Petroleum Refinery Wastewater Research Articles

Performance analysis of four-stage rotating biological contactor in nitrification and COD removal from petroleum refinery wastewater

The petroleum refining process generates large quantities of wastewater that discharge of untreated wastewater into water bodies results in environmental and human health effects due to the release of toxic containments. In this study, the biological removal of ammonia from petroleum refinery wastewater in a bench-scale rotating biological contactor (RBC) under continuous operation was investigated. The experiments were conducted base on a central composite design to evaluate the effect of four significant independent variables on the performance of the system. Response surface methodology was applied to minimize the number of runs and investigating the interactive effects of variables on ammonia and chemical oxygen demand (COD) removals. The RBC was operated at different hydraulic loading rates of 0.005, 0.008, and 0.016 m3/m2d. The optimum conditions were the temperature of 32.19 °C, influent ammonia concentration of 20.54 mg/l, the flow rate of 5.57 mL/min, and discs rotational speed of 4.58 rpm for ammonia and COD removal efficiency simultaneously. The maximum removal efficiency of ammonia and COD were obtained at 99.07 % and 85.76 % respectively. Finally, our results suggest that RBC may be considered as a promising method for petroleum refinery wastewater treatment, especially in simultaneously COD and ammonia removal.

Synthesis of magnetic zincoxysulfide core/shell nanocomposites (Ni@ZnO0.6S0.4) for COD photocatalytic degradation in oil refinery wastewater

In this work, magnetic Ni@ZnO0.6S0.4, Ni@ZnS and Ni@ZnO a core/shell nanocomposites were prepared through the facile two-step precipitation process as photocatalysts for COD degradation in refinery wastewater. Multiple analysis methods were used to describe the morphology, phase structure and magnetic characteristics of the synthesized photocatalysts such as field emission scanning electron microscope (FESEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The COD degradation efficiency from ZnO0.6S0.4 nanocatalyst has been investigated as a function of photocatalyst dose, pH and an irradiation time. The Ni@ZnO0.6S0.4 photocatalyst could efficiently degrade the COD content (89%) under visible light irradiation (LED lamp) within 3 hr. The as-acquired Ni@ZnO0.6S0.4 having magnetic properties was readily collected via a simple magnet. More significantly, nearly no lowering of photocatalytic degradation was noticed even after five sequential reaction cycles suggestive of Ni@ZnO0.6S0.4 photocatalyst show perfect stability to reuse.

A Reliable and Rapid Method for Simultaneous Determination of Furfural and Hydroxymethyl Furfural in Oil Refinery Wastewaters by Ant Colony/Partial Least-Squares Analysis

A Reliable and Rapid Method for Simultaneous Determination of Furfural and Hydroxymethyl Furfural in Oil Refinery Wastewaters by Ant Colony/Partial Least-Squares Analysis

Treatment of Iraqi Petroleum Refinery Wastewater by Advanced Oxidation Processes

Iraq is facing a major environmental crisis due to oil-spills which polluted the Tigris River and caused many problems in the environment depending on the volume of the oil spilled. Therefore these problems need emergency solutions and one of the solutions is treatment using Advanced Oxidation Processes (AOPs). In this research the degradation of acidic aqueous solutions of the synthetic diesel oil water emulsion has been studied by advanced oxidation processes (AOPs) using Fenton reagent (Fe2+/H2O2). The effect of different process parameters, such as pH, oxidant’s dose (FeSO4/H2O2) and the reaction times on the removal of diesel oil were investigated in terms of chemical oxygen demand (COD). At an optimum concentration optimum of [H2O2] = 11×10−2 M; [Fe2+] = 7.4×10−3 M, pH=3.5 and reaction time 60 min reduced COD 65% of diesel oil at [Diesel Oil] = 1300 ± 23 mg O2/L. The real oily wastewater was collected from Baghdad south gas power plant-2 and its composition is unknown. The treatment of this wastewater by Fenton oxidations under optimal conditions were removed 86% of the initial COD and 97 % of total petroleum hydrocarbons TPH of the oily wastewater.

