Refinery Wastewater Treatment Research Articles

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.

Petroleum Refinery Wastewater Treatment using Three Steps Modified Nanohybrid Membrane Coupled with Ozonation as Integrated Pre-treatment

Polyethersulfone as membrane material possesses superior characteristics; however, it is limited by its semi-hydrophobic nature, which renders it prone to fouling and restricts the practical applications. Three-steps modifications of PES membranes consist of ZnO nanoparticle incorporation, UV irradiation, and cross-linked PVA coating were carried out to improve membrane performance and stability. The membranes were fabricated using the dry/wet phase inversion technique. The results revealed that the modifications significantly improved membrane structural characteristics. Three-steps combination treatments enhanced the membrane surface hydrophilicity by lowering the contact angle from 70° to 61.4°. A three-step modification including ZnO loading, UV irradiation, and PVA coating on PES membranes can increase the rejection of organic matter from 16% to 54% despite sacrificing permeate flux. Crosslinked PVA coating at a concentration of 3 wt-% increased the water permeability from 4.6 to 8.6 L.m-2. h-1 while maintaining the rejection rate. Ozonation for 3 hours as pre-treatment enhanced the total dissolved solids, chemical oxygen demand, and Ammonia rejections up to 18.6%, 16.7%, and NH3 87.1%, respectively. Quantitative fouling evaluation revealed that three-steps modification on PES membrane significantly improved the anti-fouling property of the membrane.

Experimental Investigation of the Effect of Implanting TiO2-NPs on PVC for Long-Term UF Membrane Performance to Treat Refinery Wastewater.

This study investigated the impact of implanting TiO2-NPs within a membrane to minimize the influence of long-term operation on the membrane characteristics. Four poly vinyle chloride-titanium oxide (PVC-TiO2-NPs) membranes were prepared to create an ultrafiltration membrane (UF) that would effectively treat actual refinery wastewater. The hypothesis of this work was that TiO2-NPs would function as a hydrophilic modification of the PVC membrane and excellent self-cleaning material, which in turn would greatly extend the membrane’s lifetime. The membranes were characterized via Fourier transforms infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy dispersive X-ray (EDX), atomic force microscope (AFM), and scanning electron microscope (SEM). The removal efficiency of turbidity, total suspended solid (TSS), oil and grease, heavy metals and chemical oxygen demand (COD) were investigated. Contact angle (CA) reduced by 12.7% and 27.5% on the top and bottom surfaces, respectively. The PVC membrane with TiO2-NPs had larger mean pore size on its surface and more holes with larger size inside the membrane structure. The addition of TiO2-NPs could remarkably enhance the antifouling property of the PVC membrane. The pure water permeability (PWP) of the membrane was enhanced by 95.3% with an increase of TiO2 to 1.5 gm/100gm. The PWP after backwashing was reduced from 22.3% for PVC to 10.1% with 1.5 gm TiO2-NPs. The long-term performance was improved from five days for PVC to 23 d with an increase in TiO2-NPs to 1.5 gm. The improvements of PVC-TiO2-NPs long-term were related to the enhancement of the hydrophilic character of the membrane and increase tensile strength due to the reinforcement effect of TiO2-NPs. These results clearly identify the impact of the TiO2-NPs content on the long-term PVC/TiO2-NPs performance and confirm our hypothesis that it is possible to use TiO2-NPs to effectively enhance the lifetime of membranes during their long-term operation.

Oily wastewater treatment by a continuous flow microbial fuel cell and packages of cells with serial and parallel flow connections

