Effect of solids retention time on the performance and biological characteristics of a membrane bioreactor

The purpose of this study was to compare the performance of a pilot-scale membrane bioreactor (MBR) in the treatment of municipal strength wastewater at solid retention times (SRTs) ranging from 30 days to two days. Cumulative nitrogen and phosphorus mass balances resulted in closures exceeding 90% at each steady state period. Biomass production rate and biomass viability generally increased with decreasing SRT, whereas overall enzymatic activity did not change significantly at most SRTs, but was highest at the two day SRT. Nitrification decreased at two day SRT but did not fail completely. At higher SRTs, nitrification was not noticeably affected by the sludge age. Phospholipid fatty acid (PLFA) analysis showed substantially diverse biomass in the sludge at different SRTs. Different ratios of gram positive bacteria, eukaryotic organisms, and yeast cells were observed in the mixed liquor at varying SRTs. On the other hand, BIOLOG analysis indicated that the overall capacity of the biomass to degrade different carbon substrates did not change significantly at different SRTs. The concentration of metals in the MBR mixed liquor declined steadily with decreasing SRT. The MBR effluent contained negligible amounts of Fe, Zn, Mn, and Co at each condition, indicating the retention of these metals regardless of the SRT.

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Characteristics of simultaneous nitrogen and phosphorus removal in a pilot-scale sequencing anoxic/anaerobic membrane bioreactor at various conditions

Desalination ◽

10.1016/j.desal.2008.11.045 ◽

2010 ◽

Vol 250 (2) ◽

pp. 801-804 ◽

Cited By ~ 24

Author(s):

Kyung-Guen Song ◽

Jinwoo Cho ◽

Kang-Woo Cho ◽

Sang-Don Kim ◽

Kyu-Hong Ahn

Keyword(s):

Phosphorus Removal ◽

Membrane Bioreactor ◽

Pilot Scale ◽

Nitrogen And Phosphorus ◽

Nitrogen And Phosphorus Removal ◽

Anaerobic Membrane Bioreactor

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Performance of a pilot scale membrane bioreactor coupled with SBR (SM-SBR) - experiences in seasonal temperature changes

Water Science & Technology Water Supply ◽

10.2166/ws.2004.0016 ◽

2004 ◽

Vol 4 (1) ◽

pp. 135-142 ◽

Cited By ~ 4

Author(s):

H. Shin ◽

S. Kang ◽

C. Lee ◽

J. Lim

Keyword(s):

Membrane Fouling ◽

Membrane Bioreactor ◽

Batch Reactor ◽

Domestic Wastewater ◽

Pilot Scale ◽

Endogenous Respiration ◽

Seasonal Temperature ◽

Nitrogen And Phosphorus ◽

Submerged Membrane Bioreactor ◽

Aeration Time

The submerged membrane bioreactor is one of the recent technologies for domestic wastewater treatment. In this study, the performance of the pilot-scale submerged membrane bioreactor coupled with sequencing batch reactor (SM-SBR) was investigated. The reactor was operated in sequencing batch modes with a 3-hour cycles consisting of anoxic and aerobic conditions to treat organics, nitrogen and phosphorus. Despite large fluctuations in influent conditions, COD removal was found to be higher than 95%. Sufficient nitrification was obtained within a few weeks after start-up and during the stable period. Moreover, complete nitrification occurred despite of short aeration time. Total nitrogen (TN) removal efficiency was up to 85%. The insufficient organic loading caused by the membrane fouling led to the increase of HRT, leading to endogenous respiration and/or deactivation of nitrifying microorganisms. DGGE patterns confirmed the shift in microbial community structure. The ammonia-oxidizers (i.e. Nitrospira) became dominant in the mixed liquor during long-term operations. Nitrification and denitrification processes were greatly affected by the temperature, while organic removal and phosphorus removal efficiencies were relatively stable below 15°C.

