Comparison of membrane bioreactor systems in wastewater treatment (original) (raw)
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Journal of Membrane Science, 2011
In this study, the SMBR was compared in terms of membrane fouling with and without the addition of suspended medium in the membrane reactor. The effectiveness of medium in suspension in submerged membrane bioreactor (SMBR) was evaluated at different filtration flux. The SMBR was operated at a flux of 5-30 L/m 2 h (corresponding hydraulic retention time of 10-1.7 h) with and without suspended medium. The suspended medium used in this study was granular activated carbon (GAC; particle size 300-600 mm) at air scouring (aeration) rates of 0.5-1.5 m 3 m −2 membrane area h −1. At higher aeration rate of 1.5 m 3 /m 2 membrane area h, the effect of flux on membrane resistance was found to be negligible. The reduction of aeration rate from 1.5 to 1.0 m 3 m −2 membrane area h −1 resulted in a sudden rise of TMP. The addition of suspended medium prevented a sudden rise of TMP (total membrane resistance reduced from 51 × 10 11 to 20 × 10 11 m −1). The organic removal efficiency remained high irrespective of flux. The molecular weight distribution (MWD) and excitation emission matrix (EEM) analysis of SMBR effluent showed a range of organic (composed of amino acids, biopolymers, humics and fulvic acids type substances) removed by the GAC both by scouring and adsorption mechanisms.
A Novel Sponge‐Submerged Membrane Bioreactor (SSMBR) for Wastewater Treatment and Reuse
Separation Science and Technology, 2008
Membrane fouling has been regarded as one of the biggest challenges to widespread application of membrane bioreactor (MBR). This study focuses on minimizing the membrane fouling and improving the performance of submerged membrane bioreactor (SMBR) by porous sponge addition. The effects of sponge addition on sustainable flux and membrane fouling were investigated. Acclimatized sponge could significantly increase the suspended growth in SMBR with biomass of 16.7 g/L(sponge). With sponge volume fraction of 10%, SSMBR could enhance sustainable flux up to 50 L/m 2 .h compared with sustainable flux of SMBR (only 25 L/m 2 .h). SSMBR also exhibited excellent results in terms of DOC removal (over 95%), COD removal (over 97%), lower transmembrane pressure development and oxygen uptake rate. Over 89% of NH 4-N and 98% of PO 4-P were removed when SSMBR was operated with a MLSS concentration of 15 g/L.
Reaktor, 2009
The application of membrane to replace secondary clarifier of conventional activated sludge, known as membrane bioreactor, has led to a small footprint size of treatment with excellent effluent quality. The use of MBR eliminates almost all disadvantages encountered in conventional wastewater treatment plant such as low biomass concentration and washout of fine suspended solids. However, fouling remains as a main drawback. To minimize membrane fouling, a new configuration of submerged membrane bioreactor for aerobic industrial wastewater treatment has been developed. For the new configuration, a bed of porous particle is applied to cover the submerged ends-free mounted ultrafiltration membrane. Membrane performance was assessed based on flux productivity and selectivity. By using tapioca wastewater containing high organic matter as feed solution, reasonably high and stable fluxes around 11 l/m 2 .h were achieved with COD removal efficiency of more than 99%. The fouling analysis also shows that the newly configured ends-free membrane bioreactor exhibits lower irreversible resistance compared with the submerged one. In addition, the performance of pilot scale system, using a membrane module with 10 m 2 effective area and reactor tank with 120 L volume, was also assessed. The flux achieved from the pilot scale system around 8 l/m 2 .h with COD removal of more than 99%. Hence, this study has demonstrated the feasibility of the newly configured submerged ends-free MBR at larger scale.
This study focuses on comparing the performance of submerged membrane bioreactor (SMBR) and submerged membrane adsorption bioreactor (SMABR) over a period of 20 days at a hydraulic retention time (HRT) of 3.1 hours. The effects of PAC on critical flux and membrane fouling were also investigated. The SMABR exhibited better results in terms of mixed liquor suspended solids (MLSS) growth, DOC removal (over 96%), COD removal (over 95%), transmembrane pressure (TMP) and oxygen uptake rate. Nearly 100% of bacteria and 100% removals of total coliforms were removed in both systems. The addition of PAC could maintain the critical flux at a lower TMP value (7.5 kPa), while irreversible fouling caused by PAC occurred when the filtration flux exceeded critical flux.
Despite the intrinsic potential benefits of Submerged Membrane Bioreactor (sMBR) to wastewater treatment and the role it plays on water reuse, the reduction in the membrane permeability caused by fouling phenomenon still remains one of the major drawbacks of such a system. The efficacy of the process is constrained by the accumulation of materials on the surface of or within the membrane. In order to minimize and control the negative effect of fouling in membrane bioreactor different methods has been developed and tested, such as the addition of certain chemicals in the mixed liquor as Powdered Activated Carbon (PAC), metal salts, organic and inorganic polyelectrolytes and biopolymer. Although the addition of chemicals in the mixed liquor reduces membrane fouling in sMBR, resulting in an enhanced filterability, it is important to keep in mind this procedure increases operational costs. Thus, several researches has been focused on hybrid system as an alternative to the conventional MBR (C-MBR) trying to combine the advantages of biofilm and MBR processes in order to overcome some of the limitation of C-MBR. Addition of biofilm supports in activated sludge processes can assist in biodegradation, improving nutrient removal and filterability of membrane, which leads to an increased capacity and overall improved performance of existing activated sludge reactor [1,2]. Within this context, the present study aimed to compare the overall performances of BF-MBR and C-MBR in removal of organic matter, nitrogen and the influence on membrane filterability.
