Electro-kinetic dewatering of oily sludges.

An oily sludge from a rendering facility was treated using electro-kinetic (EK) techniques employing two different experimental designs. The bench scale used vertical electrodes under different operational conditions, i.e. varied electrode spacing at 4, 6 and 8 cm with electric potential of 10, 20 and 30 V, respectively. The highest water removal efficiency (56.3%) at bench scale was achieved at a 4 cm spacing and 30 V. Comparison of the water removal efficiency (51.9%) achieved at the 20 V at 4 cm spacing showed that power consumption at 30 V was 1.5 times larger than that at 20 V, suggesting a further increase of electric potential is unnecessary. The solids content increased from an initial 5 to 11.5 and 14.1% for 20 and 30 V, respectively. The removal of oil and grease (O&G) was not significant at this experimental design. Another larger scale experiment using a pair of horizontal electrodes in a cylinder with 15 cm i.d. was conducted at 60 V at an initial spacing of 22 cm. More than 40.0% of water was removed and a very efficient oil separation from the sludge was achieved indicating the viability of electro-kinetic recovery of oil from industrial sludge.

[1]  C. Knowles,et al.  Electrokinetic remediation of metals and organics from historically contaminated soil , 2000 .

[2]  J. Q. Shang,et al.  Effects of electrode materials and current intermittence in electro-osmosis , 2001 .

[3]  C. J. Athmer,et al.  Scale-up aspects of the Lasagna™ process for in situ soil decontamination , 1997 .

[4]  K. Lo,et al.  Electroosmotic strengthening of soft sensitive clays , 1991 .

[5]  H. N. Stein,et al.  Full scale electrokinetic dewatering of waste sludge , 2002 .

[6]  C. Bennett,et al.  Momentum, Heat, and Mass Transfer , 1962 .

[7]  W. Stahl,et al.  Improvement of filtration kinetics by pressure electrofiltration , 2002 .

[8]  A. Cundy,et al.  Electrokinetic iron pan generation in unconsolidated sediments: implications for contaminated land remediation and soil engineering , 2005 .

[9]  Petri Latostenmaa,et al.  Electrokinetic soil remediation--critical overview. , 2002, The Science of the total environment.

[10]  Z. Zorin,et al.  Measurement of viscosity of liquids in quartz capillaries , 1970 .

[11]  D. R. Crow.  Principles and Applications of Electrochemistry , 1974 .

[12]  A. E. Greenberg,et al.  Standard methods for the examination of water and wastewater : supplement to the sixteenth edition , 1988 .

[13]  Shiva Habibi.  A new electrokinetic technology for revitalization of oily sludge , 2004 .

[14]  Chih-Huang Weng,et al.  Sludge Dewatering By Electrokinetic Technique: Effect Of Processing Time And Potential Gradient , 2003 .

[15]  Ronald L. Droste,et al.  Theory And Practice Of Water And Wastewater Treatment , 1996 .

[16]  I. Neretnieks,et al.  Electroremediation: Removal of Heavy Metals from Soils by Using Cation Selective Membrane , 1998 .

[17]  Philip H. Brodsky,et al.  The Lasagna Technology for In Situ Soil Remediation. 2. Large Field Test , 1999 .