Role of extracellular polymeric substances (EPSs) in membrane fouling of membrane bioreactor coupled with worm reactor

Membrane bioreactor (MBR) has developed rapidly in recent years; however, the membrane fouling problems are affecting its further widespread application. This paper discusses the role of metal ions in the mixture in the mechanism; also on the high-priced metal ions coexist in the mixture when the effects of biological flocculation process; finally, the direction of future research in this area are summarized.

Download Full-text

Investigation of long-term operation and biomass activity in a membrane bioreactor system

Water Science & Technology ◽

10.2166/wst.2011.416 ◽

2011 ◽

Vol 63 (9) ◽

pp. 1906-1912 ◽

Cited By ~ 6

Author(s):

Simos Malamis ◽

Andreas Andreadakis ◽

Daniel Mamais ◽

Constantinos Noutsopoulos

Keyword(s):

Membrane Fouling ◽

Membrane Bioreactor ◽

Extracellular Polymeric Substances ◽

Operating Conditions ◽

Term Operation ◽

Solids Retention ◽

Biomass Activity ◽

Long Term Performance ◽

Term Performance

The aim of this work was to evaluate the long-term performance of a Membrane Bioreactor (MBR) that operated continuously for 2.5 years and to assess membrane fouling and biomass activity under various operating conditions. Furthermore, a method for the characterisation of influent wastewater was developed based on its separation into various fractions. The MBR system operated at the solids retention times (SRT) of 10, 15, 20 and 33 days. The increase of SRT resulted in a decrease of the fouling rate associated with the reduction of extracellular polymeric substances. Moreover, the SRT increase resulted in a significant reduction of the Oxygen Uptake Rate (OUR) due to the lower availability of substrate and in a notable decrease of the maximum OUR since high SRT allowed the development of slower growing microorganisms. Biomass consisted of small flocs due to extensive deflocculation caused by intense aeration. Finally, the method developed for wastewater characterisation is straightforward and less time consuming than the usual method that is employed.

Download Full-text

Biomass Characteristics and Their Effect on Membrane Bioreactor Fouling

Molecules ◽

10.3390/molecules24162867 ◽

2019 ◽

Vol 24 (16) ◽

pp. 2867 ◽

Cited By ~ 5

Author(s):

Petros K. Gkotsis ◽

Anastasios I. Zouboulis

Keyword(s):

Membrane Fouling ◽

Membrane Bioreactor ◽

Suspended Solids ◽

Extracellular Polymeric Substances ◽

Membrane Surface ◽

Membrane Resistance ◽

Soluble Microbial Products ◽

Gelling Properties ◽

Microbial Products ◽

Soluble Part

Biomass characteristics are regarded as particularly influential for fouling in Membrane Bio-Reactors (MBRs). They primarily include the Mixed Liquor Suspended Solids (MLSS), the colloids and the Extracellular Polymeric Substances (EPS). Among them, the soluble part of EPS, which is also known as Soluble Microbial Products (SMP), is the most significant foulant, i.e., it is principally responsible for membrane fouling and affects all fundamental fouling indices, such as the Trans-Membrane Pressure (TMP) and the membrane resistance and permeability. Recent research in the field of MBRs, tends to consider the carbohydrate fraction of SMP (SMPc) the most important characteristic for fouling, mainly due to the hydrophilic and gelling properties, which are exhibited by polysaccharides and allow them to be easily attached on the membrane surface. Other wastewater and biomass characteristics, which affect indirectly membrane fouling, include temperature, viscosity, dissolved oxygen (DO), foaming, hydrophobicity and surface charge. The main methods employed for the characterization and assessment of biomass quality, in terms of filterability and fouling potential, can be divided into direct (such as FDT, SFI, TTF100, MFI, DFCM) or indirect (such as CST, TOC, PSA, RH) methods, and they are shortly presented in this review.