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Effect of solids retention time on nitrogen and phosphorus removal from municipal wastewater in a sequencing batch membrane bioreactor

Environmental Technology ◽

10.1080/09593330.2016.1212934 ◽

2016 ◽

Vol 38 (7) ◽

pp. 806-815 ◽

Cited By ~ 2

Author(s):

Tiago José Belli ◽

Jossy Karla Brasil Bernardelli ◽

Rayra Emanuelly da Costa ◽

João Paulo Bassin ◽

Miriam Cristina Santos Amaral ◽

...

Keyword(s):

Retention Time ◽

Phosphorus Removal ◽

Membrane Bioreactor ◽

Municipal Wastewater ◽

Nitrogen And Phosphorus ◽

Nitrogen And Phosphorus Removal ◽

Solids Retention Time ◽

Solids Retention

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Multi-year diagnosis of unpredictable fouling occurrences in a full-scale membrane bioreactor

Water Science & Technology ◽

10.2166/wst.2020.354 ◽

2020 ◽

Author(s):

A. L. Carlson ◽

G. T. Daigger ◽

N. G. Love ◽

E. Hart

Keyword(s):

Membrane Bioreactor ◽

Treatment Plant ◽

Normal Operation ◽

Total Carbohydrate ◽

Multivariate Statistical ◽

Mixed Liquor ◽

Gram Positive Bacteria ◽

Polymer Bridging ◽

Traverse City

Abstract The membrane bioreactor (MBR) at the Traverse City Regional Wastewater Treatment Plant has experienced sudden and unpredictable periods of substantial permeability decline since 2011. Early observations detected irregularly-shaped gram-positive bacteria that correlated with plant upsets. Use of biomolecular techniques, such as DNA sequencing of laboratory isolates and the mixed liquor microbial community, and fluorescent in situ hybridization, identified the dispersed organisms as members of the genus Staphylococcus. However, Staphylococcus species were consistently present during normal operation and therefore were more likely to be an indicator of the upset, not the cause. The results suggest that these microorganisms are responding to specific influent wastewater constituents. We chemically analysed seven mixed liquor samples from periods of permeability decline in 2017 and 2018, and four samples from a period of normal operation. During upset conditions, the total carbohydrate content exceeded that of normal operation by 40%. Additionally, mixed liquor calcium concentrations were 65% above normal during the upset in 2017. It is hypothesized and supported through multivariate statistical analysis and estimation of specific resistance to filtration values that a calcium-intermediated polymer bridging mechanism with extracellular polymeric substance constituents is a major contributor to fouling and permeability disruptions in the Traverse City MBR.

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Outdoor flat-panel membrane photobioreactor to treat the effluent of an anaerobic membrane bioreactor. Influence of operating, design, and environmental conditions

Water Science & Technology ◽

10.2166/wst.2018.259 ◽

2018 ◽

Vol 78 (1) ◽

pp. 195-206 ◽

Cited By ~ 8

Author(s):

J. González-Camejo ◽

R. Barat ◽

M. V. Ruano ◽

A. Seco ◽

J. Ferrer

Keyword(s):

Retention Time ◽

Membrane Bioreactor ◽

Sewage Treatment ◽

Biomass Productivity ◽

Pilot Scale ◽

Industrial Scale ◽

Nitrogen And Phosphorus ◽

Nitrogen And Phosphorus Removal ◽

Biomass Retention ◽

Made In

Abstract As microalgae have the ability to simultaneously remove nutrients from wastewater streams while producing valuable biomass, microalgae-based wastewater treatment is a win–win strategy. Although recent advances have been made in this field in lab conditions, the transition to outdoor conditions on an industrial scale must be further investigated. In this work an outdoor pilot-scale membrane photobioreactor plant was operated for tertiary sewage treatment. The effects of different parameters on microalgae performance were studied including: temperature, light irradiance (solar and artificial irradiance), hydraulic retention time (HRT), biomass retention time (BRT), air sparging system and influent nutrient concentration. In addition the competition between microalgae and ammonium oxidising bacteria for ammonium was also evaluated. Maximum nitrogen and phosphorus removal rates of 12.5 ± 4.2 mgN·L−1·d−1 and 1.5 ± 0.4 mgP·L−1·d−1, respectively, were achieved at a BRT of 4.5 days and HRT of 2.5 days, while a maximum biomass productivity of 78 ± 13 mgVSS·L−1·d−1 (VSS: volatile suspended solids) was reached. While the results obtained so far are promising, they need to be improved to make the transition to industrial scale operations feasible.

