DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING KING FAHD UNIVERSITY OF PETROLEUM & MINERALS

1. DEPARTMENT OF CIVIL & ENVIRONMENTAL ENGINEERING KING FAHD UNIVERSITY OF PETROLEUM & MINERALS World Environment Day 2013 (WED13) THEME: Think.Eat.Save CHALLENGES IN THE ELECTROKINETIC REMEDIATION OF NATURAL SAUDI ARABIAN SOIL FOR AGRICULTURE: EFFECTS OF SALINITY AND SODICITY Presenter: S. Lukman Authors: N.D. Mu’azu, S. Lukman, M.H.Essa and M.S. Al-Suwaiyan Host: Royal Commission for Jubail: Environmental Protection and Control Department 5th June, 2013

2. Outline • Introduction • Justification, problem statement, objectives & uniqueness • Literature background • Materials and methods • Results and discussion • Conclusion • Recommendations • Acknowledgement

3. Introduction Saline-sodic soils • High electrical conductivity ( > 4 dS/m) • High pH > 8.2 • Dominated by 2:1 type clay minerals, e.g. montmorillonite • ESP (exchangeable sodium percentage) > 15 • Source: Abrol et al., 1980; Abrol et al. 1988 • Major sources of soluble salts in soils: weathering of primary minerals and native rocks, residual fossil salts, atmospheric deposition, saline irrigation and drainage waters, saline groundwater, seawater intrusion, additions of inorganic and organic fertilizers, sludges and sewage effluents, brines from natural salt deposits, and brines from oil and gas fields and mining (Jurinak and Suarez, 1990; Tanji, 1990). 3

4. Introduction (Cont’d) Saline-sodic soils and plant growth • Lowers the permeability of the soil to air and water • Lowers the availability of some essential plant nutrients • Accumulates certain elements in plants at toxic levels, e.g. Na • Tolerance of various crops to exchangeable sodium (ESP) (Abrol et al. 1988) 4 4

5. Introduction (Cont’d) Saline-Sodic Soils and Contamination • Soil contamination by mixed pollutants • Decontamination challenge for low permeability/heterogeneous soils • In situ soil remediation – The LasagnaTM process Fig. 1: Typical horizontal and vertical configurations of the LasagnaTM process- Transport mechanisms (Ho et al. 1995)

6. Problem Statement • Low permeability soils • Mixed contaminants – HMs (Zn, Cu, Cr, Pb, Cd) & kerosene, phenol • - Synergistic or antagonistic effects • Saline-sodic soil • Need for low cost adsorbent

7. Objectives • Explore the possibility of remediating saline-sodic soils using integrated electrokinetics-adsorption technique • Understand the challenges involved in remediating saline-sodic soils using the technique

8. Uniqueness of the Research • Remediation of Mixed contaminants: Multiple heavy metals, petroleum hydrocarbons and organic pollutant • This is the first study to investigate remediation of saline-sodic soil using electrokinetics-adsorption technique

9. Literature Review • Lasagna Process: From Inception to Date Fig. 2: Integrated segments behind the integrated electrokinetics-adsorption technology

10. Literature Review (Cont’d)

11. Literature Review (Cont’d) Table 3: Characteristics of the Lasagna process and competing technologies (Ho et al. 1999)

12. Materials & Methods Preparation, Production and Characterization of Clay and GAC Clay Xtics pH Moisture content Soil organic matter Hydraulic conductivity Electrical conductivity Specific surface area Pore volume Specific gravity Plastic limit Plasticity index Particle size distribution Particle size distribution

13. Materials & Methods (Cont’d) Bench-Scale Integrated Electrokinetics-Adsorption Study Reactor Design and Experimental Procedures Plate 7: Reactor for electrokinetics-adsorption studies

14. Plate 8: Complete experimental setup

15. Materials & Methods (Cont’d) Analytical Procedures for Contaminant Extraction and Analysis • Heavy Metals- • Digestion-EPA Method 3050B for acid digestion of soils, sediments and sludges • Quantitation-EPA Method 7000B for HM analysis using FLAA (Aanalyst 700, PE) • Mercury-EPAMethod 7473 for mercury analysis in solids and solutions by thermal decomposition, amalgamation, and AAS (SMS 100, PE) • Kerosene and Phenol: • Extraction-EPA Method 3540C for extracting semi-volatile and non-volatile organics from soil matrixes (Soxhlet extraction) • Method 3545 for pressurized fluid extraction (ASE 200, Dionex) • Temp program- The initial temperature was set at 50 0 C, ramped at 10 0 C/min to 300 0 C and held at this temperature for 9 min (33 min)

16. Materials & Methods (Cont’d) • Data Reliability – Accuracy and repeatability, QC protocols • Accuracy – • RSD • Precision – • QC/QA Protocols – ICB and ICV, CCB and CCV

