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1
Bellona, C. L., A. Wuertle, P. Xu e J. E. Drewes. "Evaluation of a bench-scale membrane fouling protocol to determine fouling propensities of membranes during full-scale water reuse applications". Water Science and Technology 62, n. 5 (1 settembre 2010): 1198–204. http://dx.doi.org/10.2166/wst.2010.416.
Abstract (sommario):
There is increasing interest in recycling wastewater effluents for augmentation of existing water supplies. The treatment of wastewater effluents by an integrated membrane system, such as microfiltration pre-treatment followed by reverse osmosis, is the industry standard for groundwater recharge or reservoir augmentation projects. Membrane fouling, especially effluent organic matter fouling, is a major challenge for water reuse applications employing high-pressure membranes. While fouling control through pre-treatment is an important aspect in membrane system design and operation, selecting low fouling membranes is an equally important aspect. Although recent research has begun to elucidate fouling mechanisms, little work has been performed to develop methods to pre-determine the effluent organic matter fouling propensities of high-pressure membranes so that low-fouling membranes can be pre-selected for reuse applications. The purpose of this study was to utilize a bench-scale testing protocol to test the relative effluent organic matter fouling propensities of commercially available NF and RO membranes when treating wastewater effluents. Bench-scale fouling test results were then compared to operational data generated during pilot- and full-scale membrane testing. Pilot- and full-scale testing using recycled water demonstrated that membranes foul at significantly different rates and that the extent of fouling could be estimated utilizing the proposed bench-scale testing protocol.
2
Wray, Heather E., Robert C. Andrews e Pierre R. Bérubé. "Coagulation optimization for DOC removal: pilot-scale analysis of UF fouling and disinfection byproduct formation potential". Water Supply 16, n. 2 (26 ottobre 2015): 473–80. http://dx.doi.org/10.2166/ws.2015.157.
Abstract (sommario):
A pilot-scale study was performed to evaluate a coagulant dose which had been optimized for biopolymer (i.e., foulant) removal on subsequent ultrafiltration (UF) fouling, as well as disinfection by-product (DBP) precursor removal. Polyaluminum chloride (PACl) dosages were selected based on a point of diminishing returns for biopolymer removal (0.5 mg/L) and directly compared to that applied at full-scale (6 mg/L). Membrane fouling (reversible and irreversible) was measured as resistance increase over a 48 hour filtration period. DBP formation potential (total trihalomethanes (TTHMs), haloacetic acids (HAA9) and total adsorbable organic halides (AOX)) were measured in both raw and treated waters. Results of the study indicate that application of a PACl dose optimized for biopolymer reduction (0.5 mg/L) resulted in 65% less irreversible UF fouling when compared to 6 mg/L. The addition of PACl prior to the membrane resulted in up to a 14% reduction in DBP precursors relative to the UF membrane alone. A similar level of DBP precursor reduction was achieved for both 0.5 and 6 mg/L dosages. The results have implications for cost savings, which may be realized due to decreased chemical use, as well as increased membrane life associated with lower irreversible fouling rates.
3
Kim, J., e T. I. Yoon. "Direct observations of membrane scale in membrane bioreactor for wastewater treatment application". Water Science and Technology 61, n. 9 (1 maggio 2010): 2267–72. http://dx.doi.org/10.2166/wst.2010.124.
Abstract (sommario):
The formation of inorganic fouling on MF membrane was investigated in membrane bioreactor (MBR) treating industrial wastewater. Membrane autopsy works using microscopic techniques and surface analysis were carried out at the completion of pilot-scale operation to analyze foulant materials extensively. Scaling occurred on the membrane surface significantly in the MBR treating calcium-rich wastewater (LSI > 2.0). Our experiments showed that the coverage of the membrane surface by the inorganic fouling consisted mostly of calcium while the internal fouling within membrane pores due to the scale formation was almost negligible. Most of calcium was rejected on the MF membrane surface as scale formation of calcium carbonate (>90% as rejection). The sequence sodium hypochlorite-citric acid for the removal of membrane scale was more effective than the sequence citric acid-sodium hypochlorite cleaning. It appeared that the structure of organic compounds combined with calcium became loose by the addition of the sodium hypochlorite, thereby releasing calcium more easily from the membrane by applying the acid cleaning agent.
4
Jang, N. Y., Y. Watanabe e S. Minegishi. "Performance of ultrafiltration membrane process combined with coagulation/sedimentation". Water Science and Technology 51, n. 6-7 (1 marzo 2005): 209–19. http://dx.doi.org/10.2166/wst.2005.0640.
Abstract (sommario):
Effects of coagulation/sedimentation as a pre-treatment on the dead-end ultrafiltration (UF) membrane process were studied in terms of membrane fouling and removal efficiency of natural dissolved organic matter, using Chitose River water. Two types of experiment were carried out. One was a bench scale membrane filtration with jar-test and the other was membrane filtration pilot plant combined with the Jet Mixed Separator (JMS) as a pre-coagulation/sedimentation unit. In the bench scale experiment, the effects of coagulant dosage, pH and membrane operating pressure on the membrane fouling and removal efficiency of natural dissolved organic matter were investigated. In the pilot plant experiment, we also investigated the effect of pre-coagulation/sedimentation on the membrane fouling and the removal efficiency of natural dissolved organic matter. Coagulation/sedimentation prior to membrane filtration process controlled the membrane fouling and increased the removal efficiency of natural dissolved organic matter.
5
Zouboulis, A. I., P. K. Gkotsis, D. X. Zamboulis e M. G. Mitrakas. "Application of powdered activated carbon (PAC) for membrane fouling control in a pilot-scale MBR system". Water Science and Technology 75, n. 10 (27 febbraio 2017): 2350–57. http://dx.doi.org/10.2166/wst.2017.108.
Abstract (sommario):
Membrane fouling is considered to be the most serious drawback in wastewater treatment when using membrane bioreactors (MBRs), leading to membrane permeability decrease and efficiency deterioration. This work aims to develop an integrated methodology for membrane fouling control, using powdered activated carbon (PAC), which will enhance the adsorption of soluble microbial products (SMP) and improve membrane filterability, by altering the mixed liquor's characteristics. Reversible fouling was assessed in terms of sludge filterability measurements, according to the standard time-to-filter (TTF) method, while irreversible fouling was assessed in terms of SMP removal. Results showed that the addition of PAC at the concentration of 3 g/L in the mixed liquor reduced SMP concentration and enhanced substantially the sludge filterability. Furthermore, the TTFPAC/TTFno PAC ratios were lower, than the corresponding SMPPAC./SMPno PAC ratios, indicating that the batch-mode, short-term addition of PAC promotes the reversible, rather than the irreversible fouling mitigation.
6
Ohgai, T., Y. Oguchi, K. Ohno, T. Kamei, Y. Magara e M. Itoh. "Development of evaluation methods to introduce a nanofiltration membrane process in drinking water treatment". Water Supply 6, n. 2 (1 marzo 2006): 9–17. http://dx.doi.org/10.2166/ws.2006.042.
Abstract (sommario):
The objective of this study was to develop a new prediction method for evaluating performance of full-scale nanofiltration (NF) pilot plant by using small-scale pilot plants. Operating experiments using both multistage array pilot plant and two small-scale pilot plants in parallel had been conducted for about a year. From this experiment, it was revealed that data obtained from small-scale pilot plants could predict the performance of multistage pilot plant from the viewpoint of flux and rejection. In other words, both permeate water quantity of multistage pilot plant without noticeable fouling caused by aluminium from coagulant and permeate water quality of multistage pilot plant could be estimated.
7
Righetto, Ilaria, Raed A. Al-Juboori, Juho Uzkurt Kaljunen, Ngoc Huynh e Anna Mikola. "Nitrogen Recovery from Landfill Leachate Using Lab- and Pilot-Scale Membrane Contactors: Research into Fouling Development and Membrane Characterization Effects". Membranes 12, n. 9 (27 agosto 2022): 837. http://dx.doi.org/10.3390/membranes12090837.