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Dynamic characterization of a FeCl3-dosed anaerobic membrane bioreactor (AnMBR) treating municipal wastewater

Water Science & Technology ◽

10.2166/wst.2018.175 ◽

2018 ◽

Vol 2017 (2) ◽

pp. 481-491 ◽

Cited By ~ 1

Author(s):

Qirong Dong ◽

Wayne Parker ◽

Martha Dagnew

Keyword(s):

Membrane Bioreactor ◽

Suspended Solids ◽

Municipal Wastewater ◽

Pilot Scale ◽

Delayed Response ◽

Transient Model ◽

Mixed Liquor ◽

Anaerobic Membrane Bioreactor ◽

Membrane Performance ◽

The Impact

Abstract A transient study was conducted at pilot scale to assess the impact of Fe dosage on the dynamics of biological and membrane performance of an anaerobic membrane bioreactor (AnMBR) treating authentic municipal wastewater. A transient model of the AnMBR system was employed to assist with interpretation of the observed responses in the mixed liquor under different FeCl3 dosages. A high dosage (43 mg FeCl3/LSewage) resulted in a significant accumulation of fixed suspended solids and volatile suspended solids (VSS) and reduction of colloidal COD in the mixed liquor. The elevated dosages appeared to reduce the biodegradability of VSS that was present in the raw wastewater. Intermediate dosages of FeCl3 (21–12 mg/L) had less effect on these responses and did not appear to affect VSS biodegradation. Membrane performance was significantly affected by FeCl3 dosage as indicated by reversible resistance (RR) and physically irreversible resistance (IR). RR was closely related to the colloidal COD in the mixed liquor, thus responded quickly to Fe dosage. Physically, IR had a delayed response to changes in the colloidal COD concentrations in the mixed liquor and this was attributed to the effect of slow mass transfer of colloidal matter between the mixed liquor and the membrane.

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Effects of recirculation and separation times on nitrogen removal in baffled membrane bioreactor (B-MBR)

Water Science & Technology ◽

10.2166/wst.2018.270 ◽

2018 ◽

Vol 77 (12) ◽

pp. 2803-2811 ◽

Cited By ~ 2

Author(s):

T. Miyoshi ◽

T. Tsumuraya ◽

T. P. Nguyen ◽

K. Kimura ◽

Y. Watanabe

Keyword(s):

Removal Efficiency ◽

Nitrogen Removal ◽

Membrane Bioreactor ◽

Municipal Wastewater ◽

Oxygen Demand ◽

Pilot Scale ◽

Operating Conditions ◽

Nitrogen And Phosphorus ◽

Experimental Apparatus ◽

Do Concentration

Abstract In this study, we investigated the effects of recirculation and separation times on removals of organic matter, nitrogen, and phosphorus in a baffled membrane bioreactor (B-MBR) treating real municipal wastewater. A pilot-scale B-MBR experimental apparatus was operated under two different sets of recirculation and separation times. The results revealed that, irrespective of operating conditions, the biochemical oxygen demand (BOD) and concentration of total nitrogen (T-N) in the treated water can be lowered to less than 3 and 5 mg/L, respectively. Although T-N was effectively removed in the two different operating conditions, increase in the fraction of recirculation time results in tiny deterioration of nitrogen removal efficiency in the B-MBR. Phosphorus removal efficiency was also slightly decreased as the fraction of recirculation time (ratio between recirculation and separation times) was increased. The results of the measurement of dissolved oxygen (DO) profiles at different points of the B-MBR apparatus indicate that the increase in DO concentration in the anoxic zone of the B-MBR becomes much more pronounced by increasing recirculation intensity. On the basis of the results obtained in this study, it can be concluded that efficient removal of BOD, T-N, and total phosphorus can be achieved by the B-MBR as long as appropriate recirculation intensity is selected.

