title: Use of microwave pretreatment for enhanced anaerobiosis of secondary sludge.
abstract: This work elucidates the effects of pretreatment of secondary sludge by microwave irradiation on anaerobic digestion. The soluble chemical oxygen demand (COD) concentration increased up to 22% as microwave irradiation time increased, which indicated the sludge particles disintegrated. Three identical automated bioreactors with working volume of 5 l were used as anaerobic digesters at mesophilic temperature (35 degrees C). The reactors were separately fed with sludge with microwave pretreated- and control- sludge at different hydraulic retention times (HRT). The volatile solid (VS) reduction in the control operation was approximately 23.2 +/- 1.3%, while it was 25.7 +/- 0.8% for the reactors with the pretreated sludge. The average biogas production rate with the pretreated sludge at 8, 10, 12, and 15 days HRTs was 240 +/- 11, 183 +/- 9, 147 +/- 8, and 117 +/- 7 ml/l/d respectively, while those with the control sludge were 134 +/- 12 and 94 +/- 7 ml/l/d at 10 and 15 days HRTs. Maximum rates of COD removal and methane production with the pretreated sludge were 64% and 79% higher than those of the control system, respectively.
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Nam-gu, Pohang, Kyungbuk 790-784, South Korea. sludge@postech.ac.kr
authors.forename: B
authors.initials: B
authors.lastname: Park
authors.forename: J H
authors.initials: JH
authors.lastname: Ahn
authors.forename: J
authors.initials: J
authors.lastname: Kim
authors.forename: S
authors.initials: S
authors.lastname: Hwang
mesh_terms: D000693:Anaerobiosis; D007723:Korea; D008697:Methane / Q000378:metabolism; D008872:Microwaves; D010100:Oxygen / Q000032:analysis; D012722:Sewage / Q000032:analysis / Q000737:chemistry*; D018505:Waste Management / Q000191:economics / Q000379:methods*
chemical_list: D012722:Sewage; D008697:Methane; D010100:Oxygen