Two-stage biofilm-MBR for nitrogen removal and enhanced membrane performance

2012 ◽  
Vol 66 (3) ◽  
pp. 588-593 ◽  
Author(s):  
Cheng Sun ◽  
TorOve Leiknes
Keyword(s):  
Nitrogen Removal ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Suspended Solids ◽  
Feed Solution ◽  
Organic Load ◽  
Two Stage ◽  
Membrane Unit ◽  
Membrane Performance ◽  
Recycle Ratio

A two-stage biofilm-membrane bioreactor (MBR) was developed in this study. High total nitrogen removal (maximum: 81.4% with recycle ratio = 3.5) was observed by recycling the suspension liquid between an anaerobic FBBR and an aerobic MBBR. Very low (less than 60 mg/L) suspended solids was kept in the membrane unit, which could improve the membrane filtration performance. Membrane fouling was further reduced by increasing the recycle ratio. When influent organic load increased, the membrane fouling rate increased, coupling with higher FCOD and suspended solids (SS) values in the feed solution around the membrane.

scholarly journals Membrane Fouling Controlled by Adjustment of Biological Treatment Parameters in Step-Aerating MBR

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 553
Author(s):  
Dimitra C. Banti ◽  
Manassis Mitrakas ◽  
Petros Samaras
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Municipal Wastewater ◽  
Operating Conditions ◽  
Transmembrane Pressure ◽  
Aeration Tank ◽  
Filamentous Bacteria ◽  
Membrane Performance ◽  
Low Concentrations ◽  
Fouling Reduction

A promising solution for membrane fouling reduction in membrane bioreactors (MBRs) could be the adjustment of operating parameters of the MBR, such as hydraulic retention time (HRT), food/microorganisms (F/M) loading and dissolved oxygen (DO) concentration, aiming to modify the sludge morphology to the direction of improvement of the membrane filtration. In this work, these parameters were investigated in a step-aerating pilot MBR that treated municipal wastewater, in order to control the filamentous population. When F/M loading in the first aeration tank (AT1) was ≤0.65 ± 0.2 g COD/g MLSS/d at 20 ± 3 °C, DO = 2.5 ± 0.1 mg/L and HRT = 1.6 h, the filamentous bacteria were controlled effectively at a moderate filament index of 1.5–3. The moderate population of filamentous bacteria improved the membrane performance, leading to low transmembrane pressure (TMP) at values ≤2 kPa for a great period, while at the control MBR the TMP gradually increased reaching 14 kPa. Soluble microbial products (SMP), were also maintained at low concentrations, contributing additionally to the reduction of ΤΜP. Finally, the step-aerating MBR process and the selected imposed operating conditions of HRT, F/M and DO improved the MBR performance in terms of fouling control, facilitating its future wider application.

scholarly journals In-Situ Ultrasound-Assisted Control of Polymeric Membrane Fouling

2021 ◽  
Author(s):  
Westphalen Dornelas Camara Heloisa
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Separation ◽  
Feed Solution ◽  
Solution Concentration ◽  
Polymeric Membrane ◽  
Permeate Flux ◽  
Latex Paint ◽  
Water And Wastewater Treatment ◽  
Maximum Increase

Membrane separation processes have been more widely applied to industrial activities, especially in water and wastewater treatment. However, there are still challenges associated to the use of membranes. Concentration polarization and fouling can cause significant permeate flux decay during the filtration process, hindering its efficiency and increasing cost. Among many strategies, the combination of membrane filtration with ultrasound (US) application has shown promising results in reducing membrane fouling. The main goal of this research was to identify the effect of US frequency, US power intensity and feed solution concentration on permeate flux during ultrafiltration of simulated latex paint effluent. Maximum increase in permeate flux of 19.7% was obtained by applying 20 kHz and 0.29 W.cm-2 to feed solution with 0.075 wt.% of solid concentration. The effect of feed flow rate was analyzed showing that an increase in feed flowrate is not beneficial to the fouling minimization process. Overall, the application of US improves permeate flux by reducing fouling of ultrafiltration polymeric membrane.

scholarly journals Assessing Enzyme Immobilization on Reverse Asymmetric Membranes and Biocatalytic Reactor Performance

