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Abstract
1. Abstract The new process for process water production from river water is divided into three stages: prefiltration, ultrafiltration and reverse osmosis. The latter technique has been state-of-the-art in the preparation of drinking water, boiler feed water and ultrapure water from conventionally pretreated raw water for many years. On the other hand, ultrafiltration is new to this sector and has only recently been used on the industrial scale. It is used as a single-stage process to purify drinking and process water as well as surface water as an alternative to conventional treatment processes (e.g. ozonization-precipitation-flocculation-coagulation-chlorination-gravel filtration). Multistage, fairly complex processes are employed in the conventional pretreatment of river water. The use of different chemicals necessitates special safety measures and careful harmonization and control of water chemistry in view of the requirements of downstream reverse osmosis. By contrast, processes based on membrane technology enable a simply designed plant to be used with several advantages. Axiva in cooperation with the water supply company for the Höchst Industrial Park have developed and successfully tested an efficient and cost-effective ultrafiltration process for river water in pilot-scale operation over several years. During this trial period low-energy systems based on different filtration concepts (cross-flow, dead-end), efficient hydrophilic membranes and a specific operating and backflushing technique specially designed for the application were employed. In this way reliable plant operation with high availability was obtained and suspended particles and microorganisms were removed from the river water (River Main) without any problem. The permeate quality was very high throughout the trial period (< 0.05 NTU) and met the requirements for feed water to the RO plant.
... At that time, UF and RO were optimized for reduced energy, capital and operational investment costs, better recoveries, and zero discharge (Rautenbach et al., 1996). These focal points were addressed in further studies (Clever et al., 2000;Lorain et al., 2007;Knops et al., 2007;Sun et al., 2015;Loganathan et al., 2015;Ho et al., 2015). ...
... Typically, UF is used as a pretreatment operation for RO (Clever et al., 2000;Lorain et al., 2007;Knops et al., 2007;Sun et al., 2015;Ho et al., 2015;Loganathan et al., 2015). The research of Rosberg (1997) focused on UF as a pretreatment for RO and nanofiltration. ...
... The study of Clever et al. (2000) used pre-filtration, UF, and RO to treat river water to yield process water. The pre-filtration removed suspended matter to prevent clogging of the UF membranes. ...
... At that time, UF and RO were optimized for reduced energy, capital and operational investment costs, better recoveries, and zero discharge (Rautenbach et al., 1996). These focal points were addressed in further studies (Clever et al., 2000;Lorain et al., 2007;Knops et al., 2007;Sun et al., 2015;Loganathan et al., 2015;Ho et al., 2015). ...
... Typically, UF is used as a pretreatment operation for RO (Clever et al., 2000;Lorain et al., 2007;Knops et al., 2007;Sun et al., 2015;Ho et al., 2015;Loganathan et al., 2015). The research of Rosberg (1997) focused on UF as a pretreatment for RO and nanofiltration. ...
... The study of Clever et al. (2000) used pre-filtration, UF, and RO to treat river water to yield process water. The pre-filtration removed suspended matter to prevent clogging of the UF membranes. ...
... The production of clear and sparkling water that is safe as far as disease is concerned usually require chemical precipitation, adsorption, sedimentation, and filtration [5]. Each step of this process has to be controlled to get an optimal performance of the overall process, which results in a complex control system [28]. Nowadays, UF is used to replace clarification step in conventional water treatment plant, i.e., coagulation, sedimentation, and filtration and can be defined as a clarification and disinfections membrane operation. ...
... As mentioned before, application of UF for drinking water supply can be in form of single operation, i.e., without any pre-treatment except a common screen filter [28]. UF can be used on its own for treating drinking water where the feed water is not too high in terms of organic content [2]. ...
... Primarily, the development of UF technology in water application is focused in producing filtrate for drinking water [17]. Recently, UF has become an efficient pre-treatment for reverse osmosis (RO) system [28]. It is important to re-evaluate the cost and operating benefits of UF as pre-treatment particularly for high fouling feed water source such as surface water, a wastewater, or an open-intake seawater [17]. ...
