PRETREATMENT OF OIL PRODUCED WATER USING LOW COST ADSORBENTS

International Journal of Mechanical and Production Engineering Research and Development (IJMPERD) ISSN (P): 2249–6890; ISSN (E): 2249–8001 Vol. 10, Issue 3, Jun 2020, 2435–2444 © TJPR Pvt. Ltd.

PRETREATMENT OF OIL PRODUCED WATER USING LOW COST ADSORBENTS OMAR HAMYAR AL-ABRI1, NAGESWARA RAO LAKKIMSETTY2* & FEROZ SHAIK3 1,2 3

National University of Science and Technology, Muscat, Sultanate of Oman

Prince Mohammad Bin Fahd University, Al Khobar, Kingdom of Saudi Arabia

ABSTRACT The treatment of oil produced water (OPW) was an enormous task for oil and gas industry. Various costly technologies have been adopted on field to treat OPW before reuse or disposal to environment. Adsorption technology with low cost adsorbents was quite effective to treat OPW to certain extent. In the present studies, low cost adsorbents from raw date seeds (DSA) and coconut shells (CSA) were prepared, characterized and employed for the treatment of OPW. OPW was characterized using Fourier Transform Infrared (FTIR) spectroscopy and Gas Chromatography-Mass Spectroscopy (GS-MS), before and after the treatment with low cost adsorbents. Prepared adsorbents were characterized with Scanning Electron Microscopy (SEM) and X-ray Diffractometer, before and after activation. The effect of contact time and dosage on percentage removal efficiency of dissolved oxygen (DO), chemical oxygen demand carbon (TOC), and oil & grease were evaluated. The maximum percentage removal efficiency of DO=33.3%, COD=43.4%, TDS=66.4%, TSS=15%, BOD=96.6%, TOC=80.4% and oil & grease = 99.9% was achieved with DSA and DO=25.6%, COD=37.4%, TDS=61.1%, TSS=5.3%, BOD=96.6%, TOC=79.2%, and oil & grease=99.8% was achieved with CSA, respectively for a dosage of 10 g/100 mL and contact time 60 min.

KEYWORDS: Low Cost Adsorbents, Oil Produced Water, Date Seeds, Coconut Shells, Activated Carbon & Adsorption

Original Article

(COD), total dissolved solids (TDS), total suspended solids (TSS), biological oxygen demand (BOD), total organic

Received: Jun 06, 2020; Accepted: Jun 26, 2020; Published: Jul 07, 2020; Paper Id.: IJMPERDJUN2020226

1.0 INTRODUCTION Oil produced water (OPW) has been a major byproduct in oil and gas extraction processes. It flows upward in large volume in the case of oil wells and in lesser volume in the case of gas wells (Huishu, 2013). Large quantities of OPW generated globally and it was estimated to be in the range of 250 million barrels per day. OPW was harmful to the environment, if it is discharged without treatment. It contains high concentrations of dissolved solids, metals, radioactive materials, inorganic and organic toxic compounds, biological content etc. Most of the OPW has been reinjected back to the oil wells to enhance oil production and some of it was injected for the purpose of disposal.

The composition of OPW can vary from one well to another based on the nature of the geological formation (Al Anezi et al., 2018). Various technologies used for treating oil produced water but the selection of a particular technology depends on the required quality of treated water. Actually there was environmental and federal regulations controlling oil produced water treatment and discharge processes. If oil produced water has to be discharged to the ocean, then toxic chemicals and oil and grease contents have to be removed. While if it was to be discharged onshore then along with other impurities, salt must also be removed and if it was to be injected then oil content, solids, and bacteria have to be eliminated (Nasiri and Jafari, 2017). Pretreatment and treatment processes of oil produced water can be classified based on the purpose, which to be used for: Gravity separation, physical www.tjprc.org

