Comparison of linear alkylbenzene sulfonates removal in conventional activated sludge systems and membrane bioreactors

2004 ◽  
Vol 50 (5) ◽  
pp. 219-225 ◽  
Author(s):  
H. De Wever ◽  
S. Van Roy ◽  
C. Dotremont ◽  
J. Müller ◽  
T. Knepper
Keyword(s):  
Activated Sludge ◽  
Membrane Bioreactors ◽  
Operating Conditions ◽  
Biological Degradation ◽  
Linear Alkylbenzene ◽  
Conventional Activated Sludge ◽  
Operational Variables ◽  
Linear Alkylbenzene Sulfonates ◽  
Model Components ◽  
Activated Sludge Systems

The potential of a membrane bioreactor (MBR) and a conventional activated sludge (CAS) system to remove polar micropollutants was evaluated using linear alkylbenzene sulfonates (LAS) as model components. Removal efficiencies over 97% were achieved in both reactor systems. The appearance of biological breakdown metabolites and the respirometric response of the sludges to LAS addition indicated that LAS removal was due to biodegradation, rather than sorption phenomena. The effect of operational variables, such as hydraulic retention time, LAS composition and hydrophobicity of the membrane used in the MBR, was negligible in the range tested. A stepwise increase in LAS influent concentration resulted in higher residual effluent concentrations but did not change the procentual removal efficiency. Because an increase in LAS and SPC effluent concentration occurred to a larger extent in the CAS than in the MBR under similar operating conditions, MBRs may turn out to be be more robust with respect to biological degradation of micropollutants than CAS.

Sludge production in membrane bioreactors under different conditions

2000 ◽  
Vol 41 (10-11) ◽  
pp. 251-258 ◽  
Author(s):  
J. Wagner ◽  
K-H. Rosenwinkel
Keyword(s):  
Activated Sludge ◽  
Pilot Plant ◽  
Membrane Bioreactors ◽  
Conventional Activated Sludge ◽  
Theoretical Approaches ◽  
One Year ◽  
Conventional Systems ◽  
The University ◽  
Activated Sludge Systems ◽  
Sludge Production

With membrane bioreactors, the production of surplus sludge is lower than with conventional activated sludge systems, a fact that has been confirmed in a large number of analyses. There is, however, no consensus about the dimension of the reactions and their respective causes. In order to examine these, at the University of Hanover a pilot plant with a capacity of 220 l was run for one year without any extraction of surplus sludge. The plant was started with 2 g MLSS/l; after one year, this value had risen to approximately 18 g MLSS/l. In order to be able to set the plant for different sludge loads (0.04 to 0.2 kg COD/(kg MLSS · d)), the wastewater was artificially stocked up. The emerging result was that in contrast to conventional systems the sludge growth was lower, but still continuously existing. Then, comparisons with theoretical approaches were run – among others with the ASM1-Model – which confirmed the findings. One possible reason could be the different biocoenoses, which was assumed to be the cause after several microscopic examinations had been run.

scholarly journals Modeling of Wastewater Treatment Processes in Membrane Bioreactors Compared to Conventional Activated Sludge Systems

Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 285 ◽  
Author(s):  
Marta Bis ◽  
Agnieszka Montusiewicz ◽  
Adam Piotrowicz ◽  
Grzegorz Łagód
Keyword(s):  
Activated Sludge ◽  
Total Nitrogen ◽  
Biomass Concentration ◽  
Membrane Bioreactors ◽  
Effluent Quality ◽  
Conventional Activated Sludge ◽  
Treatment Processes ◽  
Significant Difference ◽  
Interesting Alternative ◽  
Activated Sludge Systems

Membrane techniques constitute an interesting alternative to conventional activated sludge systems (CAS). In membrane bioreactors (MBR), the biomass separated on membranes is retained independently of sludge sedimentation properties. As a consequence, a high biomass concentration as well as low food to microorganisms ratio can be obtained. Moreover, the development of a characteristic activated sludge population is stimulated by the specific conditions prevailing in MBRs. In the study, the operation and treatment efficiency of the MBR and CAS processes were examined and compared. Simulation was performed with the use of GPS-X software. The effluent quality obtained for the MBR system was either better or comparable to that of CAS. The most significant difference concerned the elimination of total suspended solids, which amounted to 99.8% in the MBR. Regarding nutrients, a low concentration of total phosphorus in the effluent from CAS and MBR was obtained (0.67 gP m−3 and 0.50 gP m−3, respectively). Greater differences were achieved in the case of total nitrogen. Although almost complete nitrification took place in both systems, a lower concentration of nitrate in the effluent from MBR in comparison to CAS, i.e., 11.2 gN m−3 and 14.1 gN m−3, respectively, allowed us to obtain a higher removal of total nitrogen (80.8% and 76.1%, respectively).