Pilot scale study on a new membrane bioreactor hybrid system in municipal wastewater treatment
Bioresource Technology, 2013
A pilot scale membrane bioreactor hybrid system (MBR-HS) was evaluated for municipal wastewater treatment. This novel system comprised of a granular activated carbon-sponge fluidized bed bioreactor (GACS-FBBR) followed by a submerge membrane bioreactor (MBR) with the capacity of 2L per minute. The results indicated that the MBR-HS could effectively remove 90% DOC and 95% NH 4-N. PO 4-P removal efficiency was remained stable at about 70% throughout the experiment. Specific oxygen uptake rate (SOUR) of activated sludge increased from 0.72 to 2.21 mg O 2 /gVSS.h for the first 10 days and then followed by a steady stage until the end of experiment. Sludge volume index (SVI) was always below 50 mL/g, demonstrated an excellent settling properties of sludge. The system also showed an achievement in terms of low trans-membrane pressure (TMP) development rate. The TMP increasing rate was only 0.65 kPa/ day, suggesting GACS-FBBR can be a promising pre-treatment for MBR.
Despite the intrinsic potential benefits of Submerged Membrane Bioreactor (sMBR) to wastewater treatment and the role it plays on water reuse, the reduction in the membrane permeability caused by fouling phenomenon still remains one of the major drawbacks of such a system. The efficacy of the process is constrained by the accumulation of materials on the surface of or within the membrane. In order to minimize and control the negative effect of fouling in membrane bioreactor different methods has been developed and tested, such as the addition of certain chemicals in the mixed liquor as Powdered Activated Carbon (PAC), metal salts, organic and inorganic polyelectrolytes and biopolymer. Although the addition of chemicals in the mixed liquor reduces membrane fouling in sMBR, resulting in an enhanced filterability, it is important to keep in mind this procedure increases operational costs. Thus, several researches has been focused on hybrid system as an alternative to the conventional M...
Membrane bioreactor performance improvement by adding adsorbent and coagulant: a comparative study
Desalination and Water Treatment, 2015
Membrane bioreactors (MBRs) have become popular in recent years due to its excellent organic pollutants removal efficiency. However, its popularity has been restricted by a major constraint which is high maintenance cost incurred by membrane fouling in the system. Currently, hybrid MBRs with additives were found efficient in controlling membrane fouling. In this study, the performance of two additives consist of powdered activated carbon (PAC) and alum in enhancing membrane fouling control in MBRs were determined and compared. Three 6L laboratory-scale submerged MBRs known as conventional MBR (without additive), MBR-PAC (added with PAC), and MBR-Coagulant (added with alum) with SRT 30 were set up. It was observed that the MBRs with additive could enhance MLSS concentrations by about 7-13% and reduce the protein concentration (one of the main foulants) by 43-70%, respectively. The results revealed that by adding alum and PAC into the MBRs, membrane fouling control of MBRs could be improved. MBR-PAC performed best in this study as it could be operated steadily without any sign of transmembrane pressure "jump" as compared to the other two MBRs even it was operated under "stress" condition by treating high strength wastewater during the experimental filtration period.
2009
The application of membrane to replace secondary clarifier of conventional activated sludge, known as membrane bioreactor, has led to a small footprint size of treatment with excellent effluent quality. The use of MBR eliminates almost all disadvantages encountered in conventional wastewater treatment plant such as low biomass concentration and washout of fine suspended solids. However, fouling remains as a main drawback. To minimize membrane fouling, a new configuration of submerged membrane bioreactor for aerobic industrial wastewater treatment has been developed. For the new configuration, a bed of porous particle is applied to cover the submerged ends-free mounted ultrafiltration membrane. Membrane performance was assessed based on flux productivity and selectivity. By using tapioca wastewater containing high organic matter as feed solution, reasonably high and stable fluxes around 11 l/m.h were achieved with COD removal efficiency of more than 99%. The fouling analysis also sho...
Separation and Purification Technology, 2016
The performance and membrane fouling of a lab-scale submerged sponge-membrane bioreactor (Sponge-MBR) and a conventional MBR were investigated and compared for hospital wastewater treatment at low fluxes of 2-6 LMH. COD removal by the Sponge-MBR was similar to that of the MBR, while the Sponge-MBR achieved 9-16% removed more total nitrogen than the MBR. This was due to 60% of total biomass being entrapped in the sponges, which enhanced simultaneous nitrification denitrification. Additionally, the fouling rates of the Sponge-MBR were 11-, 6.2and 3.8-times less than those of the MBR at flux rates of 2, 4 and 6 LMH, respectively. It indicates the addition of sponge media into a MBR could effectively reduce the fouling caused by cake formation and absorption of soluble substances in a low flux scenario.