Membrane Bioreactors
Petros K. Gkotsis, Manasis M. Mitrakas, Athanasia K. Tolkou, Anastasios I. Zouboulis, Batch and continuous dosing of conventional and composite coagulation agents for fouling control in a pilot-scale MBR, Chemical Engineering Journal 311 (2017) 255–264
Yasemin Kaya, A. Murat Bacaksiz, Hasan Bayrak, Z. Beril Gönder, Ilda Vergili, Halil Hasar, Gulsum Yilmaz, Treatment of chemical synthesis-based pharmaceutical wastewater in an ozonation-anaerobic membrane bioreactor (AnMBR) system, Chemical Engineering Journal 322 (2017) 293–301
Borte Kose, Hale Ozgun, Mustafa Evren Ersahin, Nadir Dizge, Derya Y. Koseoglu-Imer, Burcu Atay , Recep Kaya, Mahmut Altınbas, Sema Sayılı, Pelin Hoshan, Doga Atay, Esra Eren, Cumali Kinaci , Ismail Koyuncu, Performance evaluation of a submerged membrane bioreactor for the treatment of brackish oil and natural gas field produced water, Desalination 285 (2012) 295–300
Halil Hasara, Sezahat A. Unsal, Ubeyde Ipek, Serdar Karatas, Ozer Cınarc, Cevat Yamand, Cumali Kınacıe, Stripping/flocculation/membrane bioreactor/reverse osmosis treatment of municipal landfill leachate, Journal of Hazardous Materials 171 (2009) 309–317
Membrane Contactors
D. I. Petukhov, Ar. A. Eliseev, A. A. Poyarkov, A.V. Lukashin, An. A. Eliseev, Porous polypropylene membrane contactors for dehumidification of gases, NANOSYSTEMS: PHYSICS, CHEMISTRY, MATHEMATICS, 2017, 8 (6), P. 798–803
T Sverak, P Bulejko, J Ostrezi, O Kristof, J Kalivoda, P Kejik, K Mayerova, M Adamcik, 2017 IOP Conf. Ser.: Earth Environ. Sci. 92 012061
Membrane Distillation
Xing Yang, Hongjiao Pang, Jianhua Zhang, Audra Liubinas , Mikel Duke, Sustainable waste water deammonification by vacuum membrane distillation without pH adjustment: Role of water chemistry, Chemical Engineering Journal 328 (2017) 884–893
Microfiltration of Liquids
Mayank Shekhar, Amritanshu Shriwastav, Purnendu Bose, Shemeera Hameed, Microfiltration of algae: Impact of algal species, backwashing mode and duration of filtration cycle, Algal Research 23 (2017) 104–112
Microfiltration of Gases
Pavel Bulejko, Mirko Dohnal, Jiří Pospíšil, Tomáš Svěrák, Air filtration performance of symmetric polypropylene hollow-fibre membranes for nanoparticle removal, Separation and Purification Technology 197 (2018) 122–128
Bulejko, P. Numerical Comparison of Prediction Models for Aerosol Filtration Efficiency Applied on a Hollow-Fiber Membrane Pore Structure. Nanomaterials, 2018, roč. 8, č. 6, s. 1-24. ISSN: 2079-4991.
