Unraveling oxidation behaviors for intracellular and extracellular from different oxidants (HOCl vs. H₂O₂) catalyzed by ferrous iron in waste activated sludge dewatering

TY - JOUR

T1 - Unraveling oxidation behaviors for intracellular and extracellular from different oxidants (HOCl vs. H2O2) catalyzed by ferrous iron in waste activated sludge dewatering

AU - Yu, Wenbo

AU - Wen, Qianqian

AU - Yang, Jiakuan

AU - Xiao, Keke

AU - Zhu, Yuwei

AU - Tao, Shuangyi

AU - Lv, Yang

AU - Liang, Sha

AU - Fan, Wei

AU - Zhu, Suiyi

AU - Liu, Bingchuan

AU - Hou, Huijie

AU - Hu, Jingping

N1 - Publisher Copyright: © 2018 Elsevier Ltd

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Cell lysis in sludge pretreatment by advanced oxidation process (AOP) has a great effect on sludge dewaterability. Cell lysis caused by reactive radicals (e.g. hydroxyl radical) was dependent on the reaction site of AOP. However, little is known about the accurate radical generation site of AOP in sludge pretreatment. In this study, two kinds of oxidation behaviors from different oxidants (HOCl vs. H2O2) catalyzed by ferrous iron were comparatively investigated. Higher amount of living cells (84.3%) and hydroxyl radicals (9.86 × 10−5 M), and more fragmentized sludge flocs (particle sizes of D50 was 50.1 vs. 57.3 μm of RS) were detected in sludge conditioned by Fe2+/H2O2, which implied that Fenton reaction mainly happened at surface and outside of sludge flocs (such as EPS layer and liquid phase). Thus, it could be regarded as “extracellular oxidation”. Fewer living cells (undetectable), fewer amount of hydroxyl radicals (undetectable in sludge), and more integrated sludge flocs (particle size of D50 was 56.1 vs. 57.3 μm of RS) were determined in sludge conditioned by Fe2+/Ca(ClO)2. Hence, it could be regarded as “Intracellular oxidation”. In addition, sludge pretreatment based on Fe2+/Ca(ClO)2 could achieve simultaneous deep-dewatering performance and total coliforms inactivation. Based on response surface methodology, the optimal dosages of Fe2+ and Ca(ClO)2 were proposed as 106.1 and 234.5 mg/g volatile solids respectively, without any acidification of sludge. Under these optimal dosages, the water content of dewatered sludge cake was 51.9 ± 0.1 wt% and the pH of the final filtrate was 5.8 ± 0.2. Total coliforms of sludge could be inactivated in 10 s after Fe2+/Ca(ClO)2 addition.

AB - Cell lysis in sludge pretreatment by advanced oxidation process (AOP) has a great effect on sludge dewaterability. Cell lysis caused by reactive radicals (e.g. hydroxyl radical) was dependent on the reaction site of AOP. However, little is known about the accurate radical generation site of AOP in sludge pretreatment. In this study, two kinds of oxidation behaviors from different oxidants (HOCl vs. H2O2) catalyzed by ferrous iron were comparatively investigated. Higher amount of living cells (84.3%) and hydroxyl radicals (9.86 × 10−5 M), and more fragmentized sludge flocs (particle sizes of D50 was 50.1 vs. 57.3 μm of RS) were detected in sludge conditioned by Fe2+/H2O2, which implied that Fenton reaction mainly happened at surface and outside of sludge flocs (such as EPS layer and liquid phase). Thus, it could be regarded as “extracellular oxidation”. Fewer living cells (undetectable), fewer amount of hydroxyl radicals (undetectable in sludge), and more integrated sludge flocs (particle size of D50 was 56.1 vs. 57.3 μm of RS) were determined in sludge conditioned by Fe2+/Ca(ClO)2. Hence, it could be regarded as “Intracellular oxidation”. In addition, sludge pretreatment based on Fe2+/Ca(ClO)2 could achieve simultaneous deep-dewatering performance and total coliforms inactivation. Based on response surface methodology, the optimal dosages of Fe2+ and Ca(ClO)2 were proposed as 106.1 and 234.5 mg/g volatile solids respectively, without any acidification of sludge. Under these optimal dosages, the water content of dewatered sludge cake was 51.9 ± 0.1 wt% and the pH of the final filtrate was 5.8 ± 0.2. Total coliforms of sludge could be inactivated in 10 s after Fe2+/Ca(ClO)2 addition.

KW - Cell lysis

KW - Deep-dewatering

KW - Extracellular and intracellular oxidation

KW - Hypochlorite acid

KW - Oxidation intensity

KW - Waste activated sludge

UR - http://www.scopus.com/inward/record.url?scp=85055285888&partnerID=8YFLogxK

U2 - 10.1016/j.watres.2018.10.033

DO - 10.1016/j.watres.2018.10.033

M3 - 文章

C2 - 30347276

AN - SCOPUS:85055285888

SN - 0043-1354

VL - 148

SP - 60

EP - 69

JO - Water Research

JF - Water Research

ER -