Abstract (sommario):
Membrane contactor technology affords great opportunities for nitrogen recovery from waste streams. This study presents a performance comparison between lab- and pilot-scale membrane contactors using landfill leachate samples. Polypropylene (PP) and polytetrafluoroethylene (PTFE) fibers in different dimensions were compared in terms of ammonia (NH3) recovery on a lab scale using a synthetic ammonium solution. The effect of pre-treating the leachate with tannin coagulation on nitrogen recovery was also evaluated. An ammonia transfer on the lab and pilot scale was scrutinized using landfill leachate as a feed solution. It was found that PTFE fibers performed better than PP fibers. Among PTFE fibers, the most porous one (denoted as M1) had the highest NH3 flux of 19.2 g/m2.h. Tannin pre-treatment reduced fouling and increased NH3, which in turn improved nitrogen recovery. The mass transfer coefficient of the lab-scale reactor was more than double that of the pilot reactor (1.80 × 10−7 m/s vs. 4.45 × 10−7 m/s). This was likely attributed to the difference in reactor design. An analysis of the membrane surface showed that the landfill leachate caused a combination of inorganic and organic fouling. Cleaning with UV and 0.01 M H2O2 was capable of removing the fouling completely and restoring the membrane characteristics.
8
Gkotsis, Petros, Efrosini Peleka e Anastasios Zouboulis. "The Use of Natural Minerals in a Pilot-Scale MBR for Membrane Fouling Mitigation". Separations 7, n. 2 (23 aprile 2020): 24. http://dx.doi.org/10.3390/separations7020024.
Abstract (sommario):
This study examines the effect of bentonite and zeolite concentration (0.25–5 g/L) on the membrane fouling of a fully automated, pilot-scale membrane bioreactor (MBR) treating high-strength synthetic municipal wastewater. Reversible fouling was estimated by sludge filterability measurements and irreversible fouling was estimated by the reduction of the carbohydrate fraction of soluble microbial products (SMPc), which are considered to be significant MBR foulants. Both minerals were added to biomass samples (during batch-mode experiments) which were obtained from the system’s aeration tank. Results showed that the optimal bentonite and zeolite concentrations were 3.5–4 g/L and 2.5–3.5 g/L, respectively. Interestingly, above these values, the addition of both minerals increased the examined fouling indices, i.e., the measured filterability times and the SMPc concentration, implying that they might act as foulants at high concentrations. Optical microscopy images of the biomass samples showed that the addition of minerals at the optimal concentrations did not affect significantly filamentous microorganisms, since filament index (FI) was practically unaffected (~2). Finally, regarding the system’s treating performance, it was found that the pilot-scale MBR can operate successfully with high-strength synthetic municipal wastewater, since remarkable behaviour was exhibited in terms of organics (BOD5, COD) and ammonium (NH4+-N) removal (>98%).
9
Yu, Tong, Chenlu Xu, Feng Chen, Haoshuai Yin, Hao Sun, Lihua Cheng e Xuejun Bi. "Microcoagulation improved the performance of the UF–RO system treating the effluent from a coastal municipal wastewater treatment plant: a pilot-scale study". Journal of Water Reuse and Desalination 11, n. 2 (25 gennaio 2021): 177–88. http://dx.doi.org/10.2166/wrd.2021.099.
Abstract (sommario):
Abstract Microcoagulation has recently been considered as a promising pretreatment for an ultrafiltration (UF) process from numerous studies. To investigate the effects of microcoagulation on the performance of the UF–reverse osmosis (RO) system treating wastewater with high and fluctuant salinity, different dosages of coagulant (poly-aluminum chloride) were added prior to the UF unit in a pilot-scale UF–RO system for a 10-week period operation. Microcoagulation obviously improved the contaminant removal and cleaning efficiencies, including water backwash, chemical enhanced backwash and cleaning in place processes. Organic fouling was dominated during the initial stage of the RO membrane fouling. The microbial communities of water samples and foulant on the RO membrane were similar to those of seawater and foulant on the RO membranes from seawater RO plants. The microbial community of the foulant on the membrane was similar to that of UF permeate and RO concentrate. These results demonstrated that microcoagulation could improve the performance of the UF–RO system treating the effluent with high and fluctuant salinity from a coastal municipal wastewater treatment plant.
10
Kimura, K., Y. Hane e Y. Watanabe. "Effect of pre-coagulation on mitigating irreversible fouling during ultrafiltration of a surface water". Water Science and Technology 51, n. 6-7 (1 marzo 2005): 93–100. http://dx.doi.org/10.2166/wst.2005.0626.
Abstract (sommario):
Membrane fouling can be divided into two types: reversible fouling and irreversible fouling. The former can be easily canceled by physical cleaning (e.g., backwashing) while the latter needs chemical cleaning to be mitigated. For more efficient use of membranes, the control of irreversible membrane fouling is of importance. In this study, the effectiveness of pre-coagulation/sedimentation on irreversible membrane fouling was investigated, based on the pilot-scale operation of the membrane unit installed at an existing water purification plant. The membrane employed was a low-pressure ultrafiltration (UF) membrane made of polysulfone and having a molecular weight cut-off of 750,000 daltons. Although pre-coagulation/sedimentation significantly mitigated membrane fouling mainly through the reduction of reversible membrane fouling, the degree of irreversible fouling was not reduced by the pre-treatment. This was because the irreversible fouling observed during this study was mainly attributed to polysaccharides/protein like fractions of organic substances that cannot be efficiently removed by coagulation/sedimentation. Aluminium used as coagulant was thought to cause irreversible fouling to some extent but did not in the pilot operation, which could probable be explained by the fact that coagulation was conducted at relatively high pH (7.0) in this study.
11
Bian, Hanxiao, Zhiping Zhu, Qianwen Sui e Shunli Wang. "The Pilot Study of the Influence of Free Ammonia on Membrane Fouling during the Partial Nitrosation of Pig Farm Anaerobic Digestion Liquid". Membranes 11, n. 11 (19 novembre 2021): 894. http://dx.doi.org/10.3390/membranes11110894.
Abstract (sommario):
The problem of membrane fouling is a key factor restricting the application of the membrane bioreactor (MBR) in the partial nitrosation (PN) and anaerobic ammonia oxidation (anammox) processes. In this study, the pilot-scale continuous flow MBR was used to start up the partial nitrosation process in order to investigate the change trend of mid-transmembrane pressure (TMP) in the process of start-up, which was further explored to clarify the membrane fouling mechanism in the pilot-scale reactor. The results showed that the MBR system was in a stable operating condition during the partial nitrosation operation and that the online automatic backwash operation mode is beneficial in alleviating membrane fouling and reducing the cost of membrane washing. Particular attention was paid to the influence trend of free ammonia (FA)on membrane fouling, and it was found that the increase in FA concentration plays the most critical role in membrane fouling. The increase in FA concentration led to an increase in the extracellular polymer (EPS), dissolved microorganism product (SMP) and soluble chemical oxygen demand (SCOD) concentration. FA was extremely significantly correlated with EPS and SCOD, and the FA concentration was approximately 20.7 mg/L. The SCODeff (effluent SCOD concentration) concentration was approximately 147 mg/L higher than the SCODinf (influent SCOD concentration) concentration. FA mainly affects membrane fouling by affecting the concentration of EPS and SCOD.
12
Crittenden, B. D., S. T. Kolaczkowski, T. Takemoto e D. Z. Phillips. "Crude Oil Fouling in a Pilot-Scale Parallel Tube Apparatus". Heat Transfer Engineering 30, n. 10-11 (ottobre 2009): 777–85. http://dx.doi.org/10.1080/01457630902744135.
13
Odriozola, Magela, Jules B. van Lier e Henri Spanjers. "Optimising the Flux Enhancer Dosing Strategy in a Pilot-Scale Anaerobic Membrane Bioreactor by Mathematical Modelling". Membranes 12, n. 2 (26 gennaio 2022): 151. http://dx.doi.org/10.3390/membranes12020151.
