scholarly journals Membrane Bioreactor Technology: The Effect of Membrane Filtration on Biogas Potential of the Excess Sludge

Membranes ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 397
Author(s):  
Magdalena Zielińska ◽  
Katarzyna Bernat ◽  
Wioleta Mikucka

Although the membrane bioreactor technology is gaining increasing interest because of high efficiency of wastewater treatment and reuse, data on the anaerobic transformations of retentate are scarce and divergent. The effects of transmembrane pressure (TMP) in microfiltration (MF) and ultrafiltration (UF) on the pollutant rejection, susceptibility of ceramic membrane to fouling, hydraulic parameters of membrane module, and biogas productivity of retentate were determined. Irrespective of the membrane cut-off and TMP (0.2–0.4 MPa), 97.4 ± 0.7% of COD (chemical oxygen demand), 89.0 ± 4.1% of total nitrogen, and 61.4 ± 0.5% of total phosphorus were removed from municipal wastewater and the permeates can be reused for irrigation. Despite smaller pore diameter, UF membrane was more hydraulically efficient. MF membrane had 1.4–4.6 times higher filtration resistances than UF membrane. In MF and UF, an increase in TMP resulted in an increase in permeate flux. Despite complete retention of suspended solids, strong shearing forces in the membrane installation changed the kinetics of biogas production from retentate in comparison to the kinetics obtained when excess sludge from a secondary clarifier was anaerobically processed. MF retentates had 1.15 to 1.28 times lower cumulative biogas production than the excess sludge. Processing of MF and UF retentates resulted in about 60% elongation of period in which 90% of the cumulative biogas production was achieved.

2017 ◽  
Vol 76 (7) ◽  
pp. 1796-1804 ◽  
Author(s):  
Konstantinos Azis ◽  
Charalampos Vardalachakis ◽  
Spyridon Ntougias ◽  
Paraschos Melidis

The aim of this study was to assess the efficacy and effluent quality of a pilot-scale intermittently aerated and fed, externally submerged membrane bioreactor (MBRes) treating municipal wastewater. The effluent quality of the MBRes was evaluated regarding system ability to comply with the Greek legislative limits for restricted and unrestricted wastewater reuse. The average permeate flux was 13.9 L m−2 h−1, while the transmembrane pressure remained above the level of −110 mbar. Experimental data showed that biochemical oxygen demand, chemical oxygen demand, total nitrogen, PO43−- P and total suspended solids removal efficiencies were 97.8, 93.1, 89.6, 93.2 and 100%, respectively, whereas turbidity was reduced by 94.1%. Total coliforms and Escherichia coli were fully eliminated by ultrafiltration and disinfection methods, such as chlorination and ultraviolet radiation. In agreement with the Greek legislation (Joint Ministerial Decree 145116/11) and the guidelines recommended for the Mediterranean countries, the disinfected effluent of the MBRes system can be safely reused directly for urban purposes.


2013 ◽  
Vol 68 (11) ◽  
pp. 2374-2381 ◽  
Author(s):  
Lu Chen ◽  
Jiang Wei ◽  
Weiguo Wang ◽  
Cunwen Wang

The treatment of wastewater by microalgae cultivation has attracted more and more attention. However, the way to harvest microalgae cells from the wastewater and the treatment of the large quantity of residual solution have become critical issues. In this work, a new approach for the treatment of municipal wastewater is presented. The combination of flocculation for removing mainly microalgae and thereafter membrane filtration for chemical oxygen demand (COD) and conductivity reduction of the residual solution after flocculation is discussed. The COD concentration of the wastewater decreased from 260 to 84 mg/L after flocculation by chitosan. Five ultrafiltration (UF) membranes and two nanofiltration (NF) membranes were used for filtration to find a suitable membrane for COD and conductivity reduction. Among the five UF membranes, GR82PE showed the best performance, whose permeate flux and COD retention at 4 bar were 189.66 L/(m2·h) and 43.03%, respectively. NF membranes showed higher COD and conductivity retentions than UF membranes. The COD retention of Desal5-DK reached 98.3% at 20 bar. Lastly, the flux recovery after the filtration test of each membrane is also discussed.


2019 ◽  
Vol 79 (3) ◽  
pp. 458-465
Author(s):  
V. A. Razafimanantsoa ◽  
D. Adyasari ◽  
A. K. Sahu ◽  
B. Rusten ◽  
T. Bilstad ◽  
...  

