Rapid start-up of denitrifying granular sludge by dosing with semi-starvation fluctuation C/N ratio strategy

Effect of fluctuating hydraulic retention time (HRT) on denitrification in the UASB reactors

“…The fact that granules had formed earlier in R DF could be attributed to a higher hydraulic shear force, and in R UF could be attributed to appropriately reduce influent organic matter content, these two special condition could promote biomass aggregation, which took place at a much shorter period. These studies were consistent with the results of earlier studies [15,25]. These results indicate that the use of both UF-HRT and DF-HRT strategies could shorten the adaptive period compared to the C-HRT strategy.…”

“…method. Heat EPS extraction procedures [15] were used and extracellular polysaccharides (PS) and extracellular proteins (PN) were assayed by the anthrone-sulfuric acid method [22] and Coomassie brilliant blue assay [23], respectively. The PS and PN were measured by the UV spectrophotometry (Tianmei, UV2600, UV/Vis spectrophotometer, China).…”

“…Niu el al. [15] reported that microbes could use proteins of EPS as carbon sources to survive periods with scarce carbon source availability. Correspondingly, the decreased PN concentration in R UF could also be attributed to both low hydraulic shear force and microbial utilization.…”

“…In addition, increasing evidence indicated that QS was strongly related to reactor performance, EPS content and sludge granulation [13,14]. A further study showed that QS in activated sludge flocs could regulate both reactor performance and EPS content, and accelerating sludge granulation through a response to changes in the concentration of acyl homoserine lactones (AHLs) [15]. Moreover, QS is closely related to the external environment, and the disturbed external environment could severely affect QS [14,15].…”

“…A further study showed that QS in activated sludge flocs could regulate both reactor performance and EPS content, and accelerating sludge granulation through a response to changes in the concentration of acyl homoserine lactones (AHLs) [15]. Moreover, QS is closely related to the external environment, and the disturbed external environment could severely affect QS [14,15]. Sun et al [14] and Yang et al [16] provided intermittent feeding and starvation strategies that severely affected the QS system.…”