This study reports the results of the application of microbial fuel cells (MFC) in refinery wastewater (RW) treatment. In this research, the effect of hydraulic retention time (HRT), and scale-up on the performance of a novel expandable modular design of single-chamber MFC (SCMFC) has been investigated. In the first part of the paper, the effect of HRT on chemical oxygen demand (COD) removal and electricity generation was examined. The generated steady open-circuit voltage (OCV) was 785 mV at HRT 90 h, and the provided maximum power density (PD) was 113 mW/m2 at HRT 15 h. At HRT of 45 h, COD removal increased up to 87% via an increase in the HRT. In the second part, the scale-up of SCMFC was investigated by serial (SFC) or parallel (PFC) connecting the outlets and inlets of fluid flows. The average produced OCV was 760 mV in PFC mode, and average produced PD in PFC and SFC modes were 97 and 75.6 mW/m2, respectively. COD removal in SFC and PFC modes were reported to be 89 and 42%, respectively. Compared to PFC mode, SFC mode was more efficient in terms of COD removal and coulombic efficiency. However, it produced lower PD compared to PFC mode. It is possible to control the quality and capacity of wastewater treatment by using combining the SFC and PFC mode connections in packages of MFCs.

Electrochemical treatment of sunflower oil refinery wastewater and optimization of the parameters using response surface methodology

Combined electrocoagulation (EC) + electrooxidation (EO) process was compared with electrochemical peroxidation (ECP) treatment process to treat sunflower oil refinery wastewater. The effect of applied current density, pH/H2O2 dosage, and operation time in the removal of chemical oxygen demand (COD), soluble COD, total organic carbon, and dissolved organic carbon (DOC) were studied using Box Behnken Design. In EC process, decrease in organic concentration was observed as the time and current density increased. The optimized conditions for EC process were achieved at pH 6.07 when a current density of 5.69 mA cm−2 was applied for 18 min. The EO removed about 90% of DOC at an optimized pH of 5.27 and current density of 11.56 mA cm−2 when operated for 400 min. The combined EC + EO process was successful compare to ECP process in removing between 90 and 95% of organic pollutant from the sunflower oil refinery wastewater. The energy consumption was calculated to compare between the process efficiency of EC + EO and ECP and found that EC + EO was more efficient process. The reaction rate followed a first order kinetics validated with a high R2 value (0.96).

Monitoring microbial community structure and variations in a full-scale petroleum refinery wastewater treatment plant

This research investigated the process efficiency and microbial communities and their diversity in a full-scale wastewater treatment plant (WWTP) fed with petroleum refining wastewater (PRW) that contained toxic hydrocarbon contaminants and carcinogens. Process parameters and bacterial community structures were monitored for six months to create a link between microbial dynamics and influent characteristics of petrochemical wastewater. The WWTP showed a stable process with efficiencies >70% for both soluble chemical oxygen demand (SCOD) and benzene removal. More than 30 genera were identified by metagenomic analysis, and the bacterial populations changed significantly during the operation period. Among them, genera Sulfuritalea (11.9 ± 3.5%), Ottowia (4.3 ± 2.2%), Thauera (3.1 ± 7.2%) and Hyphomicrobium (1.3 ± 0.7%) were dominant and important bacterial genera that may have been responsible for the degradation of aromatic compounds such as benzene and phenol.

Potential use of green TiO2 and recycled membrane in a photocatalytic membrane reactor for oil refinery wastewater polishing

Membrane bioreactors (MBRs) have been successfully used in oil refinery wastewater treatments. However, a polishing treatment of the MBR permeate is required to remove the recalcitrant organic compounds. In this study, the coupling of a photocatalytic membrane reactor (PMR) and MBR was investigated for the treatment of oil refinery wastewater. Titanium dioxide (TiO2) nanoparticles, synthesised by a cleaner route assisted by microwave radiation, and recycled membrane, an end-of-life reverse osmosis membrane converted to an ultrafiltration membrane by oxidation, were prepared for use as a PMR. The recycled membrane could completely retain the catalyst particles. The PMR exhibited higher efficiency and stability in the removal of organic matter than those of the individual photocatalysis and membrane processes. Adsorption of organic compounds was observed on the catalyst surface. These compounds were degraded releasing active sites for reaction/adsorption. A chemical oxygen demand analysis revealed that up to 60% of the organic matter in the MBR permeate was decomposed in the PMR, which also contributed to membrane fouling mitigation. The membrane fouling resistance in the PMR was 7.3 times lower than that in the system operated without the catalyst. In addition, membrane degradation was not observed upon the use of the catalyst. The results indicate that the PMR with the green TiO2 and recycled membrane is a highly active, stable, and promising system for the polishing of oil refinery wastewater previously treated by the MBR.