The use of ultrafiltration technology for water applications is a relatively recent concept, although in the beginning, it is already commonly used in many industrial applications such as food or pharmaceutical industries. Ultrafiltration is proven to be a competitive treatment compared with conventional ones. In some cases, combination of ultrafiltration with conventional process is also feasible particularly for high fouling tendency feed water or for removal of specific contaminants. Recently, ultrafiltration has been recognized as competitive pre-treatment for reverse osmosis system. A system designed with an ultrafiltration as pre-treatment prior to reverse osmosis system has been referred to as an Integrated Membrane System (IMS). The application of IMS is a must for sites require very extensive conventional pre-treatment or where wide fluctuation of raw water quality is expected. However, the UF design was generally dismissed as commercial alternative to conventional filtration due to its high membrane cost. Nevertheless, today, the UF membrane price has gone far down, even below conventional treatment system with the new coming Asian membrane industries. Therefore, there is no doubt, UF is now becoming a competitive pretreatment system for RO in a wide range of raw water quality. Meanwhile, the application of membrane to replace secondary clarifier of conventional activated sludge, known as membrane bioreactor (MBR), has also led to a small footprint size of treatment with excellent effluent quality. The use of MBR eliminates almost all disadvantages encountered in conventional wastewater treatment plant such as low biomass concentration and washout of fine suspended solids. Today, there are more than 1000 installations of MBR all over the world. However, fouling still become a main drawback. To minimize membrane fouling, a new configuration of submerged membrane bioreactor for aerobic industrial wastewater treatment has been developed. In this configuration, a bed of porous particle is applied to cover the submerged ends-free mounted ultrafiltration membrane into which a new configuration is made. Membrane performance was assessed based on flux productivity and selectivity. A reasonably high and stable flux around 11 l/m2.h was achieved with COD removal efficiency of more than 99% from wastewater containing high organic matter. The fouling analysis also show that this newly configured ends-free membrane bioreactor exhibit lower irreversible resistance compared with the submerged one. The performance of pilot scale system, with 10 m2 membrane area in a 120 L tank volume, was also studied. The resulting flux from the pilot scale system is around 8 l/m2.h with COD removal of more than 99%. Hence, this study has demonstrated the feasibility of the newly configured submerged ends-free MBR at larger scale.
... Other works also faced technical difficulties when implementing direct UF, especially during high turbidity events. Clever et al. 3 assessed direct UF of river water (unknown turbidity) by means of a dead end module (35 m 2 ) for 10 months and reported some problems during high turbidity events when temperatures were below 10 ∘ C. Pianta et al. 9 worked with karstic spring water (mean turbidity 1.5 NTU but up to 130 NTU during storm events) both in dead end and cross-flow modes (7.2 m 2 UF membrane surface area) for 12 months. It was concluded that direct UF (dead end mode) working at 140 L m −2 h −1 was appropriate for karstic waters with turbidity peaks below 20 NTU for a short period of time; under greater turbidity scenarios, cross-flow should be applied (70 L m −2 h −1 could be maintained over five consecutive days at mean turbidity of 40 NTU). ...
... Specific cake resistance ( ) (m −2 ), which represents the increase of the cake layer resistance build up, was calculated by Equation (3), where v is the specific volume (m 3 m −2 ), which is the filtered volume (V) (m 3 ) per unit area, A is the membrane surface area (55 m 2 ), J is the water flux (m 3 m −2 s −1 ) and t is the time (s). ...
BACKGROUND
The feasibility and competitiveness of substituting the conventional pre‐treatment of drinking water treatment plants (dioxichlorination, coagulation/flocculation, settling, sand filtration) by raw river water direct ultrafiltration ( UF ) was addressed.
RESULTS
A full scale UF module was operated continuously for 2 years, treating highly variable surface water. The sustainable hydraulic conditions leading to a greater water yield from the direct UF treatment scheme under different scenarios were defined. Summer periods enabled the attainment of higher filtration fluxes, although raw river water showed greater turbidity and total suspended solids content. Winter periods presented higher dissolved organic carbon concentration, with greater biopolymers content, which have been claimed as main membrane foulants. A preliminary micro‐coagulation of FeCl 3 (<1.5 mg Fe( III ) L ⁻¹ ) enabled supporting harsher hydraulic conditions and thus, implementing similar conditions throughout the year. Impacts of micro‐coagulation were more pronounced on filtration, particularly in winter, but a positive effect was also noticed in hydraulic and chemical cleaning stages, increasing the efficiency of the former and decreasing by half the frequency of the latter.
CONCLUSION
Direct UF proved to be competitive with the current conventional pre‐treatment, leading to a significant reduction in reagents needs and sludge production and an increased and more stable product water quality. © 2016 Society of Chemical Industry
... On the other hand, a process water production from river water, including prefiltration, UF and RO, has been tested. The combination of UF and RO can produce deionised water from surface waters and avoids the waste formation (Clever et al., 2000). Nevertheless some of them need to be tested and applied for the salts elimination in the water streams of the steel industry, in particular for water streams coming from specific plant, such as HSM and BF. ...