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separation (filtration and hydro cyclones) and adsorption techniques were used to remove oil and grease, membrane filtration, ion exchange and electrocoagulation were used for heavy metal and inorganics removal, chemical biocides, ultraviolet light, ozone techniques were used for microbial treatment (Igunnu and Chen, 2012). However, most of these technologies were costly and energy intensive. Researchers are working to develop cost effective technologies to treat OPW or at least to employ as pretreatment step. Chemical coagulation technique was used to remove turbidity from OPW. Ferric chloride and aluminum sulfate were used as coagulants. Experimental results showed that aluminum sulfate was more effective than ferric chloride in removing the turbidity from OPW (Rodriguez et al., 2020). Hu et al., (2020) employed struvite precipitation technique for simultaneous recovery of metal ions from OPW. Chemical coagulation integrated with adsorption was employed to treat dissolved and dispersed oil droplets from OPW. Ferric chloride (FeCl 3) with organoclay (OC) was used in a complete stirred tank reactor (CSTR) as a pretreatment for dissolved air floatation (DAF). The integrated process was evaluated and compared to the individual processes of coagulation-DAF, adsorption-DAF and DAF without pretreatment for the removal of dispersed oil and other organics from OPW (Younker, 2014). Low cost adsorbents prepared from kiwi peels was used for the treatment of oil droplets from OPW. The percentage removal of oil droplets was linearly changing with adsorbent dosage, contact time and pH (Jafer and Hassan, 2019). Activated carbon has been prepared from waste neem leaves and waste tea. These low cost adsorbent were used successfully for the bleaching of oil (Furqan butt, 2020). Photocatalysis is another technique which was widely used to treat trace organics present in OPW. Two advanced oxidative processes were applied to treat a real sample of OPW from Rio Grande do Norte, Brazil. The experimental results demonstrated that the two photocatalytic process were effective for the removal of dissolved organic matter in OPW (Silva et al., 2019). Fathy et al., (2017) synthesized amorphous carbon thin film from palm oil tree leaves. A series of batch adsorption experiments were conducted for the treatment of OPW and evaluated the pollutant removal efficiency. TiO2 photocatalyst was employed in suspension and immobilization on glass substrate to treat the organics present in OPW. The experimental results showed over 80% of organics removal from OPW (Feroz et al., 2017). Commercially reverse osmosis (RO) membrane technology was widely employed for the treatment of OPW, due its high salinity. Fouling of membranes was still a major operational issue in this technology. The use of low-cost adsorbent technology as a pretreatment step to RO was considered as an effective option. Low cost adsorbents can be prepared from various organic waste materials such walnut shells, date seeds, coconut shells etc. This also minimize the waste disposal to environment and can be used for pretreatment of OPW. In this study, activated carbon prepared from date seeds (DSA) and coconut shells (CSA) were applied for the treatment of OPW. Characterization of adsorbents, before and after activation was carried out using SEM and XRD. OPW was characterized before and after treatment using FT-IR and GC-MS. A comparison of performance on using of both low-cost adsorbents for the treatment of OPW was evaluated.

2.0 MATERIALS AND METHODS OPW samples were collected from Oman oil field and stored at 4 oC to avoid any contamination. Raw date seeds and coconut shells were collected from domestic uses and farms in the Muscat area, Sultanate of Oman. Analytical grade reagents were procured and used as pure as supplied. Dissolved oxygen (DO) and total dissolved solids (TDS) was measured using water analysis kit (Eutech PCD 650), chemical oxygen demand (COD) was measured using COD reactor (AQ 400, thermos scientific Orion COD125), total organic carbon (TOC) was measured using Shimadzu TOC analyzer (LCSH/CSN, Japan), and oil and grease using EPA 1664 method.

Perkin Elmer Scanning Electron Microscopy was used to analysis the surface morphology of the adsorbent before

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and after activation. STOE1 PDSII Diffractometer equipped with MO x-ray was used for XRD analysis. Bruker Fourier Transform Infrared (USA) spectroscopy was used to analysis OPW sample spectra before and after treatment at wave number 3500 – 500 nm. Agilent 7870 B/5977 A GC-MS was used to analysis OPW spectra before and after treatment.