Phenol and ammonia removal in petroleum refinery wastewater using a poly(vinyl) alcohol coated polysulfone nanohybrid membrane

Petroleum refinery wastewater (PRW) contains high concentrations of phenolic compounds and ammonia that are noxious and harmful to the environment, especially to human health. The improper treatment of PRW could cause serious problems. In this study, a membrane with a polyvinyl alcohol (PVA) coating was fabricated to improve PRW treatment for phenolic compounds and ammonia removal. The fabricated membranes were investigated using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), water contact angle, mechanical strength, permeability, pollutant rejection, and foulant resistance. The coated membranes exhibited improved surface properties and mechanical strength compared to that of uncoated pristine polysulfone (PSf) membranes. The membranes also showed excellent phenol and ammonia removal up to 82.68 % and 92.42 %, respectively. Although the permeate flux decreased with increasing PVA concentration, the antifouling behavior of the membrane was significantly improved. Therefore, the fabricated membranes showed great potential for petroleum wastewater treatment.

Treatment of petroleum wastewater using synthesised haematite (α-Fe2O3) photocatalyst and optimisation with response surface methodology

ABSTRACT Haematite (α-Fe2O3) photocatalyst (HPC) has been synthesised by a modified solution combustion method. The prepared catalyst was characterised with a Scanning Electron Microscopy (SEM) and X-ray Diffractometer (XRD). Catalyst characterisation confirmed its composition and phase, but it also showed a slight lack in uniformity and crystallinity due to uncontrolled combustion caused by the modifications made to the preparation procedure. The photocatalyst was tested for the removal of pollutants present in the petroleum refinery wastewater (PRW) under UV-A lamp solar irradiation. A central composite design (CCD) with response surface methodology (RSM) was employed for optimisation of the model. The PRW treatment achieved a marked improvement in biodegradability, raising the biological oxygen demand (BOD)/chemical oxygen demand (COD) ratio from 0.074 to 0.604 in 90 min and percentage COD removal was 90.85% at a catalyst concentration of 5 g/L, pH 7.5 and hydrogen peroxide (H2O2)/COD ratio of 1 mg/mg. RSM optimisation predicted a maximum theoretical BOD/COD ratio of 0.661 and percentage COD removal of 94.73% at a catalyst concentration of 1.494 g/L, pH 7.5 and hydrogen peroxide (H2O2)/COD ratio of 1 mg/mg.

Enhanced degradation of furfural by heat-activated persulfate/nZVI-rGO oxidation system: Degradation pathway and improving the biodegradability of oil refinery wastewater

Oil refinery wastewater is characterized by high values of temperature and furfural concentration. Furfural is a toxic and non-biodegradable substance in aqueous media that its absorption through the skin causes acute neurological and pulmonary effects. In this study, a heat-activated persulfate (HAP) system in combination with reduced graphene oxide-supported nano zero-valent iron catalyst (nZVI-rGO) was developed for oil refinery wastewater treatment. Five operational parameters regarding furfural removal were statistically modeled by an orthogonal central composite design (OCCD) and then optimized by genetic algorithm (GA) technique. The main characteristics of the nZVI-rGO as well as its reusability were investigated by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy mapping (EDX-mapping), X-ray diffraction analysis (XRD) and vibrating sample magnetometer (VSM) analysis. The optimum values for the solution temperature, nZVI-rGO dosage, persulfate (PS) concentration, solution pH and reaction time were predicted to be 70 °C, 1.25 g L−1, 4.28 mmol L−1, 5.46 and 50 min, respectively. Under the optimized conditions, the experimental furfural removal efficiency in HAP/nZVI-rGO and HAP oxidation systems were obtained to be 97.80 and 68.20 %, respectively. Sulfate radical (SO4•-) has greater participation in furfural mineralization than hydroxyl radical (HO•). The major intermediates resulting from the furfural mineralization were short-chain acids including acetic acid and formic acid. Regardless, almost complete furfural mineralization was achieved after 100 min of the oxidation reaction. The optimized HAP/nZVI-rGO process was able to significantly improve the biodegradability of wastewater by more than 2 times.

