Enhancement of the dewaterability of sludge during bioleaching mainly controlled by microbial quantity change and the decrease of slime extracellular polymeric substances content

Degradation of slime extracellular polymeric substances and inhibited sludge flocs destruction contribute to sludge dewaterability enhancement during fungal treatment of sludge using filamentous fungus Mucor sp. GY-1

“…GY-1. This phenomenon is consistent with other reports in that the sludge dewaterability in the aerobic digestion system was firstly improved and then deteriorated (Huo et al, 2014;Zhou et al, 2014). The treatment systems inoculated with 1%, 5% and 10% of Mucor sp.…”

“…In sludge bioleaching driven by chemolithotrophic autotrophs including Acidithiobacillus ferrooxidans and/or Acidithiobacillus thiooxidans, the growth of these two autotrophs using Fe 2+ and S 0 resulted in the increase of Fe 3+ concentration, the decrease of sludge pH, and changes of sludge properties, all of which contribute on the improvement of sludge dewaterability (Huo et al, 2014). However, during the fungal treatment of sludge, the filamentous fungus Mucor sp.…”

“…In addition, the macromolecules in EPS cause the retention of water in sludge flocs and increase the amount of interstitial water in such flocs (Yang and Li, 2009). Hence, a lower EPS content is more beneficial for the improvement of sludge dewaterability (Yu et al, 2008;Huo et al, 2014;Zhou et al, 2014). Besides, EPS in sludge flocs can be stratified into slime EPS, loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS), in which the protein content or the content ratio of protein to polysaccharide (PN/PS) in slime layer significantly impacted the sludge dewaterability (Yu et al, 2008;Liu et al, 2010;Zhou et al, 2014).…”

“…Recent advances in sludge dewatering reveal that sludge dewaterability is controlled by many factors, including sludge pH, surface charge of sludge particles, sludge particle size and even sludge extracellular polymeric substances (Olböter and Vogelpohl, 1993;Yu et al, 2008;Sheng et al, 2010;Subramanian et al, 2010b;Huo et al, 2014;Zhou et al, 2014). In general, sludge extracellular polymeric substances (EPS) are regarded as key factors in the thickening and dewatering of sludge , because they help in the formation of bioflocs in activated sludge and contribute to the structural, surface charge and settling properties of sludge .…”

Improving dewaterability of waste activated sludge through advanced oxidization process

“…In contrast, the bound water is difficult to be removed mechanically because it combines with the sludge structure by capillary forces or even chemical bonds. To increase the WAS dewaterability and therefore reduce WAS disposal costs, sludge conditioning is widely used as a pretreatment prior to dewatering to transform bound water into free water (Huo et al, 2014).…”