title: Reversibility of the structure and dewaterability of anaerobic digested sludge.
abstract: The reversibility of the structure and dewaterability of broken anaerobic digested sludge (ADS) is important to ensure the efficiency of sludge treatment or management processes. This study investigated the effect of continuous strong shear (CSS) and multipulse shear (MPS) on the zeta potential, size (median size, d50), mass fractal dimension (D(F)), and capillary suction time (CST) of ADS aggregates. Moreover, the self-regrowth (SR) of broken ADS aggregates during slow mixing was also analyzed. The results show that raw ADS with d50 of 56.5 μm was insensitive to CSS-SR or MPS-SR, though the size slightly decreased after the breakage phase. For conditioned ADS with d50 larger than 600 μm, the breakage in small-scale surface erosion changed to large-scale fragmentation as the CSS strength increased. In most cases, after CSS or MPS, the broken ADS had a relatively more compact structure than before and d50 is at least 200 μm. The CST of the broken fragments from optimally dosed ADS increased, whereas that corresponding to overdosed ADS decreased. MPS treatment resulted in larger and more compact broken ADS fragments with a lower CST value than CSS. During the subsequent slow mixing, the broken ADS aggregates did not recover their charge, size, and dewaterability to the initial values before breakage. In addition, less than 15% self-regrowth in terms of percentage of the regrowth factor was observed in broken ADS after CSS at average velocity gradient no less than 1905.6 sec(-1).
authors.affiliation: College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China.. Electronic address: shengyiqi09@163.com.
authors.forename: Yiqi
authors.initials: Y
authors.lastname: Sheng
authors.affiliation: College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China.. Electronic address: wangyilimai@126.com.
authors.forename: Yili
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.affiliation: College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Qian
authors.affiliation: College of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400044, China.
authors.forename: Huaili
authors.initials: H
authors.lastname: Zheng
authors.affiliation: College of Environmental Science and Engineering, Beijing Key Lab for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing 100083, China.
authors.forename: Xiaoxiu
authors.initials: X
authors.lastname: Lun
mesh_terms: D000693:Anaerobiosis; D012722:Sewage / Q000737:chemistry*; D033081:Shear Strength; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D012722:Sewage
keywords: Anaerobic digested sludge; Dewaterability; Floc strength; Reversibility; Shear; Structure