17. Results & Discussion Characteristics of the Saline-Sodic Soil (Lukman et al. 2013)

18. Results & Discussion (Cont’d) • XRD and SEM • Table 7: Mineralogical composition Table 8: Elemental composition

19. Results & Discussion (Cont’d) Experimental design • 3 experiments were conducted using100 mg/kg for each contaminant • EK-GAC-1: 1 V/cm • EK-GAC-2: 0.6 V/cm • EK : 0.6 V/cm

20. Results & Discussion (Cont’d) Soil pH distribution Presence of calcite in the soil minerals 20

21. Results & Discussion (Cont’d) Soil Electrical Conductivity Pristine clay EC = 27.6 dS/m 21 21

22. Results & Discussion (Cont’d) Variations of current, temperature and cumulative electroosmotic flow • High current flow (due to salinity) through the soil may have significant impacts: • Average Current: EK-GAC-1: 0.88 A (Max. 2.8A), EK-GAC-2: 0.61 A and EK: 0.71 A • 2 – 3 orders of magnitude higher than those obtained in similar studies • Soil temperature (Ave): EK-GAC-2: 28.5 oC (Max. 34.6 oC) and EK: 30 oC (Max. 40.5 oC) • Our finding from this study reveals that increasing the voltage gradient more than 1 V/cm leads to considerable rise in the soil temperature which may not be neglected for practical purposes • EO flow (Ave): EK-GAC-2: PV=0.75 (Vol. 1388 mL ) and EK: PV=0.66 (Vol. 1214 mL) • Maximum temperature and electroosmotic flow recorded coincided with the period in which maximum current was recorded • Electrode corrosion: Higher in EK-GAC-1 than in EK-GAC-2 and EK • Process fluid recycle frequency: C1 = 16 times, A1 = 9 times, C2 = 18 times, A2 = 11 times • 2 N NaOH and 1 N HNO3were used as the anolyte and catholyte respectively • Energy consumption: EK-GAC-1: 8.2kWhr/m3, EK-GAC-2: 3.4kWhr/m3 and EK: 4kWhr/m3 22 22

23. Results & Discussion (Cont’d) Contaminant removal efficiency

24. Results & Discussion (Cont’d) Theoretical solubilities of some metal hydroxides versus pH (Weiner, 2008)

25. Conclusion • Phenol and Zn were found to have the highest and lowest removal efficiency • Soil salinity was found to be responsible for the following: • excessive soil heating • reduction in the soil moisture content • high energy and process fluid consumption • high EC and electroosmotic flow rate • Overall, integrating electrokinetics with adsorption using locally produced GAC from date palm pits is a promising solution to removal of heavy metals and organics from contaminatedsodic soils

26. Recommendations • Different types of electrodes should be investigated for this type of soil • Optimization of operating parameters affecting percent removal such as: • voltage gradient • polarity reversal rate • pulse and continuous current applications • Pilot scale implementation of the study 26

27. Acknowledgement The authors would like to acknowledge the support provided by King Abdul-Aziz City for Science and Technology (KACST) through the Science & Technology Unit at King Fahd University of Petroleum & Minerals (KFUPM) for funding this work through Project No. 11-Env1669-04, as part of the National Science, Technology and Innovation Plan.

28. References • Abrol, I.P., Chhabra, R. and Gupta, R.K. (1980). “A fresh look at the diagnostic criteria for sodic soils.” In: Int. Symp. on Salt Affected Soils. Central Soil Salinity Research Institute, Karnal. February 18-21, 1980. • Abrol, I. P., Yadav, J. S. P., and Massoud, F. I. (1988). "Salt-Affected Soils and Their Management," Food and Agriculture Organization of the United Nations. • Jurinak, J.J., and Suarez, D.L. (1990). “The chemistry of salt-affected soils and water. In “Agricultural Salinity Assessment and Management.” (K.K. Tanji, ed.), ASCE Manuals Prac. No. 71, pp. 42–63. Am. Soc. Civ. Eng., New York. • Tanji, K.K., ed. (1990). “Nature and extent of agricultural salinity.” In:AgriculturalSalinity Assessment and Management (K.K. Tanji, ed.), ASCE Manuals Prac. No. 71, Am. Soc. Civ. Eng., New York. • Ho, S. V., Sheridan, P. W., Athmer, C. J., Heitkamp, M. A., Brackin, J. M., Weber, D., and Brodsky, P. H. (1995). “Integrated In Situ Soil Remediation Technology: The Lasagna Process.” Environmental Science & Technology 29, 2528-2534. • Ho, S. V., Hughes, B. M., Brodsky, P. H., Merz, J. S., and Egley, L. P. (1999). “Advancing the use of an innovative cleanup technology: Case study of Lasagna™.” Remediation Journal9, 103-116. • S. Lukman, EssaM.H., Nuhu D. Mu’azu, Bukhari A. and C. Basheer (2013), "Adsorption and Desorption of Heavy Metals onto Natural Clay Material: Effect of pH." Journal of Environmental Science and Technology, 6 (1): 1 - 15. • Weiner, E. R. (2008). "Applications of environmental aquatic chemistry: a practical guide." Taylor & Francis Group. 28

29. Thank you for listening