1 Sewage Sludge Drying with Microwave Irradiation: Guray Salihoğlu*, Sibel Yenikaya, N. Kamil Salihoğlu, Gokhan Yenikaya *D epartment of Environmental Engineering, University of Uludag, Bursa, 16059, Turkey Department of Electrical-Electronic Engineering, University of Uludag, Bursa, 16059, Turkey
Content 2 02 Materials & Methods 01 Introduction • Sludge 04 Dewatering & Conclusions Drying 03 Results & Discussion • Impact of the Factors on Drying • Microwave Modeling
Sludge Management 3 Mechanica Sludge Microwave Drying Additional Drying l Management • Can be a preferred • Increased calorifjc fuel ? • Large amounts Cement plant co- Dewaterin • 20-35 % DS step in sludge value and high g management • Easy handling incineration moisture • Heats the material • Reduced volume content • Cement plants use rapidly • WWTP Exit: 1- dried sewage sludge • Instant on/ofg control as a substitute for 4% DS • Increase the calorifjc fossil fuel value • Co-incineration in cement plants is possible
Objectives 4 • T o investigate the effjciency of microwave technology as a sludge drying method • T o compare the energy consumption with that of electrical heating • T o investigate the infmuence of the addition of ionic species such as salt to the drying performance
Materials & Methods 5 Mechanically dewatered Microwave Drying Monitoring sludge • 2.45 GHz : Resonance • Characterization • Moisture contents, frequency of water experiments: • Evaporation rates, molecules Composition, dielectric • Drying • Salt addition : 5% • Fixed & Rotary modes constants performances • Power: 900 W • Hot and cold • Time intervals: 1-10 regions minutes • Energy • Air cure : 10 minutes consumption • Thermal camera Electrical drying to compare the energy images consumption levels
Results & Discussion Fixed mode arison of moisture losses in fjxed and rotary operation modes provided concentrated heating and fjxed mode more evaporation > rotary mode 7TH INTERNATIONAL CONFERENCE ON SUSTAINABLE SOLID WASTE MANAGEMENT, 26-29 June 2019, Heraklion, Crete Island, Greece
Results & Discussion Salt addition arison of moisture losses in sludge with salt and without salt resulted in a lower level of moisture without salt loss > with 7TH INTERNATIONAL CONFERENCE ON SUSTAINABLE SOLID WASTE MANAGEMENT, 26-29 June 2019, Heraklion, Crete Island, Greece
Results & Discussion Higher arison of temperatures in sludge with salt and without salt temperatur e levels with salt with salt : 75.62±4.51 o C without salt: 65.19 ±4.06 o C evaporation? Low 7TH INTERNATIONAL CONFERENCE ON SUSTAINABLE SOLID WASTE MANAGEMENT, 26-29 June 2019, Heraklion, Crete Island, Greece
Dielectric characteristics of the Results & Discussion sludge studied Dielectric constant Relative dielectric (Relative loss factor: permittivity): Conversion ability of The ability to the energy into heat store the energy Low evaporation with salt ε ’’/ ε ’ ε ’ ε ’’ added sludge although (×10 -3 ) temperature levels are high? 76.22 10.18 0.134 Sludge without salt 58.18 18.90 0.325 Sludge with Salt addition to salt the sludge Measured by Network analyzer (Agilent, E506 1B) decreased the dielectric Salt addition might have changed Loss Tangent constant and the molecular structure of the High loss tangent is an increased the sludge limiting the evaporation. indication of the use of Salt might have associated with dielectric loss microwave power sludge water, thereby might have transferred into heat factor , thus decreased the free water and increased the converted it into bound water 7TH INTERNATIONAL CONFERENCE ON SUSTAINABLE SOLID WASTE MANAGEMENT,26-29 June 2019, Heraklion, Crete Island, Greece dissipation (capillary or particle).
Electric fjeld distribution Maximum 10 intensity when the oven is empty when the sewage sludge sample was ins tric fjeld is stronger near the walls of the oven • When the sample was placed, electromagnetic waves were refmected from • The distribution is symmetrical relative the oven walls and the sample surface. • Therefore the electric fjeld was dense on to the XZ plane the corner points of the tray 7TH INTERNATIONAL CONFERENCE ON SUSTAINABLE SOLID WASTE MANAGEMENT,26-29 June 2019, Heraklion, Crete Island, Greece
Energy Consumption: Electrical 11 ∼ Microwave 30% moisture loss Less time and 30% moisture loss energy consumption duration less energy Microwave : 0.231 with Microwave : 10 min. kW Electrical: 30 min. microwave Electrical: 0.444 kW
Conclusions 12 Salt addition • Decreased the moisture loss Moisture loss • Decreased the dielectric constant Fixed mode > rotary mode • Increased uniform heat distribution Concentrated heating in the fixed mode Less Time and Less Energy with Microwave Electrical drying consumed more energy Electric field was dense on the for a certain moisture corner points of the tray, more loss targeted in sludge. evaporation Evaporation continued during air cure after drying. 7TH INTERNATIONAL CONFERENCE ON SUSTAINABLE SOLID WASTE MANAGEMENT,26-29 June 2019, Heraklion, Crete Island, Greece
13 7TH INTERNATIONAL CONFERENCE ON SUSTAINABLE SOLID WASTE MANAGEMENT,26-29 June 2019, Heraklion, Crete Island, Greece
References 14 1. Yu, Q., Lei, H.Y ., Yu, G.W., Feng, X., Li, Z.X., Wu, Z.C.: Infmuence of microwave irradiation on sludge dewaterability. Chem Eng J 155 (1-2), 88-93 (2009). doi:10.1016/j.cej.2009.07.010 2. Gil, A., Siles, J.A., Martin, M.A., Chica, A.F ., Estevez-Pastor, F .S., T oro-Baptista, E.: Efgect of microwave pretreatment on semi-continuous anaerobic digestion of sewage sludge. Renewable Energy 115 , 917-925 (2018). doi:10.1016/j.renene.2017.07.112 3. Kumar, S., Kumar, R., Mehrotra, S.P .: Infmuence of granulated blast furnace slag on the reaction, structure and properties of fmy ash based geopolymer. J Mater Sci 45 (3), 607-615 (2010). doi:10.1007/s10853-009-3934-5 4. Mawioo, P .M., Garcia, H.A., Hooijmans, C.M., Velkushanova, K., Simonic, M., Mijatovic, I., Brdjanovic, D.: A pilot-scale microwave technology for sludge sanitization and drying. Science of the T otal Environment 601-602 , 1437-1448 (2017). 5. Domínguez, A., Menéndez, J.A., Inguanzo, M., Pis, J.J.: Sewage sludge drying using microwave energy and characterization by IRTF . Afjnidad 61 (512), 280-285 (2004). 6. Bennamoun, L., Chen, Z., Afzal, M.T.: Microwave drying of wastewater sludge: Experimental and modeling study. Drying T echnology 34 (2), 235-243 (2016). 7. Jinping, L., Jinhua, G., Jieqiong, J., Ni, W.: Study on New Thermal Drying Methods for Sewage Sludge Using Microwave and its Mechanism. Aer Adv Eng Res 30 , 1103-1108 (2015). 8. T yagi, V.K., Lo, S.L.: Microwave irradiation: A sustainable way for sludge treatment and 7TH INTERNATIONAL CONFERENCE ON SUSTAINABLE SOLID WASTE MANAGEMENT,26-29 June 2019, Heraklion, Crete Island, Greece resource recovery. Renew Sust Energ Rev 18 , 288-305 (2013).
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