Abstract (sommario):
Flux enhancers (FEs) have been successfully applied for fouling mitigation in membrane bioreactors. However, more research is needed to compare and optimise different dosing strategies to improve the filtration performance, while minimising the use of FEs and preventing overdosing. Therefore, the goal of this research is to develop an optimised control strategy for FE dosing into an AnMBR by developing a comprehensive integrated mathematical model. The integrated model includes filtration, flocculation, and biochemical processes to predict the effect of FE dosing on sludge filterability and membrane fouling rate in an AnMBR. The biochemical model was based on an ADM1, modified to include FEs and colloidal material. We developed an empirical model for the FE-induced flocculation of colloidal material. Various alternate filtration models from the literature and our own empirical models were implemented, calibrated, and validated; the best alternatives were selected based on model accuracy and capacity of the model to predict the effect of varying sludge characteristics on the corresponding output, that is fouling rate or sludge filterability. The results showed that fouling rate and sludge filterability were satisfactorily predicted by the selected filtration models. The best integrated model was successfully applied in the simulation environment to compare three feedback and two feedforward control tools to manipulate FE dosing to an AnMBR. The modelling results revealed that the most appropriate control tool was a feedback sludge filterability controller that dosed FEs continuously, referred to as ∆R20_10. Compared to the other control tools, application of the ∆R20_10 controller resulted in a more stable sludge filterability and steady fouling rate, when the AnMBR was subject to specific disturbances. The simulation environment developed in this research was shown to be a useful tool to test strategies for dosing flux enhancer into AnMBRs.
14
Takeuchi, Haruka, Naoyuki Yamashita, Norihide Nakada e Hiroaki Tanaka. "Removal Characteristics of N-Nitrosamines and Their Precursors by Pilot-Scale Integrated Membrane Systems for Water Reuse". International Journal of Environmental Research and Public Health 15, n. 9 (7 settembre 2018): 1960. http://dx.doi.org/10.3390/ijerph15091960.
Abstract (sommario):
This study investigated the removal characteristics of N-Nitrosamines and their precursors at three pilot-scale water reclamation plants. These plants applies different integrated membrane systems: (1) microfiltration (MF)/nanofiltration (NF)/reverse osmosis (RO) membrane; (2) sand filtration/three-stage RO; and (3) ultrafiltration (UF)/NF and UF/RO. Variable removal of N-Nitrosodimethylamine (NDMA) by the RO processes could be attributed to membrane fouling and the feed water temperature. The effect of membrane fouling on N-Nitrosamine removal was extensively evaluated at one of the plants by conducting one month of operation and chemical cleaning of the RO element. Membrane fouling enhanced N-Nitrosamine removal by the pilot-scale RO process. This finding contributes to better understanding of the variable removal of NDMA by RO processes. This study also investigated the removal characteristics of N-Nitrosamine precursors. The NF and RO processes greatly reduced NDMA formation potential (FP), but the UF process had little effect. The contributions of MF, NF, and RO processes for reducing FPs of NDMA, N-Nitrosopyrrolidine and N-Nitrosodiethylamine were different, suggesting different size distributions of their precursors.
15
Martinez-Sosa, D., B. Helmreich, T. Netter, S. Paris, F. Bischof e H. Horn. "Pilot-scale anaerobic submerged membrane bioreactor (AnSMBR) treating municipal wastewater: the fouling phenomenon and long-term operation". Water Science and Technology 64, n. 9 (1 novembre 2011): 1804–11. http://dx.doi.org/10.2166/wst.2011.745.
Abstract (sommario):
An anaerobic submerged membrane bioreactor (AnSMBR) on pilot-scale treating a mixture composed of municipal wastewater and glucose under mesophilic temperature conditions was operated for 206 days. The performance of the AnSMBR was evaluated at different fluxes, biomass concentrations and gas sparging velocities (GSV). GSV was used to control fouling. In addition, the AnSMBR was operated in cycles that included relaxation and backwashing phases. The increase in the transmembrane pressure (fouling rate) was measured under different operational conditions and was used to evaluate the stability of the process. The fouling rate could be controlled for a long period of time at a flux of 7 l m−2 h−1 with a GSV of 62 m/h and an average biomass concentration of 14.8 g TSS/L. The membrane was physically cleaned after 156 days of operation. The cleaning efficiency was almost 100% indicating that no irreversible fouling was developed inside the pores of the membrane. The COD removal efficiency was close to 90%. As in anaerobic processes, nutrients were not exposed to degradation and almost no pathogens were found in the effluent, hence the effluent could be used for irrigation in agriculture.
16
Zhou, Hao, Jiakai Zhang, Weichen Ma e Hua Shi. "Experimental study of the fouling characteristics in a pilot-scale facility: Influence of the fouling surface". Asia-Pacific Journal of Chemical Engineering 13, n. 5 (settembre 2018): e2243. http://dx.doi.org/10.1002/apj.2243.
17
Chung, Monique Mi Song, April J. Arbour e Jen-Yi Huang. "Microbubble-Assisted Cleaning-in-Place Process for Ultrafiltration System and Its Environmental Performance". Membranes 13, n. 4 (10 aprile 2023): 424. http://dx.doi.org/10.3390/membranes13040424.
Abstract (sommario):
Membrane filtration is a key technology in dairy processing for the separation of dairy liquids to clarify, concentrate, and fractionate a variety of dairy products. Ultrafiltration (UF) is widely applied for whey separation, protein concentration and standardization, and lactose-free milk production, though its performance can be hindered by membrane fouling. As an automated cleaning process commonly used in the food and beverage industries, cleaning in place (CIP) uses large amounts of water, chemicals, and energy, resulting in significant environmental impacts. This study introduced micron-scale air-filled bubbles (microbubbles; MBs) with mean diameters smaller than 5 μm into cleaning liquids to clean a pilot-scale UF system. During the UF of model milk for concentration, cake formation was identified as the dominant membrane fouling mechanism. The MB-assisted CIP process was conducted at two bubble number densities (2021 and 10,569 bubbles per mL of cleaning liquid) and two flow rates (130 and 190 L/min). For all the cleaning conditions tested, MB addition largely increased the membrane flux recovery by 31–72%; however, the effects of bubble density and flow rate were insignificant. Alkaline wash was found to be the main step in removing proteinaceous foulant from the UF membrane, though MBs did not show a significant effect on the removal due to the operational uncertainty of the pilot-scale system. The environmental benefits of MB incorporation were quantified by a comparative life cycle assessment and the results indicated that MB-assisted CIP had up to 37% lower environmental impact than control CIP. This is the first study incorporating MBs into a full CIP cycle at the pilot scale and proving their effectiveness in enhancing membrane cleaning. This novel CIP process can help reduce water and energy use in dairy processing and improve the environmental sustainability of the dairy industry.
18
Yoo, Sung. "Operating Cost Reduction of In-line Coagulation/Ultrafiltration Membrane Process Attributed to Coagulation Condition Optimization for Irreversible Fouling Control". Water 10, n. 8 (11 agosto 2018): 1076. http://dx.doi.org/10.3390/w10081076.
Abstract (sommario):
This study examined the optimum coagulation conditions for reducing irreversible fouling during the in-line coagulation/ultrafiltration (UF) membrane process and assessed the decrease in operating cost. The coagulation conditions that generated charge-neutralization, sweep-flocculation, and under-dosing mechanisms were obtained by a jar-test, and a pilot-scale in-line coagulation/UF membrane process was operated under the coagulation conditions. Charge-neutralization and sweep-flocculation mechanisms reduced irreversible fouling effectively, and the under-dosing mechanism was able to reduce irreversible fouling only when flocs of a certain size or larger were formed. This revealed that floc size was a more important factor in reducing irreversible fouling than floc structure, and once initial cake layers were created by flocs of a fixed size, the structure of formed cake layers had only a minor effect on irreversible fouling. Regarding reduction in operating cost, 0.5 mg/L and 3 h, which were necessary to produce an under-dosing mechanism, were deemed the optimum coagulant dosage and coagulant injection time, respectively, to reduce irreversible fouling. In order to analyze the operating cost reduction effect, a pilot plant was operated under optimum operating conditions, and the total operating cost was approximately 11.2% lower than without in-line coagulation.