2021 ◽  
Author(s):  
Amirah Syakirah Zahirulain ◽  
Fauziah Marpani ◽  
Syazana Mohamad Pauzi ◽  
'Azzah Nazihah Che Abd Rahim ◽  
Hang Thi Thuy Cao ◽  
...  
Keyword(s):  
Enzyme Immobilization ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Separation ◽  
Permeate Flux ◽  
Reactor Performance ◽  
Membrane Performance ◽  
Reverse Mode ◽  
Substrate Conversion ◽  
Product Separation

Abstract Integration of membrane filtration and biocatalysis has appealing benefits in terms of simultaneous substrate conversion and product separation in one reactor. Nevertheless, the interaction between enzymes and membrane is complex and the mechanism of enzyme docking on membrane is similar to membrane fouling. In this study, focus is given on the assessment of enzyme immobilization mechanism on reverse asymmetric polymer membrane based on the permeate flux data during the procedure. Evaluation of membrane performance in terms of its permeability, fouling mechanisms, enzyme loading, enzyme reusability and biocatalytic productivity were also conducted. Alcohol Dehydrogenase (EC 1.1.1.1), able to catalyze formaldehyde to methanol with subsequent oxidation of NADH to NAD was selected as the model enzyme. Two commercial, asymmetric, flat sheet polymer membranes (PES and PVDF) were immobilized with the enzyme in the reverse mode. Combination of concentration polarization phenomenon and pressure driven filtration successfully immobilized almost 100% of the enzymes in the feed solutions. The biocatalytic membrane reactor recorded more than 90% conversion, stable permeate flux with no enzyme leaching even after 5 cycles. The technique showing promising results to be expanded to continuous membrane separation setup for repeated use of enzymes.

scholarly journals Separation and Concentration of Health Compounds by Membrane Filtration

2006 ◽  
Vol 2 (3) ◽  
Author(s):  
Zaid S Saleh ◽  
Roger Stanley ◽  
Reginald Wibisono
Keyword(s):  
Phenolic Compounds ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Apple Juice ◽  
Feed Solution ◽  
Operating Conditions ◽  
Sugar Concentration ◽  
Process Efficiency ◽  
Phenolic Fraction ◽  
Quercetin Derivatives

The performance of nano-filtration (NF) for separating phenolic compounds from sugar in apple juice was studied using 1 and 0.25 kDa molecular weight cut-off (MWCO) spiral wound membranes. If these phenolic compounds could be recovered, they could stabilize the juice from haze formation or be added as antioxidants to foods and beverages in order to increase their health properties. Batch experiments were conducted on a pilot scale rig using a diluted clear apple juice concentrate. For the 1 kDa MWCO membrane, the research determined the effect of operating conditions on process efficiency and membrane fouling. The concentration of polyphenolics on the retentate side increased by a factor of up to 4 and the sugar concentration increased by 1.5 times under optimum conditions of lower temperature (30oC), acidic pH (2), lower trans-membrane pressure (5 Bar) and higher initial sugar concentration (20 oBrix). Despite the increase in polyphenolics in the retentate, there was little difference in the phenolic composition between retentate and permeate solutions. As the molecular mass of the rejected phenolics was smaller than the membrane cut-off, this indicated that the rejection was related to the formation of a secondary membrane formed as a result of fouling. A mass balance of polyphenolics in the final retentate and permeate compared with the initial feed solution indicated that up to 4.3 gm of polyphenolics were bound per m2 of membrane. The permeate solutions collected from the 1 kDa MWCO membrane were then filtered using a 0.25 kDa MWCO membrane. Most phenolic compounds were retained by the membrane and the concentration increased by a factor of up to 2. Catechin, rutin, phloridzin and quercetin derivatives were concentrated on the retentate side. However, around 20 - 40% of chlorogenic acid and epicatechin was observed on the permeate side. It is concluded that membrane separation represents a potentially efficient and cost-effective technology to separate the phenolic fraction of fruit juice in a form suitable for use as a functional ingredient.

scholarly journals In-Situ Ultrasound-Assisted Control of Polymeric Membrane Fouling

2021 ◽  
Author(s):  
Westphalen Dornelas Camara Heloisa
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Separation ◽  
Feed Solution ◽  
Solution Concentration ◽  
Polymeric Membrane ◽  
Permeate Flux ◽  
Latex Paint ◽  
Water And Wastewater Treatment ◽  
Maximum Increase