Photocatalytic Membrane Reactors
Szabolcs Kertèsz, Jiří Cakl, Hana Jiránková, Submerged hollowfibermicrofiltration as a part of hybrid photocatalytic process for dye wastewater treatment, Desalination 343 (2014) 106–112
Svetlana Popovic, Marcel Dittrich, Jiri Cakl, Modelling of fouling of outside-in hollow-fiber membranes by TiO2 particles, Separation and Purification Technology 156 (2015) 28–35
Evaporative Cooling
Xiangjie Chena, Yuehong Su, Devrim Aydine, Xingxing Zhang, Yate Ding, David Reayd, Richard Lawd, Saffa Riffat, Experimental investigations of polymer hollow fibre integrated evaporative cooling system with the fibre bundles in a spindle shape, Energy and Buildings 154 (2017) 166–174
Xiangjie Chen, Yuehong Su, Devrim Aydin, Yate Ding, Shihao Zhang, David Reay, Saffa Riffat, A novel evaporative cooling system with a polymer hollow fibre spindle, Applied Thermal Engineering 132 (2018) 665–675
Polymer Heat Exchangers
Miroslav Raudensky, Ilya Astrouski, Miroslav Dohnal, Intensification of heat transfer of polymeric hollow fiber heat exchangers by chaotization, Applied Thermal Engineering 113 (2017) 632–638
Klarissa Weiß, Ilya Astrouski, Marcus Reppich, Miroslav Raudensky, Polymeric Hollow-Fiber Bundles as Immersed Heat Exchangers, Chem. Eng. Technol. 2018, 41, No. 7, 1–10
Xiangjie Chena, Yuehong Sua, Devrim Aydin, David Reay, Richard Law, Saffa Riffat, Experimental investigations of polymer hollow fibre heat exchangers for building heat recovery application, Energy and Buildings 125 (2016) 99–108
Horský M., Raudenská L., Dohnal M., ZENA s.r.o., Ostopovice, CZ, Patent, Výměník tepla tvořený dutými polymerními vlákny (Heat Exchanger Based on Polymer Hollow Fibers), 305 152, patent (2015)
Klarissa Weiß Ilya Astrouski Marcus Reppich Miroslav Raudenský, Polymeric Hollow Fiber Bundles as Immersed Heat Exchangers, link
T. Brozova M. Raudensky, Determination of surface wettability of polymeric hollow fibres, Journal of Elastomers & Plastics, DOI: 10.1177/0095244318765041
Some scientific papers published by our university customers
Submerged hollow fiber microfiltration as a part of hybrid photocatalytic process for dye wastewater treatment
Szabolcs Kertèsz , Jiří Cakl, Hana Jiránková
Desalination 343 (2014) 106–112
Abstract
In this study, photocatalytic degradation of an organic azo dye, Acid Red 1, has been measured under UV irradiation in an aqueous dispersion of TiO2 to find optimal conditions for a photocatalytic membrane reactor (PMR) operation.
Furthermore, to separate and recover the anatase TiO2 photocatalyst, low-pressure microfiltration using hollow fiber membranes was applied. Since the main limitation in dead-end microfiltration with hollow fibers is the formation of an external specific deposit on the outer surface of the membrane, cake layer formation was also studied.
The changes in various parameters, including decolorization, chemical oxygen demand, total organic carbon, pH and turbidity of the solution were measured and analyzed during the process. Experimental results indicate that the solutions containing the model azo dyes could be successfully decolorized using the photocatalytic process studied.
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Phycoremediation of wastewater using algal-bacterial photobioreactor[DMP1] : Effect of nutrient load and light intensity
Vaishali Ashok, Amritanshu Shriwastavb, Purnendu Bosea, Sanjay Kumar Guptac
Bioresource Technology Reports 7 (2019) 100205
Abstract
The current study demonstrates the nutrient removal efficiency of algal-bacterial photobioreactors in the semi-batch mode for secondary treated domestic wastewater. The experiments were conducted to predict the optimum conditions for running a photobioreactor at a comparatively larger scale. The main focus was on optimizing illumination costs and nutrient removal efficiency to make reactor construction and operation economically viable. Chlorella vulgaris and Chlamydomonas reinhardtii were used for the experiments. Various input parameters were varied, and nutrient removal efficiencies along with biomass, chlorophyll-a content, temperature, pH, alkalinity, dissolved organic carbon, and dissolved oxygen were monitored. Model simulations were also run to confirm optimum performance. A maximum of ~25 mg l−1 N and ~10 mg l−1 P were found to be efficiently removed within 2 days hydraulic retention time (HRT), 9 h:3 h light: dark condition and 1543 μmol photons m2 s−1 light intensity. The results demonstrate superior nutrient removal efficiency than similar to previous studies.