... On the other hand, a process water production from river water, including prefiltration, UF and RO, has been tested. The combination of UF and RO can produce deionised water from surface waters and avoids the waste formation ( Clever et al., 2000). Nevertheless some of them need to be tested and applied for the salts elimination in the water streams of the steel industry, in particular for water streams coming from specific plant, such as HSM and BF. ...
... Untuk memproduksi air yang bersih dan aman biasanya membutuhkan tahap-tahap presipitasi kimia, adsorpsi, sedimentasi dan filtrasi [8]. Masing-masing tahap harus dikendalikan untuk mendapatkan kinerja keseluruhan process yang optimal yang berakibat pada sistem pengendalian yang kompleks [34]. Saat ini UF telah digunakan untuk menggantikan tahap klarifikasi pada plant pengolahan air konvensional (koagulasi, sedimentasi, dan filtrasi), dengan demikian aplikasi UF ini dapat dikatakan sebagai operasi klarifikasi dan desinfeksi. ...
... Utamanya, perkembangan teknologi UF dalam aplikasi air difokuskan pada produksi air minum [24]. Akhir-akhir ini, UF menjadi pre-treatment yang sangat efisien untuk sistem RO [34]. Evaluasi ulang biaya dan keunggulan operasi UF untuk pre-treatment sangat penting khususnya untuk umpan dengan tendensi fouling tinggi seperti air permukaan, limbah cair, dan air laut [Bates, 1999]. ...
Kecenderungan yang terlihat saat ini menunjukkan bahwa kebutuhan air baik untuk kebutuhan domestik ataupun untuk industri terus meningkat dari tahun ke tahun. Peningkatan ini antara lain disebabkan oleh pertambahan populasi penduduk dan juga laju pertumbuhan industri. Di lain sisi, ketersediaan sumber-sumber air khususnya air tawar semakin menipis. Hal ini sebagian besar disebabkan oleh pencemaran serta kerusakan lingkungan yang semakin parah. Air laut yang di lain pihak berada dalam jumlah berlimpah, tidak dapat langsung digunakan tanpa terlebih dahulu diolah secara khusus. Indonesia sendiri saat ini telah mengalami krisis air, ditandai dengan sulitnya akses memperoleh air bersih dan terbatasnya fasilitas sanitasi yang memadai. Pengolahan air dengan demikian menjadi salah satu kunci untuk mengatasi masalah krisis air terutama bila dikaitkan dengan beragamnya kualitas air yang tersedia.
Krisis air yang dihadapi juga tidak terlepas dari permasalahan limbah yang ada. Sudah menjadi rahasia umum bahwa tidak sedikit pencemaran lingkungan yang terjadi disebabkan oleh pembuangan limbah industri yang tidak melewati proses pengolahan terlebih dahulu. Industri sendiri dalam menjalankan aktivitasnya menggunakan air dalam jumlah yang signifikan, air bahkan menjadi komponen utama dan penentu kualitas produk di sejumlah industri misalnya industri minuman, industri tapioka, dsb. Ketidaksadaran pihak industri dalam menangani limbah yang dihasilkannya sangatlah mengkhawatirkan mengingat saat ini ketersediaan air tawar semakin langka. Sementara di sisi lain, pertumbuhan industri juga terus meningkat akibatnya limbah yang dihasilkan juga kian bertambah. Keterbatasan teknologi pengolahan limbah menyebabkan efluen yang dihasilkan memiliki kualitas yang jauh dari standar baku mutu limbah padahal pengolahan limbah sendiri merupakan komponen yang cukup mahal. Akibatnya selama ini limbah selalu dianggap sebagai sektor non-profit dan bahkan menjadi “cost center”. Penerapan pajak lingkungan yang mengharuskan pihak industri membayar pajak per volume limbah yang dihasilkan semakin menguatkan anggapan ini. Kondisi perekonomian yang tidak kondunsif juga semakin mempersulit permasalahan limbah ini.
Pada situasi seperti ini, reklamasi merupakan cara untuk mengatasi permasalahan pemenuhan kebutuhan akan air. Sistem pengolahan limbah dengan konsep “re-use” (guna-ulang) merupakan salah satu cara untuk mengatasi ketersediaan air. Teknologi membran merupakan pilihan yang tepat dengan kemampuannya sebagai proses pemisahan yang sangat selektif untuk menghasilkan produk berkualitas tinggi. Penggunaan teknologi membran bahkan dalam beberapa pengolahan limbah menggeser anggapan “limbah sebagai cost” menjadi “limbah sebagai profit”. Konsep pemanfaatan kembali yang ditawarkan oleh teknologi membran terbukti dapat menghasilkan keuntungan diantaranya penghematan dari segi biaya operasional (air, listrik, bahan kimia, dll). Hal ini tentunya memberikan implikasi positif tidak saja bagi pihak industri karena proses menjadi hampir selalu menguntungkan (profitable) tetapi juga bagi kelestarian lingkungan yang selama ini acapkali terabaikan.
