Treatment Of Petroleum Refinery Wastewater Research Articles

Oil refinery wastewater treatment in biofilm reactor followed by sand filtration aiming water reuse

Oil refinery wastewater was sequentially treated in a moving-bed biofilm reactor (MBBR) and a slow-rate sand filter (SF) in order to obtain an effluent with adequate characteristics for downstream reverse osmosis (RO) operation. Experiments were conducted in bench scale units and the results showed that the MBBR was able to remove 90% chemical oxygen demand (COD), 75% NH4+, 95% phenols, operating with a hydraulic retention time (HRT) of 9 h. Additional removal of COD (15–40%) and ammonia (30–60%) was achieved in the slow-rate SF that was also effective for removing microorganisms. The silt density index (SDI) of the treated wastewater (4.5) was below the maximum limit recommended for RO operation. The quality of the effluent from the combined treatment system (MBBR+SF) was already adequate for cooling tower make-up. The RO produced an effluent with quality compatible with that required for use in boilers.

Treatment of Petroleum Refinery Wastewater by using UASB Reactors

Petroleum refineries discharged large amount of wastewater -during the refining process- that conta ins hazardous constituents that is hard to degrade. Anaerobic tre atment process is well known as an efficient method to degrade high s trength wastewaters. Up-flow Anaerobic Sludge Blanker (UASB) is a common process used for various wastewater treatments. Two UASB reactors were set up and operated in parallel to ev aluate the treatment efficiency of petroleum refinery wastewater. In thi s study four organic volumetric loading rates were applied (i.e. 0.58, 0.89, 1.21 and 2.34 kg/m 3 ·d), two loads to each reactor. Each load was appli ed for a period of 60 days for the reactor to acclimat ize and reach steady state, and then the second load applied. The chemic al oxygen demand (COD) removals were satisfactory with the removal efficiencies at the loadings applied were 78, 82, 83 and 81 % respectiv ely.

Oil refinery wastewater treatment using physicochemical, Fenton and Photo-Fenton oxidation processes

The objective of this study was to investigate the application of advanced oxidation processes (AOPs) to the treatment of wastewaters contaminated with hydrocarbon oil. Three different oil-contaminated wastewaters were examined and compared: (i) a ‘real’ hydrocarbon wastewater collected from an oil refinery (Conoco-Phillips Whitegate refinery, County Cork, Ireland); (ii) a ‘real’ hydrocarbon wastewater collected from a car-wash facility located at a petroleum filling station; and (iii) a ‘synthetic’ hydrocarbon wastewater generated by emulsifying diesel oil and water. The AOPs investigated were Fe2+/H2O2 (Fenton's reagent), Fe2+/H2O2/UV (Photo-Fenton's reagent) which may be used as an alternative to, or in conjunction with, conventional treatment techniques. Laboratory-scale batch and continuous-flow experiments were undertaken. The photo-Fenton parametric concentrations to maximize COD removal were optimized: pH = 3, H2O2 = 400 mg/L, and Fe2+ = 40 mg/L. In the case of the oil-refinery wastewater, photo-Fenton treatment achieved approximately 50% COD removal and, when preceded by physicochemical treatment, the percentage removal increased to approximately 75%.

Process modeling and kinetic evaluation of petroleum refinery wastewater treatment in a photocatalytic reactor using TiO2 nanoparticles

The photocatalytic oxidation and mineralization of petroleum refinery wastewater in aqueous catalyst suspensions of titanium dioxide (TiO2), Degussa P25 (80% anatase, 20% rutile), were carried out in a batch circulating photocatalytic reactor. The experiments were conducted based on a central composite design (CCD) and analyzed using response surface methodology (RSM). In order to analyze the process, four significant variables viz. pH (2–10), catalyst concentration (0–200mg/l), temperature (22.5–52.5°C), and reaction time (30–150min) and TCOD removal as the process response were studied. From the data derived from the factorial design, the ANOVA analysis revealed that the first-order effects of reaction time, pH, temperature and catalyst concentration and second-order effect of pH, catalyst concentration and temperature produce the main effect on TCOD removal efficiency. A maximum reduction in TCOD of more than 83% was achieved at the optimum conditions (pH of 4, catalyst concentration of 100mg/l, temperature of 45°C and reaction time of 120min). The reaction kinetics showed that reactive activation energy for TCOD conversion was calculated to be 19.34kJ/mol.