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Aerosol filtration using hollow-fiber membranes: Effect of permeatem velocity and dust amount on separation of submicron TiO2 particles
Pavel Bulejko, Tomáš Svěrák, Mirko Dohnal, Jiří Pospíšil
Powder Technology 340 (2018) 344–353
Abstract
This work aimed to determine filtration performance of polypropylene hollow-fiber membranes in removing submicron particles from air. Experiments were performed in a chamber simulating dust environment with synthetic submicron-size particles (micronized TiO2). Ahollow-fiber membrane with 300 fibers of a filtration area of 0.43 m2 was tested. By measuring number of particles in chamber (upstream) and on the suction side of the membrane (downstream), the filtration efficiency was determined. Two different weights of synthetic dust (50 and 100 mg) and two permeate velocities (15 and 30 cm/s) were used to compare their influence on particle collection efficiency. Particle counting was carried out using a TSI 3075 condensation particle counter connected to a TSI 3080 scanning mobility particle sizer in 32 particle size channels from 17 to 600 nm. Pressure drop evolution with intense particle loading was recorded and fouling of the membrane was observed after 25, 50 and 90 h of filtration using SEM. The results showed high efficiency, mostly higher than 99.9% with higher pressure drops compared to other materials on HEPA level.
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Impact of salinity on the population dynamics of microorganisms in a membrane bioreactor treating produced water
Borte Kose Mutlu, Hale Ozguna, Mustafa Evren Ersahin, Recep Kaya, Selvihan Eliduzgun, Mahmut Altinbas, Cumali Kinaci, Ismail Koyuncu
Science of the Total Environment 646 (2019) 1080–1089
Abstract
Biomass characteristics may change subject to a salinity increase when treating high strength wastewater. In this study, the impact of salinity in a membrane bioreactor (MBR) was investigated for the treatment of produced water (PW). MBR was operated as a pre-treatment prior to nanofiltration (NF) and reverse osmosis (RO). Mixed PW, that was originated from different oil, gas, and oil-gas wells, were subjected to pre-treatment for 146 days including three different operational phases: Low-salinity (~10 mS/cm), gradual increased salinity (10–40 mS/cm) and high salinity (~40 mS/cm). The results of this study showed that microorganisms could adapt using real wastewater and treat PW up to a certain level of the salinity. At high salinity levels of PW, the floc structure started to be disrupted and membrane fouling was accelerated. PCR-DGGE analysis confirmed the changes in microbial communities' composition in relation with high salinity. The results of the final treatment experiments presented that NF and RO treatment produced high-quality effluents that could be suitable for reuse.
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Membrane bioreactors: Two decades of research and implementation
Santosa, W. Mab, S.J. Judd
Desalination 273 (2011) 148–154
Abstract
Membrane bioreactor technology is widely recognised as offering a key option for enhanced wastewater treatment or reuse. This brief review of the technology incorporates four key aspects: (a) market growth, (b) research areas, (c) product supply diversity and specifications, and (d) practitioner needs. Market growth and research topics were assessed through an examination of the appropriate literature and databases, specifically Scopus for the latter. Available MBR membrane products were identified from the Internet and other searches and the specifications verified through contact with the suppliers. Appropriate practitioners were identified through networking and verified as either being active in the operation and maintenance of full-scale MBRs or with an extensive experience of them within the industrial community. Results indicate that the footprint of modules normalised against membrane area changes significantly across the currently commercially-available product range, notwithstanding generically similar construction, such that opportunities for interchanging may be limited. The survey of research papers revealed the most comprehensively researched topic to be at odds with its practical constraints as identified by the practitioners.