CWWQI on the Evaluation of Effluent Wastewater from Al-Dora Refinery WWTP

This study aimed to evaluate effluent wastewater form Al-Dora refinery wastewater treatment plant (DWWTP). The quality of wastewater for agricultural irrigation was evaluated using Canadian Wastewater Quality Index (CWWQI). Seven physical, chemical and biological parameters, namely, pH, SO4, Cl−, phenol, COD, BOD5 and TDS were analyzed from April 2018 to March 2019. Results of CWWQI referred to variation in the acceptability of the treated wastewater for reuse in crop irrigation. The treated wastewater had CWWQI of 80.19, which reflects good quality. Hence, the treated wastewater was suitable for irrigation of many crops.

Considering a membrane bioreactor for the treatment of vegetable oil refinery wastewaters at industrially relevant organic loading rates.

The present study aims to shed more light on the use of membrane bioreactors (MBRs) for the treatment of vegetable oil refinery wastewaters (VORWs). A MBR was operated for 157days in which it was fed with real VORW of varying composition at a range of organic loading rates (0.20 ± 0.05-3.79 ± 0.29 kg CODm-3day-1). The hitherto unconsidered fate of VORW constituents through the biological process was followed using gas chromatography/mass spectrometry analysis. This analysis revealed that only 19% of the identified feed constituents remained in the MBR effluent whereas ten new compounds were formed. Linear correlation analysis attributed the effluent residual COD to soluble microbial products (SMP) and non-readily biodegradable recalcitrant oily compounds. Trend of change of MLSS, mixed liquor viscosity and SMP with increasing OLR suggested that when MBR is operated under industrial conditions for the VORW treatment, the mixed liquor fouling propensity potentially increases with increasing OLR in the range studied.

A bioaugmentation agent allowing the advanced treatment of refractory refinery wastewater in a biological aerated filter and analysis of its microbial community

AbstractBACKGROUNDThe performance of a biological aerated filter (BAF) with activated sludge and nut shell activated carbon was evaluated for the advanced treatment of intractable refinery wastewater. Bioaugmenting the BAF with Pseudomonas sp. FS‐01 and Bacillus sp. FS‐02 and the microbial community structure between the upgrade system and the original system were also studied.RESULTSDuring the steady state of the BAF, the influent chemical oxygen demand (COD) was in the range 80–128 mg L−1, and ammonia nitrogen (NH4+‐N) was in the range 15–20 mg L−1. The BAF with activated carbon from nut shells as a supporting material can remove over 32% of influent COD and 95% of NH4+‐N. On bioaugmentation, the average effluent COD and NH4+‐N concentrations were 31.8 and 0.4 mg L−1, respectively. The predominant genera in BAF1 were Nitrospira, an unranked member of the Anaerolineaceae and an unclassified member of the Rhizobiales, while the dominant genera in BAF2 were Pseudomonas, Bacillus and an unranked member of the Anaerolineaceae.CONCLUSIONSThe coconut shell activated carbon has outstanding properties for removing COD and NH4+‐N, along with high shock loading resistance. Bioaugmentation can improve the COD remove efficiency by 35% in relation to only adding sludge. Microbial diversity analysis indicated that bioaugmentation accelerated the transformation of the bacterial community structure, quickly becoming dominant strains. This bioaugmented process may be a promising alternative technology for the treatment of refractory wastewater. © 2019 Society of Chemical Industry

Efficiency of a coagulation/flocculation–membrane filtration hybrid process for the treatment of vegetable oil refinery wastewater for safe reuse and recovery

