Kinetic parameters and inhibition response of ammonia‐ and nitrite‐oxidizing bacteria in membrane bioreactors and conventional activated sludge processes

Abstract Increasing stringency of environmental discharge standards has triggered an industry-wide inclination towards membrane bioreactors over conventional activated sludge processes to ensure fulfilment of environmental discharge criteria. Yet, despite its plentiful advantages, high aeration costs remain as a key deterrent to the widespread adoption of the MBR technology. This backdrop created an impetus for a wastewater treatment company to develop an efficient MBR air scouring protocol that can be realized in existing plants without retrofitting. Known as pulsed cyclic aeration, plant trial applications have demonstrated that fouling control and aeration savings can be improved by >30%, resulting in scouring energy consumptions that can be as low as 0.049 kWh/m3.

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Effects of Fluctuating Iron Dosage on Nitrification in Integrated Fixed Film and Conventional Activated Sludge Processes

Water Environment Research ◽

10.2175/106143008x274275 ◽

2009 ◽

Vol 81 (9) ◽

pp. 907-921

Author(s):

Anne-Emmanuelle Stricker ◽

Lori Lishman ◽

Ashley Barrie

Keyword(s):

Activated Sludge ◽

Conventional Activated Sludge ◽

Fixed Film ◽

Activated Sludge Processes

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Comparative study of membrane bioreactor (MBR) and activated sludge processes in the treatment of Moroccan domestic wastewater

Water Science & Technology ◽

10.2166/wst.2018.384 ◽

2018 ◽

Vol 78 (5) ◽

pp. 1129-1136 ◽

Cited By ~ 6

Author(s):

S. Kitanou ◽

M. Tahri ◽

B. Bachiri ◽

M. Mahi ◽

M. Hafsi ◽

...

Keyword(s):

Activated Sludge ◽

Membrane Bioreactor ◽

Ceramic Membrane ◽

Oxygen Demand ◽

Domestic Wastewater ◽

Pilot Scale ◽

Quality Parameters ◽

Effluent Quality ◽

Conventional Activated Sludge ◽

Activated Sludge Processes

Abstract The study was based on an external pilot-scale membrane bioreactor (MBR) with a ceramic membrane compared to a conventional activated sludge process (ASP) plant. Both systems received their influent from domestic wastewater. The MBR produced an effluent of much better quality than the ASP in terms of total suspended solids (TSS), 5-day biological oxygen demand (BOD5) and chemical oxygen demand (COD), total phosphorus (TP) and total nitrogen (TN). Other effluent quality parameters also indicated substantial differences between the ASP and the MBR. This study leads to the conclusion that in the case of domestic wastewater, MBR treatment leads to excellent effluent quality. Hence, the replacement of ASP by MBR may be justified on the basis of the improved removal of solids, nutrients, and micropollutants. Furthermore, in terms of reuse the high quality of the treated water allows it to be reused for irrigation.

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Operation of different membrane bioreactors: experimental results and physiological state of the micro-organisms

Water Science & Technology ◽

10.2166/wst.2000.0659 ◽

2000 ◽

Vol 41 (10-11) ◽

pp. 269-277 ◽

Cited By ~ 48

Author(s):

S. Rosenberger ◽

R. Witzig ◽

W. Manz ◽

U. Szewzyk ◽

M. Kraume

Keyword(s):

Activated Sludge ◽

Municipal Wastewater ◽

Physiological State ◽

High Strength ◽

Dry Weight ◽

Pilot Scale ◽

Membrane Bioreactors ◽

Conventional Activated Sludge ◽

Consumption Rates ◽

Microfiltration Membranes

Lab-scale and pilot-scale activated sludge bioreactors with integrated microfiltration membranes were operated over a period of up to three years. During the entire operation period no excess sludge was removed from the bioreactors apart from sampling, resulting in highly concentrated biomass in the reactors. The dry weight of the sludge ranged from 15 to 23 g MLSS l–1 for a plant fed with municipal wastewater and up to 60 g ll–1 for a lab-scale plant fed with high strength molasses. Stable biomass concentrations were reached at F/M ratios as low as approximately 0.07 kg COD (kg MLSS)–1 d–1. The degradation performance of the analyzed reactors was high and stable. Direct microscopical studies revealed high amounts of free suspended cells and at various times also high numbers of filamentous bacteria. Surprisingly only low numbers of protozoa were observed during most of the time. By use of fluorescent in situ hybridization (FISH) only about 40% to 50% of all bacteria emitted probe conferred fluorescence signals sufficient for detection, compared to around 80% cells detectable in conventional activated sludge. Studies on oxygen consumption rates indicated that the biomass in the bioreactor was substrate limited. These data suggest that substrate is mainly oxidized and not used for growth purposes which offers the possibility to operate membrane bioreactors with significantly reduced secondary sludge production.

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