Petrochemical Wastewater Treatment Plant Research Articles

Chlorinated solvents in a petrochemical wastewater treatment plant: An assessment of their removal using self-organising maps

The self-organising map approach was used to assess the efficiency of chlorinated solvent removal from petrochemical wastewater in a refinery wastewater treatment plant. Chlorinated solvents and inorganic anions (11 variables) were determined in 72 wastewater samples, collected from three different purification streams. The classification of variables identified technical solvents, brine from oil desalting and runoff sulphates as pollution sources in the refinery, affecting the quality of wastewater treatment plant influent. The classification of samples revealed the formation of five clusters: the first three clusters contained samples collected from the drainage water, process water and oiled rainwater treatment streams. The fourth cluster consisted mainly of samples collected after biological treatment, and the fifth one of samples collected after an unusual event. SOM analysis showed that the biological treatment step significantly reduced concentrations of chlorinated solvents in wastewater.

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.

DETERMINATION OF AROMATIC VOLATILE COMPOUNDS IN PETROCHEMICAL WASTEWATER

Abstract A method based on headspace and capillary gas chromatography with flame ionization detector technique was validated for the simultaneous determination of five individual aromatic volatile pollutants: benzene, toluene, ethylbenzene, m/p-xylene and o-xylene. The validation took in consideration liniarity, accuracy, precision, limit of detection, limit of quantification and uncertainty estimation criteria and concluded that the proposed method is suitable to determine the pollutants of interest. The samples were taken from the effluent of petrochemical wastewater treatment plant before, during and after the tertiary biological treatment. The concentrations of the volatile aromatic pollutants in all analysed samples have been found below the internal quality procedure requirements (1 µg/L for benzene and 10 µg/L for its derivatives). It was noticed that the concentration decreases during the tertiary treatment. In the samples of the discharged effluent in the Black Sea the concentrations of all determined compounds were under the limit of detection.

Effect of sonication assisted by titanium dioxide and ferrous ions on polyaromatic hydrocarbons (PAHs) and toxicity removals from a petrochemical industry wastewater in Turkey

AbstractBACKGROUND: In Izmir (Turkey) polyaromatic hydracarbon (PAH) removal efficiencies are low in petrochemical industry aerobic biological wastewater treatment plants because bacteria are not able to overcome the inhibition of these toxic and refractory organics. In order to increase PAHs removal, sonication process was chosen among other advanced treatment processes include sonication processes. The effects of ambient conditions, increasing sonication time, sonication temperature, TiO2 and Fe+2 concentrations on sonication at a petrochemical industry wastewater treatment plant in Izmir (Turkey) was investigated in a 650 W sonicator, at a frequency of 35 kHz and a 500 mL glass reactor.RESULTS: Increasing the temperature improved PAH removal after 150 min sonication at 30 °C and 60 °C. The maximum total PAH removal efficiencies were the same in a reactor containing 20 mg L−1 TiO2 and in a TiO2‐free reactor at 30 °C and 60 °C after 150 min sonication. Maximum 91% and 97% total PAH removals were obtained in a control reactor and a reactor containing 20 mg L−1 Fe+2 at 30 °C and 60 °C, respectively, after 150 min sonication. The PAH concentration was toxic to Daphnia magna, so that the EC50 value decreased significantly from 342.56 ng mL−1 to EC50 = 9.88 ng mL−1 and to EC50 = 3.35 ng mL−1, at the lowest TiO2 (0.1 mg L−1) and Fe+2 (2 mg L−1) concentrations, respectively, after 150 min sonication at 30 °C.CONCLUSION: PAHs and the acute toxicity in a petrochemical industry wastewater were removed efficiently through sonication. Copyright © 2010 Society of Chemical Industry

