title: Zero-valent iron enhanced methanogenic activity in anaerobic digestion of waste activated sludge after heat and alkali pretreatment.
abstract: Heat or alkali pretreatment is the effective method to improve hydrolysis of waste sludge and then enhance anaerobic sludge digestion. However the pretreatment may inactivate the methanogens in the sludge. In the present work, zero-valent iron (ZVI) was used to enhance the methanogenic activity in anaerobic sludge digester under two methanogens-suppressing conditions, i.e. heat-pretreatment and alkali condition respectively. With the addition of ZVI, the lag time of methane production was shortened, and the methane yield increased by 91.5% compared to the control group. The consumption of VFA was accelerated by ZVI, especially for acetate, indicating that the acetoclastic methanogenesis was enhanced. In the alkali-condition experiment, the hydrogen produced decreased from 27.6 to 18.8 mL when increasing the ZVI dosage from 0 to 10 g/L. Correspondingly, the methane yield increased from 1.9 to 32.2 mL, which meant that the H2-utilizing methanogenes was enriched. These results suggested that the addition of ZVI into anaerobic digestion of sludge after pretreated by the heat or alkali process could efficiently recover the methanogenic activity and increase the methane production and sludge reduction.
authors: Dalian University of Technology, Key Laboratory of Industrial Ecology and Environmental Engineering, China. Electronic address: zhangyb@dlut.edu.cn.
authors: Yaobin
authors: Y
authors: Zhang
authors: Dalian University of Technology, Key Laboratory of Industrial Ecology and Environmental Engineering, China. Electronic address: ffffyh@gmail.com.
authors: Yinghong
authors: Y
authors: Feng
authors: Dalian University of Technology, Key Laboratory of Industrial Ecology and Environmental Engineering, China.
authors: Xie
authors: X
authors: Quan
mesh_terms: D000468:Alkalies / Q000737:chemistry*; D000693:Anaerobiosis; D019149:Bioreactors; D006358:Hot Temperature; D007501:Iron / Q000737:chemistry / Q000378:metabolism*; D008697:Methane / Q000378:metabolism*; D059013:Microbial Consortia; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D000468:Alkalies; D012722:Sewage; D007501:Iron; D008697:Methane
keywords: Alkali treatment; Anaerobic digestion; Heat pretreatment; Waste activated sludge; Zero-valent iron (ZVI)