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).

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.

Adsorption and biodegradation of azo dye in biofilm processes

2004 ◽  
Vol 49 (11-12) ◽  
pp. 237-245 ◽  
Author(s):  
J. Li ◽  
P.L. Bishop
Keyword(s):  
Activated Sludge ◽  
Azo Dye ◽  
Operating Conditions ◽  
Acid Orange 7 ◽  
Sludge Flocs ◽  
Treatment Processes ◽  
Adsorption Capacities ◽  
Significant Difference ◽  
Aerobic Nitrification ◽  
Activated Sludge Systems

The removal of a common azo dye, acid orange 7 (AO7), in biofilm systems was investigated in this study. The abiotic and biotic fate of AO7 was examined under a variety of operating conditions: aerobic nitrification, anoxic denitrification and anaerobic digestion. A comparison of the performance between biofilm and activated sludge treatment processes was made. The adsorption of AO7 onto biofilm matrix and activated sludge flocs was found to fit the Langmuir equation. However, there is a significant difference in the adsorption capacities between biofilm and activated sludge. AO7 was recalcitrant in both biofilm and activated sludge systems under aerobic conditions. Under anaerobic conditions, AO7 was readily decolorized. AO7 decolorization was also observed under anoxic conditions. However, the presence of nitrate inhibited AO7 decolorization.

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.

Feasibility of submerged anaerobic membrane bioreactor (SAMBR) for treatment of low-strength wastewater

2008 ◽  
Vol 58 (10) ◽  
pp. 1925-1931 ◽  
Author(s):  
Z. Huang ◽  
S. L. Ong ◽  
H. Y. Ng
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactors ◽  
Organic Loading Rate ◽  
Effluent Quality ◽  
Significant Difference ◽  
Anaerobic Membrane Bioreactors ◽  
High Purification ◽  
Low Strength ◽  
Set Up ◽  
Internal Pore

Two 6-L submerged anaerobic membrane bioreactors (SAMBR) with SRT of 30 and 60 d (denoted as R30 and R60, respectively) were set up and operated for five months, with a mixture of glucose as substrate. Feasibility of SAMBR was studied for treatment of low-strength wastewater. First two months were identified as acclimation stage. A COD removal efficiency was achieved stably at around 99% and biogas productions were maintained at 0.023 and 0.028 L CH4/gMLVSS∙d for R30 and R60, respectively. Even though R60 contained higher MLVSS concentration, no significant difference of treatment performances between both reactors was found due to the low organic loading rate and high purification function of membrane. In the investigation of membrane fouling, less irreversible fouling was observed for R30 compared to R60. High non-flocculent concentration of R60 would be responsible for membrane internal pore blocking and deteriorated effluent quality.

MBR Varsseveld: 5 years of operational experience

2010 ◽  
Vol 5 (1) ◽  
Author(s):  
A.G.N. van Bentem ◽  
N. Nijman ◽  
P.F.T. Schyns ◽  
C.P. Petri
Keyword(s):  
Domestic Wastewater ◽  
Research Programme ◽  
Operational Experience ◽  
Real Situation ◽  
Effluent Quality ◽  
Conventional Activated Sludge ◽  
New Type ◽  
Demonstration Plant ◽  
Membrane Lifetime ◽  
Activated Sludge Systems

The Membrane Bio Reactor (MBR) in Varsseveld is the first full-scale plant in the Netherlands and functions as a demonstration plant for MBR technology. It has been in operation for 5 years and many lessons have been learnt in that time. To gain experience with this new type of treatment and to demonstrate that MBR is suitable for purification of domestic wastewater in a real situation a vast research programme was undertaken. Based on the operational experiences and the research program it can be concluded that the MBR Varsseveld shows promising results. Compared to conventional activated sludge systems with sand filtration (CAS-SF), the MBR produces superior effluent quality. Energy consumption remains up to 30% higher than the CAS-SF system but there is possibility for further improvements. The cleaning philosophy, that combines a regular maintenance cleaning with 2-yearly intensive cleanings, is effective at maintaining the membranes in optimal condition. Based on the experiences with the Zenon ZW500d membranes, a membrane lifetime of up to 10 years is expected.

scholarly journals Evaluation of the accuracy of two simple methods for microscopic activated sludge analysis

2018 ◽  
Vol 78 (10) ◽  
pp. 2104-2112
Author(s):  
Mateusz Sobczyk ◽  
Agnieszka Pajdak-Stós ◽  
Edyta Fiałkowska ◽  
Wioleta Kocerba-Soroka ◽  
Joanna Starzycka-Giża ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Microscopic Analysis ◽  
Volume Index ◽  
Sign Test ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Effluent Quality ◽  
Significant Difference

Abstract Biological microscopic analysis is a popular method employed in wastewater treatment plants worldwide for evaluating activated sludge condition. However, many operators still have reservations regarding its reliability. In this study, we evaluated and compared two methods of microscopic sludge investigation: the sludge index (SI) and the Eikelboom–van Buijsen method (EB). We investigated 79 activated sludge samples from nine treatment plants located in southern Poland over a 1-year period. For each sample, sludge volume index values were calculated and compared with the results of evaluation made on the basis of microscopic analysis. Additionally, the effluent quality was analysed in 45 of 79 cases, including investigation of suspended solids, biochemical oxygen demand, chemical oxygen demand, total nitrogen and total phosphorous. The sign test and Wilcoxon matched pairs test showed that a significant difference existed between the two investigated methods. General conclusions from both methods do not provide reliable information concerning nitrogen and phosphorus removal. The EB method had a tendency to be more conservative in its general conclusions than the SI method. Both are highly reliable for estimating activated sludge quality and solid separation properties.

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