Demonstration Case of Petrochemical Wastewater Treatment Plant

Problem statement: The wastewater from petrochemical complex is varying in flow, organic contaminant loading and composition due to various operating condition of the petrochemical complex. This study is demonstration case of petrochemical wastewater treatment plant. Approach: This study is demonstration case on Basrah petroch emical wastewater treatment plant whereas the description of wastewater composi tion and system of treatment had reviewed and the experimental work on the most important control parameters (F/M ratio and MCRT) had implemented. Results: The experimental results showed that (i) The optim um rate of BOD removal could be obtained at food to microorganism ratio be tween 0.1-0.15 where this optimum ratio exists at the maximum zone settling velocity (ii) The desi gn effluent BOD5 could be obtained at a MLSS concentration of 6000 mg L -1 and in about 26-30 day of mean cell residence time Conclusion: The experimental data from petrochemical wastewater treatment plant in Basra City (south of Iraq) showed that the extended Aeration offers the most d esirable features for the treatment of petrochemical wastewater where the specification of this method apply with experimental results as well as that the study show that control parameters (F/M ratio and MCRT) is a good tool to control the effluent wastewater quality of petrochemical w astewater treatment plant.

Treatment of succinonitrile wastewater by immobilized high efficiency microorganism strains

Using succinonitrile as a sole source of carbon and nitrogen, two bacterium strains named as J-1-3 and J-13-1 were isolated and screened out from the treatment facilities of Shanghai petrochemical wastewater treatment plant treating acrylic fiber production wastewater. The optimal growth conditions of the two strains in the degradation of succinonitrile with varied initial concentrations were determined through flask tests as follows: temperature 30 degrees C, shaker rotary speed of 250 r/min, inoculum percentage 0.1%, and initial pH 6. Results indicate that the two strains, especially J-13-1, exhibited a high efficiency for succinonitrile degradation. Thereafter, the bacterium strains were immobilized separately by sodium alginate and polyvinyl alcohol 1750 +/- 50, and applied to succinonitrile degradation again. Results show that in a very broad range of the initial succinonitrile concentration, i.e., 30-5,000 mg/L, the sodium alginate immobilized grains could degrade more than 80% of succinonitrile after 24 h under the experimental conditions of 30 degrees C, pH 6.5, and shaker rotary speed of 250 r/min. However, the polyvinyl alcohol immobilized grains tended to inflate and break down due to a weak mechanical strength.

Identification and degradation characterization of hexachlorobutadiene degrading strain Serratia marcescens HL1

A bacterium (strain HL1) capable of growing with hexachlorobutadiene (HCBD) as sole carbon and energy sources was isolated from a mixture of soil contaminated with HCBD and activated sludge obtained from petrochemical plant wastewater treatment plant by using enrichment culture. Biochemical characteristics and phylogenetic analysis based on 16S rDNA sequence indicate that strain HL1 clearly belongs to Serratia marcescens sp. Resting cells of strain HL1 were found to remove HCBD from culture fluids with the concomitant release of chloride ion under aerobic conditions. The ranges of pH value and temperature for satisfactory growth of strain HL1 cells were from 7.0 to 8.0 and 25 to 30°C, respectively. Capability of resting cells to degrade HCBD was induced by HCBD in the culture fluids. HCBD (20mg/l) was removed from culture fluids by resting cells in 4 d without lag phase, but for 50mg/l and 80mg/l HCBD 7 days were needed with lag phase. Growth of strain HL1 cells was inhibited by HCBD at the concentration up to 160mg/l. First order kinetics could be fitted to the biodegradation of HCBD by HL1 cells after lag phase at initial concentrations of 20, 50, and 80mg/l. Strain HL1 also showed strong capacity to degrade chloroprene, trichloroethylene, tetrachloroethylene, and vinyl chloride at solely initial concentration of 50mg/l. Results could offer useful information for the application of strain HL1 in bioremediation or control of HCBD-polluted environment.