Technologies of Removal of Organics in Reverse Osmosis Concentrates from Petroleum Refinery Wastewater

Technologies of Removal of Organics in Reverse Osmosis Concentrates from Petroleum Refinery Wastewater

Rapid aerobic granulation using biochar for the treatment of petroleum refinery wastewater

Aerobic granular sludge technology has great potential for the treatment of petroleum refinery wastewater. However, strategies to shorten the granulation time and improvement the stability still need to be developed. In this work, biochar was prepared from waste petroleum activated sludge (biochar-WPS) and used in a sequencing batch reactor for the treatment of petroleum refinery wastewater. Biochar-WPS presented the surface area of 229.77 m2/g, pore volume of 0.28 cm3/g, H/C and O/C atomic ratios of 0.42 and 0.21, respectively. The porous structure and a high degree of hydrophilicity were found to facilitate microbial colonization and adhesion as well as particle aggregation. Application of biochar-WPS resulted in the formation of more substantial and stable aerobic granules (~ 66% of granules > 0.46 mm diameter) 15 days earlier compared with the control. The addition of biochar-WPS enhanced the average removal efficiency of chemical organic demand (~ 3%), oil (~ 4%) and total nitrogen (~ 10%) over the control. Increased microbial richness and diversity were observed within the formed granules and had an increased (~ 4%) proportion of denitrifying bacteria. These results indicate that an aerobic granulation mechanism using biochar-WPS is a feasible option for the treatment of petroleum refinery wastewater.

EFFECT OF PETROLUME REFINERY WASTEWATER ON PLANT GROWTH IN INTEGRATED MICROBIAL FUEL CELL-CONSTRUCTED WETLANDS SYSTEMS

Three identically designed microbial fuel cell-constructed wetland (MFC-CW) systems were constructed and setup in this study for simultaneous biotreatment of petroleum refinery wastewater (PRW) and bioelectricity generation. MFC-CW1 and MFC-CW2 were planted with Canna indica, and Phragmites australis, respectively. MFC-CW3 was unplanted and considered as the control. These three systems were operated simultaneously in a batch mode for two cycles to evaluate the effect of PRW biotreatment on the growth and development of the selected plants and the potential of generated bioelectricity as well. The operation period for each cycle was 8 days. Results demonstrated that maximum removal efficiency of the organic content represented as chemical oxygen demand (COD) were 98.75%, 97.67%, and 97.83% observed in MFC-CW1, MFC-CW2, and MFC-CW3, respectively, whereby, the highest power generation were 19.86, 19.04, and 18.7 mW/m2, respectively. On the other hand, both types of plants exhibited notable growth and new sprouts appearance. The potential convergence of the results in the three MFC-CWs, and the healthy growth of both types of plants clearly and potentially indicated that the dominant mechanism of organic pollutant removal was via biodegradation process by the anodic biofilm in the MFC rather than being removed by phytoremediation process.

Physical pretreatment of petroleum refinery wastewater instead of chemicals addition for collaborative removal of oil and suspended solids

