Biotreatment of oily wastewater by rhamnolipids in aerated active sludge system

Abstract

Abstract:Oily wastewater generated by various industries creates a major ecological problem throughout the world. The traditional methods for the oily wastewater treatment are inefficient and costly. Surfactants can promote the biodegradation of petroleum hydrocarbons by dispersing oil into aqueous environment. In the present study, we applied rhamnolipid-containing cell-free culture broth to enhance the biodegradation of crude oil and lubricating oil in a conventional aerobically-activated sludge system. At 20 °C, rhamnolipids (11.2 mg/L) increased the removal efficiency of crude oil from 17.7% (in the absence of rhamnolipids) to 63%. At 25 °C, the removal efficiency of crude oil was over 80% with the presence of rhamnolipids compared with 22.3% in the absence of rhamnolipids. Similarly, rhamnolipid treatment (22.5 mg/L) for 24 h at 20 °C significantly increased the removal rate of lubricating oil to 92% compared with 24% in the absence of rhamnolipids. The enhanced removal of hydrocarbons was mainly attributed to the improved solubility and the reduced interfacial tension by rhamnolipids. We conclude that a direct application of the crude rhamnolipid solution from cell culture is effective and economic in removing oily contaminants from wastewater.

Biodegradation of Petroleum Oil Effluents and Production of Biosurfactants: Effect of Initial Oil Concentration

“…the removal efficiency of crude oil was over 80% in the presence of rhamnolipids compared to 22.3% in the absence of rhamnolipids (Zhang et al, 2009).…”

“…A microbial surfactant (biosurfactant) especially the rhamnolipid biosurfactant was investigated for its potential to enhance bioavailability, and hence the biodegradation of octadecane (Zhang and Miller, 1992); crude oil (Nelly et al, 2004;Zhang et al, 2005Zhang et al, , 2009; different carbon sources (n-hexadecane, paraffin oil, glycerol, and molasses) (Rashedi et al, 2006); xylene, benzene, n-hexane, Bombay high crude oil, kerosene, gasoline, and diesel fuel (Thahira et al, 2003); Arabian light crude, Al-Shaheen crude, diesel, and oil slops (Eugene et al, 2006). Also, many researchers studied the biodegradation of oily wastes as well as the production of biosurfactants (Cameotra and Singh, 2009;Gokcen et al, 2008;Reda and Ashraf, 2009;Suppasil and Kulnaree, 2007;Zhang et al, 2009;Zheng et al, 2007). The present study was focused on the effect of the initial oil concentration on the efficiency of oil biodegradation and rhamnolipid production using Pseudomonas aeruginosa ATCC 9027.…”

Photocatalytic pretreatment of oily wastewater from the restaurant by a vacuum ultraviolet/TiO2 system

“…Thereby appropriate treatment of this wastewater is necessary in order to reduce the impact of their discharge. To date, several methods have been used for the treatment of theses wastes, such as air flotation [1], electroflotation [2], electrochemical technology [3], adsorption [4], immobilized lipase [5], biotreatment [6], coagulation/flocculation [7] and membrane processes [8]. However, these processes have several disadvantages such as high operation costs, corrosion and recontamination problems.…”

Notice of Retraction: Research on Treatment of Harbor Oily Wastewater by Coagulation-Sedimentation Process

“…At present, the traditional treatment processes for oily wastewater included chemical coagulation, chemical oxidization, membrane separation, absorption, flotation, and biotreatment [1][2][3][4][5][6]. Compared with other processes, the coagulation/flocculation method is one of the most important physio-chemical reactions, and widely used in water treatment for its capability of destabilizing and aggregating colloids [4], in which, poly-aluminum chloride (PAC) and polyacrylamide (PAM) are widely used as coagulant and flocculent in the treatment of various types of wastewater [7].…”

“…Compared with other processes, the coagulation/flocculation method is one of the most important physio-chemical reactions, and widely used in water treatment for its capability of destabilizing and aggregating colloids [4], in which, poly-aluminum chloride (PAC) and polyacrylamide (PAM) are widely used as coagulant and flocculent in the treatment of various types of wastewater [7]. In this study, coagulation-sedimentation process was adopted to treat harbor oily wastewater, with the PAC and PAM as coagulant and flocculent.…”