19
Nywening, J. P., H. Zhou e H. Husain. "Comparison of mixed liquor filterability measured with bench and pilot-scale membrane bioreactors". Water Science and Technology 56, n. 6 (1 settembre 2007): 155–62. http://dx.doi.org/10.2166/wst.2007.644.
Abstract (sommario):
Parallel experimental tests to measure mixed liquor filterability for submerged membrane bioreactors were conducted over a six month period using three ZW-500 pilot plants and a ZW-10 lab-scale filterability apparatus. Non-air sparged conditions during the tests yielded operation behaviour that was equivalent to dead-end filtration. The fouling resistance increased linearly with the intercepted mass until a critical point was reached at which point significant cake compression was induced and the resistance began to increase exponentially. Although the point of cake compression appears to be dependent on the membrane module design, similar resistance per unit solid mass intercepted per unit area (Rmass) values were observed when the same mixed liquor was filtered. Coupled with the established correlation between the Rmass and the critical flux, it is suggested that the filterability test results from a side-stream, lab-scale module may be used to predict fouling potential in a full scale MBR wastewater treatment system without interrupting the full-scale MBR operation.
20
Qin, J. J., M. N. Wai, M. H. Oo, K. A. Kekre e H. Seah. "Impact of anti-scalant on fouling of reverse osmosis membranes in reclamation of secondary effluent". Water Science and Technology 60, n. 11 (1 dicembre 2009): 2767–74. http://dx.doi.org/10.2166/wst.2009.717.
Abstract (sommario):
The objective of the study was to evaluate the impact of anti-scalant on fouling of reverse osmosis (RO) membranes in reclamation of secondary effluent which was produced by a conventional activated sludge process at Kranji Water Reclamation Plant with the capacity of 151,000 m3/d. The study was carried out using a RO pilot plant with the capacity of 2.4 m3/h. The RO plant was in 2:1 configuration and was operated at 75% recovery and at membrane flux of 17 l m−2 h−1. Pilot trials were conducted with and without anti-scalant. Compositions of feed and concentrate streams were analyzed and the pilot data were normalized. The results of the study showed that the plant operation was stable during the first few days after stopping dosage of anti-scalant but after 3–6 days of operation the membranes were fouled. The time lag effect of anti-scalant without dosage was not reported previously and could be potentially beneficial to save chemicals. The membrane fouling was more serious at the second stage due to the formation of calcium phosphate scale when the pilot plant was operated without anti-scalant. The flux of fouled membranes could be completely recovered after clean-in-place (CIP) with citric acid, indicating that scaling dominated the fouling of the RO membranes. These findings in the study could be applied to select an appropriate anti-scalant for prevention from formation of calcium phosphate scale in the RO operation.
21
Kimura, Katsuki, Nobuhiro Yamato, Hiroshi Yamamura e Yoshimasa Watanabe. "Membrane Fouling in Pilot-Scale Membrane Bioreactors (MBRs) Treating Municipal Wastewater". Environmental Science & Technology 39, n. 16 (agosto 2005): 6293–99. http://dx.doi.org/10.1021/es0502425.
22
Sanciolo, Peter, Paul Monis, Justin Lewis, Greg Ryan, Andrew Salveson, Nicola Fontaine, Judy Blackbeard e Stephen Gray. "Effectiveness and Energy Requirements of Pasteurisation for the Treatment of Unfiltered Secondary Effluent from a Municipal Wastewater Treatment Plant". Water 12, n. 8 (24 luglio 2020): 2100. http://dx.doi.org/10.3390/w12082100.
Abstract (sommario):
Pasteurisation was investigated as a process to achieve high microbial quality standards in the recycling of water from unfiltered secondary effluents from a wastewater treatment plants in Melbourne, Australia. The relative heat sensitivity of key bacterial, viral, protozoan and helminth wastewater organisms (Escherichia coli, Enterococcus, FRNA bacteriophage, adenovirus, coxsackievirus, Cryptosporidium, and Ascaris) were determined by laboratory scale tests. The FRNA phage were found to be the most heat resistant, followed by enterococci and E. coli. Pilot scale challenge testing of a 2 ML/day pasteurisation pilot plant using unfiltered municipal wastewater and male specific coliphage (MS2) phage showed that temperatures between 69 °C and 75 °C achieved log reductions values between 0.9 ± 0.1 and 5.0 ± 0.5 respectively in the contact chamber. Fouling of the heat exchangers during operation using unfiltered secondary treated effluent was found to increase the energy consumption of the plant from 2.2 kWh/kL to 5.1 kWh/kL. The economic feasibility of pasteurisation for the current municipal application with high heat exchanger fouling potential can be expected to depend largely on the available waste heat from co-generation and on the efforts required to control fouling of the heat exchangers.
23
Shin, H., e S. Kang. "Performance and membrane fouling in a pilot scale SBR process coupled with membrane". Water Science and Technology 47, n. 1 (1 gennaio 2003): 139–44. http://dx.doi.org/10.2166/wst.2003.0036.
Abstract (sommario):
The performance of the pilot-scale submerged membrane coupled with sequencing batch reactor (SM-SBR) for upgrading effluent quality was investigated in this study. The reactor was operated with 3-hour cycle with alternating anoxic and aerobic conditions to treat organics, nitrogen and phosphate. Despite various influent characteristics, COD removal was always higher than 95%. Sufficient nitrification was obtained within a few weeks after start-up and during the stable period, complete nitrification occurred despite short aeration time. Total nitrogen (TN) removal efficiency was reached up to 85%. Membrane flux was critical for TN removal so that the decrease of flux by membrane fouling led to increase of HRT, and it caused the endogenous respiration of microorganisms such as nitrifying bacteria. The stirred cell test revealed the significant role of the soluble fraction in membrane permeability and dissolved solids played a major role in the short-term fouling mechanism. The cake resistance by the soluble COD fraction of supernatant or soluble microbial products (SMP) was investigated as a major part of total resistance.
24
Koyuncu, I., E. Kural e D. Topacik. "Pilot scale nanofiltration membrane separation for waste management in textile industry". Water Science and Technology 43, n. 10 (1 maggio 2001): 233–40. http://dx.doi.org/10.2166/wst.2001.0629.
Abstract (sommario):
This paper presents the pilot scale membrane separation studies on dyehouse effluents of textile industry. Nanofiltration (NF) membranes which have 2 m2 of surface area were evaluated for membrane fouling on permeate flux and their suitability in separating COD, color and conductivity in relation to operating pressure and feed concentration from textile industry dyehouse effluents. Successive batch runs demonstrated that any serious membrane fouling was not experienced for NF membrane tested in treating this type of wastewater. The permeate flux was found to increase significantly with operating pressure. Flux decreased with increasing recovery rate. The overall removal efficiencies of COD, color and conductivity were found as greater than 97%. COD was lower than 10 mg/l at 12 bar pressures. Permeate COD was also increased with increasing recovery and COD was 30 mg/l with recovery of 80%. Almost complete color removal was achieved with nanofiltration membrane. Color value was also decreased from 500 Pt-Co to 10 Pt-Co unit. This significant reduction in color and COD makes possible the recycle of the permeate in the dyehouse. Permeate conductivity was decreasing with increasing pressure and retention of conductivity increases with increasing pressures. This phenomenon is expected from the analysis of conductivity mass transport model. Economical analysis have been done and the total estimated cost will be 0.81 $/m3 based on 1000 m3/day of and this value is very economical for Istanbul City due to increasing industrial water supply tariffs.
25
Choi, Yongjun, Younggeun Lee, Kwanghee Shin, Youngkyu Park e Sangho Lee. "Analysis of long-term performance of full-scale reverse osmosis desalination plant using artificial neural network and tree model". Environmental Engineering Research 25, n. 5 (23 ottobre 2019): 763–70. http://dx.doi.org/10.4491/eer.2019.324.