Treatment of real (RVORW) and synthetic (SVORW) vegetable oil refinery wastewaters using membrane filtration system was experimentally studied. Experimental runs with SVORW were used to identify the best conditions to perform with RVORW treatment. The bench-scale experiment was carried out using a commercial ceramic 0.245m2 ultrafiltration (UF) membrane (150kDa) in cross-flow filtration (CFF) mode at a flow rate of 3000 L⋅h−1 and a trans-membrane pressure (TMP) of 1.2bars. However, such membrane is vulnerable to fouling and it is insufficient to give water of good quality suitable for reuse. This investigation, aims to improve the purification performances of UF by exploring its combination with other treatment options, i.e. optimized coagulation/flocculation (CF) as pre-treatment and dead-end filtration (DEF) as post-treatment for better treated-water quality. According to the results, when using CF as pre-treatment under optimal conditions (2.4 g⋅L-1of aluminium sulfate, 60.05 mg⋅L-1 of CHT flocculant, under initial pH of 9.23), the hybrid CF/UF process allows to achieve the best treated RVORW water quality with turbidity, COD and TOC removals reaching 100 %, 98 % and 97 % respectively compared to those of CF and UF used separately, with membrane permeability of 135 L⋅h−1⋅m-2⋅bar−1 which is in agreement with an industrial application.

Homogeneous solar Fenton and alternative processes in a pilot-scale rotatable reactor for the treatment of petroleum refinery wastewater

Applicability of the solar Fenton process for the treatment of a real refinery wastewater was investigated. A novel solar-reactor was used with the capability of automatic rotating against the sun, enabling maximum utilization of direct and single reflective sunlight beams. The COD and TOC criteria were measured to follow the pollutants removal. Results revealed optimal operating conditions of 694.7mg/L hydrogen peroxide, 67.3mg/L ferrous salt and solution pH of 3.2. Under these conditions, COD and TOC were, respectively, decreased to 79.6 and 73.2 % after 180min sunlight envision. For comparison, alternative H2O2 / Fe2+, S2O82- / Fe2+, NaOCl / Fe2+, NaOCl, S2O82- and H2O2 processes, all activated with sunlight, were performed. The present pollutants were identified by means of the GC/MS headspace technique, showing significant removal of the majority of petroleum aliphatic and aromatic hydrocarbons and that biodegradability was feasible since BOD5/COD reached from 0.36 to 0.62. The process performance was compared with the previously reported similar processes for treating specified pollutants and wastewaters. High preference of the employed process using the particular solar-reactor was probed based on different criteria. Meanwhile, the total operating costs was estimated to be quite low, compared to other processes.

Evaluation of different polymeric coagulants for the treatment of oil refinery wastewater

Wastewater from oil refinery industries has major pollution potentials with mutagenic and toxic compounds. Due to water scarcity in South Africa, oil refinery industries are compelled to find appropriate technology to treat their wastewater for reuse. With regards to this, most of the chemo-physical treatment processes are inadequate and are faced with major environmental and economic challenges. Therefore, this study aimed to find replaceable and cost-effective coagulants to the conventional coagulant for the treatment of a local South Africa oil refinery wastewater using dissolved air flotation (DAF) Jar tests. Three polymeric coagulants for the removal of turbidity, total suspended solids, chemical oxygen demand, and soap oil and grease (SOG) were investigated. At defined experimental conditions of recycle ratio (10%), air saturator pressure (350 kPa) and pH at 5, each coagulant was evaluated from a dosage of 10 mg/L to 50 mg/L. Above 80% of the aforementioned oily pollutants were removed at the coagulant dosage of 50 mg/L. Among the coagulants evaluated, PASS was found as the most suitable alternative coagulant to alum, to enhance and aggregate the air bubble–oil droplet interface for easy separation by the DAF. From the results, PASS is foreseen as promising and economical for pre-treatment of industrial wastewater, which is due to its lower cost and easy degradability.