Biodegradation potential and bacterial diversity of a petrochemical wastewater treatment plant in Iran

An activated sludge treatment was evaluated for its effectiveness in cleaning up a petrochemical wastewater in Iran. For assessing biodegradation potential of activated sludge, seven characteristics of wastewater (temperature, pH, dissolved oxygen, chemical oxygen demand, concentrations of ethylene dichloride, vinyl chloride, and total hydrocarbons) were monitored during six months. It was shown that dominant pollutants in order of magnitude were normal-alkanes (C 10–C 21), aromatics, and polycyclic hydrocarbons. The activated sludge treatment revealed maximum reduction of 89%, 99%, 92%, and 80% in COD, ethylene dichloride, vinyl chloride and total hydrocarbons concentrations, respectively. Preliminary screening of culturable petrochemical-degrading microorganisms of the activated sludge resulted in the collection of 67 bacterial and one mold species. Bacterial strains mainly belonged to Pseudomonas, Flavobacterium, Comamonas, Cytophaga, Acidovorax, Sphingomonas, Bacillus and Acinetobacter genera. The isolated mold was identified as Trichoderma sp.

Biodegradation kinetics of benzene, methyl tert‐butyl ether, and toluene as a substrate under various substrate concentrations

AbstractOwing to the complexity of conventional methods and shortcomings in determining kinetic parameters, a convenient approach using the nonlinear regression analysis of Monod or Haldane type nonlinear equations is presented. This method has been proven to provide accurate estimates of kinetic parameters. The major work in this study consisted of the testing of aromatic compound‐degrading cultures in batch experiments for the biodegradation of benzene, methyl tert‐butyl ether (MTBE), and toluene. Additionally, batch growth data of three pure cultures (i.e., Pseudomonas aeruginosa YAMT421, Ralstonia sp. YABE411 and Pseudomonas sp. YATO411) isolated from an industrial petrochemical wastewater treatment plant under aerobic conditions were assessed with the nonlinear regression technique and with a trial‐and‐error procedure to determine the kinetic parameters. The growth rates of MTBE‐, benzene‐, and toluene‐degrading cultures on MTBE, benzene, and toluene were significant. Monod's model was a good fit for MTBE, benzene and toluene at low substrate concentrations. In contrast, Haldane's equation fitted well in substrate inhibition concentration. Monod and Haldane's expressions were found to describe the results of these experiments well, with fitting values higher than 98%. The kinetic parameters, including a maximum specific growth rate (µm), a half‐saturation constant (Ks), and an inhibition constant (Ki), were given. Copyright © 2007 Society of Chemical Industry

Adsorption Characteristics of Benzene on Biosolid Adsorbent and Commercial Activated Carbons

This study selected biosolids from a petrochemical waste-water treatment plant as the raw material. The sludge was immersed in 0.5-5 M of zinc chloride (ZnCl2) solutions and pyrolyzed at different temperatures and times. Results indicated that the 1-M ZnCl2-immersed biosolids pyrolyzed at 500 °C for 30 min could be reused and were optimal biosolid adsorbents for benzene adsorption. Pore volume distribution analysis indicated that the mesopore contributed more than the macropore and micropore in the biosolid adsorbent. The benzene adsorption capacity of the biosolid adsorbent was 65 and 55% of the G206 (granular-activated carbon) and BPL (coal-based activated carbon; Calgon, Carbon Corp.) activated carbons, respectively. Data from the adsorption and desorption cycles indicated that the benzene adsorption capacity of the biosolid adsorbent was insignificantly reduced compared with the first-run capacity of the adsorbent; therefore, the biosolid adsorbent could be reused as a commercial adsorbent, although its production cost is high.