Membrane separation processes have been more widely applied to industrial activities, especially in water and wastewater treatment. However, there are still challenges associated to the use of membranes. Concentration polarization and fouling can cause significant permeate flux decay during the filtration process, hindering its efficiency and increasing cost. Among many strategies, the combination of membrane filtration with ultrasound (US) application has shown promising results in reducing membrane fouling. The main goal of this research was to identify the effect of US frequency, US power intensity and feed solution concentration on permeate flux during ultrafiltration of simulated latex paint effluent. Maximum increase in permeate flux of 19.7% was obtained by applying 20 kHz and 0.29 W.cm-2 to feed solution with 0.075 wt.% of solid concentration. The effect of feed flow rate was analyzed showing that an increase in feed flowrate is not beneficial to the fouling minimization process. Overall, the application of US improves permeate flux by reducing fouling of ultrafiltration polymeric membrane.

scholarly journals Treatment of Tannery Wastewater with Vibratory Shear-Enhanced Processing Membrane Filtration

Separations ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 20 ◽  
Author(s):  
Anastasios Zouboulis ◽  
Efrosyni Peleka ◽  
Anastasia Ntolia
Keyword(s):  
Vibration Amplitude ◽  
Membrane Filtration ◽  
Suspended Solids ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Treated Wastewater ◽  
Treatment Efficiency ◽  
Membrane Unit ◽  
Membrane Type

The performance of a vibratory shear-enhanced process (VSEP) combined with an appropriate membrane unit for the treatment of simulated or industrial tannery wastewaters was investigated. The fundamental operational and pollution parameters were evaluated, i.e., the membrane type, the applied vibration amplitude, as well as the removal rates (%) of tannins, chemical oxygen demand (COD), Ntotal, turbidity and color. Regarding the system’s treatment efficiency, specific emphasis was given towards the removal of organics (expressed as COD values), suspended solids (SS), conductivity (as an index of dissolved solids’ presence) and total nitrogen. The removal of organic matter in terms of COD exceeded 75% for all the examined cases. The quality of treated wastewater was affected not only by the membrane specific type (i.e., the respective pore diameters), but also by the applied vibration amplitude. Furthermore, an average 50% removal rate, regarding the aforementioned parameters, was observed both for the simulated and the industrial tannery wastewaters during the microfiltration (MF) experiments. That removal rate was further increased up to 85%, when ultrafiltration (UF) was applied, and up to 99% during the Reverse Osmosis (RO) experiments, considering the maximum applied vibration amplitude (31.75 mm).

A two-stage subsurface vertical flow constructed wetland for high-rate nitrogen removal

2008 ◽  
Vol 57 (12) ◽  
pp. 1881-1887 ◽  
Author(s):  
Guenter Langergraber ◽  
Klaus Leroch ◽  
Alexander Pressl ◽  
Roland Rohrhofer ◽  
Raimund Haberl
Keyword(s):  
Grain Size ◽  
Nitrogen Removal ◽  
Constructed Wetland ◽  
High Rate ◽  
Organic Load ◽  
Vertical Flow ◽  
Two Stage ◽  
Drainage Layer ◽  
Main Layer ◽  
Specific Investment

By using a two-stage constructed wetland (CW) system operated with an organic load of 40 g COD·m−2·d−1 (2 m2 per person equivalent) average nitrogen removal efficiencies of about 50% and average nitrogen elimination rates of 980 g N·m−2·yr−1 could be achieved. Two vertical flow beds with intermittent loading have been operated in series. The first stage uses sand with a grain size of 2–3.2 mm for the main layer and has a drainage layer that is impounded; the second stage sand with a grain size of 0.06–4 mm and a drainage layer with free drainage. The high nitrogen removal can be achieved without recirculation thus it is possible to operate the two-stage CW system without energy input. The paper shows performance data for the two-stage CW system regarding removal of organic matter and nitrogen for the two year operating period of the system. Additionally, its efficiency is compared with the efficiency of a single-stage vertical flow CW system designed and operated according to the Austrian design standards with 4 m2 per person equivalent. The comparison shows that a higher effluent quality could be reached with the two-stage system although the two-stage CW system is operated with the double organic load or half the specific surface area requirement, respectively. Another advantage is that the specific investment costs of the two-stage CW system amount to 1,200 EUR per person (without mechanical pre-treatment) and are only about 60% of the specific investment costs of the singe-stage CW system.

