Effect of solid retention time on sludge filterability and biomass activity: Long-term experiment on a pilot-scale membrane bioreactor treating municipal wastewater

Comparison between mixed liquors of two side-stream membrane bioreactors treating wastewaters from waste management plants with high and low solids anaerobic digestion

“…This difference can be probably attributed to the considerable higher concentration of SMP C in MBR-HS than in MBR-LS. These positive correlations between CST and SMP c have been reported by (Reid et al, 2008;Sabia et al, 2013).…”

“…Sabia et al, 2013 reported that ratio SMPp/SMPc sharply increased with the sludge retention time (SRT). In fact, SMPc were higher than SMPp for low SRT, whereas at high SRT the ratio SMPp/SMPc reached values between 5 and 10.…”

An innovative respirometric method to assess the autotrophic active fraction: Application to an alternate oxic–anoxic MBR pilot plant

“…SOUR progressively decreased throughout the experiments, even when the aerated fraction was 0.8. This behavior has been noticed by other authors [22,37] in pilot plants that are operated with continuous aeration and complete sludge retention. In such conditions, the SOUR decrease can be imputable to biomass ageing, which involves a progressive reduction of its metabolic activity.…”

“…Indeed, the nitrification efficiency was almost independent of the f XA values down to 1%; for lower values, a sharp decrease in nitrification efficiency was observed. Higher SRT values did not significantly affect the nitrification efficiency, even if they enabled high percentages of autotrophic active fraction, but they induced lower heterotrophic metabolic activity because of sludge ageing [37].…”

Theoretic similitude of the aerobic biological growth kinetics for the stabilization of organic matter in wastewaters treatment

“…Within the context of wastewater treatment engineering, the decomposition of organic matter may be adequately described as the loss of biomass or the loss of activity through the activation of microorganisms degraders of the same (Manser, 2006). In contrast to the above, the biomass activities, and the concentration of microbial products can be analyzed through aerobic growth kinetics for the stabilization of organic matter in aerobic biological reactors (Sabia, 2013), and through them, the activated sludge models have the purpose of modeling the concentrations of nutrients and not the number and conditions of the microorganisms (Chiavola, 2014). The application of aerobic microbian growth kinetics in the design of reactors for the stabilization of organic matter, requires a balance between the steady state approach and the unidimensional approach, which are widely used and implemented in the design of the aerobic biological treatment of municipal wastewaters (Eldyasti, 2012).…”