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Improvement in aerobic sludge digestion through pH control: initial assessment of pilot-scale studies

Canadian Journal of Civil Engineering ◽

10.1139/l87-072 ◽

1987 ◽

Vol 14 (4) ◽

pp. 477-484 ◽

Cited By ~ 4

Author(s):

B. C. Anderson ◽

D. S. Mavinic

Keyword(s):

Sodium Bicarbonate ◽

Hydrated Lime ◽

Ph Control ◽

Pilot Scale ◽

High Rate ◽

Initial Assessment ◽

Mixed Liquor ◽

Solids Retention ◽

Digestion Efficiency ◽

The Individual

Waste-activated sludges from an extended-aeration, pilot-scale wastewater treatment facility and a high-rate, full-scale system were aerobically digested in 150 L pilot-scale digesters, operated in a semicontinuous (daily fill-and-draw) mode, at a standard 15-day solids retention time (SRT). To offset the mixed-liquor pH (MLpH) decrease normally encountered in these digesters (as a result of nitrification), hydrated lime and sodium bicarbonate were used in separate experiments to control MLpH in the series pH 6, 7, 8, and 9. Digester performance in the first stage of this work was assessed solely on the basis of reduction in total volatile suspended solids.The extended-aeration type sludge exhibited the greatest improvement in process performance under all pH-controlled conditions. Improvements in digestion efficiency of up to 80% over the uncontrolled reactors were noted. The use of lime resulted in greater digestion enhancement than did sodium bicarbonate with this sludge, without a significant increase in sludge solids production (owing to the low chemical doses required). Digestion efficiency of the high-rate type sludge was little improved (on a relative basis) with either chemical; however, absolute efficiencies in the individual digesters were, in some cases, nearly double those of the comparative extended-aeration sludge digesters. This difference appears to be a function of the process from which the digesting sludge originated, and seems to be influenced by the amount of easily oxidizable, endogenous substrate contained in the biomass. It was concluded that the extended-aeration type sludge was most amenable to enhanced digestion through pH control; as well, cost and process considerations made lime the chemical of choice. Key words: activated sludge, aerobic digestion, hydrated lime, mixed-liquor pH control, nitrification, process enhancement, pilot-scale, sodium bicarbonate.

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Heterotrophic Kinetic Parameter Estimation for Enhanced Biological Phosphorus Removal Processes Operated in Conventional and Membrane-Assisted Modes

Water Quality Research Journal ◽

10.2166/wqrj.2006.008 ◽

2006 ◽

Vol 41 (1) ◽

pp. 72-83 ◽

Cited By ~ 2

Author(s):

Zhe Zhang ◽

Eric R. Hall

Keyword(s):

Parameter Estimation ◽

Phosphorus Removal ◽

Growth Yield ◽

Pilot Scale ◽

Enhanced Biological Phosphorus Removal ◽

Biological Phosphorus Removal ◽

Nitrogen And Phosphorus ◽

Parameter Values ◽

The Impact ◽

Biological Phosphorus

Abstract Parameter estimation and wastewater characterization are crucial for modelling of the membrane enhanced biological phosphorus removal (MEBPR) process. Prior to determining the values of a subset of kinetic and stoichiometric parameters used in ASM No. 2 (ASM2), the carbon, nitrogen and phosphorus fractions of influent wastewater at the University of British Columbia (UBC) pilot plant were characterized. It was found that the UBC wastewater contained fractions of volatile acids (SA), readily fermentable biodegradable COD (SF) and slowly biodegradable COD (XS) that fell within the ASM2 default value ranges. The contents of soluble inert COD (SI) and particulate inert COD (XI) were somewhat higher than ASM2 default values. Mixed liquor samples from pilot-scale MEBPR and conventional enhanced biological phosphorus removal (CEBPR) processes operated under parallel conditions, were then analyzed experimentally to assess the impact of operation in a membrane-assisted mode on the growth yield (YH), decay coefficient (bH) and maximum specific growth rate of heterotrophic biomass (µH). The resulting values for YH, bH and µH were slightly lower for the MEBPR train than for the CEBPR train, but the differences were not statistically significant. It is suggested that MEBPR simulation using ASM2 could be accomplished satisfactorily using parameter values determined for a conventional biological phosphorus removal process, if MEBPR parameter values are not available.

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