Optimal sludge retention time for a bench scale MBR treating municipal sewage

2008 ◽  
Vol 57 (3) ◽  
pp. 319-322 ◽  
Author(s):  
A. Pollice ◽  
G. Laera ◽  
D. Saturno ◽  
C. Giordano ◽  
R. Sandulli
Keyword(s):  
Activated Sludge ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Operating Conditions ◽  
Municipal Sewage ◽  
Process Conditions ◽  
Physical Parameters ◽  
Municipal Wastewater Treatment ◽  
Bench Scale ◽  
Conventional Activated Sludge

Membrane bioreactors allow for higher sludge concentrations and improved degradation efficiencies with respect to conventional activated sludge. However, in the current practice these systems are often operated under sub-optimal conditions, since so far no precise indications have yet been issued on the optimal operating conditions of MBR for municipal wastewater treatment. This paper reports some results of four years of operation of a bench scale membrane bioreactor where steady state conditions were investigated under different sludge retention times. The whole experimental campaign was oriented towards the investigation of optimal process conditions in terms of COD removal and nitrification, biomass activity and growth, and sludge characteristics. The membrane bioreactor treated real municipal sewage, and four different sludge ages were tested (20, 40, 60, and 80 days) and compared with previous data on complete sludge retention. The results showed that the the biology of the system, as assessed by the oxygen uptake rate, is less affected than the sludge physical parameters. In particular, although the growth yield was observed to dramatically drop for SRT higher than 80 days, the biological activity was maintained under all the tested conditions. These considerations suggest that high SRT are convenient in terms of limited excess sludge production without losses of the treatment capacity. Physical characteristics such as the viscosity and the filterability appear to be negatively affected by prolonged sludge retention times, but their values remain within the ranges normally reported for conventional activated sludge.

scholarly journals LCA of a Membrane Bioreactor Compared to Activated Sludge System for Municipal Wastewater Treatment

Membranes ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 421
Author(s):  
Dimitra C. Banti ◽  
Michail Tsangas ◽  
Petros Samaras ◽  
Antonis Zorpas
Keyword(s):  
Wastewater Treatment ◽  
Life Cycle ◽  
Activated Sludge ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Real Data ◽  
Municipal Wastewater Treatment ◽  
Conventional Activated Sludge

Membrane bioreactor (MBR) systems are connected to several advantages compared to the conventional activated sludge (CAS) units. This work aims to the examination of the life cycle environmental impact of an MBR against a CAS unit when treating municipal wastewater with similar influent loading (BOD = 400 mg/L) and giving similar high-quality effluent (BOD < 5 mg/L). The MBR unit contained a denitrification, an aeration and a membrane tank, whereas the CAS unit included an equalization, a denitrification, a nitrification, a sedimentation, a mixing, a flocculation tank and a drum filter. Several impact categories factors were calculated by implementing the Life Cycle Assessment (LCA) methodology, including acidification potential, eutrophication potential, global warming potential (GWP), ozone depletion potential and photochemical ozone creation potential of the plants throughout their life cycle. Real data from two wastewater treatment plants were used. The research focused on two parameters which constitute the main differences between the two treatment plants: The excess sludge removal life cycle contribution—where GWPMBR = 0.50 kg CO2-eq*FU−1 and GWPCAS = 2.67 kg CO2-eq*FU−1 without sludge removal—and the wastewater treatment plant life cycle contribution—where GWPMBR = 0.002 kg CO2-eq*FU−1 and GWPCAS = 0.14 kg CO2-eq*FU−1 without land area contribution. Finally, in all the examined cases the environmental superiority of the MBR process was found.

scholarly journals Study the Effect of Temperature on the Performance of Hollow Fiber Membrane Bioreactor in Wastewater Treatment

2014 ◽  
Vol 8 (1) ◽  
pp. 25-29
Author(s):  
Alaa K. Mohammed ◽  
Qusay Fathel ◽  
Safaa A. Ali
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Membrane Bioreactor ◽  
Chemical Engineering ◽  
Municipal Wastewater ◽  
Hollow Fiber Membrane ◽  
Effect Of Temperature ◽  
Municipal Wastewater Treatment ◽  
Conventional Activated Sludge ◽  
Engineering Department

A membrane bioreactor (MBR) is one of the modifications to the conventional activated sludge process, since it is the combination of a membrane module and a bioreactor. In the present study, 100 liters lab-scale aerobic MBR was seeded with 1.5 Liter activated sludge and municipal wastewater from AL-Rustumiya municipal wastewater treatment station, two hollow fibers sample (MI,MII) manufactured in the University of Technology/ Chemical Engineering Department, were used as biomembranes. Trans membrane pressure TMP was studied and it was found that the optimum value of TMP was 10 cm Hg vacuum which gave optimum effluent flux 400 ml/hr for MI and 350 ml/hr for MII. The experimental work involves the effect of temperature 25, 35, 45°C on the performance of the MBR fibers sample (MI, MII) and its effect on biomass growth and removal efficiency of the COD, BOD. Both samples show good performance in 25°C.