Abstract (sommario):
The reverse osmosis (RO) technology is currently the leading desalination method. However, until recently, application of RO technology on a large scale has been primarily limited by membrane fouling. The mechanism of fouling is complex, which is not well understood in full-scale plants. Although many studies about modeling and prediction of fouling have been done, in most cases, the experimental data set of lab or pilot scale systems, which may not show fouling characteristics well in full-scale systems were used. In this study, both artificial neural network (ANN) model and tree model (TM) was evaluated to analyze long-term performance of full scale reverse osmosis desalination plant. The results of application of the ANN and TM indicated high correlation coefficients between the measured and simulated output variables. However, it is not easy to use ANN for the full scale plant operation because the final model is not expressed as a form of mathematical functions. TM has advantages over ANN because the model can be obtained as forms of simple function and it showed reasonably high <i>R</i><sup>2</sup>. Therefore, TM is shown to be more adequate than ANN for developing models in which the full-scale RO plant data is considered as an input.
26
Kouadio, P., e M. Tétrault. "Nanofiltration of colored surface water: Quebec's experience". Water Supply 3, n. 5-6 (1 dicembre 2003): 15–22. http://dx.doi.org/10.2166/ws.2003.0145.
Abstract (sommario):
Three colored surface water nanofiltration pilot-scale projects were conducted in the province of Quebec (eastern Canada), between November 2000 and March 2002, by the company H2O Innovation (2000) inc., for the municipalities of Lac Bouchette, Latulipe-et-Gaboury and Charlesbourg (now part of Quebec City). Results indicated that nanofiltration permeate quality has an advance on present drinking water regulation standard in Quebec, but important membrane fouling occurred. Fouling can be controlled by pretreatment and optimization of the operating conditions.
27
Odriozola, Magela, Nicolás Morales, Jose R. Vázquez-Padín, Maria Lousada-Ferreira, Henri Spanjers e Jules B. van Lier. "Fouling Mitigation by Cationic Polymer Addition into a Pilot-Scale Anaerobic Membrane Bioreactor Fed with Blackwater". Polymers 12, n. 10 (16 ottobre 2020): 2383. http://dx.doi.org/10.3390/polym12102383.
Abstract (sommario):
Cationic polymers have proven to be suitable flux enhancers (FEs) in large-scale aerobic membrane bioreactors (MBRs), whereas in anaerobic membrane bioreactors (AnMBRs) research is scarce, and so far, only done at lab-scale. Results from MBRs cannot be directly translated to AnMBRs because the extent and nature of membrane fouling under anaerobic and aerobic conditions are different. Our research focused on the long-term effect of dosing the cationic polymer Adifloc KD451 to a pilot AnMBR, fed with source-separated domestic blackwater. A single dosage of Adifloc KD451 at 50 mg L−1 significantly enhanced the filtration performance in the AnMBR, revealed by a decrease in both fouling rate and total filtration resistance. Nevertheless, FE addition had an immediate negative effect on the specific methanogenic activity (SMA), but this was a reversible process that had no adverse effect on permeate quality or chemical oxygen demand (COD) removal in the AnMBR. Moreover, the FE had a long-term positive effect on AnMBR filtration performance and sludge filterability. These findings indicate that dosing Adifloc KD451 is a suitable strategy for fouling mitigation in AnMBRs because it led to a long-term improvement in filtration performance, while having no significant adverse effects on permeate quality or COD removal.
28
Huck, P. M., S. Peldszus, C. Hallé, H. Ruiz, X. Jin, M. Van Dyke, G. Amy, W. Uhl, M. Theodoulou e D. B. Mosqueda-Jimenez. "Pilot scale evaluation of biofiltration as an innovative pre-treatment for ultrafiltration membranes for drinking water treatment". Water Supply 11, n. 1 (1 marzo 2011): 23–29. http://dx.doi.org/10.2166/ws.2011.004.
Abstract (sommario):
Fouling remains one of the major constraints on the use of low pressure membranes in drinking water treatment. Work over the last few years has shown the importance of biopolymers (carbohydrates and protein-like material) as foulants for ultrafiltration (UF) membranes. The purpose of this study was to investigate at pilot scale the use of rapid biofiltration (without prior coagulation or ozone addition) as an innovative pretreatment to reduce fouling of UF membranes. The investigation was carried out on a water with a higher than average DOC and significant temperature variation. The biofilters, each operated at a hydraulic loading of 5 m/h, had empty bed contact times of 5, 10 and 15 minutes. The membrane unit was operated at a flux equivalent to 60 LMH at 20°C. The investigation confirmed the encouraging results obtained in an earlier smaller scale study with essentially the same water. Increased biofiltration contact time (i.e. increased bed depth) led to lower rates of hydraulically irreversible fouling. The initial biofiltration backwash procedure, involving air scour as is common in chemically assisted filtration, led in some cases to an increased rate of membrane fouling immediately after the backwash. An alternative backwashing strategy was developed, however the feasibility of operating with this approach over very long periods of time needs to be confirmed. To assist in full-scale implementation of this “green” and simple pretreatment, the design and operating conditions for the biofilters should be optimized for various types of waters. It is expected that biofiltration pretreatment will be of particular interest for small and/or isolated systems where a higher initial capital cost may be acceptable because of operational simplicity and reduced chemical requirements.
29
Lu, Shu, Xing Li e Jian Yu Tian. "Pilot-Study of Micro-Polluted Water Treatment by UF Membrane at Different Fluxes". Applied Mechanics and Materials 448-453 (ottobre 2013): 1197–201. http://dx.doi.org/10.4028/www.scientific.net/amm.448-453.1197.
Abstract (sommario):
A pilot-scale ultrafiltration (UF) experiment was conducted to determine the effect of membrane flux on pollutants removal performance and membrane fouling. The study results showed that with the increase of the membrane flux (20, 30 and 40 LMH respectively), the removal of turbidity, CODMnand UV254were slightly decreased. Every 10 LMH more flux increased, the UV254removal was reduced double. The growth rate of the trans-membrane pressure (TMP) became faster when the membrane flux increased, and 20 LMH could be considered as the critical flux in the raw water quality and working conditions. Membrane fouling rate could be delayed by air bubbling and backwashing. The larger the membrane flux was, the more TMP could be reduced. Furthermore, the effect of delaying the membrane fouling by backwashing was better than by air bubbling.
30
Galjaard, G., J. C. Kruithof, H. Scheerman, J. Verdouw e J. C. Schippers. "Enhanced pre-coat engineering (EPCE®) for micro- and ultrafiltration: steps to full-scale application". Water Supply 3, n. 5-6 (1 dicembre 2003): 125–32. http://dx.doi.org/10.2166/ws.2003.0158.
Abstract (sommario):
Ultrafiltration of surface water without pre-treatment frequently suffers from high fouling rates and irreversible fouling. Enhanced pre-coat engineering (EPCE) has been developed with the aim to enable ultrafiltration plants to treat surface water directly at high and stable flux rates. In this study in-line coagulation with ferric chloride and polyaluminium chloride and EPCE are compared on pilot scale using capillary membranes with IJssel Lake water as feed water. The in-line coagulation experiments resulted in relatively low flux rates and irreversible fouling, whereas EPCE enabled us to achieve a flux rate of 100 l/(h.m2) and a dosage of less than 25 g/m3. However, a couple of technical questions need to be answered before fullscale application can be implemented with all types of ultrafiltration systems.
31
Itonaga, T., K. Kimura e Y. Watanabe. "Influence of suspension viscosity and colloidal particles on permeability of membrane used in membrane bioreactor (MBR)". Water Science and Technology 50, n. 12 (1 dicembre 2004): 301–9. http://dx.doi.org/10.2166/wst.2004.0727.
