fiber membrane bioreactor (HF-MBR) Seyed Mohammad Reza Razavi, Taghi Miri ∗ Department of Chemical Engineering, Faculty of Engineering, Arak University, Arak 38156-8-8349, Iran a r t i c l e i n f o Article history: Received 28 June 2015 Received in revised form 12 September 2015 Accepted 27 September 2015 Keywords: Hollow fiber membrane bioreactor (HF-MBR) Petroleum refinery wastewater Wastewater Treatment BOD5 COD Ultrafiltration a b s t r a c t In this paper, the capability of hollow-fiber membrane bioreactor (HF-MBR) for real petroleum refin- ery wastewater treatment was studied. A pilot immersed HF-MBR was designed, and the treatment investigated under various hydraulic retention time (HRT), flux, temperature, and different operational conditions. The bioreactor included an ultrafiltration membrane (UF) and Arak refinery wastewater used as the influent stream. The HF-MBR was running throughout 160 days. The result indicated that aver- age elimination efficiencies of chemical oxygen demand (COD), biological oxygen demand (BOD 5 ), total suspended solids (TSS), volatile suspended solids (VSS) and turbidity were attained 82%, 89%, 98%, 99%, and 98%, respectively. Furthermore, the mixed liquor-suspended solid (MLSS) and mixed liquor volatile- suspended solids (MLVSS) concentration raised from minimal concentration to about 6.6 and 6.1 g/L, respectively. © 2015 Published by Elsevier Ltd. 1. Introduction Petroleum refinery wastewater is one the largest wastewa- ter produced in the manufacturing operations. In every site, for each barrel of oil, about ten barrels of wastewater are created [1]. The produced wastewater typically contains dissolved and sus- pended oil substances, dissolved minerals, heavy metals, chemical ingredients, and dissolved gases [2]. The salt concentration varies considerably [3] and the oil and grease concentrations is between 2 and 600 mg/L while the total organic carbon (TOC) concentration is between 15 and 1500 mg/L [4]. On the other side, because of the increasing amount of the fresh water is used and wastewater produced in the petroleum industry, one should consider reusing the treated wastewater as a complement to restricted fresh water sources in water-stress area [5]. Problems of water pollution have to be resolved urgently. To decrease hydrocarbon contaminants from wastewater, physical and chemical ways have been utilized containing photo-electro cat- alytic purification, hydro cyclones, coagulation, and flocculation [5]. These types of treatment method are only ideal for initial treatment. Therefore, even more effective treatment methods and processes ∗ Corresponding author. Tel.: +98 863 2625436. E-mail address: t-miri@araku.ac.ir (T. Miri). must be put to use before reuse and/or release to the environment [1,6]. One of the many treatment methods employed for treatment of greasy/salty wastewater is membrane filtration [7]. Membrane purification is acting a far more important position in the treating oily wastewater because of its benefits. The benefits are includ- ing: no chemical additives are essential to separate the emulsion, high COD treatment efficiencies are reached, and treatment tools can be small and completely automatic [8]. Several reports have already been published on the oily wastewater treatment with various membranes [9–13]. Usually, biological treatment of wastewater is known as the economic and environmental method [14]. Joining of activated sludge method and membrane filtration has many benefits such as the ability of running the system at high mixed liquor suspended solids (MLSS) concentration, little footprint, good disinfection abil- ity, higher volumetric loading and high effluent quality [14,15]. By utilizing micro or ultrafiltration membrane method (with pore sizes which range from 0.05 to 0.4 micrometer), MBR techniques permit the whole physical maintenance of bacterial flocs and almost all suspended solids within the bioreactor [14]. The membrane bioreactor (MBR) has been widely utilized to treat both municipal and industrial wastewater [15–17]. Therefore, the MBR method has now become an interesting choice for the treatment and reutilization of industrial and urban wastewaters, as shown by their continually increasing numbers and capacity [14]. http://dx.doi.org/10.1016/j.jwpe.2015.09.011 2214-7144/© 2015 Published by Elsevier Ltd.