2.1 Preparation of Low-Cost Adsorbents The collected raw date seeds materials were washed to remove impurities and then soaked in distill water. After soaking for sufficient time, the material was dried at 105o C in a drying oven for 24 hours. The dried material then washed with 60% phosphoric acid (H3PO4) for chemical activation, thereafter washed multiple times using distill water till pH become neutral.

The drying procedure was repeated for complete removal of moisture from the materials. Dried materials were crushed in ball mill and sieved to 2 mm size. The sieved material (2 mm) was stored in a desiccator. Again the material was chemically activated with 60% H3PO4 acid. The material was filled in stainless steel perforated cylinders. These cylinders kept in muffle furnace and partial oxidation (control carbonization) was carried out at 300 oC for 3 hours. The activated carbon from date seeds (DSA) was then taken out, cooled and stored in air tight polyethylene covers. Same procedure was followed to prepare activated carbon from coconut shells (CSA).

2.2 Characterization Date seeds were characterized using SEM and XRD before and after activation. Coconut shell characterized using SEM before and after activation. OPW was characterized before and after treatment using FT-IR and GC-MS. 2.3 Experimentation 100 mL of OPW was taken in glass beaker for each experimental run. Calculated amount of prepared activated carbon was added. The glass beaker was placed on magnetic stirrer and allowed constant stirring at 500 RPM. Samples were collected at each time interval and analyzed for different parameters using standard procedures. The percentage removal efficiency was estimated using equation 1.

Percentage removal efficiency =

(𝐶𝑜 − 𝐶𝑓 ) 𝐶𝑜

𝑥100 (1)

Where, c0 and cf are the initial and final concentrations in mg/L respectively. The characteristics of OPW before the treatment was showed in the table 1.

Table 1: Characteristics of OPW before Treatment Parameter Value DO, mg/L 3.9 COD, mg/L 1136 TDS, mg/L 8890 TSS, mg/L 55 BOD, mg/L 355 TOC, mg/L 265 Oil & Grease, mg/L 22.5

3.0 RESULTS AND DISCUSSIONS 3.1 Characterization of Adsorbents Figures 1a and 1b showed the SEM images of DSA before and after activation. Figures 2a and 2b showed the SEM images of CSA before and after activation. It was observed that calcination breaks the lignocellulose bonds in the raw adsorbent, www.tjprc.org

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which resulted a dense spherical hole as an active site for adsorption process. Figure 3a and 3b showed the XRD spectra of DSA before and after activation. The peaks at angles 23.4o, 44o and 27o in Figure 3b indicated the presence of carbon and graphite in DSA.

Figure 1a: DSA Before Activation.

Figure 2a: CSA Before Activation.

Figure 3a: DSA Before Activation

Figure 1b: DSA After Activation.

Figure 2b: CSA After Activation.

Figure 3b: DSA After Activation.

3.2 Characterization of OPW Impact Factor (JCC): 8.8746

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The FT-IR spectra of OPW before treatment was showed in Figure 4a. Stretching peaks were observed at wave numbers 1540, 1640, 2870, 2926 and 3400 cm-1. These peaks indicated the presence of high aliphatic, hydroxyl and C=C bonds group compounds. However, after treatment using DSA, the FITR spectra as showed in figure 4b showed less intense peaks at wave numbers 3200 and 3500 cm-1. This indicates the adsorption of hydroxyl group compounds. The peaks between 1540 and 1640 cm-1 almost disappeared, which indicated that carbonyl group (C=O) compounds completely adsorbed by DSA. The peak between 1200 and 1000 cm-1 indicates the presence of C-O bond group compounds and at 830 cm-1 peak represents

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Figure 4a: FTIR Spectra Before Treatment.

Figure 4b: FTIR Spectra After Treatment.

Figures 5a and 5b showed the GC–MS spectra of OPW before and after treatment with DSA, respectively. The intense peaks that appeared before treatment was almost most disappeared after treatment, which indicated that DSA effectively removed pollutants from OPW. CAARU_19_E_878_O1_4

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Figure 5a: OPW Before Treatment. Figure 5b: OPW After Treatment.