Abstract (sommario):
In this study, pilot scale experiments were carried out to examine membrane fouling occurring in membrane bioreactors (MBR) with or without pre-treatment (coagulation/sedimentation). Especially, the influence of suspension viscosity and dissolved organic matter (DOM) on membrane fouling was investigated. The pre-coagulation/sedimentation process improved the performance of a MBR in terms of membrane permeability by controlling irreversible fouling and formation of thick cake layer. The upper limit of MLSS concentration for an efficient operation in MBR without pre-treatment was suggested to be around 10 g/L based on the measurement of suspension viscosity. In this study, it was difficult to directly relate membrane fouling to DOM detected in the membrane chamber. A series of laboratory scale dead-end filtration experiments was carried out to investigate which fractions in biomass suspension would be the most influential in the deterioration of membrane permeability. Based on the dead-end tests, it was shown that the deterioration of membrane permeability was mainly caused by the colloidal particle fraction in the biomass suspension.
32
Wang, Jingwei, Bing Wu, Yu Liu, Anthony G. Fane e Jia Wei Chew. "Monitoring local membrane fouling mitigation by fluidized GAC in lab-scale and pilot-scale AnFMBRs". Separation and Purification Technology 199 (giugno 2018): 331–45. http://dx.doi.org/10.1016/j.seppur.2018.01.067.
33
Rabie, Hamid R., Pierre Côté e Nicholas Adams. "A method for assessing membrane fouling in pilot- and full-scale systems". Desalination 141, n. 3 (dicembre 2001): 237–43. http://dx.doi.org/10.1016/s0011-9164(01)85002-5.
34
Rahman, I., S. Ndiongue, X. Jin, M. I. Van Dyke, W. B. Anderson e P. M. Huck. "Fouling of low-pressure membranes during drinking water treatment: effect of NOM components and biofiltration pretreatment". Water Supply 14, n. 3 (11 dicembre 2013): 453–60. http://dx.doi.org/10.2166/ws.2013.221.
Abstract (sommario):
Fouling is a major challenge for low-pressure membrane drinking water treatment systems. Previous research has demonstrated that under the right conditions, biofiltration is an effective method to reduce fouling of low-pressure polymeric membranes. This study provides additional insight into the effect of biofiltration as a pretreatment for fouling reduction by using river water with different raw water quality characteristics than has been examined in previous studies. Two parallel pilot-scale dual media (sand/anthracite) biological filters were operated continuously over a period of 14 months. Liquid chromatography–organic carbon detection analysis confirmed that the parallel biofilters performed similarly with both averaging on 21% biopolymer removal. Raw and treated water biopolymer concentrations were correlated, with increased absolute removals occurring at higher raw water concentrations. Ultrafiltration (UF) membrane fouling experiments showed substantial improvement in performance following biofiltration pretreatment by reducing hydraulically irreversible and reversible fouling rates by 14–68% and 8–55%, respectively. The results also reaffirm the importance of biopolymers at concentrations as low as ∼0.1 mg/L on irreversible and reversible UF membrane fouling and a minimal impact of humic substances.
35
Otaki, M., S. Takizawa e S. Ohgaki. "Control and modeling of membrane fouling due to microorganism growth by UV pretreatment". Water Science and Technology 38, n. 4-5 (1 agosto 1998): 405–12. http://dx.doi.org/10.2166/wst.1998.0679.
Abstract (sommario):
Control of membrane-fouling is an important topic for extending continuous running time and reducing the frequency of chemical cleaning in membrane processes. Since the microorganism contribution to membrane fouling was considered to be significant, UV was thought to be effective to control membrane fouling. In this study, a pilot plant scale MF-membrane system (flow rate = 5 m3d−1) was operated in order to investigate the effect of UV pretreatment. As the experimental results, it was found that UV irradiation prevented the membrane fouling by control the microorganism concentration in the feed. And the continuous running time of membrane was extended 6 times longer than that of a process without UV pretreatment. In order to know how UV pretreatment prevented fouling, we also investigated the residual bactericidal effect which persists in water even after UV irradiation. However, the residual bactericidal effect wasn't observed in our experiment, therefore inhibition of microorganism growth by the residual effect in the membrane module could be ignored. We developed the theoretical model of microorganism growth on membrane as a membrane fouling material. This model can explain the observed membrane fouling due to microorganism growth.
36
Kulesha, Olga, Zakhar Maletskyi e Harsha Ratnaweera. "Multivariate Chemometric Analysis of Membrane Fouling Patterns in Biofilm Ceramic Membrane Bioreactor". Water 10, n. 8 (26 luglio 2018): 982. http://dx.doi.org/10.3390/w10080982.
Abstract (sommario):
Membrane fouling highly limits the development of Membrane bioreactor technology (MBR), which is among the key solutions to water scarcity. The current study deals with the determination of the fouling propensity of filtered biomass in a pilot-scale biofilm membrane bioreactor to enable the prediction of fouling intensity. The system was designed to treat domestic wastewater with the application of ceramic microfiltration membranes. Partial least squares regression analysis of the data obtained during the long-term operation of the biofilm-MBR (BF-MBR) system demonstrated that Mixed liquor suspended solids (MLSS), diluted sludge volume index (DSVI), chemical oxygen demand (COD), and their slopes are the most significant for the estimation and prediction of fouling intensity, while normalized permeability and its slope were found to be the most reliable fouling indicators. Three models were derived depending on the applied operating conditions, which enabled an accurate prediction of the fouling intensities in the system. The results will help to prevent severe membrane fouling via the change of operating conditions to prolong the effective lifetime of the membrane modules and to save energy and resources for the maintenance of the system.
37
Grélot, A., C. Machinal, K. Drouet, A. Tazi-Pain, J. C. Schrotter, A. Grasmick e S. Grinwis. "In the search of alternative cleaning solutions for MBR plants". Water Science and Technology 58, n. 10 (1 novembre 2008): 2041–49. http://dx.doi.org/10.2166/wst.2008.759.
Abstract (sommario):
The objective of the study was to identify alternative cleaning reagents to chlorine for membrane permeability regeneration in MBR applications. Indeed, chlorine is prohibited in some countries because of the formation of by-products such as THM. The study was focused on the comparison of ten cleaning reagents performances and in particular on their ability to remove irreversible fouling. The tests were carried on with the A3 Water Solutions' Maxflow membrane (flat sheet membrane). A specific experimental protocol was defined at lab scale to develop an irreversible fouling by filtering sludge supernatant. The more promising reagents at lab scale were then tested on the A3 membrane continuously immersed in a MBR pilot plant functioning under typical biological conditions (MLSS = 11 g/l; SRT = 28days). A full scale test was finally performed with hydrogen peroxide, one of the best reagents. Chlorine was taken as reference for all performed tests. The cleaning performances of the selected reagents were different at the different scales, probably due to the difficulty to obtain an irreversible membrane fouling at larger scales. This testing procedure will be reproduced with other membrane materials to have a better understanding of interactions between irreversible fouling, material nature and chemical reagents.
38
Parlar, İlker, Yakubu A. Jarma, Taylan O. Pek, Nalan Kabay, Mehmet Kitis, Nevzat O. Yigit e Mithat Yuksel. "Effect of Antiscalant Usage and Air Diffuser Perforation Diameter on Filtration Performance of Submerged Flat Sheet MBR for Treatment of High Salinity and Scaling Propensity Wastewater". Water 15, n. 6 (19 marzo 2023): 1191. http://dx.doi.org/10.3390/w15061191.
Abstract (sommario):
Membrane fouling and mineral scaling remain major drawbacks for MBR technology. Membrane fouling reduces the filtration ability in MBR systems by increasing transmembrane pressure (TMP) and thus increases the operational cost. This study focused on the application of commercially available antiscalant in a pilot MBR system and the effect of diffuser perforation diameter for the treatment of high mineral scaling propensity wastewater. Submerged flat sheet membranes (Kubota, nominal pore size: 0.4 µm) were used in the pilot-scale test unit operated in the wastewater treatment plant of ITOB Organized Industrial Zone, Izmir, Turkey. The commercially available antiscalants employed were coded AS-1 and AS-2 for antiscalant study. Long term effect of the two antiscalants employed was investigated under high mixed liquor suspended solid (MLSS) concentration (17–21 g/L) for two months of MBR operation. The effect of low MLSS concentration (10–13 g/L) was also studied without changing the concentration of antiscalant type and concentration. AS-1 was found to be more effective in terms of mineral scale control. The effect of diffuser perforation diameter (1, 3 and 5 mm) on mineral scaling minimization in MBR pilot system was also studied. The best performance with respect to membrane fouling control was found with an air diffuser having 3 mm of diffuser perforated diameter. Some quality analyses of the product water were also carried out to assess the effect of antiscalant addition on microbial activities in the MBR unit. The findings in this study reveal that the use of antiscalants has not affected biological treatment performance of MBR pilot system. The removal ranges obtained during all MBR studies were 98.47–99.9%, 84.62–99.4%, 89.5–98.5%, 86.90–99.9%, 67.01–99.2%, 75.03–93.9%, and 20.36–71.5% for total suspended solid (TSS), color, chemical oxygen demand (COD), NH4-N, PO4-P, NO2-N, and total nitrogen (TN) respectively.
