title: Electrochemical pretreatment of waste activated sludge: effect of process conditions on sludge disintegration degree and methane production.
abstract: Waste activated sludge (WAS) requires a long digestion time because of a rate-limiting hydrolysis step - the first phase of anaerobic digestion (AD). Pretreatment can be used prior to AD to facilitate the hydrolysis step and improve the efficiency of WAS digestion. This study evaluated a novel application of electrochemical (EC) technology employed as the pretreatment method prior to AD of WAS, focusing on the effect of process conditions on sludge disintegration and subsequent AD process. A superior process condition of EC pretreatment was obtained by reaction time of 30 min, electrolysis voltage of 20 V, and electrode distance of 5 cm, under which the disintegration degree of WAS ranged between 9.02% and 9.72%. In the subsequent batch AD tests, 206 mL/g volatile solid (VS) methane production in EC pretreated sludge was obtained, which was 20.47% higher than that of unpretreated sludge. The AD time was 19 days shorter for EC pretreated sludge compared to the unpretreated sludge. Additionally, the EC + AD reactor achieved 41.84% of VS removal at the end of AD. The analysis of energy consumption showed that EC pretreatment could be effective in enhancing sludge AD with reduced energy consumption when compared to other pretreatment methods.
authors.affiliation: a School of Environmental Science and Engineering , Shanghai Jiao Tong University , Shanghai , People's Republic of China.
authors.forename: Caihong
authors.initials: C
authors.lastname: Ye
authors.affiliation: a School of Environmental Science and Engineering , Shanghai Jiao Tong University , Shanghai , People's Republic of China.
authors.forename: Haiping
authors.initials: H
authors.lastname: Yuan
authors.affiliation: b National Engineering Research Center for Urban Pollution Control, School of Environmental Science and Engineering , Tongji University , Shanghai , People's Republic of China.
authors.forename: Xiaohu
authors.initials: X
authors.lastname: Dai
authors.affiliation: a School of Environmental Science and Engineering , Shanghai Jiao Tong University , Shanghai , People's Republic of China.
authors.forename: Ziyang
authors.initials: Z
authors.lastname: Lou
authors.affiliation: a School of Environmental Science and Engineering , Shanghai Jiao Tong University , Shanghai , People's Republic of China.
authors.forename: Nanwen
authors.initials: N
authors.lastname: Zhu
mesh_terms: D000693:Anaerobiosis; D057919:Biological Oxygen Demand Analysis; D055664:Electrochemical Techniques; D004566:Electrodes; D006868:Hydrolysis; D008697:Methane / Q000378:metabolism; D012722:Sewage; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D012722:Sewage; D008697:Methane
keywords: VS removal; Waste activated sludge; anaerobic digestion; electrochemical pretreatment; methane production