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.

Evaluating the application of Microbacterium sp. strain BR1 for the removal of sulfamethoxazole in full-scale membrane bioreactors

2015 ◽  
Vol 72 (10) ◽  
pp. 1754-1761 ◽  
Author(s):  
A. Fenu ◽  
B. M. R. Donckels ◽  
T. Beffa ◽  
C. Bemfohr ◽  
M. Weemaes
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Membrane Bioreactors ◽  
Full Scale ◽  
Process Conditions ◽  
Municipal Wastewater Treatment ◽  
Viable Biomass ◽  
The One ◽  
Micro Organisms

Microbacterium sp. strain BR1 is a bacterial strain that recently received attention for its capability to mineralize sulfamethoxazole (SMX) and other sulfonamides. In this study, the survival of Microbacterium sp. in municipal sludge waters was tested in batch experiments to explore optimal process conditions. Inoculation of Microbacterium sp. was subsequently performed in a pilot membrane bioreactor (MBR) operated in two configurations: treating full-scale MBR permeate (post-treatment) and treating raw municipal wastewater. SMX removal by Microbacterium sp. could not be proved in any of the configurations, except for SMX concentrations far higher than the ones normally found in municipal wastewater. By use of molecular tools (fluorescence in situ hybridization analysis) a low capability to survive in activated sludge systems was assessed. After inoculation, Microbacterium sp. was reduced to a small fraction of the viable biomass. The observed growth rate appeared to be many times lower than the one of typical activated sludge micro-organisms. Possibilities of application in full-scale municipal wastewater treatment are scarce.

Removal of endocrine disrupter compounds from municipal wastewater by an innovative biological technology

2008 ◽  
Vol 58 (4) ◽  
pp. 953-956 ◽  
Author(s):  
L. Balest ◽  
G. Mascolo ◽  
C. Di Iaconi ◽  
A. Lopez
Keyword(s):  
Activated Sludge ◽  
Biological Treatment ◽  
Municipal Wastewater ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Municipal Sewage ◽  
Activated Sludge Process ◽  
Endocrine Disrupter ◽  
Conventional Activated Sludge ◽  
Conventional Activated Sludge Process

The removal of selected endocrine disrupter compounds (EDCs), namely estrone(E1), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), bisphenol A (BPA) and 4-tert-octylphenol (4t-OP) from municipal wastewater was investigated using a sequencing batch biofilter granular reactor (SBBGR), a new system for biological treatment based on aerobic granular biomass. This new biological treatment is characterized by high biomass concentration (up to 40 g/L), high sludge retention times (up to 6 months) and low sludge production (i.e., an order of magnitude lower than commonly reported for conventional biological technologies). The investigation was carried out comparing a demonstration SBBGR system with a conventional full-scale activated sludge process. Results showed that the SBBGR performed better than a conventional activated sludge process in removing E1, E2, BPA and 4t-OP. In fact, the average removal percentages of the above mentioned EDCs, obtained during a four month operating period, were 62.2, 68, 91.8, 77.9% and 56.4, 36.3, 71.3, 64.6% for the demonstrative SBBGR system and the conventional activated sludge process of the municipal sewage treatment plant, respectively

Mathematical Modeling of Aerobic Membrane Bioreactor (MBR) Using Hybrid Activated Sludge Model No. 3 (ASM3)

2010 ◽  
Vol 113-116 ◽  
pp. 1424-1428
Author(s):  
Yu Tian ◽  
Lin Chen ◽  
Xin Ying Su ◽  
Chu Qing Cao
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Recent Trend ◽  
Trial And Error ◽  
Municipal Wastewater Treatment ◽  
Sludge Retention Time ◽  
Microbial Products ◽  
Operating Strategies

Recent trend for membrane bioreactor (MBR) operation was to apply a low sludge retention time (SRT) to decrease the fouling propensity and simplify the overall maintenance. However, the correct control and operation of MBRs under low SRT conditions were not well-established. In this study, modeling of MBR system for municipal wastewater treatment was evaluated using hybrid Activated Sludge Models 3 (ASM3), which helped in determining the control and operating strategies. The experiment-based, manual trial-and-error approach used to calibrate the hybrid ASM3 was verified to be useful for MBR modeling at 30 d sludge retention time (SRT). Furthermore, the consistency relationships among carbon oxygen demanded (COD), soluble microbial products (SMP) and mixed liquor suspended solids (MLSS) were established in the process of modeling, implying that the accurate simulation of MLSS were the prerequisites for the COD and SMP prediction.

scholarly journals Fate of selected pharmaceutically active compounds in the integrated fixed film activated sludge process

2017 ◽  
Vol 75 (11) ◽  
pp. 2680-2691 ◽  
Author(s):  
K. J. Murray ◽  
W. J. Parker ◽  
L. M. Bragg ◽  
M. R. Servos
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Nitrification Rate ◽  
Process Conditions ◽  
Batch Reactors ◽  
Experimental Conditions ◽  
Conventional Activated Sludge ◽  
Fixed Film ◽  
Solids Retention ◽  
Biomass Activity