Comparative evaluation of As, Se and V removal technologies for the treatment of oil refinery wastewater

In this study, a broad range of readily deployable metal removal technologies were tested on a US refinery's wastewater to determine vanadium, arsenic and selenium removal performance. The bench-scale treatability studies were designed and performed so that test conditions could be as uniform as possible given the different mechanisms of action and engineering applications of each technology. The experimental data show that both ferric precipitation and reactive filtration were able to remove As, Se and V more efficiently from the wastewater than other tested technologies. Additionally, granular ferric hydroxide (GFH) adsorption was also effective in both V and As removal. Although the thiol-SAMMS adsorbent was developed for mercury removal, it also demonstrated appreciable selenium removal. None of the tested membrane filtration technologies showed any significant metals removal. This was attributed to the dissolved form of the metals as well as the wastewater's fouling characteristics.

Photocatalytic Degradation of Aniline Using TiO2Nanoparticles in a Vertical Circulating Photocatalytic Reactor

Photocatalytic degradation of aniline in the presence of titanium dioxide (TiO2) and ultraviolet (UV) illumination was performed in a vertical circulating photocatalytic reactor. The effects of catalyst concentration (0–80 mg/L), initial pH (2–12), temperature (293–323 K), and irradiation time (0–120 min) on aniline photodegradation were investigated in order to obtain the optimum operational conditions. The results reveal that the aniline degradation efficiency can be effectively improved by increasing pH from 2 to 12 and temperature from 313 to 323 K. Besides, the effect of temperature on aniline photo degradation was found to be unremarkable in the range of 293–313 K. The optimum catalyst concentration was about 60 mg/L. The Langmuir Hinshelwood kinetic model could successfully elucidate the effects of the catalyst concentration, pH, and temperature on the rate of heterogeneous photooxidation of aniline. The data obtained by applying the Langmuir Hinshelwood treatment are consistent with the available kinetic parameters. The activated energy for the photocatalytic degradation of aniline is 20.337 kj/mol. The possibility of the reactor use in the treatment of a real petroleum refinery wastewater was also investigated. The results of the experiments indicated that it can therefore be potentially applied for the treatment of wastewater contaminated by different organic pollutants.

Phylogenetic and functional diversity of metagenomic libraries of phenol degrading sludge from petroleum refinery wastewater treatment system

In petrochemical refinery wastewater treatment plants (WWTP), different concentrations of pollutant compounds are received daily in the influent stream, including significant amounts of phenolic compounds, creating propitious conditions for the development of particular microorganisms that can rapidly adapt to such environment. In the present work, the microbial sludge from a refinery WWTP was enriched for phenol, cloned into fosmid vectors and pyrosequenced. The fosmid libraries yielded 13,200 clones and a comprehensive bioinformatic analysis of the sequence data set revealed a complex and diverse bacterial community in the phenol degrading sludge. The phylogenetic analyses using MEGAN in combination with RDP classifier showed a massive predominance of Proteobacteria, represented mostly by the genera Diaphorobacter, Pseudomonas, Thauera and Comamonas. The functional classification of phenol degrading sludge sequence data set generated by MG-RAST showed the wide metabolic diversity of the microbial sludge, with a high percentage of genes involved in the aerobic and anaerobic degradation of phenol and derivatives. In addition, genes related to the metabolism of many other organic and xenobiotic compounds, such as toluene, biphenyl, naphthalene and benzoate, were found. Results gathered herein demonstrated that the phenol degrading sludge has complex phylogenetic and functional diversities, showing the potential of such community to degrade several pollutant compounds. This microbiota is likely to represent a rich resource of versatile and unknown enzymes which may be exploited for biotechnological processes such as bioremediation.