Abstract The goal of this study was to investigate what kind of impact the removal of particulate organic matter with 33μm rotating belt filter (RBF) (as a primary treatment) will have on the membrane bioreactor (MBR) performance. Two small MBR pilot plants were operated in parallel, where one train treated 2mm screened municipal wastewater (Train A) and the other train treated wastewater that had passed through a RBF with a 33μm filter cloth (Train B). The RBF was operated without a filter mat on the belt. About one third of the organic matter was removed by the fine mesh filter. The assessment of the overall performance showed that the two pilot plants achieved approximately the same removal efficiencies with regard to total suspended solids (TSS), chemical oxygen demand (COD), total phosphorus and total nitrogen. It was also observed that the system with 33μm RBF as a primary treatment produced more sludge, which could be used for biogas production, and required about 30% less aeration downstream. Transmembrane pressure was significantly lower for the train receiving 33μm primary treated wastewater compared to the control receiving 2mm screened wastewater.


2021 ◽  
Vol 83 (6) ◽  
pp. 1459-1469
Author(s):  
Yulan Gao ◽  
Jie Yang ◽  
Xinwei Song ◽  
Dongmei Shen ◽  
Wanfen Wang ◽  
...  

Abstract Several water treatment techniques have been combined using the sequencing batch reactor with the membrane bioreactor for addressing water pollution. However, cleaning of the membrane is dependent on the approach involved as well as the operating conditions. In the present study, the sequencing-batch membrane bioreactor was used to treat real mixed municipal wastewater. The pollutant removal and membrane filtration performances were examined. The results show that the average removal rates of chemical oxygen demand (COD), total nitrogen, NH3-N, total phosphorus, and turbidity were 90.75, 63.52, 92.85, 87.58, and 99.48%, respectively, when the system was in continuous operation for 95 days. The membrane had a significant effect on COD and turbidity removal and provided stable performances for nitrogen and phosphorus removal. By observing the appearance of the membrane modules before and after the cleaning operation, it was concluded that the deposited sludge and granular sediment on the membrane surface can be effectively removed by hydraulic cleaning. In addition, recovery of membrane filtration performance to 60% of that of a new membrane can be achieved. Furthermore, we found that different sequences and duration of cleaning have different effects on the recovery of membrane filtration performance.


2015 ◽  
Vol 73 (3) ◽  
Author(s):  
Zakariah Yusuf ◽  
Norhaliza Abdul Wahab ◽  
Shafishuhaza Sahlan ◽  
Abdul Halim Abdul Raof

Recently, membrane technology has become more attractive particularly in solid-liquid separation process. Membrane bioreactor (MBR) has found to be a reliable technology to replace the conventional activated sludge (CAS) process for water and wastewater treatment by adopting membrane filtration technology and bioreactor. However, numerous drawbacks arise when using membrane which includes high maintenance cost and fouling problem. An optimal MBR plant operation is needed to be determined in order to reduce fouling and at the same time reduce the cost of running the MBR. It is crucial to have a reliable MBR filtration prediction that can measure and predict the filtration dynamic performance especially the effect of fouling to the filtration and cleaning operations. With this prediction tool, suitable action can be taken to improve the operation in order to find the optimum setting of the filtration process. This paper presents the permeate flux measurement and prediction development for submerged membrane filtration process. Three input filtration parameters were used to predict the permeate flux in the filtration process. This work  employed feed forward artificial neural network (FFNN) and radial basis function neural network (RBFNN) for the prediction purpose. The permeate flux prediction method was developed using operation settings such as aeration airflow, suction pump voltage and transmembrane pressure (TMP) under schedule relaxation condition.  The result shows that FFNN method gives better performance compared with RBFNN method in terms of accuracy and reliability. 


2000 ◽  
Vol 41 (10-11) ◽  
pp. 243-250 ◽  
Author(s):  
X-j. Fan ◽  
V. Urbain ◽  
Y. Qian ◽  
J. Manem

A cross-flow membrane bioreactor (MBR) for raw municipal wastewater treatment, consisting of a suspended growth bioreactor and a ceramic membrane ultrafiltration unit, was run over a period of more than 300 days in a wastewater treatment plant (WWTP). Sludge Retention Times (SRT) of 20, 10 and 5 days, respectively, and Hydraulic Retention Times (HRT) of 15 and 7.5 hours were tested. Membrane fouling was found to be a function of SRT and permeate flux. Under an SRT of 20 days and flux of 71 l/m2\ · h at 30°C, the MBR was successfully run over 70 days without the need for chemical cleaning. However chemical cleaning had to be undertaken every 3–5 days at shorter sludge retention times (typically an SRT of five days and a flux of 143 l/m2\ · h at 30°C). In this study, fouling materials were removed efficiently through chemical cleaning, with an average permeablity recovery of 87±11%.