Download Full-text

Performance of membrane bioreactor combined with pre-coagulation/sedimentation

Water Science & Technology Water Supply ◽

10.2166/ws.2004.0017 ◽

2004 ◽

Vol 4 (1) ◽

pp. 143-149 ◽

Cited By ~ 3

Author(s):

T. Itonaga ◽

Y. Watanabe

Keyword(s):

Membrane Fouling ◽

Membrane Bioreactor ◽

Suspended Solids ◽

Extracellular Polymeric Substances ◽

Municipal Wastewater ◽

Treatment Plant ◽

Municipal Wastewater Treatment ◽

Term Operation ◽

Made In

This paper deals with the performance of a hybrid membrane bioreactor (MBR) combined with pre-coagulation/sedimentation. Primary clarifier effluent in a municipal wastewater treatment plant was fed into the hybrid MBR to investigate its performance during long-term operation. Pre-coagulation/sedimentation process efficiently removed the suspended solids including organic matter and phosphorus. Comparison of the hybrid MBR and conventional MBR was made in terms of the permeate quality and membrane fouling. As the organic loading to the MBR was significantly reduced by the pre-coagulation/sedimentation, production and accumulation of extracellular polymeric substances (EPS) may be limited. Therefore, the mixed liquor viscosity in the hybrid MBR was much lower than that in the conventional MBR. These effect caused by pre-coagulation/sedimentation brought a remarkable improvement in both permeate quality and membrane permeability.

Download Full-text

Swine manure treatment by anaerobic membrane bioreactor with carbon, nitrogen and phosphorus recovery

Water Science & Technology ◽

10.2166/wst.2017.278 ◽

2017 ◽

Vol 76 (8) ◽

pp. 1939-1949 ◽

Cited By ~ 4

Author(s):

Fan Bu ◽

Shiyun Du ◽

Li Xie ◽

Rong Cao ◽

Qi Zhou

Keyword(s):

Relaxation Rate ◽

Membrane Fouling ◽

Membrane Bioreactor ◽

Extracellular Polymeric Substances ◽

Swine Manure ◽

Phosphorus Recovery ◽

Methane Yield ◽

Continuous Stirred Tank Reactor ◽

Chemical Cleaning ◽

Anaerobic Membrane Bioreactor

Swine manure wastewater was treated in an anaerobic membrane bioreactor (AnMBR) that combined a continuous stirred tank reactor (CSTR) and a hollow-fiber ultrafiltration membrane, and the feasibility of ammonia and phosphorus recovery in the permeate was investigated. The AnMBR system was operated steadily with a high mixed liquor suspended solids (MLSS) concentration of 32.32 ± 6.24 g/L for 120 days, achieving an average methane yield of 280 mL/gVSadded and total chemical oxygen demand removal efficiency of 96%. The methane yield of the AnMBR is 83% higher than that of the single CSTR. The membrane fouling mechanism was examined, and MLSS and the polysaccharide contents of the extracellular polymeric substances were found to be the direct causes of membrane fouling. The effects of the permeation/relaxation rate and physical, chemical cleaning on membrane fouling were assessed for membrane fouling control, and results showed that a decrease in the permeation/relaxation rate together with chemical cleaning effectively reduced membrane fouling. In addition, a crystallization process was used for ammonia and phosphorus recovery from the permeate, and pH 9 was the optimal condition for struvite formation. The study has an instructive significance to the industrial applications of AnMBRs in treating high strength wastewater with nutrient recovery.

