Diesel Fuel Contaminated Water Treatment by Sonication: a Potential 20-Minute Sump and Stormwater Remedy Presented by: Roxanne Bessette, E.I. Co-author: Dr. Robert W. Peters, P.E. UAB Department of Civil, Construction, and Environmental Engineering Presented at the 2007 Alabama Water Resources Conference, Orange Beach, AL, September 5-7, 2007.

Situation: Diesel Usage = Diesel Spills = Receiving Waters Impacted

Current Treatment: Gravity Phase Separation and Mechanical Recovery

Limitations of Current Treatment Cannot handle large spills rapidly; Cannot handle peak storm flows of the Southeastern U.S.; Minimal removal at <100mg/L, NPDES O&G discharge limit is usually 15 mg/L; and Overflow must be sent to local POTW at a per gallon service charge ($$$$!).

Sonochemical Treatment: Unique Aspects Organic compounds rapidly oxidized (seconds to minutes) Rapid emulsification of immiscible liquids (seconds) Extreme conditions on the micro-scale with ambient bulk solution conditions

Acoustically Induced Cavitation

Cavitation: Quick Overview Microbubble is spherical at first and then shrinks rapidly Microbubble formed near solid surface yielding an asymmetric implosion expelling a ~400 kph liquid jet The jet develops opposite the solid surface and moves towards it Implosion heats gases to ~5,500ºC Pressure ~ atm at collapsing interface Microbubble shown is ~150 μm …can be much larger depending on kHz Source: Suslick, Scientific American Feb 1989

Acoustical Cavitation = Micro High Energy Rapidly Quenched In less than a μs, implosion energy causes: Ionization N 2  NO x  NO 2 - Radical Creation O 2 and H 2 O  OH  Luminescence Visible and UV Pressures of ~500 atm Temperatures of ~5,500 o C for gases ~2,100 o C for immediately surrounding liquid

Bench-Scale Treatment Method Initial Off Road No. 2 Diesel Fuel Concentration: 195 mg/L Volume Treated: 100 mL Sonicator Frequency: 20 kHz Sonicator Max Power Output: 950 W Experimental Conditions Sonication Equipment: Branson 910 BC Power Supply and 902 J Converter

Bench-Scale Treatment Method Experimental Matrix RepTime Sonicated (min) 1CV0255 DUP 5 MS 1020IBMeth BlK 2CV0255 DUP 1010 MS 20IB 3CV0255 DUP 5 MS 1020IB CV= Calibration Verification; DUP= Duplicate Sample; MS=Matrix Spike; IB=Instrument Blank; Meth Blk=Method Blank

Bench-Scale Analytical Method Sample Preparation by SW C Separatory Funnel Liquid to Liquid Extraction

Sample Analysis by SW B Nonhalogenated Organics Using GC/FID Bench-Scale Analytical Method

Bench-Scale Diesel Sump Water Treatment Results

Electrical Energy per Mass of Contaminate Removed (kWh/kg) EE/M= (10 6 ) P t (60) V (C i -C f ) where: P = Power, (kW) t = treatment time, (min) V = Volume of Treated Solution, (L) C i = Initial Contaminate Concentration, (mg/L) C f = Final Contaminate Concentration, (mg/L) 93% removal of No. 2 Diesel Fuel requires 8,203.8 kWh/kg ( kWh/mg) This number is approximately 3-4 fold greater than the TCE and CCl 4 sonication energy requirements found by Peters, et al. (2005); Paper presented at the 15 th Annual AEHS Meeting and West Coast Conference on Soils, Sediments, and Water, San Diego, CA.

Published Sonochemical Degradation Rates of Various Organic Compounds (Reality Check) CompoundSonication Condition k (min –1 ) (Mass Transfer Rate Constant) Source 2,4,6-trinitrotoluene (TNT) 20kHz M.R. Hoffmann et al., Ultrasonics Sonochemistry 3 (1996) S163-S172 Carbon Tetrachloride 20 kHz, 130W Chlorophenol20 kHz, 96W Ku et al., Water Res. 31 (1997) Anthracene (PAH) 20kHz, 600W Z. Laughrey et al., Ultrasonics Sonochemistry 8 (2001) Phenanthrene (PAH) Pyrene (PAH) Styrene (Hydrocarbon) 520kHz, 14.6W De Visscher et al., J. Phys. Chem., 100 No.28 (1996) Ethylbenzene (Hydrocarbon)

Removal Efficiencies Comparison Belt Strippers (common current technology) [O&G]* mg/L10, Oil/water removal efficiency per API** 90%50%MinimalCommon NPDES Discharge Limit *DRO is a subgroup of O&G **Removal time frame commonly on the order of hours to days Sonication (proposed technology) 198 mg/L No.2 Off-road Diesel 95% removed  10 mg/L in 20 min

Bench-Scale Diesel Sump Water Treatment Conclusions Sonochemical Treatment Potential Rapid treatment to handle storm event runoff (minutes vs. days) Exceeds gravity separation treatment efficiency by 45% kWh/mg removal energy requirement for ~200mg/L initial concentration Tested conditions achieves NPDES discharge standard of 15 mg/L

Acknowledgements Dr. Robert W. Peters, P.E. -for opportunities and encouragement UAB Department of Civil, Construction, and Environmental Engineering -for research facilities support Sound Environmental Practice LLC -for funding

Thanks for this opportunity….Questions?