Oil-Refinery Wastewater Treatment Aiming Reuse by Advanced Oxidation Processes (AOPs) Combined with Biological Activated Carbon (BAC)

The treatment of a refinery wastewater by Advanced Oxidation Processes (AOP) coupled with Biological Activated Carbon (BAC) was investigated aiming to generate water for reuse. O3/UV and H2O2/UV processes were employed to oxidize the organic matter and the BAC process to remove residual organic matter from the AOP effluent. AOP promoted oxidation of recalcitrant organic matter as observed by moderate drops on the treated wastewater absorbance (31–79%) and TOC values (10–18%). BAC filters showed to be effective, reaching average efficiencies of 65% in a sufficiently long period of operation (84 days), while GAC filters were saturated after 28 days. Effluent TOC values in the range of 4 to 8.5 mg/L were achieved by the combined treatment (H2O2/UV + BAC), allowing water reuse.

Treatment of petroleum refinery wastewater by distillation-assisted catalytic oxidation under low temperature and low pressure

A distillation-assisted catalytic oxidation (DACO) process under low temperature (100 degrees C) and atmospheric pressure was investigated to treat heavily contaminated wastewater from oil refining industry. The DACO experiments were carried out in a distillation batch reactor, using CuO/gamma-A1(2)O3 as catalyst. The experimental temperature was kept at 100 degrees C and H2O2 oxidant was supplied into the reactive system with 200 mL/L. The results demonstrated that more than 92.2% of chemical oxygen demand removal was obtained and the absorbance of the refinery wastewater after treatment was zero, indicating significant decolorization efficiency for the solution. The research of life and stability showed that the catalyst had a good stability. The present study indicates that this DACO approach may have a significant application potential for industrial wastewater treatment.

The effect of hydraulic retention time on the performance and fouling characteristics of membrane sequencing batch reactors used for the treatment of synthetic petroleum refinery wastewater

The use of membrane sequencing batch reactors, operated at HRT of 8, 16 and 24h, was considered for the treatment of a synthetic petroleum wastewater. Increase in HRT resulted in statistically significant decrease in MLSS. Removal efficiencies higher than 97% were found for the three model hydrocarbon pollutants at all HRTs, with air stripping making a small contribution to overall removal. Particle size distribution (PSD) and microscopic analysis showed reduction in the protozoan populations in the activated sludge with decreasing HRT. PSD analysis also showed a higher proportion of larger and smaller sized particles at the lowest HRT. The rate of membrane fouling was found to increase with decreasing HRT; SMP, especially carbohydrate SMP, and mixed liquor apparent viscosity also showed a pronounced increase with decreasing HRT, whereas the concentration of EPS and its components decreased. FTIR analysis identified organic compounds as the main component of membrane pore fouling.

Calibration and verification of models of organic carbon removal kinetics in Aerated Submerged Fixed-Bed Biofilm Reactors (ASFBBR): a case study of wastewater from an oil-refinery

The article presents a case-study on the calibration and verification of mathematical models of organic carbon removal kinetics in biofilm. The chosen Harremöes and Wanner & Reichert models were calibrated with a set of model parameters obtained both during dedicated studies conducted at pilot- and lab-scales for petrochemical wastewater conditions and from the literature. Next, the models were successfully verified through studies carried out utilizing a pilot ASFBBR type bioreactor installed in an oil-refinery wastewater treatment plant. During verification the pilot biofilm reactor worked under varying surface organic loading rates (SOL), dissolved oxygen concentrations and temperatures. The verification proved that the models can be applied in practice to petrochemical wastewater treatment engineering for e.g. biofilm bioreactor dimensioning.