Download Full-text

Effect of Extracellular Polymeric Substances on Operation of Membrane Bioreactor

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.549.491 ◽

2012 ◽

Vol 549 ◽

pp. 491-495

Author(s):

Wan You Zhang ◽

Xin Yan Wang ◽

Li Juan Xi

Keyword(s):

Membrane Fouling ◽

Membrane Bioreactor ◽

Extracellular Polymeric Substances ◽

Membrane Resistance ◽

Volume Index ◽

Direct Influence ◽

Sludge Volume Index ◽

Simple Method ◽

Modified Fouling Index ◽

The Relationship

In order to study the relationship between extracellular polymeric substances (EPS) and membrane fouling, the effect of extracellular polymeric substances (EPS) on the operation of membrane bioreactor (MBR) was investigated in this paper. The operation of membrane was analyzed by evaluating sludge volume index (SVI), modified fouling index (MFI), and membrane resistance (Rt), respectively. The results showed that SVI, MFI, and Rt increased with the accumulation of EPS, and membrane fouling aggravated with the increase of EPS, this illustrated that the content of EPS had a direct influence on SVI, MFI, Rt and membrane fouling. The consequences could offer a simple method to monitor the concentration of EPS by analyzing SVI, MFI, or Rt.

Download Full-text

Role of zeolite in reducing membrane fouling in a hybrid membrane bioreactor system applied for wastewater treatment

10.5004/dwt.2017.21673 ◽

2017 ◽

Vol 98 ◽

pp. 52-58 ◽

Cited By ~ 3

Author(s):

Hossein Shahbeig ◽

Mohammad Reza Mehrnia ◽

Hamid Reza Tashauoei ◽

Maryam Rezaei

Keyword(s):

Wastewater Treatment ◽

Membrane Fouling ◽

Membrane Bioreactor ◽

Hybrid Membrane ◽

Bioreactor System

Download Full-text

Electrically enhanced MBR system for total nutrient removal in remote northern applications

Water Science & Technology ◽

10.2166/wst.2012.908 ◽

2012 ◽

Vol 65 (4) ◽

pp. 737-742 ◽

Cited By ~ 16

Author(s):

V. Wei ◽

M. Elektorowicz ◽

J. A. Oleszkiewicz

Keyword(s):

Wastewater Treatment ◽

Nutrient Removal ◽

Membrane Fouling ◽

Membrane Bioreactor ◽

Extracellular Polymeric Substances ◽

Climatic Conditions ◽

Transmembrane Pressure ◽

Treatment Technology ◽

Electrically Enhanced ◽

P Removal

Thousands of sparsely populated communities scatter in the remote areas of northern Canada. It is economically preferable to adopt the decentralized systems to treat the domestic wastewater because of the vast human inhabitant distribution and cold climatic conditions. Electro-technologies such as electrofiltration, elctrofloatation, electrocoagulation and electrokinetic separation have been applied in water and conventional wastewater treatment for decades due to the minimum requirements of chemicals as well as ease of operation. The membrane bioreactor (MBR) is gaining popularity in recent years as an alternative water/wastewater treatment technology. However, few studies have been conducted to hyphenate these two technologies. The purpose of this work is to design a novel electrically enhanced membrane bioreactor (EMBR) as an alternative decentralized wastewater treatment system with improved nutrient removal and reduced membrane fouling. Two identical submerged membranes (GE ZW-1 hollow fiber module) were used for the experiment, with one as a control. The EMBR and control MBR were operated for 4 months at room temperature (20 ± 2 °C) with synthetic feed and 2 months at 10 °C with real sewage. The following results were observed: (1) the transmembrane pressure (TMP) increased significantly more slowly in the EMBR and the interval between the cleaning cycles of the EMBR increased at least twice; (2) the dissolved chemical oxygen demand (COD) or total organic carbon (TOC) in the EMBR biomass was reduced from 30 to 51%, correspondingly, concentrations of the extracellular polymeric substances (EPS), the major suspicious membrane foulants, decreased by 26–46% in the EMBR; (3) both control and EMBR removed >99% of ammonium-N and >95% of dissolved COD, in addition, ortho-P removal in the EMBR was >90%, compared with 47–61% of ortho-P removal in the MBR; and (4) the advantage of the EMBR over the conventional MBR in terms of membrane fouling retardation and phosphorus removal was further demonstrated at an operating temperature of 10 °C when fed with real sewage. The EMBR system has the potential for highly automated control and minimal maintenance, which is particularly suitable for remote northern applications.

Download Full-text