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Wastewater treatment by high-growth bioreactor integrated with settling-cum-membrane separation
Subrata Hait, Vinod Tare
Desalination 270 (2011) 233–240
Abstract
A different approach of wastewater treatment has been investigated in this study by operating bioreactor at low mixed liquor suspended solids (MLSS) concentrations, thereby maintaining high F/M ratio to target higher nutrient removal through higher biomass yield. A 10-L capacity laboratory-scale bioreactor followed by settling-cum-membrane separation employing hollow fiber membrane module (pore size: 0.1 μm) was set up and operated under batch mode at a hydraulic retention time (HRT) of 24 h using simulated domestic wastewater as feed. Average removal efficiencies of bioreactor were approximately 84% soluble chemical oxygen demand (SCOD), 95.5% total COD (TCOD), 90% NH4+–N, and 87% total Kjeldahl nitrogen (TKN). True yield coefficient (YT) and decay coefficient (Kd) for bioreactor were estimated at 0.397 kg VSS/kg SCOD and 0.0549 day− 1, respectively. Significant proliferation of non-flocculating microorganisms was observed in the system with decreasing solids retention time (SRT) and thereby deteriorating biomass settling property indicated by enhanced sludge volume index (SVI). Significant proliferation of non-flocculating microorganisms with better ability to access substrate from bulk solution through smaller mass transfer resistance most probably contributed to better organics removal. The modified approach of wastewater treatment can be a good basis to develop high-growth membrane bioreactor (MBR) as opposed to conventional MBR operation.
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Performance evaluation of a submerged membrane bioreactor for the treatment of brackish oil and natural gas field produced water
Borte Kose, Hale Ozgun, Mustafa Evren Ersahin, Nadir Dizge, Derya Y. Koseoglu-Imer, Burcu Atay, Recep Kaya, Mahmut Altınbas, Sema Sayılı, Pelin Hoshan, Doga Atay, Esra Eren, Cumali Kinaci, Ismail Koyuncu
Desalination 285 (2012) 295–300
Abstract
Produced water, which is co-produced during oil and gas manufacturing, represents one of the largest sources of oily wastewaters. Therefore, treatment of this produced water may improve the economic viability and lead to a new source of water for beneficial use. In this study a submerged hollow fiber membrane bioreactor (MBR) has been studied experimentally for the treatment of brackish oil and natural gas field produced water. This type of wastewater is also characterized with relatively moderate to high amount of salt, oil and total petroleum hydrocarbons (TPH). However, the bacteria which are growing in conventional activated sludge and MBR cannot survive at these strict conditions, therefore acclimation of the bacteria is of vital importance. The performance of the biological system, membrane permeability, the rate and extent of TPH biodegradability have been investigated under different sludge age and F/M ratios. The results obtained by gas chromatography analyses showed that the MBR system could be very effective in the removal of TPH from produced water and a significant improvement in the effluent quality was achieved.
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Co-axial hollow fiber module for air gap membrane distillation
Alpatova, A.S. Alsaadi, M. Alharthia, J.-G. Leea, N. Ghaffour
Journal of Membrane Science 578 (2019) 172–182
Abstract
A novel air gap membrane distillation (AGMD) module in which non-porous polymeric hollow fiber condensers (i.e., heat exchangers) were inserted inside the porous hollow fiber membranes was developed. In this module the hot feed was circulated on the outer side of the membrane's lumen and the coolant was circulated counter-currently inside the condenser fibers. The condensation of water vapor occurred in the air gap between the inner surface of the membrane fibers and the outer surface of the condenser fibers. By varying the number of condenser fibers inside the lumen, a different ratio of membrane fiber active surface area to the total surface area of condenser fibers and corresponding packing densities were achieved and examined in desalination of Red Sea water. The effect of membrane type on process performance was investigated with three different hollow fiber membranes with varied wall thickness (two capillary and one tubular). At a feed temperature of 85 °C, the water vapor flux increased from 12 kg/m2h to 18 kg/m2h with the increase in condenser fibers packing density from 9% to 28%, and then decreased to 14 kg/m2h when packing density was increased to 36% due to condensing surface constrain inside the lumen. A higher efficiency of the AGMD process was observed in the case of capillary membranes as compared to tubular membranes due to reduction in wall thickness which facilitated lower mass transfer resistance. The effect of operating conditions including feed and coolant flow rates and temperature difference between the feed and coolant solutions was also investigated. The increase in the feed flow rate had significant effect on vapor flux comparing to that of coolant for all tested AGMD configurations. This effect was more pronounced at high feed temperatures. Based on observed results, an optimal module design was suggested.