Fouling analysis of ultrafiltration and nanofiltration membranes

2006 ◽  
Vol 1 (4) ◽  
Author(s):  
D. B. Mosqueda-Jimenez ◽  
P. M. Huck
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Feed Solution ◽  
Nanofiltration Membranes ◽  
Biological Matter ◽  
Membrane Pretreatment ◽  
Microbiological Analyses

Chemical and microbiological analyses were performed in an attempt to obtain a better understanding of the reduction of membrane fouling via the use of feed pretreatment. Biofiltration was chosen as pretreatment due to its potential to be a sustainable process coupled with membrane filtration. Biofiltration effectively reduced the concentration of organic and biological matter in the feed solution, decreasing the material deposited on the membrane surface approximately by half. More importantly, it reduced the loss of permeability during the operation of UF and NF membranes. However, it is believed that the performance of biofiltration as membrane pretreatment can be further improved with a greater understanding of the material that causes membrane fouling. This way the biofilter design and operation can be optimized to specifically minimize the concentration of this fouling material.

Long-term behaviour of a two-stage CW system regarding nitrogen removal

2011 ◽  
Vol 64 (5) ◽  
pp. 1137-1141 ◽  
Author(s):  
Guenter Langergraber ◽  
Alexander Pressl ◽  
Klaus Leroch ◽  
Roland Rohrhofer ◽  
Raimund Haberl
Keyword(s):  
Grain Size ◽  
Nitrogen Removal ◽  
Elimination Rate ◽  
Organic Load ◽  
Two Stage ◽  
Drainage Layer ◽  
Main Layer ◽  
In Series ◽  
Biofilm Development ◽  
Nitrogen Elimination

In the first two years of operation a nitrogen removal efficiency of 53% and a high average elimination rate of 1,000 g N m−2 yr−1 could be observed for a two-stage vertical flow (VF) constructed wetland (CW) system. The two-stage system consists of two VF beds with intermittent loading operated in series, each stage having a surface area of 10 m2. The first stage uses sand with a grain size of 2–3.2 mm for the 50 cm main layer and has a drainage layer that is impounded; the second stage sand with a grain size of 0.06–4 mm and a conventional drainage layer (with free drainage). The two-stage VF system was designed for and operated with an organic load of 40 g COD m−2 d−1 (i.e. 2 m2 per person equivalent). Data from the following years of operation showed that from the third year nitrogen elimination increased and stabilized. The median values of the nitrogen elimination rate in the first five years of operation have been 3.51, 2.76, 4.20, 3.84 and 4.07 g N m−2 d−1, the median value of the last three years being 3.8 g N m−2 d−1 and 1,380 g N m−2 yr−1, respectively, and the nitrogen removal >60%. It can be assumed that the vegetation as well as the biofilm development in the two-stage VF CW system plays the major role for the enhancement of the nitrogen elimination rate.

Coagulation/flocculation/ultrafiltration for natural organic matter removal in drinking water production

2004 ◽  
Vol 4 (5-6) ◽  
pp. 215-222 ◽  
Author(s):  
A.R. Costa ◽  
M.N. de Pinho
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Water Production ◽  
Cellulose Acetate Membranes ◽  
Wide Range ◽  
Drinking Water Production

Membrane fouling by natural organic matter (NOM), namely by humic substances (HS), is a major problem in water treatment for drinking water production using membrane processes. Membrane fouling is dependent on membrane morphology like pore size and on water characteristics namely NOM nature. This work addresses the evaluation of the efficiency of ultrafiltration (UF) and Coagulation/Flocculation/UF performance in terms of permeation fluxes and HS removal, of the water from Tagus River (Valada). The operation of coagulation with chitosan was evaluated as a pretreatment for minimization of membrane fouling. UF experiments were carried out in flat cells of 13.2×10−4 m2 of membrane surface area and at transmembrane pressures from 1 to 4 bar. Five cellulose acetate membranes were laboratory made to cover a wide range of molecular weight cut-off (MWCO): 2,300, 11,000, 28,000, 60,000 and 75,000 Da. Severe fouling is observed for the membranes with the highest cut-off. In the permeation experiments of raw water, coagulation prior to membrane filtration led to a significant improvement of the permeation performance of the membranes with the highest MWCO due to the particles and colloidal matter removal.

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