The conventional petroleum refinery wastewater pretreatment process, usually consisting of an American Petroleum Institute (API) separator and air flotation tank, mainly achieves suspended solids (SS) and oil removal but also presents many shortcomings, such as chemical consumption, flotation scum production and land occupation. A physical method coupled by hydrocyclone-intensified filtration (HIF) and mixed fibrous coalescer was first proposed, followed by a lab-scale experimental investigation of the feasibility of collaborative suspended solids (SS) and oil removal. A 1 m3/h pilot-scale physical pretreatment unit was also set up to comprehensively evaluate the collaborative removal efficiency of oil and SS and the operation stability in raw petroleum refinery wastewater. The effect of the initial oil concentration, mainly emulsified oil, on the removal efficiency was thoroughly explored by the physical pretreatment process. The mean oil and SS concentrations of the petroleum refinery wastewater was decreased from 1078.9 mg/L and 214.2 mg/L to 9.7 mg/L and 31.2 mg/L, respectively, due to the physical pretreatment process. Additionally, the mean effluent oil concentration of the pilot-scale physical pretreatment unit decreased to 11.1 mg/L, and that of the flotation tank effluent was 18.8 mg/L, which also indicated that the physical pretreatment process had better performance in coping with influent fluctuations (with mean values from 14.4 mg/L to 5214.1 mg/L). SS and most of the oil in the petroleum refinery wastewater were efficiently separated by the hydrocyclone-intensified filter based on interception and adsorption by the filter media and thorough surface renewal of the filter media in the hydrocyclone, followed by further emulsified oil removal due to the X-shaped heterogeneous fibers. No flocculants were added to the physical pretreatment unit, thus achieving remarkable savings of 80.64 t/year poly-aluminum chloride (PAC) and 53.12 t/year polyacrylamide (PAM). Compared with a conventional pretreatment process with a capacity of 800 m3/h, the physical pretreatment process saves approximately 196 thousand USD/year due to chemicals consumption elimination and the oil sludge reduction arising therefrom. The physical pretreatment process instead of chemicals addition can help achieve the environmentally friendly goals of near-zero consumption of chemical flocculant, a near-zero increase in oil sludge and near-zero emission of VOCs.

Molecular transformation of dissolved organic matter in refinery wastewater.

Dissolved organic matter (DOM) has an important impact on the water treatment and reuse of petroleum refinery wastewater. In order to improve the treatment efficiency, it is necessary to understand the chemical composition of the DOM in the treatment processes. In this paper, the molecular composition of DOM in wastewater samples from a representative refinery were characterized. The transformation of various compounds along the wastewater treatment processes was investigated. A total of 61 heteroatomic class species were detected from the DOM extracts, in which CHO (molecules composed of carbon, hydrogen, and oxygen atoms) and CHOS (CHO molecules that also contained sulfur) class species were the most abundant and account for 78.43% in relative mass peak abundance. The solid phase extraction DOM from the dichloromethane unextractable fraction exhibited a more complex molecular composition and contained more oxygen atoms than in the dichloromethane extract. During wastewater treatment processes, the chemical oxygen demand (COD) and ammonia-nitrogen were reduced by more than 90%. Volatile organic compounds (VOCs) accounted for about 30% of the total COD, in which benzene and toluene were dominant. After biochemical treatment, the VOCs were effectively removed but the molecular diversity of the DOM was increased and new compounds were generated. Sulfur-containing class species were more recalcitrant to biodegradation, so the origin and transformation of these compounds should be the subject of further research.

Catalytic thermolysis treatment of petroleum refinery wastewater collected from effluent treatment plant

AbstractCatalytic thermolysis of petroleum refinery wastewater was investigated as a pretreatment process. Effects of various parameters like temperature, pH, dose of catalyst and time were investigated for chemical oxygen demand (COD), turbidity, and element reduction. CuSO4, FeSO4, FeCl3, and 1:1 ratio (v:v) mixture of CuSO4 and FeCl3 were used as a catalyst. The maximum reduction of COD and turbidity were 90 and 98% by mixture (1:1) of CuSO4 and FeCl3 at 70 °C, 7 pH, 1.0 kg/m3 dose in 90 min reaction time. The removal of an element like Cr, Mn, Ni, and Pb was analyzed by ICP-OES. The sludge precipitated after catalytic thermolysis was characterized using scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), Fourier transform infrared (FTIR) and thermo-gravimetric analysis (TGA)/derivative thermal analysis (DTA) analyses. Sludge from CuSO4 and mixture of CuSO4 and FeCl3 treatment has a compact structure with irregular granule which favors adsorption.