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Simultaneous removal of organic matter and nitrogen compounds by combining a membrane bioreactor and a membrane biofilm reactor
Halil Hasar
Bioresource Technology 100 (2009) 2699–2705
Abstract
Hydrogen-based membrane biofilm reactors (MBfR) have been applied to the denitrification of nitrate-containing water and wastewater. Adding an aerobic membrane bioreactor (MBR) to a MBfR provides significant nitrification and organic oxidation because most wastewater also contains a significant concentration of organic material and ammonium nitrogen. This study describes experiments that investigate the removal of organic and nitrogenous compounds in the combined MBR/MBfR system. The experiments demonstrate that the MBR/MBfR combination successfully performs COD oxidation and nitrogen removal for organic and ammonium loads in the ranges of 1000–4300 g COD/m3-d and 200–230 g N/m3-d, respectively. Total-nitrogen removal was controlled by nitrification in the MBR, because the MBfR denitrified all of the provided by the MBR. The nitrate flux in the MBfR was in the range of 4–8 g N/m2-d for cases of almost complete denitrification (>99 %); the H2 flux was varied from 1.4 to 2.8 g H2/m2-d.
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Stripping/flocculation/membrane bioreactor/reverse osmosis treatment of municipal landfill leachate
Halil Hasar, Sezahat A. Unsal, Ubeyde Ipek, Serdar Karatas, Ozer Cınar, Cevat Yaman, Cumali Kınacı
Journal of Hazardous Materials 171 (2009) 309–317
Abstract
This study presents a configuration for the complete treatment of landfill leachate with high organic and ammonium concentrations. Ammonia stripping is performed to overcome the ammonia toxicity to aerobic microorganisms. By coagulation–flocculation process, COD and suspended solids (SS) were removed 36 and 46%, respectively. After pretreatment, an aerobic/anoxic membrane bioreactor (Aer/An MBR) accomplished the COD and total inorganic nitrogen (total-Ni) removals above 90 and 92%, respectively, at SRT of 30 days. Concentrations of COD and total-Ni (not considering organic nitrogen) in the Aer/An MBR effluent decreased to 450 and 40 mg/l, respectively, by significant organic oxidation and nitrification/denitrification processes. As an advanced treatment for the leachate, the reverse osmosis (RO) was applied to the collected Aer/An MBR effluents. Reverse osmosis provided high quality effluent by reducing the effluent COD from MBR to less than 4.0 mg/l at SRT of 30 days.
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Modelling of fouling of outside-in hollow-fiber membranes by TiO2 particles
Svetlana Popovic, Marcel Dittrich, Jiri Cakl
Separation and Purification Technology 156 (2015) 28–35
Abstract
The advantage of using suspended TiO2 particles in a photocatalytic membrane reactor is a higher surface area with respect to immobilized particles and, therefore, a higher catalytic activity. Detoxified water can be separated from the suspended catalyst by application of membrane processes such as microfiltration. Unfortunately, during the microfiltration, fouling of membranes by catalyst particles occurs, due to which the flux decreases or the transmembrane pressure increases, so cleaning by back-flushing of the permeate should be performed frequently. We have developed a mathematical model describing the pressure rise on a hollow-fiber module used for the constant flux, outside-in microfiltration of TiO2 dispersion. Unlike other models treating fouling of hollow-fiber membranes, our model incorporates a variation of the bulk concentration of TiO2 particles as a very important parameter with respect to the reaction. By the application of the model, we can predict some critical points of the photocatalytic membrane reactor operation such as the critical value of the suction pressure and the optimum time when cleaning of the membrane should be introduced.