Electrochemical treatment of petroleum refinery wastewater with three-dimensional multi-phase electrode

In this study, petroleum refinery wastewater was treated by an electrochemical process with three-dimensional multi-phase electrode, which introduced Fe particle and air into a traditional two-dimensional reactor. The effect of Fe particle and air on the electrochemical process, and the optimal experimental conditions including initial pH, cell voltage were investigated. The experimental results showed that the effluent with a satisfied COD removal efficiency (92.8%) and low salinity (84μS cm−1) was obtained when the initial pH was 6.5, cell voltage was 12V and fine Fe particle was introduced. This result can be also supported by the analysis of GC–MS, UV spectrum and Conductivity. Moreover, the possible reaction mechanism of this process was discussed by comparing the results of variant reaction systems with different metal particles. All of these results suggested that the electrochemical system with three-dimensional multi-phase electrode was an effective approach to treat petroleum refinery wastewater.

Treatment of petroleum refinery wastewater by ultrasound-dispersed nanoscale zero-valent iron particles

Petroleum refineries release wastewater, which is rich in organic pollutants and cannot be treated easily. This study presents the treatment of petroleum refinery wastewater using nanoscale zero valent iron (NZVI) in the presence of ultrasonication. NZVI characteristics were analyzed using SEM and XRD. The influence of NZVI dosage and initial pH on % chemical oxygen demand (COD) reduction was studied. From the results, it can be inferred that a dosage of 0.15 g/l and an initial pH are optimum for the effective degradation of effluents. The degradation data were found to follow first order kinetics. The results indicate that using NZVI in combination with ultrasonication is an efficient method for the treatment of petroleum refinery wastewater.

MBBR evaluation for oil refinery wastewater treatment, with post-ozonation and BAC, for wastewater reuse

This work evaluated the performance of a Moving Bed Biofilm Reactor (MBBR) in the treatment of an oil refinery wastewater. Also, it investigated the possibility of reuse of the MBBR effluent, after ozonation in series with a biological activated carbon (BAC) column. The best performance of the MBBR was achieved with a hydraulic retention time (HRT) of 6 hours, employing a bed to bioreactor volume ratio (V(B)/V(R)) of 0.6. COD and N-NH₄(+) MBBR effluent concentrations ranged from 40 to 75 mg L⁻¹ (removal efficiency of 69-89%) and 2 to 6 mg L⁻¹ (removal efficiency of 45-86%), respectively. Ozonation carried out for 15 min with an ozone concentration of 5 mg L⁻¹ was able to improve the treated wastewater biodegradability. The treatment performance of the BAC columns was practically the same for ozonated and non ozonated MBBR effluents. The dissolved organic carbon (DOC) content of the columns of the activated carbon columns (CAG) was in the range of 2.1-3.8 mg L⁻¹, and the corresponding DOC removal efficiencies were comprised between 52 and 75%. The effluent obtained at the end of the proposed treatment presented a quality, which meet the requirements for water reuse in the oil refinery.

Process Optimization of a Petroleum Refinery Wastewater Treatment Facility Using Process Modeling and Site Specific Biokinetic Constants

Process Optimization of a Petroleum Refinery Wastewater Treatment Facility Using Process Modeling and Site Specific Biokinetic Constants

Diversity of nitrifying bacteria in a full-scale petroleum refinery wastewater treatment plant experiencing unstable nitrification

We have investigated bacterial populations relevant to nitrification in a full-scale activated sludge plant receiving wastewater from a petroleum refinery showing unstable nitrification. Inhibition of ammonia oxidation was related to phenol concentration according to a model of non-competitive inhibition. While the number of ammonia-oxidizing bacteria (AOB) did not correlate with nitrification performance, the total number of nitrite-oxidizing bacteria (NOB) dropped considerably during periods of nitrite accumulation or no nitrification. Diversity of nitrifiers in the sludge of the full-scale facility was examined at a time of full nitrification with the construction of clone libraries of ammonia monooxygenase ( amoA) gene and of the 16S rRNA gene of NOB. Nucleotide sequences of amoA gene belonged to one dominant population, associated with Nitrosomonas europaea, and to a minor population related to the Nitrosomonas nitrosa lineage. The majority of sequences retrieved in the NOB-like clone library also clustered within a single operational taxonomic unit. The high dominance of Nitrobacter over Nitrospira and the low diversity of nitrifying bacteria observed in this wastewater treatment plant might account for the increased risk of failure in the presence of disturbances.