The Reuse of Biosludge as an Adsorbent from a Petrochemical Wastewater Treatment Plant

Biosludge was obtained from a petrochemical industry’s biological wastewater treatment plant. Zinc chloride (ZnCl2) was used as a sludge activation agent during the pyrolytic process. Scanning electron microscope (SEM) image photographs, element composition, surface functional group, and pore structure were analyzed for the sludge adsorbent characteristics. Results indicated the proper ZnCl2-immersed concentration, pyrolytic temperature, and time could produce adsorbent from the bio-sludge. The optimal conditions for a larger surface area adsorbent were 3 M ZnCl2-immersed sludge pyrolyzed at 600 °C for 30 min and washed with 3 N hydrochloric acid (HCl) solution and distilled water. The predominant pore size of the sludge adsorbent was the mesopore.

Adsorption characteristics of benzene on biosolid adsorbent

This study selected biosolids from a petrochemical wastewater treatment plant as the raw material. The sludge was immersed in 0 to 5 mol l(-1) of ZnCl2 solutions and pyrolyzed at different temperatures. When the sludge was pyrolyzed for 30 min at temperatures of 400, 500, 600, and 700 degrees C, the corresponding surface area of the biosolid adsorbent was 46, 401, 921, and 727 m2/g, respectively. Pore size analysis indicated that the mesopore (20 to 500 A) contributed more than the macropore and micropore in the sludge pyrolytic residue. When the benzene influent concentration was 800 ppmv, the adsorption capacity ranged from 59 to 164 mg/g for different biosolid adsorbents. A larger BET surface area and smaller average pore diameter yielded a larger benzene adsorption capacity.

Pyrolytic kinetics of sludge from a petrochemical factory wastewater treatment plant--a transition state theory approach.

The pyrolysis of hydrocarbon-rich sludge in an oxygen-free environment can provide useful liquefaction products and residues. When applied to sewage sludge, energy and time costs are the major factors that affect the operation. Therefore, it is important to understand how the process is affected by temperature. The pyrolysis kinetics of sludge from a petrochemical factory wastewater treatment plant was studied to reveal the effects of temperature on the reaction rate and the magnitude of deltaH and deltaS of the reaction barrier. Oven-dried sludge samples were pyrolyzed in an isothermal reactor under six different temperatures. The residues were weighed at frequent intervals within a total 30-min experiment period. Data analysis indicated that a first order reaction model could describe the pyrolysis kinetics, across all experimental temperature ranges. When transition state theory was applied, the results indicated that the major reaction barrier came from the entropy term of the activation free energy. Therefore, increasing the pyrolysis temperature to overcome the reaction barrier yielded no apparent improvement, but strategies that reduced the entropy should significantly improve the reaction.

The Effect of Benzene, Toluene, and o-Xylene on COD Removal in an Aerobic Fluidized Bed Reactor Utilizing Acetic Acid as the Main Carbon Source

A laboratory-scale fluidized bed reactor (FBR) model was operated to examine the effect of BTX on the removal of COD in the presence of acetic acid, which was readily degradable. An activated sludge culture was taken from a petrochemical industry wastewater treatment plant and acclimated first to acetic acid (up to 2,000 mg COD/L), and then to BTX (up to 3 mg/L) as a total concentration. Microbial oxygen uptake rates are controlled during the adaptation period. Then this culture is used as inoculum in the FBR unit. The system was initially operated with a total BTX concentration of 6 mg/L, and concentrations of 12 and 18 mg/L, respectively, were tried during an operational period of 42 days, while the theoretically estimated COD concentration (due to the acetic acid in the system) was kept constant, remaining at 2,000 ± 75 mg/L. An organic loading rate of 1.3 kg/m3/day and a hydraulic retention time of 36 h are the fixed operating parameters used during this study. It was seen that the dissolved COD concentrations in the effluent were relatively low and similar for 6 and 12 mg/L influent BTX concentrations. However, the dissolved COD concentration of effluent wastewater increased significantly when the total influent wastewater BTX concentration was 18 mg/L. The BTX concentration of the effluent wastewater was less than 1 mg/L, indicating BTX was accumulated onto the GAC, or it was biodegraded by attached micro-organisms. The experiments, which were carried out under shock loads of BTX at given intervals (with the FBR operating semicontinuously), proved this result with a very low (actually undetectable) effluent wastewater BTX concentration and a tendency to increase the effluent COD concentration caused foam formation in the reactor due to the adverse effect of BTX.