2018 ◽  
pp. 11-18

Biofouling is a serious and challenging problem in water treatment systems which hinder the efficiency of membrane filtration performance. The aim of this study was to investigate the biofouling propensity and biological treatment performance of a bacterial consortium in a biological membrane bioreactor for the treatment of dye wastewater. During bioreactor operation with the bacterial consortium, a significant relationship was revealed between transmembrane pressure (TMP) and extracellular polymeric substances (EPS). When tested for dye and chemical oxygen demand (COD) removal, SMBR showed increased removal performance with the operating time, possibly owing to the biofilm formation on membrane and the adaptation of sludge. Thus, it is expected that the results of this study will be valuable for further development of a suitable biofouling mitigation strategy for batik wastewater treatment in membrane bioreactor. Keywords: Biofouling; biofilm, Batik wastewater; bacterial consortium; extracellular polymeric substances


2017 ◽  
Vol 76 (4) ◽  
pp. 953-962
Author(s):  
B. Düppenbecker ◽  
S. Kale ◽  
M. Engelhart ◽  
P. Cornel

This study focuses on the use of fluidized glass beads as turbulence promoters in a laboratory-scale anaerobic membrane bioreactor treating municipal wastewater at 20 °C. The addition of fluidized glass beads into an external tubular ceramic membrane enabled the operation at low crossflow velocities of 0.053–0.073 m/s (mean fluxes between 5.5 and 9.7 L/(m2·h)) with runtimes >300 h. Glass beads with a diameter of 1.5 mm were more effective than smaller ones with a diameter of 0.8–1.2 mm. Increasing the bed voidage from 74 to 80% did not show any beneficial effect. As scanning electron microscope examination showed, the fluidized glass beads damaged the used membrane by abrasion. The overall total chemical oxygen demand (COD) removal was between 77 and 83%, although mean hydraulic retention times were only between 1.3 and 2.3 h. The production of total methane was increased about 30% in comparison to the bioreactor without membrane. The increased methane production is presumably attributed to biological conversion of rejected, dissolved and particulate organic matter. The total required electrical energy was predicted to be about 0.3 kWh/m3.


2015 ◽  
Vol 72 (12) ◽  
pp. 2301-2307 ◽  
Author(s):  
Xiaodi Yue ◽  
Yoong Keat Kelvin Koh ◽  
How Yong Ng

In this study, a ceramic membrane with a pore size of 80 nm was incorporated into an anaerobic membrane bioreactor for excellent stability and integrity. Chemical oxygen demand (COD) removal efficiencies by biodegradation reached 78.6 ± 6.0% with mixed liquor suspended solids (MLSS) of 12.8 ± 1.2 g/L. Even though the total methane generated was 0.3 ± 0.03 L/g CODutilized, around 67.4% of it dissolved in permeate and was lost beyond collection. As a result, dissolved methane was 2.7 times of the theoretical saturating concentration calculated from Henry's law. When transmembrane pressure (TMP) of the ceramic membrane reached 30 kPa after 25.3 d, 95.2% of the total resistance was attributed to the cake layer, which made it the major contributor to membrane fouling. Compared to the mixed liquor, cake layer was rich in colloids and soluble products that could bind the solids to form a dense cake layer. The Methanosarcinaceae family preferred to attach to the ceramic membranes.


2013 ◽  
Vol 788 ◽  
pp. 152-155
Author(s):  
Tomáš Bakalár ◽  
Milan Búgel ◽  
Henrieta Pavolová ◽  
Gabriel Müller

The influence of transmembrane pressure on the permeate flux, and the critical and limiting fluxes in microfiltration of two sorbents Bentonite a natural sorbent, montmorillonite based clay and Lewatit S1468 a synthetic sorbent, styrene-divinylbenzene based copolymer were studied. An asymmetric single-channel inorganic ceramic membrane based on α-Al2O3 was used. The experimental data were obtained by continuous microfiltration equipment. According to the results the limiting flux ranged from 37 to 70 l.m-2.h-1 for Bentonite suspensions. It was not possible to estimate the limiting flux for Lewatit S1468 suspension.


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