TY - JOUR
T1 - Impact of ultrasonic treatment on dewaterability of sludge during Fenton oxidation
AU - Jiang, Jianguo
AU - Gong, Changxiu
AU - Tian, Sicong
AU - Yang, Shihui
AU - Zhang, Yujing
PY - 2014/12
Y1 - 2014/12
N2 - Fenton oxidation was compared with Fenton oxidation coupled with ultrasonication (Fenton + US) for sludge dewatering. Different Fenton reagent (H2O2, Fe2+) concentrations, pH, and reaction times were studied in different systems on the basis of the specific resistance to filtration (SRF) and capillary suction time (CST). It was found that Fenton + US can significantly reduce Fe2+ and H2O2 dosages and reaction times. After ultrasonication of the system at pH 3, with an ultrasonic frequency of 25 kHz and a sound energy density of 100 W/L, the Fe2+, H2O2 dosage, and reaction time were reduced by 66.7, 75.0, and 75.0 %, respectively, when compared with Fenton oxidation at the same dewaterability of sludge. The microstructure of sludge and hydroxyl radical (·OH) density in Fenton oxidation and Fenton + US was further examined. Fenton + US produced more · OH in a sludge system than did individual Fenton oxidation. The concentration of · OH in Fenton + US fell from 79.2 to 6 mg/L over 3.5 h, while the concentration of · OH in Fenton oxidation fell from 59.6 to 1 mg/L over 2 h, thus destroying the microstructure of sludge more effectively. Sludge treated using Fenton + US for 30 min showed a much thinner and looser microstructure.
AB - Fenton oxidation was compared with Fenton oxidation coupled with ultrasonication (Fenton + US) for sludge dewatering. Different Fenton reagent (H2O2, Fe2+) concentrations, pH, and reaction times were studied in different systems on the basis of the specific resistance to filtration (SRF) and capillary suction time (CST). It was found that Fenton + US can significantly reduce Fe2+ and H2O2 dosages and reaction times. After ultrasonication of the system at pH 3, with an ultrasonic frequency of 25 kHz and a sound energy density of 100 W/L, the Fe2+, H2O2 dosage, and reaction time were reduced by 66.7, 75.0, and 75.0 %, respectively, when compared with Fenton oxidation at the same dewaterability of sludge. The microstructure of sludge and hydroxyl radical (·OH) density in Fenton oxidation and Fenton + US was further examined. Fenton + US produced more · OH in a sludge system than did individual Fenton oxidation. The concentration of · OH in Fenton + US fell from 79.2 to 6 mg/L over 3.5 h, while the concentration of · OH in Fenton oxidation fell from 59.6 to 1 mg/L over 2 h, thus destroying the microstructure of sludge more effectively. Sludge treated using Fenton + US for 30 min showed a much thinner and looser microstructure.
KW - Sludge
KW - Ultrasonic coupling
KW - Fenton oxidation
KW - Dewaterability
KW - Microstructure
UR - http://www.scopus.com/inward/record.url?scp=84927123681&partnerID=8YFLogxK
U2 - 10.1007/s10661-014-3988-y
DO - 10.1007/s10661-014-3988-y
M3 - Article
C2 - 25108663
VL - 186
SP - 8081
EP - 8088
JO - Environmental Monitoring and Assessment
JF - Environmental Monitoring and Assessment
SN - 0167-6369
IS - 12
ER -