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Air filtration performance of symmetric polypropylene hollow-fibre membranes for nanoparticle removal
Pavel Bulejko, Mirko Dohnal, Jiří Pospíšil, Tomáš Svěrák
Separation and Purification Technology 197 (2018) 122–128
Abstract
This work aimed to determine filtration performance of polypropylene hollow-fibre membranes (HFMs) for removing submicron particles from air. Experiments were performed in a glass chamber supplied with a nanoaerosol particles formed by burning incense sticks. Three types of HFMs varying in packing density, active filtration area and pore-size distribution were tested in an outside-in configuration. By measuring the number of particles upstream and downstream of the HFM, the filtration efficiency was determined. Three permeate velocities (5, 10 and 15 cm/s) were used to compare the velocity effect on filtration efficiency. Particle counting was carried out using a TSI 3075 condensation particle counter connected to a TSI 3080 scanning mobility particle sizer in 48 particle size channels from 18.1 to 100 nm. The results show high efficiency, mostly higher than 99% for particles above 60 nm size. The most penetrating particle sizes (MPPS) were between 35.9 and 40 nm at 5 cm/s with an efficiency of 82–86%. At permeate velocity of 10 and 15 cm/s, MPPS slightly decreased to range of 34.6–40 nm, with efficiency decreasing to 72–84% and 69–83%, respectively. The quality factor of HFMs was within the 2–28 kPa−1 range.
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Batch and continuous dosing of conventional and composite coagulation agents for fouling control in a pilot-scale MBR
Petros K. Gkotsis a, Manasis M. Mitrakas b, Athanasia K. Tolkou a, Anastasios I. Zouboulis
Chemical Engineering Journal 311 (2017) 255–264
Abstract
In the present study, conventional and composite, laboratory prepared coagulation agents were added in a fully automatic pilot-scale Membrane Bioreactor unit, both in batch-mode addition (‘Process I’) and in continuous-flow addition (‘Process II’) experiments, aiming to improve the overall process operability, i.e. as a fouling control method. A systematic effort was made to: i) correlate the recorded trans-Membrane Pressure with two novel, easily generated fouling indices (Ratio a and Ratio b) and ii) elucidate the relationship between the coagulant equilibrium concentration in the activated sludge and the optimal amount of coagulant added/L of incoming wastewater, by applying the corresponding mass balance equation. In both processes, the ranking trend among the optimal coagulants can be classified as: FO 4350 SSH < PSiCAFPAC-18-10-15 < PAC A9-M, in increasing order of Soluble Microbial Products (SMP) removal, and as: PAC A9-M < PSiCAFPAC-18-10-15 < FO 4350 SSH, in increasing order of sludge filterability enhancement. Among the three coagulation agents, the cationic polyelectrolyte FO 4350 SSH was identified as the optimal one, since its continuous-flow addition was found to cause the largest TMP decrease (almost 40%), at the optimal dosage of 0.16 mg/L of incoming wastewater, which was 63 times lower than its equilibrium concentration in the bioreactor (10 mg/L). The respective low values of Ratio b and the short-term nature of continuous-flow experiments (6 days) indicate that the mitigation of reversible fouling was mainly responsible for this.
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Treatment of chemical synthesis-based pharmaceutical wastewater in an ozonation-anaerobic membrane bioreactor (AnMBR) system
Yasemin Kaya, A. Murat Bacaksiz, Hasan Bayrak, Z. Beril Gönder, Ilda Vergili, Halil Hasar, Gulsum Yilmaz
Chemical Engineering Journal 322 (2017) 293–301
Abstract
In this study, treatability of etodolac chemical synthesis wastewater from the pharmaceutical industry was investigated in a hybrid ozonation-Anaerobic Membrane Bioreactor (AnMBR) system. The AnMBR was successfully operated up to 7500 mg/L of chemical oxygen demand (COD), but sulfite inhibition occurred at this loading. A pre-ozonation process was applied to overcome the problem of sulfite inhibition resulted from raw wastewater by decreasing the sulfite concentration through oxidation to sulphate. Furthermore, it was shown that this process was also effective obtaining high etodolac removal efficiencies up to 99%. Approximately 90% COD removal efficiency was achieved by the combined system. Extracellular polymeric substance (EPS) decreased in the conditions of long sludge retention time (SRT), hydraulic retention time (HRT) and low organic loading rate (OLR) values. Therefore, the granule size also decreased during the entire operation. Real-time polymerase chain reaction (Q-PCR) and fluorescent in situ hybridization (FISH) analyses revealed that high sulfite concentration affected the microbial population in the order of methanogens, acedogens and sulphate reducing bacteria (SRB).