Upgrade of a petrochemical wastewater treatment plant by an upflow anaerobic pond

A petrochemical plant producing terephthalic acid faced a saturation of its wastewater treatment facilities due to an increase in production. In fact, the plant has been growing in recent years, and the effluents have been treated by reproducing the original activated sludge design. However, owing to lack of space, as well as energy consumption and sludge production reaching a certain level, the plant considered other options for coping with the new effluent flow and organic load. Based on the authors' previous experience with this wastewater, the consultant designed a process consisting of modifying an existing pond, in order to add an anaerobic step before the aerobic tanks already in operation. The anaerobic pond is a three-stage process, all included in the same adapted basin, with a distribution system in the bottom of each stage that creates an upflow pattern. Terephthalic acid wastewater is a mixture of several organic acids, with different anaerobic degradation kinetics, acetic and benzoic acids being more rapidly removed; the staged design takes this into account. The first two stages have a plastic floating cover (5,813 m3 and 8,719 m3 volume, respectively), while the third one is a conventional UASB type reactor (6,276 m3 volume) with a gas-liquid-solid separation device on top. The design wastewater flow is 230 m3/h, with 10,300 mg/l COD, a pH of 4.5 and a temperature of 40 °C. There is an effluent recycling pump (510 m3/h) to control upflow velocities and eventual acidification problems in the first two stages. The reactor, seeded with anaerobically adapted waste sludge from the aerobic plant, is now under start up, with the expected performance.

Using bundle filters to process petrochemical secondary effluent for industrial reuse

The objective of this project is to study the advanced treatment technique for the secondary effluent from petrochemical wastewater treatment plants in order to meet requirements for the reuse of industrial wastewater. Based on the characteristics of the secondary effluent of petrochemical wastewater, a direct filtration process with highly effective filter is selected and designed. The test results indicate that the process can achieve good results in turbidity and COD removal. It can meet the need for the industrial reuse of the secondary effluent of petrochemical wastewater as the turbidity value of effluent is less than 3 and COD of effluent is less than 40 mg/l. A great economic efficiency is obtained. The filtration system costs low because of the longer operating cycle (14-24h). It is a creative achievement in the reuse of petrochemical wastewater, and is the pioneering study in China.

Using bundle filters to process petrochemical secondary effluent for industrial reuse

The objective of this project is to study the advanced treatment technique for the secondary effluent from petrochemical wastewater treatment plants in order to meet requirements for the reuse of industrial wastewater. Based on the characteristics of the secondary effluent of petrochemical wastewater, a direct filtration process with highly effective filter is selected and designed. The test results indicate that the process can achieve good results in turbidity and COD removal. It can meet the need for the industrial reuse of the secondary effluent of petrochemical wastewater as the turbidity value of effluent is less than 3 and COD of effluent is less than 40 mg/l. A great economic efficiency is obtained. The filtration system costs low because of the longer operating cycle (14-24h). It is a creative achievement in the reuse of petrochemical wastewater, and is the pioneering study in China.

Long-Term Land Application of Activated Sludge from a Petrochemical Wastewater Treatment Plant: I - Leachate Quality