39
He, Chang-wei, Hui Wang, Luo-chun Wang, Zi-yang Lou, Li Bai, Hai-feng Zong e Zhen Zhou. "Fouling Identification for Nanofiltration Membrane and the Potential Reduction of Pollutants in the Leachate by Using Fe/Al/PAC Coagulation". Sustainability 13, n. 3 (21 gennaio 2021): 1114. http://dx.doi.org/10.3390/su13031114.
Abstract (sommario):
The reduction in the fouling is an important way to maintain the steady operation for the nanofiltration (NF) process in leachate treatment. The fouling components from the real leachate treatment process were identified using a scanning electron microscope equipped with X-ray microanalysis (SEM-EDS), infrared spectroscopy (FTIR), atomic analysis and three-dimensional fluorescence (EEM) analysis, and the coagulation of Fe/Al/PAC was selected to reduce the potential pollutants in the leachate, to reduce the potential fouling. It was found that organic humic acid and calcium-magnesium precipitates were the main pollutants in NF fouling. The foulant layer was the result of the combination of organic matter, inorganic precipitation, colloids and microorganisms, and the colloids precipitation is more important, and should be removed in advance. PAC was found to be more efficiency to reduce the colloids and the inorganic matter, among the coagulants selection, with the chemical oxygen demand (COD) removal rate of 55.1%. The commercially available coagulant-poly aluminum chloride (PAC) was chosen as a coagulant. The removal rate of leachate reached 55.1%, and the flow rate through the membrane was increased by 35.8% under the optimum condition (pH was 5.0, PAC dosage was 100 mg/L, and the membrane pressure was 0.4 MPa). Through the pilot scale test, the effluent was connected to the microfiltration membrane and then to the nanofiltration membrane and the practical engineering application is feasible.
40
Scudeller, Luisa A., Pascal Blanpain-Avet, Thierry Six, Séverine Bellayer, Maude Jimenez, Thomas Croguennec, Christophe André e Guillaume Delaplace. "Calcium Chelation by Phosphate Ions and Its Influence on Fouling Mechanisms of Whey Protein Solutions in a Plate Heat Exchanger". Foods 10, n. 2 (27 gennaio 2021): 259. http://dx.doi.org/10.3390/foods10020259.
Abstract (sommario):
Fouling of plate heat exchangers (PHEs) is a recurring problem when pasteurizing whey protein solutions. As Ca2+ is involved in denaturation/aggregation mechanisms of whey proteins, the use of calcium chelators seems to be a way to reduce the fouling of PHEs. Unfortunately, in depth studies investigating the changes of the whey protein fouling mechanism in the presence of calcium chelators are scarce. To improve our knowledge, reconstituted whey protein isolate (WPI) solutions were prepared with increasing amounts of phosphate, expressed in phosphorus (P). The fouling experiments were performed on a pilot-scale PHE, while monitoring the evolution of the pressure drop and heat transfer coefficient. The final deposit mass distribution and structure of the fouling layers were investigated, as well as the whey protein denaturation kinetics. Results suggest the existence of two different fouling mechanisms taking place, depending on the added P concentration in WPI solutions. For added P concentrations lower or equal to 20 mg/L, a spongy fouling layer consists of unfolded protein strands bound by available Ca2+. When the added P concentration is higher than 20 mg/L, a heterogeneously distributed fouling layer formed of calcium phosphate clusters covered by proteins in an arborescence structure is observed.
41
Abdelrazeq, Haneen, Majeda Khraisheh e Mohammad K. Hassan. "Long-Term Treatment of Highly Saline Brine in a Direct Contact Membrane Distillation (DCMD) Pilot Unit Using Polyethylene Membranes". Membranes 12, n. 4 (14 aprile 2022): 424. http://dx.doi.org/10.3390/membranes12040424.
Abstract (sommario):
Membrane distillation (MD) is an attractive separation process for wastewater treatment and desalination. There are continuing challenges in implementing MD technologies at a large industrial scale. This work attempts to investigate the desalination performance of a pilot-scale direct contact membrane distillation (DCMD) system using synthetic thermal brine mimicking industrial wastewater in the Gulf Cooperation Council (GCC). A commercial polyethylene membrane was used in all tests in the DCMD pilot unit. Long-term performance exhibited up to 95.6% salt rejection rates using highly saline feed (75,500 ppm) and 98% using moderate saline feed (25,200 ppm). The results include the characterization of the membrane surface evolution during the tests, the fouling determination, and the assessment of the energy consumption. The fouling effect of the polyethylene membrane was studied using Humic acid (HA) as the feed for the whole DCMD pilot unit. An optimum specific thermal energy consumption (STEC) reduction of 10% was achieved with a high flux recovery ratio of 95% after 100 h of DCMD pilot operation. At fixed operating conditions for feed inlet temperature of 70 °C, a distillate inlet temperature of 20 °C, with flowrates of 70 l/h for both streams, the correlations were as high as 0.919 between the pure water flux and water contact angle, and 0.963 between the pure water flux and salt rejection, respectively. The current pilot unit study provides better insight into existing thermal desalination plants with an emphasis on specific energy consumption (SEC). The results of this study may pave the way for the commercialization of such filtration technology at a larger scale in global communities.
42
Xu, J., F. C. Kent e K. Farahbakhsh. "An evaluation of MBR and conventional pretreatment for reverse osmosis for water reclamation". Journal of Water Reuse and Desalination 1, n. 2 (1 giugno 2011): 88–98. http://dx.doi.org/10.2166/wrd.2011.041.
Abstract (sommario):
Two wastewater polishing systems were compared in terms of their ability to protect downstream reverse osmosis (RO) processes. A conventional full-scale wastewater treatment system with primary and secondary treatment followed by rotating biological contactors (RBC) and sand filtration were compared in a side-by-side study with a pilot-scale membrane bioreactor (MBR). Effluent from the two pretreatment trains was sent to two identical RO pilot systems. The effluent water quality of the two systems was compared as well as the RO performance. The MBR pretreatment provided effluent with a turbidity (0.11 NTU) that was more than five times lower than that of the conventional system (0.58 NTU). The fouling rate of the RO system with MBR pretreatment was 50–67% of the value found for the RO system with conventional pretreatment and the difference in turbidity values was identified as the major source of this large difference. The RO effluent quality of both systems was excellent, with similar overall removals in both systems. The study emphasizes the importance of removing particulate matter for the prevention of RO fouling within water reclamation.
43
Grélot, A., P. Grelier, A. Tazi-Pain, B. Lesjean, U. Brüss e A. Grasmick. "Performances and fouling control of a flat sheet membrane in a MBR pilot-plant". Water Science and Technology 61, n. 9 (1 maggio 2010): 2185–92. http://dx.doi.org/10.2166/wst.2010.127.