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Sustainable waste water deammonification by vacuum membrane distillation without pH adjustment: Role of water chemistry
Xing Yang, Hongjiao Pang, Jianhua Zhang, Audra Liubinas, Mikel Duke
Chemical Engineering Journal 328 (2017) 884–893
Abstract
Traditional aerobic processes used for deammonification in waste water treatment plants consume the majority of electrical energy. Ammonia can instead be recovered by membrane distillation but research to date proposes chemically intensive pH adjustment to release free ammonia from bulk solutions. Here we propose the novel application of membrane distillation to deammonify waste water without any pH adjustment. To demonstrate the concept, it was first shown that simple synthetic ammonia solutions strictly follow the classic ammonia-ammonium relationship with pH which shows little release as free ammonia until at least pH 9. However vacuum membrane distillation removed essentially all ammonium in solution as low as pH 6.1 due to carbonate that is often found in waste waters. Via a novel ‘pH polarisation and buffering’ mechanism, the functional effect was established due to CO2 released from the liquid-vapour membrane boundary layer causing a pH rise that released ammonia to the permeate. Via this mechanism, high depletions, up to 99.6%, occurred consistently on solutions containing carbonate and volatile acids at low pH, including two ‘as received’ industrial waste waters such as anaerobic digester effluent. Future work can consider effects including membrane fouling and cleaning for longer term waste water deammonification by ammonia capture.
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Microfiltration of algae: Impact of algal species, backwashing mode and duration of filtration cycle
Mayank Shekhar, Amritanshu Shriwastav, Purnendu Bose, Shemeera Hameed
Algal Research 23 (2017) 104–112
Abstract
The objective of this study was to investigate and compare the microfiltration characteristics of mixed algal cultures containing two species of green microalgae: Chlorella vulgaris and Chlamydomonas reinhardtii. Submerged membrane filtration experiments with 300 mg L− 1 suspensions of pure algal cultures indicated that while membrane fouling potential was comparable in both cases, Chlorella vulgaris had a lower cake formation potential. Filtration experiments were carried out with 1000 mg L− 1 suspensions of mixed algal culture over several 12-h cycles with backwashing, either in the on-line or off-line mode. While on-line backwashing caused more fouling, this did not significantly affect the flux through the membrane, which was controlled by the cake formation on the membrane. The algal mixed culture was also filtered over many 3-h cycles with on-line backwashing. Lower cycle duration resulted in lower average cake resistance and hence allowed more membrane throughput, but at the cost of more frequent backwashing. Chemical washing of the membrane could remove the fouling resistance only partially. Thus, despite periodic chemical washing, the intrinsic membrane resistance increased consistently with cumulative throughput through the membrane.
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Investigation of membrane fouling in an anaerobic membrane bioreaktor (AnMBR) treating pharmaceutical wastewater
Yasemin Kaya, Ahmet Murat Bacaksiz, Hasan Bayrak, Ilda Vergili, Zeren Beril Gonder,Halil Hasar, Gulsum Yilmaz
Journal of Water Process Engineering 31 (2019) 100822
Abstract
This study is focused on the fouling of flat-sheet and hollow-fiber membranes in a lab-scale anaerobic membrane bioreactor (AnMBR). A comprehensive investigation including scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), fourier transform infrared (FT-IR) spectroscopy, confocal laser scanning microscopy (CLSM), zeta potential, optical profilometer and contact angle, and flux modelling was presented in this study. The effect of extracellular polymeric substances (EPS) accumulated on cake-layer were also considered. The cake-layer on the flat-sheet membrane formed much more than that on the hollow-fiber membrane. The thickness of cake-layer on the flat-sheet membrane was effectively decreased by physical stripping. However, proteins indicating structures of Amide I and Amide II, and carbohydrates were observed on the stripped hollow-fiber membrane. According to the flux modelling results, the cake-layer formation and intermediate-adsorption were found as effective mechanisms on both membranes. Especially, these mechanisms were more effective for the hollow-fiber membrane due to irreversible fouling.
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