Simultaneous sludge minimization, biological phosphorous removal and membrane fouling mitigation in a novel plant layout for MBR

Abstract

The integration of one anaerobic reactor in the mainstream (AMSR) of a pre-denitritication-MBR was evaluated with the aim to achieve simultaneous sludge minimization and phosphorous removal. The excess sludge production was reduced by 64% when the AMSR was operated under 8h of hydraulic retention time (HRT). The highest nutrients removal performances referred to organic carbon (98%), nitrogen (90%) and phosphorous (97%) were obtained under 8 h of HRT. In contrast, prolonged anaerobic-endogenous conditions were found to be detrimental for all nutrients removal performances. Similarly, the lowest membrane fouling tendency (FR=0.65•10 11 m-1 d-1) was achieved under 8 h of HRT, whereas it significantly increased under higher HRT. The highest polyphosphate accumulating organisms kinetics were achieved under HRT of 8 h, showing very high exogenous Prelease (46.67 mgPO4-P gVSS-1 h-1) and P-uptake rates (48.6 mgPO4-P gVSS-1 h-1), as well as a not negligible P-release rate under endogenous conditions at low COD/P ratio (≈ 1).

Modeling, simulation and control of biological and chemical P-removal processes for membrane bioreactors (MBRs) from lab to full-scale applications: State of the art

“…The highest P-removal efficiency was achieved with 2-stage MLE having single internal recirculation from aerobic to anoxic zone and with addition of coagulant. The study of Corsino et al (2020) evaluated the nutrient removal performance of pre-denitrification A/O configuration with recirculation of 500% (5 times of the influent flow) from aerobic to anoxic tank. The authors found that the novel layout is capable to remove 97% of the phosphorus with addition of external carbon source and without addition of coagulant.…”

Achieving complete nitrification below the washout SRT with hybrid membrane aerated biofilm reactor (MABR) treating municipal wastewater

“…Finally, the extracellular polymeric (EPS) content of the sludge was determined according to the literature (Corsino et al, 2020)…”

Insights on mechanisms of excess sludge minimization in an oxic-settling-anaerobic process under different operating conditions and plant configurations

“…Similarly, cell decay and EPS destructuration were observed in a membrane bioreactor (MBR) coupled with an anoxic side-stream reactor operating with 10 hours HRT (Fida et al, 2021). Corsino et al (2020b) found that when increasing the HRT in the ASSR from 6 h to 10 h, sludge minimization was mainly driven by endogenous decay, whereas the contribution of the uncoupling metabolism decreased. Nonetheless, Velho and co-authors observed that a 45% increase of the ASSR volume (HRT from 6 h to 10 h) did not promote a further reduction of excess sludge, since it was affected by other factors such as aerobiosis/anaerobiosis alternation (Velho et al, 2016).…”

“…According to these studies, prolonged fasting in anaerobic reactor forced bacteria to consume their conserved energy in form of adenosine-triphosphate (ATP). Once returned in the enriched-oxygen environment, the internal energy levels were restored and additional substrate consumption is promoted, thereby leading to an additional oxygen requirement (Semblante et al, 2014;Corsino et al, 2020b).…”