Investigation of Oil-in-Water Emulsions Treatment by Crude Oil Degrading Bacteria and Coagulation with Cationic Polyacrylamide

Abstract

Background: Oily wastewater which is released from different industries is one of the most common pollutants. Efficiency of conventional methods such as gravity separation and skimming, dissolved air flotation, demulsifying, coagulation and flocculation are frequently not efficient enough is not acceptable. Therefore, in this study it was intended to use a new strategy that is combined by two methods. Methods: Nine crude oil degrading bacteria were isolated from oil contaminated sites in the Persian Gulf at Terminal of Bandar Abbas. Choosing cases were cultured in the ONR7a medium supplemented with 1% (v/v) of crude-oil. Two strains that had more growth and higher oil removal were chosen and identified from nine isolated strains for further study. Due to its low price and simple usage of coagulation-flocculation process, the next step of this study was dedicated to this physical treatment method. The coagulants usage has also some limitation because of its toxicity and health hazard, therefore the coagulant content in waste treatment process should be optimized. In this study it is attempted to investigate the efficiency of bioremediation following by coagulation-flocculation process. Results: The two isolated strains are identified with biochemical and molecular methods as Alcanivorax and Idiomarina. Then crude oil biodegradation for each strain is determined by spectrophotometry and Gas Chromatography (GC). Cationic polyacrylamide (CPAM) was chosen as flocculants. The crude oil removal was determined by using 30 mg/L, 50 mg/L and 70 mg/L CPAM in jar test for synthetic oily wastewater with three different crude oil content (500 mg/L, 1000 mg/L and 1500 mg/L). The results have shown that the highest removal efficiency is reached by using 70 mg/L of CPAM in the synthetic wastewater with 1000 mg/L crude oil in there. Conclusion: The study demonstrated that the bio degradation of oily wastewater following by flocculation removes the oil significantly from the synthetic oily wastewater.

Novel Bionanocompounds: Outer Membrane Protein A and Laccase Co-Immobilized on Magnetite Nanoparticles for Produced Water Treatment

“…The last group of processes has attracted significant attention and mainly refers to the incorporation of active biomolecules or whole microorganisms into different stages during the treatment of the recovered effluents [ 24 ]. This approach is advantageous due the low toxicity and environmental friendliness of these agents [ 25 ]. One of the most useful groups of biomolecules for emulsion bioremediation (due to their interfacial activity) are biosurfactants, which have been categorized into different families including lipids, proteins, and bacteria [ 24 , 25 , 26 , 27 , 28 ].…”

“…This approach is advantageous due the low toxicity and environmental friendliness of these agents [ 25 ]. One of the most useful groups of biomolecules for emulsion bioremediation (due to their interfacial activity) are biosurfactants, which have been categorized into different families including lipids, proteins, and bacteria [ 24 , 25 , 26 , 27 , 28 ]. Despite the possible benefits, biosurfactants tend to face stability issues that compromise their performance, especially when subjected to operating conditions far from those observed in their native environments [ 29 ].…”

Hydrodynamic and Performance Evaluation of a Porous Ceramic Membrane Module Used on the Water–Oil Separation Process: An Investigation by CFD

“…Currently, there are different technologies and methods for treating water polluted with oil, which takes into account the physical, physical–chemical, chemical, and biological principles that occur in the processes [ 4 , 6 ]. Among these methods are flotation [ 7 , 8 , 9 ], coagulation [ 6 , 10 , 11 , 12 , 13 ], the use of hydrocyclones [ 14 , 15 , 16 , 17 ], biological treatment [ 18 , 19 , 20 , 21 ] and membrane separation technologies [ 21 , 22 , 23 ].…”

“…In general, the higher the crude oil content in the water, the lower the removal efficiency; therefore, it is necessary to use a combination of different methods that can enhance the processes of water purification [ 10 ]. Khan et al [ 12 ], for example, combined coagulation and flocculation to remove large particles of oil and inorganic matter from the produced water and, as a result, obtained a favorable environment for the biodegradation microorganisms, and finally, using microfiltration membrane removed the remaining dissolved oil microdroplets.…”

Spiral path three phase fluidized bed reactor for treating wastewater contaminated with engine oil

“…In Iraq, there are more than 500 car service facilities, and some of these stations discard their wastewater in emulsion form toward the sewers without any treatment (Mustafa et al 2013). There are many methods for the separation of oil-water emulsions, such as variety of filters (Cumming et al 1999), biological processes (Parhamfar et al 2018), membrane bioreactor (Capodici et al 2017), electrocoagulation and electroflotation (Ji et al 2015) and adsorption (Abdul Hamid et al 2016) and air flotation (Sulaymon and Mohammed 2010;Alwared and Faraj 2015), and each of the methods has their advantages and disadvantages.…”