Abstract (sommario):
This paper deals with the performance and the optimisation of the hydraulic operating conditions of the A3 Water Solutions flat sheet membrane technology in a MBR pilot-plant to achieve a satisfying fouling control and also a reduction in the required aeration. Two vertically stacked modules were tested at pilot-scale at Anjou Recherche under typical biological operating conditions (mixed liquor suspended solids concentration (MLSS) = 10 g/l; sludge retention time (SRT) = 28 days; food to microorganism ratio (F/M)= 0.12 kg COD/kg MLSS/d). The use of a double-deck and of specific backwashes for this membrane technology enabled to achieve satisfying membrane performances for a net flux of 25 L h−1 m−2, 20°C at a low specific aeration demand per membrane surface (SADm = 0.2 Nm3 h−1 m−2) which corresponds to a specific aeration demand per permeate volume unit (SADp) of 8 Nm3 air/m3 permeate, which is lower than reported for many commercial membrane systems. The mixed liquor characteristics (foaming, MLSS concentration) appeared to influence the fouling behaviour of the membranes but no correlation was found with the fouling rate. However, with the new operating conditions, the system is robust and can cope with fouling resulting from biological stress and daily peak flows for MLSS concentrations in the membrane tank up to 18 g/l.
44
Azis, Konstantinos, Marianthi Malioka, Spyridon Ntougias e Paraschos Melidis. "Membrane Fouling Monitoring in a Submerged Membrane Bioreactor". Proceedings 2, n. 11 (30 luglio 2018): 653. http://dx.doi.org/10.3390/proceedings2110653.
Abstract (sommario):
Use of Membrane Bioreactor (MBR) technology for municipal wastewater treatment has been increased in recent years, as it successfully overcomes the disadvantages of the conventional activated sludge process. Membrane fouling is the major disadvantage of MBRs and leads to decreased membrane performance and expanded operational expenses. In this study, fouling was monitored in a pilot-scale submerged MBR system fed with municipal wastewater. TMP was directly measured on the membrane module during the operation. To control TMP increase owing to biosolids accumulation on membrane surface, successive backwashes and air-cross flow velocity increase were applied. These measures lowered TMP and improved flux.
45
Huang, J. Y., S. Takizawa e K. Fujita. "Comparison of UV and chlorine pretreatment in pilot plant micro-filter membrane separation for drinking water". Water Supply 1, n. 5-6 (1 giugno 2001): 245–51. http://dx.doi.org/10.2166/ws.2001.0120.
Abstract (sommario):
Methods to control bio-fouling, i.e. UV-irradiation and chlorination pretreatment were evaluated in dead-end membrane filtration. Pilot-scale experiments were carried out at Kosuzume Water Purification Plant, which is located at the Sagami River in Kanagawa Prefecture, Japan. As a result, both UV-irradiation and chlorination strongly suppressed the increase of transmembrane pressure and prevented bio-fouling. However, in the case of pre-chlorination, the membrane color changed from white to brown after a long use, causing irreversible membrane fouling due probably to manganese adsorption. Suspended solids removal by membrane filtration decreased the formation potential for CHCl3, but didn't affect the CHCl2Br and CHClBr2 formation potentials. Pre-chlorination, however, increased both CHCl2Br and CHClBr2 formation potentials, thus making up for the reduction in CHCl3 formation potential due to membrane filtration. UV-irradiation pretreatment combined with membrane filtration in the water purification process is regarded as an accessible method and was proved effective in controlling bio-fouling, which gave us a better water quality without increasing trihalomethanes in contrast to pre-chlorination.
46
Zhang, Kai Hai, e Bao Zhen Wang. "Improvement of Operational Performance of MBR with the Emphasis on Enhanced N and P Removal by Modification in Design". Advanced Materials Research 777 (settembre 2013): 296–302. http://dx.doi.org/10.4028/www.scientific.net/amr.777.296.
Abstract (sommario):
Membrane bio-reactor (MBR) is an innovative and effective wastewater treatment process, which has much more extra advantages than other processes. However, membrane fouling and high operational/maintenance costs are always two important factors that restrict the development of MBR. In order to alleviate membrane fouling, larger aeration rate is usually used, which increases the operational cost and decrease N and P removal efficiencies of MBR. This paper summarizes the pilot scale experimental study on the improvement of operational performance of MBR by its design modification from one cell into three cells with micro-aeration,normal aeration and enhanced aeration conditions respectively with the package of fibrous bio-film carrier and PAC. As the result, the effluent water quality was improved significantly and membrane fouling was alleviated remarkably.
47
Kimura, K., R. Ogyu, T. Miyoshi, T. Naruse, T. Tsuyuhara e Y. Watanabe. "Membrane fouling caused by sub-micron particles in a mixed liquor suspension of an MBR". Water Science and Technology 67, n. 11 (1 giugno 2013): 2602–7. http://dx.doi.org/10.2166/wst.2013.170.
Abstract (sommario):
Membrane fouling needs to be mitigated for widespread use of membrane bioreactors (MBRs). It has been pointed out that particles with small sizes found in supernatants (sub-micron particles) of mixed liquor suspensions of MBRs are important in the evolution of membrane fouling of this technology. However, information on characteristics of sub-micron particles in MBRs is still insufficient. In this study, a pilot-scale MBR treating municipal wastewater was used to investigate and characterize sub-micron particles in an MBR and to identify the size fraction(s) responsible for irreversible fouling in an MBR. It was clearly shown that characteristics of sub-micron particles in the MBR varied considerably depending on their sizes. Results of Fourier transform infrared (FTIR) analysis and monosaccharide analysis suggested that irreversible fouling in this study was mainly caused by the specific size fraction of 0.1–0.45 μm, which was close to the size of micropores of the membrane used. Pore plugging might explain this to some extent.
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Miyoshi, Taro, Yuhei Nagai, Tomoyasu Aizawa, Katsuki Kimura e Yoshimasa Watanabe. "Proteins causing membrane fouling in membrane bioreactors". Water Science and Technology 72, n. 6 (2 giugno 2015): 844–49. http://dx.doi.org/10.2166/wst.2015.282.
Abstract (sommario):
In this study, the details of proteins causing membrane fouling in membrane bioreactors (MBRs) treating real municipal wastewater were investigated. Two separate pilot-scale MBRs were continuously operated under significantly different operating conditions; one MBR was a submerged type whereas the other was a side-stream type. The submerged and side-stream MBRs were operated for 20 and 10 days, respectively. At the end of continuous operation, the foulants were extracted from the fouled membranes. The proteins contained in the extracted foulants were enriched by using the combination of crude concentration with an ultrafiltration membrane and trichloroacetic acid precipitation, and then separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). The N-terminal amino acid sequencing analysis of the proteins which formed intensive spots on the 2D-PAGE gels allowed us to partially identify one protein (OmpA family protein originated from genus Brevundimonas or Riemerella anatipestifer) from the foulant obtained from the submerged MBR, and two proteins (OprD and OprF originated from genus Pseudomonas) from that obtained from the side-stream MBR. Despite the significant difference in operating conditions of the two MBRs, all proteins identified in this study belong to β-barrel protein. These findings strongly suggest the importance of β-barrel proteins in developing membrane fouling in MBRs.
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De Wever, H., W. Boënne, M. Danau, N. Vanderspiegel, K. Hardy e J. Limbos. "Closing the water loop in a maltery: reuse tests at pilot-scale". Water Science and Technology 54, n. 10 (1 novembre 2006): 9–15. http://dx.doi.org/10.2166/wst.2006.883.
Abstract (sommario):
This paper reports on the potential for water reuse in the malting sector. Core unit of a treatment train to close the water loop was a membrane bioreactor (MBR). We compared three different commercial submerged membranes for their fouling potential in this application and related this to the presence of extracellular polymeric substances (EPS). In a second step, we subjected MBR permeate to reverse osmosis and several (advanced) oxidation processes to evaluate the water quality achieved. Finally we performed a set of water reuse tests with waters obtained through different scenarios. The optimal scenario was then tested in a closed water loop over several malting cycles at pilot scale and the effect on water and malt quality was investigated.
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Lee, Tae-Mun, Hyunje Oh, Youn-Kyoo Choung, Sanghoun Oh, Moongu Jeon, Joon Ha Kim, Sook Hyun Nam e Sangho Lee. "Prediction of membrane fouling in the pilot-scale microfiltration system using genetic programming". Desalination 247, n. 1-3 (ottobre 2009): 285–94. http://dx.doi.org/10.1016/j.desal.2008.12.031.