Excess activated sludge from SITEL, the wastewater treatment plant of Polo Petroquímico do Sul (South Petrochemical Complex), Triunfo, State of Rio Grande do Sul (RS), Brazil, is disposed of by subsurface injection on pangola grass and rye grass fields at an average annual rate of 24 tons/ha (dry basis). In order to assess absorption of sludge constituents by plants, modifications of soil properties and leachate quality, a microplot growth-leaching experiment is being conducted at the Department of Soils of UFRGS since 1985. Pangola grass (Digitariadecumbens, Stent) and rye grass (Loliummultiflorum, Lam) are grown in summer and winter respectively. Some microplots have been loaded with sludge enriched with Cu, Zn, Cr, Ni, Cd, Pb and Hg since 1988. Plant nutrients such as K, Cu, Zn and B did not increase in leachate, even at the higher application rates employed. Ammonium and pH were not affected either, whilst nitrates increased at the highest application rates. Ca and Mg increased in leachate during the third and the fourth years of the experiment, probably due to the liming of the microplots. Electrical conductivity of leachate increased with sludge application. Na, chloride and sulphate, the more soluble ions, increased slowly during the first year and more rapidly during the subsequent years. Heavy metals Cr, Ni, Cd, Pb and Hg in leachate were not consistently affected by application of pure sludge or metals-enriched sludge. The concentrations of these constituents in leachate were found to be generally below accepted limits for potable water. Exacerbation of loading of metals, bringing about introduction of total amounts that exceed current limits of addition of metals to soil, did not produce significant alterations in leachate quality. This suggests that these limits are very safe with respect to protection of aquifers. The determination of nitrates in leachate at different sludge application rates made possible the adoption of 40 tons/ha.year as the maximum allowable sludge loading rate (on dry basis) for the real sludge farms at SITEL. This figure is approximately double the operational sludge application rate at SITEL.

Activated Carbon as an Advanced Treatment for Petrochemical Wastewaters

This paper presents the results of a study conducted with the purpose of establishing the feasibility of using activated carbon as an advanced treatment process for petrochemical wastewaters. Two pilot plants using Powdered Activated Carbon (PAC) and Granular Activated Carbon (GAC), respectively, were operated for a period of 15 weeks, fed with the effluent of a petrochemical wastewater treatment plant. The study was made using all available Brazilian carbons at the time. Isotherm tests and other carbon properties were used to select the carbons for GAC and PAC plants. The two pilot plants were operated between 8 April and 24 June 1981 at CETREL's wastewater treatment plant located at Camacari, BA, Brazil. The plant treats organic wastewaters from a petrochemical complex. During the first two GAC runs, low COD removal efficiencies were evident, and the effluent of all columns contained color due to the presence of organic colloids which were not adsorbed by the carbon. For this reason the feed to the system was pretreated to remove organic colloids. During the study period six GAC test runs were conducted using carbon GM and one using carbon HIDRO-G. Comparison of the two carbons showed that GM was the superior of the two. At all times, the GAC pilot plant using GM produced a colorless effluent from the amber-colored influent. At the same time, the PAC system, with a carbon dosage of 100 mg/l, was not capable of removing the color. One sample of carbon was regenerated to study its performance after regeneration. The analysis of the obtained data suggests that the adsorptive properties of the virgin and regenerated carbon may differ by as much as 12%. Several tests were made to determine the removal efficiency of priority pollutants in the GAC and PAC systems. These tests indicated that the GAC system is capable of reducing organic priority pollutants to below detectable limits. Metal analyses were made on several occasions on the GAC systems in addition to those conducted on priority pollutants samples. These tests indicated that metal concentrations in the GAC effluent were at or below the proposed effluent standards. The authors concluded that granular activated carbon is a sound advanced treatment process for petrochemical wastes to reduce organic priority pollutants to below detectable limits, producing an effluent with less than 150 mg/l COD.

Characterisation of a Leucothrix-type bacterium causing sludge bulking during petrochemical waste-water treatment

From a petro chemical waste-water treatment plant showing sludge bulking, two filamentous microorganisms of the Leucothrix type were isolated. Morphological and some physiological characteristics of the isolates L1 and L2 were compared with the characteristics of two cool water strains of Leucothrix mucor. The main divergences of the isolates were the requirement for biotin and thiamine (L1) or for biotin alone (L2) and the non marine character, since they can grow at a salinity of 5 ppt, without NaCl. It is suggested that the isolates may be new species of the genus Leucothrix, that can cause sludge bulking.