Treatment of petroleum refinery wastewater by electrochemical methods

Direct and indirect electrochemical oxidation by using boron doped diamond anode (BDD), direct electrochemical oxidation by using ruthenium mixed metal oxide (Ru-MMO) electrode, and electrofenton and electrocoagulation by using iron electrode were investigated for the treatment of petroleum refinery wastewater (PRW). The results have been given at the best operational conditions which were obtained for each electrochemical method. The results obtained from electrochemical methods were compared to each other. Complete phenol and COD removal can be achieved in almost all electrochemical methods, except electrocoagulation, provided that electrolysis time is prolonged. The most efficient method was the electrofenton process followed by the electrochemical oxidation using BDD anode. Phenol removal of 98.74% was achieved in 6 min of electrolysis and COD removal of 75.71% was reached after 9 min of electrolysis in electrofenton. Additionally, 99.53% phenol and 96.04% COD removal were obtained in direct electrochemical oxidation at the current density of 5 mA/cm 2. Initial phenol concentration was reduced to final phenol concentration of 0.91 mg/L after 40 min of electrolysis, and initial COD decreased to 36.7 mg/L and 23.3 mg/L after 60 min and 75 min of electrolysis, respectively. Electrocoagulation was found to be ineffective for the treatment of PRW.

Integrated Submerged Membrane Bioreactor Anaerobic/Aerobic (ISMBR-A/O) for Nitrogen and Phosphorus Removal During Oil Refinery Wastewater Treatment

Nitrogen and phosphorus removal from oil refinery wastewater using an integrated submerged membrane bioreactor anaerobic/aerobic (ISMBR-A/O) was investigated in this laboratory study. The objectives were to demonstrate suitability of the membrane bioreactor (MBR) technology to the treatment of refinery wastewater and its ability to achieve nitrogen and phosphorus removal effectively. IMBR-A/O comprised four reactor tanks: an influent tank, anaerobic tank, aerobic tank, and effluent tank. The IMBR-A/O was operated in cycles of four phases: fill, anaerobic, aerobic, and draw. During the fill phase, the influent tank was half-filled with oil refinery wastewater. During the subsequent anaerobic phase, most of the phosphorus release took place from the submerged biofilm in this reactor. In the aerobic phase, the wastewater was circulated by pumps between the influent tank and the anaerobic tank, resulting in denitrification at the start of the aerobic phase due to low oxygen concentrations, followed by nitrification and luxury uptake of phosphorus when oxygen concentrations increased. Ultimately, the treated water flowed from the effluent tank. The results show that the chemical oxygen demand (COD), 5-day biochemical oxygen demand (BOD5), oil, NH+ 4-N, total nitrogen (TN), and total phosphorus (TP) removal efficiencies were 91, 90, 91, 99, 80, and 66%, respectively.

Oil-Refinery Wastewater Treatment by Biofilm Processes: Moving Bed Reactor and Biological Activated Carbon Filter

Oil-Refinery Wastewater Treatment by Biofilm Processes: Moving Bed Reactor and Biological Activated Carbon Filter

Assessment of electrocoagulation for the treatment of petroleum refinery wastewater

Batch electrocoagulation experiments were carried out to evaluate the removal of sulfate and COD from petroleum refinery wastewater using three types of electrodes: aluminum, stainless steel, and iron. The effects of current density, electrode arrangement, electrolysis time, initial pH, and temperature were investigated for two wastewater samples with different concentrations of COD and sulfate. The experimental results indicated that the utilization of aluminum, as anode and cathode, was by far the most efficient arrangement in the reduction of both the contaminants. The treatment process was found to be largely affected by the current density and the initial composition of the wastewater. Although electrocoagulation was found to be most effective at 25°C and a pH of 8, the influence of these two parameters on the removal rate was not significant. The results demonstrated the technical feasibility of electrocoagulation as a possible and reliable technique for the pretreatment of heavily contaminated petroleum refinery wastewater.