Improving bioremediation process of petroleum wastewater using biosurfactants producing Stenotrophomonas sp. S1VKR-26 and assessment of phytotoxicity

Primarily, this study aims to evaluate the biosurfactant production capability of Stenotrophomonas sp. S1VKR-26, profiling of its bioremediation ability to remediate petroleum refinery wastewater in a lab-scale bioreactor and assessment of phytotoxicity of bioremediated petroleum wastewater. As a result, strain S1VKR-26 was found to produce 5.15 g L−1 biosurfactant, CMC of 30 mg L−1 and reduced the surface tension from 60.3 to 30.5 mN m−1. Different PAHs like naphthalene (93%), phenanthrene (86%), fluoranthene (92%), and pyrene (98.3%), total petroleum hydrocarbons (72.33%) and phenolic compounds (93.06%) were significantly remediated from the wastewater after the treatment of strain S1VKR-26. Moreover, S1VKR-26 strain treated 1:1 diluted petroleum wastewater have higher germination (100%), vigor (486), and seedling (4.86 cm) compared to untreated wastewater. Therefore, the treatment of petroleum refinery wastewater with strain S1VKR-26 could be more effective in the sense of environmental safety and irrigation for crop production in agriculture.

Remediation of Spent Caustic in the Wastewater of Oil Refinery by Photo-Fenton Process

Remediation of Spent Caustic in the Wastewater of Oil Refinery by Photo-Fenton Process

Adriatic cyanobacteria potential for cogeneration biofuel production with oil refinery wastewater remediation

Among cyanobacteria isolated from Northern Adriatic five strains were able to grow on oil refinery wastewater. Based on the sequencing of the internal transcribed spacer (ITS region) and morphological features strains were identified as Synechococcus sp. MK568070, Phormidium lucidum MK568072, Neolyngbia sp. MK568073, Pseudanabaena sp. MK568071 and Spirulina subsalsa MK573248. Selected marine cyanobacteria were tested over a range of ammonium (NH4+) concentrations simulating oil refinery effluent conditions. Three strains demonstrated high growth potential in a range 0.8–2.0 mM NH4+. Maximum biomass concentrations in stationary phase were in a range 176–590 mg/l, whereas total lipid yields were in a range 7.63–21.40% of dry weight. Although all species satisfy the criteria for biodiesel production the average degree of unsaturation was lowest in Synechococcus sp. MK568070 and Neolyngbia sp. MK568073. High proportion of polyunsaturated alpha-linolenic acid found in Spirulina subsalsa MK573248 opens up considerations for nutritional, aquaculture or other biotechnology applications of that species.

Degradation of carbazole, fluorene, dibenzothiophene and their mixture by P. aeruginosa RS1 in petroleum refinery wastewater

Refining of crude oil generates large volumes of wastewater containing phenolics, long-chain hydrocarbons, polynuclear aromatic hydrocarbons (PAHs), heterocyclics and heavy metals, and thus requires treatment before disposal. Most of the PAHs and heterocyclic PAHs are toxic, mutagenic and carcinogenic. Carbazole (CBZ), dibenzothiophene (DBT) and fluorene (FLU) are representative compounds of nitrogen and sulphur heterocyclics and PAHs containing three fused aromatic rings. CBZ, FLU, and DBT degradation in petroleum refinery wastewater (PRW) was evaluated through biostimulation and bioaugmentation approaches. For PRW bioaugmented with Pseudomonas aeruginosa RS1, altering the nutrient formulation from unoptimized to optimized media improved the degradation after 14 days from 47 ± 5.2%–69 ± 4.3 % for CBZ, 20 ± 11%–35 ± 14 % for FLU and 24 ± 10%–32 ± 13 % for DBT. Significant removal of all compounds was observed from a ternary mixture of CBZ, FLU, and DBT (10 mg/L each) in PRW supplemented with the optimized media. Acclimatization of P. aeruginosa RS1 to CBZ, FLU, DBT and their mixture impacted the removal of indigenous aromatics and heterocyclics from PRW. The results revealed importance of nutrient supplementation and culture acclimatization for enhancing degradation of recalcitrant organics from PRW.