The potential for integrated fixed film activated sludge (IFAS) processes to achieve enhanced transformation of pharmaceuticals relative to conventional activated sludge (CAS) processes was assessed. Previous studies have focused on direct comparisons of parallel reactors with and without fixed film carriers and little information is available on the impacts of how varying operating parameters impact the differences in observed pharmaceutical compound (PC) transformation capabilities between CAS reactors and those equipped with both an activated sludge (AS) and fixed film carriers. The testing was carried out using bench scale sequencing batch reactors fed with authentic municipal wastewater and operated at selected combinations of temperature and solids retention time (SRT). PC transformation efficiencies were assessed in a 22 factorial design that employed the IFAS and CAS processes, operated in parallel under identical process conditions. Nitrification rate testing that was conducted to obtain insight into the biomass activity demonstrated that IFAS consistently had improved nitrification kinetics despite lower mixed liquor volatile suspended solids levels thereby demonstrating the contribution of the biofilm to nitrification. Increased transformation of atenolol (ATEN; ranging from 10–60%) and trimethoprim (TRIM; ranging from 30–50%) in the IFAS equipped reactors relative to their respective activated sludge (AS) controls was observed under all experimental conditions. Negligible transformation of carbamazepine was observed in both reactors under all conditions investigated. More than 99% of acetaminophen was transformed in both configurations under all conditions. There was no correspondence between nitrification activity and TRIM removal in the control AS while conditions that stimulated nitrification in the control AS also resulted in enhanced removal of ATEN. The results of this study indicate that the integration of biofilms in AS processes enhances transformation of some PCs.

Bench-Scale Testing of Activated Sludge Treatment for a TMP Wastewater

1993 ◽  
Vol 28 (3) ◽  
pp. 571-596 ◽  
Author(s):  
Susan F. Liver ◽  
Henry K. Miyamoto ◽  
Steve A. Black
Keyword(s):  
Activated Sludge ◽  
Full Scale ◽  
Operating Conditions ◽  
Cold Weather ◽  
Sludge Treatment ◽  
Bench Scale ◽  
Conventional Activated Sludge ◽  
Initial Batch ◽  
Treated Effluent ◽  
Biokinetic Parameters

Abstract A continuous bench-scale treatability study determined the most desirable design and operating parameters for waste treament of effluent from an integrated Canadian TMP newsprint operation. An initial batch study indicated that the effluent was biologically treatable and provided initial biological kinetic (biokinetic) parameters for this wastewater. This information was used to design the continuous study. Conventional activated sludge treatment of the mill wastewater can produce an effluent which meets the federal regulations for BOD5, suspended solids, and toxicity to D. magna. Predictions using cumulative toxicity units (CTU) indicate that the treated effluent would also be non-toxic to O. mykiss as well. Analyses of ammonia in the treated effluent indicated that un-ionized ammonia concentrations would be non-toxic to rainbow trout. Mass balances incorporating the results of the bench-scale studies and the effect of fibre carry-over from the primary clarifier, defined the full-scale operating conditions selected as: an F/M of 0.35 d−1, HRT of 0.5 days, SRT of 6 days and an MLSS of 4400 mg/L (when no polymer is used at the primary clarifier). These conditions were arrived at by selecting the smallest HRT which still corresponded to an MLSS &lt; 5000 mg/L, an F/M &lt; 0.4 d−1 and an SRT &gt; 5 days. Based on the kinetics for biological treatment of mill effluent, at the maximum mill production, adequate BOD5 removal will still easily be obtained under the above operating conditions, even during cold weather periods. Operational concerns identified by bench-scale testing indicated that a full-scale facility should incorporate an anoxic selector (although the anoxic selector did not show measurable improvement in the bench-scale tests) and micronutrient addition for filamentous bulking control.

Effectiveness of the membrane bioreactor in the biodegradation of high molecular-weight compounds

1996 ◽  
Vol 34 (9) ◽  
pp. 197-203 ◽  
Author(s):  
H. Winnen ◽  
M. T. Suidan ◽  
P. V. Scarpino ◽  
B. Wrenn ◽  
N. Cicek ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Extended Period ◽  
Membrane System ◽  
Pilot Scale ◽  
Synthetic Wastewater ◽  
Activated Sludge Process ◽  
Conventional Activated Sludge ◽  
Heterotrophic Microorganisms

The activated sludge process has been used extensively to treat municipal wastewater. The membrane bioreactor (MBR) process is a modification of the conventional activated sludge process where the clarifier is replaced with a membrane system for separation between the mixed liquor and the effluent. This paper presents the biological and physical performance data of a pilot-scale membrane bioreactor system, fed with a synthetic wastewater. At steady state, particularly high effluent quality was obtained and maintained for an extended period of time. Heterotrophic plate counting showed that the membrane retains heterotrophic microorganisms. Bacteriophage MS-2 was used to determine the retention of viruses. The membrane proved to retain the MS-2 virus.

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