This work deals with the
effect of combined microwave-ultrasonic pretreatment on the anaerobic
biodegradability of primary, excess activated and mixed sludge. The
characteristics, biodegradability and anaerobic digester performance for
untreated primary, excess activated and mixed sludge were compared to combined
microwave-ultrasonic pretreated primary, excess activated and mixed sludge. All
sludge samples were subjected to Microwave treatment at 2450 MHz, 800 W and 3
min followed by ultrasonic treatment at a density of 0.4 W/mL, amplitude of
90%, Intensity of 150W, pulse of 55/5 for 6min. Methane production in pretreated primary
sludge was significantly greater (11.9ml/g
TCOD) than the methane
yield of the untreated primary sludge (7.9 ml/g TCOD). Cumulative methane production of
pretreated Excess Activated Sludge (EAS) was higher (66.5 ml/g TCOD) than the
methane yield from pretreated mixed sludge (44.1 ml/g TCOD). Furthermore,
digested EAS showed significantly higher dewaterability (201s) than digested primary sludge (305s) or mixed sludge (522s). The average Methane:
Carbondioxide ratio from EAS (1.85) was higher than that for mixed untreated
sludge (1.24). VS reduction was also higher for EAS than the other two sludge
types. However, pretreatment of EAS resulted in significant reduction in
dewaterability due to higher percentage of fine floc particles in the
Cite this paper
Mesfin Yeneneh, A. , Kanti Sen, T. , Chong, S. , Ming Ang, H. and Kayaalp, A. (2013) Effect of Combined Microwave-Ultrasonic Pretreatment on Anaerobic Biodegradability of Primary, Excess Activated and Mixed Sludge. Computational Water, Energy, and Environmental Engineering, 2, 7-11. doi: 10.4236/cweee.2013.23B002.
 W. J. Park, “Effects of Microwave Pretreatment on Mesophilic Anaerobic Digestion for Mixture of Primary and Secondary Sludges Compared with Thermal Pretreatment,” Environmental Engineering Research, Vol. 16, No. 2, 2011, pp. 103-109. doi:10.4491/eer.2011.16.2.103
 S. Chong, T. K. Sen, A. Kayaalp et al., “The Performance Enhancements of Upflow Anaerobic Sludge Blanket (UASB) Reactors for Domestic Sludge Treatment–A State-of-the-art Review,” Water research, Vol. 46, No. 11, 2012. pp. 3434-3470. doi:10.1016/j.watres.2012.03.066
 A. Tiehm, K. Nickel and U. Neis, “The Use of Ultrasound to Accelerate the Anaerobic Digestion of Sewage Sludge,” Sludge Rheology and Sludge Management, Vol. 36, No. 11, 1997, pp. 121-128.
 H. Carrère, C. Dumas, A. Battimelli, et al., “Pretreatment Methods to Improve Sludge Anaerobic Degradability: A Review,” Journal of Hazardous Mate-rials, Vol. 183, No. 1, 2010, pp. 1-15. doi:10.1016/j.watres.2012.03.066
 V. K. Tyagi and S.-L. Lo, “Application of PhysicoChemical Pretreatment Methods to Enhance the Sludge Disintegration and Subsequent Anaerobic Digestion: An up to Date Review,” Reviews in Environmental Science and Bio/Technology, Vol. 10, No. 3, 2011, pp. 215-242. doi:10.1016/j.watres.2012.03.066
 C. Eskicioglu, K. J. Kennedy and R. L. Droste, “Characterization of Soluble Organic Matter of Waste Activated Sludge before and after Thermal Pretreatment,” Water research, Vol. 40, No. 20, 2006, pp. 3725-3736. doi:10.1016/j.watres.2006.08.017
 C. Bougrier, C. Albasi, J. Delgenes, et al., “Effect of Ultrasonic, Thermal and Ozone Pretreatments on Waste Activated Sludge Solubilisation and Anaerobic Biodegradability,” Chemical Engineering and Processing, Vol. 45, No. 8, 2006, pp. 711-718.
 L. Appels, R. Dewil, J. Baeyens, et al., “Ultrasonically Enhanced Anaerobic Digestion of Waste Activated Sludge,” International Journal of Sustainable Engineering, Vol. 1, No. 2, 2008, pp. 94-104. doi:10.1080/19397030802243319
 O. G. Apul and F. D. Sanin, “Ultrasonic Pretreatment and Subsequent Anaerobic Digestion under Different Operational Conditions,” Bioresource technology, Vol. 101, No. 23, 2010, pp. 8984-8992.
 C. Eskicioglu, K. J. Kennedy and R. L. Droste, “Enhancement of Batch Waste Activated Sludge Digestion by Microwave Pretreatment,” Water Environment Research, Vol. 79, No. 11, 2007, pp. 2304-2317.
 B. W. Zhou, S. G. Shin, K. Hwang, et al., “Effect of microwave irradiation on cellular disintegration of Gram positive and negative cells,” Applied Microbiology and Biotechnology, Vol. 87, No. 2, 2010, pp. 765-770. doi:10.1007/s00253-010-2574-7
 M. Saha, C. Eskicioglu and J. Marin, “Microwave, Ultrasonic and Chemo-Mechanical Pretreatments for Enhancing Methane Potential of Pulpmill Wastewater Treatment Sludge,” Bioresource Technology, Vol. 102, No. 17, 2011, pp. 7815-7826. doi:10.1016/j.biortech.2011.06.053
 N. Saifuddin and S. Fazlili, “Effect of Microwave and Ultrasonic Pretreatments on Biogas Production from Anaerobic Digestion of Palm Oil Mill Effleunt,” American Journal of Engineering and Applied Sciences, Vol. 2, 2009.
 G. Xu, S. Chen, J. Shi, et al., “Combination Treatment of Ultrasound and Ozone for Improving Solubilisation and Anaerobic Biodegradability of Waste Activated Sludge,” Journal of Hazardous Materials, Vol. 180, No. 1-3, 2010, pp. 340-346. doi:10.1016/j.jhazmat.2010.04.036
 C. Eskicioglu, A. Prorot, J. Marin, et al., “Synergetic Pretreatment of Sewage Sludge by Microwave Irradiation in Presence of H2O2 for Enhanced Anaerobic Digestion,” Water Research, Vol. 42, No. 18, 2008, pp. 4674-4682. doi:10.1016/j.watres.2008.08.010
 A. M. Yeneneh, S. Chong, T. K. Sen, et al., “Effect of Ultrasonic, Microwave and Combined Microwave–Ultrasonic Pretreatment of Municipal Sludge on Anaerobic Digester Performance,” Water, Air, & Soil Pollution, Vol. 224, No. 5, 2013, pp. 1-9.
 H. Zhang, “Sludge Treatment to Increase Biogas Production,” Trita-LWR Degree Project, 2010, pp. 10-20.
 APHA, AWWA, and WEF, “Standard methods for the examination of water and wastewater,” American Public Health Association, American Water Works Association and Water Environment Federation, 2000.
 C. Eskicioglu, K. Kennedy and R. Droste, “Initial Examination of Microwave Pretreatment on Primary, Secondary and Mixed Sludges before and after Anaerobic Digestion,” Water Science and technology, Vol. 57, No. 3, 2008, pp. 311-318. doi:10.2166/wst.2008.010