Trace organics removal using three membrane bioreactor configurations: MBR, IFAS-MBR and MBMBR

2015 ◽  
Vol 71 (5) ◽  
pp. 761-768 ◽  
Author(s):  
T. de la Torre ◽  
E. Alonso ◽  
J. L. Santos ◽  
C. Rodríguez ◽  
M. A. Gómez ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Removal Rate ◽  
Treatment Plant ◽  
Operating Conditions ◽  
Removal Rates ◽  
Linear Alkylbenzene ◽  
Conventional Activated Sludge ◽  
Attached Biomass

Seventeen pharmaceutically active compounds and 22 other trace organic pollutants were analysed regularly in the influent and permeate from a semi-real plant treating municipal wastewater. The plant was operated during 29 months with different configurations which basically differed in the type of biomass present in the system. These processes were the integrated fixed-film activated sludge membrane bioreactor (IFAS-MBR), which combined suspended and attached biomass, the moving bed membrane bioreactor (MBMBR) (only attached biomass) and the MBR (only suspended biomass). Moreover, removal rates were compared to those of the wastewater treatment plant (WWTP) operating nearby with conventional activated sludge treatment. Reverse osmosis (RO) was used after the pilot plant to improve removal rates. The highest elimination was found for the IFAS-MBR, especially for hormones (100% removal); this was attributed to the presence of biofilm, which may lead to different conditions (aerobic–anoxic–anaerobic) along its profile, which increases the degradation possibilities, and also to a higher sludge age of the biofilm, which allows complete acclimation to the contaminants. Operating conditions played an important role, high mixed liquor suspended solids (MLSS) and sludge retention time (SRT) being necessary to achieve these high removal rates. Although pharmaceuticals and linear alkylbenzene sulfonates showed high removal rates (65–100%), nonylphenols and phthalate could only be removed to 10–30%. RO significantly increased removal rates to 88% mean removal rate.

New approaches to minimize excess sludge in activated sludge systems

2001 ◽  
Vol 44 (10) ◽  
pp. 203-208 ◽  
Author(s):  
G.-H. Chen ◽  
S. Saby ◽  
M. Djafer ◽  
H.-K. Mo
Keyword(s):  
Activated Sludge ◽  
Activated Sludge Process ◽  
Conventional System ◽  
Excess Sludge ◽  
Active Sludge ◽  
New Approaches ◽  
Conventional Activated Sludge ◽  
Sludge Settleability ◽  
Activated Sludge Systems ◽  
Sludge Production

This paper presents three new approaches to reduce excess sludge production in activated sludge systems: 1) modification of conventional activated sludge process with insertion of a sludge holding tank in the sludge return line; 2) chlorination of excess sludge so as to minimize excess sludge production; and 3) utilization of a metabolic uncoupler, 3, 3′, 4′, 5-Tetrachlorosalicylanilide (TCS) to maximize futile activity of sludge microorganisms thereby leading to a reduction of sludge growth. Pilot study was carried out to evaluate this modified activated sludge process (OSA). It has been confirmed that the OSA process is effective in reducing excess sludge; particularly when the ORP level in the sludge holding tank was kept at -250 mV, more than 50% of the excess sludge was reduced. This process can maintain the effluent quality and even perform with a better sludge settleability than a conventional system. Experimental work on the second approach showed that chlorination treatment of excess sludge at a chlorine dose of 0.066 g Cl2/g MLSS reduced the excess sludge by 60%, while concentration of THMS was found below 200 ppb in the treated sludge. However, such sludge chlorination treatment sacrificed sludge settleability. Thus, it is not feasible to introduce the chlorination step to a conventional system. The third approach confirmed that addition of TCS could reduce sludge growth effectively if the TCS concentration is greater than 0.4 ppm. A 0.8-ppm concentration of TCS actually reduced excess sludge by 45%. It was also experimentally demonstrated that presence of TCS increases the portion of active sludge microorganisms over the entire microbial population.

Oxygen transfer in activated sludge – new insights and potentials for cost saving

2011 ◽  
Vol 63 (12) ◽  
pp. 3034-3038 ◽  
Author(s):  
J. Henkel ◽  
P. Cornel ◽  
M. Wagner
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Oxygen Transfer ◽  
Transfer Rate ◽  
Oxygen Transfer Rate ◽  
Organic Load ◽  
Current Opinion ◽  
Conventional Activated Sludge ◽  
Current State ◽  
Activated Sludge Systems

The α-factor has the greatest impact on the calculation of the required standard oxygen transfer rate (SOTR) in activated sludge systems equipped with submerged aeration systems. Knowing the dependencies of the α-factor leads to a better design of the aeration devices and, consequently, to a more efficient use of aeration energy. Applying the current state of knowledge about oxygen transfer leads to the conclusion that, in contrast to current opinion, simultaneous aerobic stabilization requires the same SOTR as conventional activated sludge systems with advanced nutrient removal, even though a higher organic load is degraded.

Enhancement of 2,4-dichlorophenol degradation in conventional activated sludge systems bioaugmented with mixed special culture

2004 ◽  
Vol 38 (1) ◽  
pp. 245-253 ◽  
Author(s):  
Xiangchun Quan ◽  
Hanchang Shi ◽  
Hong Liu ◽  
Pingping Lv ◽  
Yi Qian
Keyword(s):  
Activated Sludge ◽  
Conventional Activated Sludge ◽  
Activated Sludge Systems
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