Volatile evolution during thermal treatment of oily sludge from a petroleum refinery wastewater treatment Plant: TGA-MS, Py-GC(EGA)/MS and kinetics study

The volatile evolution during thermal treatment of an oily sludge derived from petroleum refinery wastewater treatment plant was investigated by in-situ pyrolytic and kinetic analysis. According to kinetic mechanism model, it was found that the internal diffusion had a great influence on volatile release during 120–360 °C, while the devolatilization rate during 360–550 °C would more depend on the concentration of remaining hydrocarbons. By Py-GC/MS, oils were trapped and analyzed respectively during 60–360 °C and 360–550 °C, and above 300 compounds were identified and semi-quantified of the volatiles. During 60–360 °C, the detected volatile was mainly composed of saturated aliphatics, accounting for 68.69%. More proportion of light chain aliphatic hydrocarbons and monoaromtics were observed during 360–550 °C, and the relative content of unsaturated aliphatics increased to 33.81%. From the evolution profiles of typical oil products, the volatile release during 120–360 °C would follow the order of molecular weight. But during 360–550 °C, as a result of increasing thermal-cracking degree, the release peaks of the different volatile species were corresponded to similar temperature. The gaseous and sulfur-containing compounds were also traced. Among them, CO2 was the main product above 550 °C for the decomposition of minerals, and sulfur-containing compounds were mainly generated during < 450 °C.

Salinity footprint on anoxic-aerobic sequential moving bed reactors during petroleum refinery wastewater treatment: Effects on the dominant species

Consequence of increased NaCl (0−45 g/L) on the performance of anoxic (A1) - aerobic (A2) sequential moving bed reactors operated in series was examined while treating synthetic petroleum refinery wastewater. Influent wastewater was a concoction of phenol (750 mg/L), S2− (750 mg/L), crude oil (300 mg/L), NO3--N (1000 mg/L), NH4+-N (350 mg/L) and emulsifier (0.2 mM) along with varied NaCl. Removal of organics deteriorated in A1 (60 h HRT) with rise in NaCl and complete removal of residual organics and NH4+-N was achieved in A2 (20 h HRT) up to 30 g/L of NaCl at total 80 h HRT. Effect of salinity was never observed for S2− removal in A1. Increase in sloughing, decrease in SRT and biomass activity were the outcomes of increased NaCl. Pseudomonas aeruginosaSC2013 and Lysinibacillus sp. H200−150 tolerated higher salinity in A1 and A2, respectively. Complete restoration of the reactor performance was achieved after withdrawal of NaCl.

Treatment of petroleum refinery wastewater by electro-Fenton process using porous graphite electrodes

The present paper deals with the treatment of wastewaters generated from Al-Dewaniya petroleum refinery plant by Electro-Fenton process in a batch electrochemical reactor using porous graphite as anode and cathode materials. Effects of operating factors such as current density (5-25mA/cm2), FeSO4 concentration (0.1-0.7mM), NaCl addition (0-2g/l), and time (15–45min) on the efficiency of the chemical oxygen demand (COD) removal were studied. The results revealed that FeSO4 concentration has the main effect on the efficiency of COD removal confirming that the Electro-Fenton process was governed by reaction conditions in the bulk of solution between ferrous ions and H2O2 not upon the electrochemical reactions on the surface of electrodes. Parametric optimization was carried out using response surface methodology (RSM) combined with Box–Behnken Design (BBD) to maximize the removal of COD. Under optimized operating conditions: FeSO4 concentration (0.7mM), current density (25 A/cm2), and time (45 min) with no addition of NaCl, the removal efficiency of COD was found to be 95.9% with an energy consumption of 8.921kWh/kgCOD.