3.3 Effect of Contact Time and Dosage Two sets of experiments were run with a dosage of 10 g DSA and CSA each in 100 mL of OPW. A constant stirring was maintained and samples were collected at each time internal of 15 min, 30 min, 45 min and 60 min. Samples were analyzed for various parameters. The pH of the OPW was maintained at neutral. It was observed that the adsorption process was very slow till 30 min for both DSA and CSA and then took place rapidly between 30 to 60 min as showed in Figure 3 and 4. The www.tjprc.org

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maximum percentage removal efficiency of parameters was at 60 min contact time.

Figure 3: Effect of Contact Time for DSA.

Figure 4: Effect of Contact Time for CSA.

Another set of experiments were run by varying the adsorbent dosages from 2 to 10g at constant contact time of 60 min. Constant stirring was maintained and samples were collected at the end of 60 min and analyzed. The percentage reduction of parameters was linear with increase in adsorbent dosage. Figures 4 and 5 showed the percentage reduction of parameters with variation of adsorbent dosage. All the experiments were conducted maintaining constant pH of 7. Neutral pH was maintained to minimize the interference of either H+ or OH- ions during adsorption process with high or low pH, respectively,

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Figure 4: Effect of Activated Carbon (Date Seed) Dosage.

Figure 5: Effect of Activated Carbon (Coconut Shell) Dosage.

Table 2 showed the compared performance of DSA and CSA. The percentage reduction of parameters was higher in DSA than CSA. They may be due to structural changes during activation and availability of more active sites on DSA. Table 2: Performance Comparison at Optimum Conditions Parameter DSA CSA DO 33.3% 25.6% COD 43.4% 37.4% TDS 66.4% 61.1% TSS 15.0% 5.3% BOD 96.6% 95.8% TOC 80.4% 79.2% Oil & Grease 99.9% 99.8%

4. CONCLUSIONS Activated carbons were prepared from waste date seeds (DSA) and coconut shells (CSA). The adsorbents were characterized before and after activation using SEM and XRD. The performance of DSA was marginally higher than CSA for the treatment of pollutants present in oil produced water (OPW). OPW was characterized before and after treatment using FT-IR and GCMS. The maximum percentage removal efficiency of DO=33.3%, COD=43.4%, TDS=66.4%, TSS=15%, BOD=96.6%, TOC=80.4% and oil & grease = 99.9% was achieved with DSA and DO=25.6%, COD=37.4%, TDS=61.1%, TSS=5.3%, BOD=96.6%, TOC=79.2%, and oil & grease=99.8% was achieved with CSA, respectively.

REFERENCES 1.

Huishu, L. 2013. Oil produced water quality characterization and prediction for Wattenberg field. Oil produced water, 3(2), p.36-75.

2.

AlAnezi, K., Belkharchouche, M., Alali, S. and Abuhaimed, W. 2012. Oil produced water characterization in Kuwait and its impact on environment∗. Desalination and Water Treatment, 56(5), p.35-66.

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Nasiri, M. and Jafari, I. 2017. Oil produced water from Oil-Gas Plants: A Short Review on Challenges and Opportunities. Oil produced water from Oil and Gas Plants, 61(2), p.73-81.

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Igunnu, E. and Chen, G. 2012. Oil produced water treatment technologies. International Journal of Low-Carbon Technologies, 9(3), p.157-177.

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A. Z. Rodriguez, H. Wang, L. Hu, Y. Zhang and P. Xu, 2020. Treatment of produced water in the permian basin for hydraulic fracturing: Comparison of different coagulation processes and innovative filter media, Water, 12(3), p.770.

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Hu, L.; Yu, J.; Luo, H.; Wang, H.; Xu, P.; Zhang, Y 2020. Simultaneous recovery of ammonium, potassium and magnesium from produced water by struvite precipitation. Chem. Eng. J., 382.