Perspectives of electrochemical oxidation parameters in PRW treatment

Electrochemical oxidation as an efficient route of advanced electrochemical oxidation process AEOP had been successfully applied for the treatment of real petroleum refinery wastewater (PRW). The electrochemical oxidation was performed using batch electrochemical reactor with carbon felt anode to be compared with β-PbO2 anode. However, these anodic materials have higher oxygen evolution over potential and poor electrocatalysts for parasitic reactions with low cost. The experimental work considers a scope of operative and design parameters that influence the chemical oxygen demand (COD) removal of wastewater of a real national oil refinery effluent. Accordingly, a well-designed reactor accomplished to treat wastewater samples of 500-510 mg/L initial COD to study the effect of anode material, current density, and temperature on COD removal and oxidation kinetic. The results showed that the COD removal efficiency exhibits an exponential behaviour with the applied current density of more than 10 mA cm−2 indicating first-order reaction kinetics, and the reaction rate constant accurately estimated. Moreover, the impacts of pH and agitation speed on reaction rate constant were also studied.

Treatment of petroleum refinery wastewater by physicochemical methods

The main objective of this work was to improve the technological scheme of oil refinery wastewater treatment. Replacment of the expensive filter section in a refinery plant by coagulation in order to increase effectiveness of the process at lower cost was investigated. This research has proven that Ca(OH)2 and Al2(SO4)3 were effective in treatment of oil wastewater. Central Composite Design was applied to two factors, the Al2(SO4)3 dosage and pH. Under optimum conditions effect of removal of Turbidity did reach 100 %, Total hydrocarbons 90 % and COD 70 %. Concentration of Total hydrocarbons in wastewater after treatment were below Limits for sewerage. Prevailing mechanism for coagulation was charge neutralization, associated with deposition of positively charged aluminum hydroxide onto negatively charged particles. Applying of cogulation will let significantly reduce operating expenses up to 5,436.35 €/year, at the same efficiency, due to replacing expensive filtration processes with cost of 102,600.00 €/year.

Investigation and modeling of a hybrid petroleum refinery wastewater treatment system using neural networks

Investigation and modeling of a hybrid petroleum refinery wastewater treatment system using neural networks

OPTIMIZATION OF THE ELECTRO-FENTON PROCESS FOR COD REDUCTION FROM REFINERY WASTEWATER

This study shows the results of the experimental investigation of refinery wastewater treatment by the electro-Fenton process. The experiments were designed using Taguchi design approach with an orthogonal array (OA) of L16 runs. Four process variables (current density (CD), temperature (T), Fe2+ concentration (Fe2+), and time (t)) at four different levels were considered for the present design. Regression analysis was performed to predict a correlation for the response function (chemical oxygen demand (COD) reduction efficiency) of the treatment process by the electro-Fenton technique. Analysis of variance (ANOVA) was carried out to verify the significant variables that control COD reduction. Moreover, a linear model analysis was implemented for the signal to noise (S/N) ratios with larger the better and for means. Based on S/N ratios and means responses, the operating conditions for optimum COD reduction were: CD = 8 mA/cm2, T = 60 C, Fe2+ = 0.4 mM, and t = 6 h, at which 87.35% of COD was reduced. ANOVA shows that the operating temperature had the most significant impact on COD reduction efficiency. The R-square value for the predicted COD reduction correlation was 90.00%. Considering ranks based on delta statistics, the relative magnitude of effects of the process variables were: T, Fe2+, t, and CD.

Investigation of antifouling properties of polypropylene/TiO2 nanocomposite membrane under different aeration rate in membrane bioreactor system

This paper presents the results of aeration rate effect on antifouling properties of polypropylene (PP)/TiO2 nanocomposite membrane in membrane bioreactor (MBR) system in order to oil refinery wastewater treatment. For this purpose, three levels of aeration rate with specific aeration demand per membrane area (SADm) of 0.5, 1, and 1.5 m3/m2h was used. According to the obtained results, PP nanocomposite membrane showed high hydrophilicity, porosity, and high flux compared to neat PP membrane. Also, either low or high aeration rate had a negative influence on permeability and antifouling properties of neat PP and nanocomposite membranes. The analysis of fouling mechanism for both membranes based on Hermia’s model revealed that the cake formation is dominant mechanism for lower aeration rate while by increasing aeration rate, all models couldn’t predict experimental data. Meanwhile, by increasing aeration rate, chemical oxygen demand (COD) removal for activated sludge and both membranes decreased and increased, respectively.