Synergetic pretreatment of sewage sludge by microwave irradiation in presence of H2O2 for enhanced anaerobic digestion.
A microwave-enhanced advanced hydrogen peroxide oxidation process (MW/H(2)O(2)-AOP) was studied in order to investigate the synergetic effects of MW irradiation on H(2)O(2) treated waste activated sludges (WAS) in terms of mineralization (permanent stabilization), sludge disintegration/solubilization, and subsequent anaerobic biodegradation as well as dewaterability after digestion. Thickened WAS sample pretreated with 1gH(2)O(2)/g total solids (TS) lost 11-34% of its TS, total chemical oxygen demand (COD) and total biopolymers (humic acids, proteins and sugars) via advanced oxidation. In a temperature range of 60-120 degrees C, elevated MW temperatures (>80 degrees C) further increased the decomposition of H(2)O(2) into OH* radicals and enhanced both oxidation of COD and solubilization of particulate COD (>0.45 micron) of WAS indicating that a synergetic effect was observed when both H(2)O(2) and MW treatments were combined. However, at all temperatures tested, MW/H(2)O(2) treated samples had lower first-order mesophilic (33+/-2 degrees C) biodegradation rate constants and ultimate (after 32 days of digestion) methane yields (mL per gram sample) compared to control and MW irradiated WAS samples, indicating that synergistically (MW/H(2)O(2)-AOP) generated soluble organics were slower to biodegrade or more refractory than those generated during MW irradiation.
Eskicioglu
Cigdem
C
School of Engineering, University of British Columbia Okanagan, Kelowna, BC, Canada.
Prorot
Audrey
A
Marin
Juan
J
Droste
Ronald L
RL
Kennedy
Kevin J
KJ
D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D006861:Hydrogen Peroxide / Q000737:chemistry* / Q000378:metabolism; D008872:Microwaves; D010084:Oxidation-Reduction / Q000528:radiation effects; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology
D012722:Sewage; D006861:Hydrogen Peroxide