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J. M. Younker and M. E. Walsh, 2014. Bench-scale investigation of an integrated adsorption–coagulation–dissolved air flotation process for produced water treatment. J. Environ. Chem. Eng., 2, 692–697.

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A. S. Jafer and A. A. Hassan. 2019. Removal of oil content in oilfield produced water using chemically modified kiwi peels as efficient low-cost adsorbent, Journal of Physics: Conference Series, 1294 (7).

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P. C. Silva, N. P. Ferraz, E. A. Perpetuo and Y. J. O. Asencios. 2019 Oil produced water treatment using advanced oxidative processes: Heterogeneous-photocatalysis and photo-Fenton, Journal of sedimentary environments, 4(1); p.99-107.

10. Feroz, S., Murtuza Ali, S. and Furqan Butt. 2020. Plam oil bleaching using activated carbon prepared from neem leaves and waste tea. International Journal of Engineering Research and Technology. 13, p.557 11. Fathy, M., El-Sayed, M., Ramzi, M. and Abdelraheem, O. 2018. Adsorption separation of condensate oil from oil produced water using ACTF prepared of oil palm leaves by batch and fixed bed techniques. Egyptian Journal of Petroleum, 27(3), p.319-326.

12. Feroz, S., Khalid Al Saadi. Nageswara Rao, L, Varghese, M. 2017. Performance studies on solar photocatalysis and Photo Fenton process in treatment of polymer-based oil produced water, International Journal of Photochemistry. 3, p.1-6.

13. Feroz, S., M. A.A.Al Mashari., Varghese, M. Nageswara Rao, L .2017. Characterization and photocatalytic treatment of oil produced water using TiO2, International Journal of Applied Nanotechnology. 3, p.1-10.

AUTHORS PROFILES

Omar Hamyar Al-Abri Completed B.Sc in Chemical Engineering from National University of Science and Technology in Mechanical and Industrial Engineering department affiliated to VIT University, India.

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Dr. Lakkimsetty Nageswara Rao is presently working as Assistant Professor in Department of Mechanical & Industrial Engineering (Chemical Engineering) & Programme Manager Masters- Chemical Process Engineering at College of Engineering, National University of Science and Technology, Muscat, Sultanate of Oman. Dr. Rao has obtained his doctorate in the field of Chemical Engineering from Sri Venkateshwara University, India in the year 2013. He has worked with various organizations for 18 years which includes 6 years of research experience. Dr. Rao has 82 research publications to his credit in journals and 60 conferences of international/ National repute. He is a life member of the American Institute of Chemical Engineers, Indian Institute of Chemical Engineers, Institution of Engineers and I.S.T.E. His has a significant contribution as a peer reviewer for various reputed journals. Dr Rao has interest includes advance separation processes, Biochemical Engineering Nano-based treatment of wastewater & Environmental engineering.

Prof. Dr. Shaik. Feroz is presently working as Professor at Prince Mohammad Bin Fahd University, Al Khobar, Kingdom of Saudi Arabia. He has obtained his doctorate in the field of Chemical Engineering from Andhra University, India and Post Doc Research Fellow from Leibniz University, Germany. He has worked with various organizations for about 25 years which includes 5 years of Industrial and 20 years of teaching and research experience. Professor Feroz has more than 150 publications to his credit in journals and conferences of international repute. He is a life member of Indian Institute of Chemical Engineers and Institution of Engineers, India. He is also a member of Oman Society of Engineers and Environmental Society of Oman. Professor Feroz is associated as the Principal Investigator/CO-Investigator to a number of research projects and also involved as “Technology transfer agent” by Innovation Research Center, Sultanate of Oman. His has a significant contribution as Editorial member and peer reviewer for various reputed international journals and conferences. He was awarded “Best Researcher” by the Caledonian College of Engineering for the year 2014. Professor Feroz developed research links with various international research centers and his research interest includes solar nanophotocatalysis, solar desalination, solar photocatalytic hydrogen production and environmental engineering.

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