Pada pengolahan limbah, teknologi membran dapat diaplikasikan secara tunggal atau dikombinasikan dengan proses lain. Minimisasi limbah dilakukan dengan pengambilan (recovery) air yang terdapat dalam limbah sehingga debit limbah menjadi minimum. Ukuran pori membran yang sedemikian rupa akan menghasilkan air yang memiliki kualitas yang memenuhi syarat untuk digunakan sebagai air proses sehingga konsep guna-ulang dapat dicapai. Pada aplikasi membran terkombinasi, membran dikombinasikan dengan proses-proses fisik konvensional atau dengan proses membran sendiri. Kombinasi lainnya yang saat ini tengah berkembang dengan pesat adalah kombinasi proses membran dengan proses biologis untuk pengolahan limbah yang dikenal dengan sistem bioreaktor membran. Baik proses membran secara tunggal ataupun terkombinasi dalam aplikasinya mampu menghasilkan efluen dengan kualitas yang memenuhi syarat untuk digunakan kembali. Pada paper ini akan diulas mengenai peran membran dalam pengolahan air dan limbah cair.
... Nanofiltration (NF) is a filtration process that allows the passage of solutes with a molecular weight greater than 200 Daltons (0.0005-0.007 μm) while retaining components with a molecular weight greater than 1000 Daltons (Khan et al., 2022;Qasem et al., 2021;Xu et al., 2022). Hence, the operational spectrum of nanofiltration falls within the realm of reverse osmosis and ultrafiltration methods (Clever et al., 2000;Seidi et al., 2020b;Tian et al., 2022). NF membranes comprise multilayer thin-film polymer composites of negatively charged chemical groups Saadati et al., 2021). ...
Sustainable water recycling is an urgent concern, considering water scarcity due to climate change, and increase water consumption through human activities. In 2015, United Nations Sustainable Development Goal 6 (UN SDG6) highlighted the necessity to reuse treated wastewater to guarantee water availability for everyone. Currently, wastewater irrigation (WWI) of crops and agricultural land appears essential. The present review shows how the quality of treated wastewater impacts soil microbial activities, and discusses challenges and benefits associated with wastewater reuse in agriculture and aquaculture irrigation. Combining advanced and conventional wastewater treatment processes is specifically deliberated, considering the harmful human health impacts resulting from WWI using contaminated water (salts, organic pollutants, toxic metals, and microbial pathogens i.e. viruses and bacteria). Our literature survey reveals that, in addition to increased levels of pathogen and microbial threats to human wellbeing, poorly-treated wastewater results in plant and soil contamination with toxic organic/inorganic chemicals, and microbial pathogens. The impact of long-term emerging pollutants such as plastic nanoparticles for example should be established in further studies, with the development of standardized analytical technique for such new chemicals. Similarly, the reliable, long-term and extensive judgment on heavy metals threat to humanity's health should be explored in future investigations.
... The development of membrane technologies, namely micro-, nano-, and ultrafiltration and the reverse osmosis method, should be recognized as a breakthrough of the last few decades in matters of water treatment [17][18][19][20][21]. However, with all their advantages, membrane technologies have not yet become widespread as an independent tool for largescale water treatment [22,23], and they remain an extremely effective but expensive element in the water treatment cycle at the fine post-treatment stage. ...
Citation: Malyushevskaya, A.P.; Koszelnik, P.; Yushchishina, A.; Mitryasova, O.; Mats, A.; Gruca-Rokosz, R. Synergy Effect during Water Treatment by Electric Discharge and Chlorination. Environments 2023, 10, 93. Abstract: Water treatment, such as disinfection, is an integral stage of its use for human life. The use of plasma technology with high-voltage electric discharge in a liquid for obtaining a bactericidal effect is discussed. It has been experimentally shown that among the factors accompanying a high-voltage electric discharge in a liquid and affecting the viability of bacteria, cavitation is the main one. Simultaneous use of electric discharge in the special cavitation mode and oxidizing agents makes it possible to achieve stable disinfection of water. At the same time, bactericidal doses of the oxidizing agent are reduced by a factor of 10 relative to existing standards, and the energy costs for electric discharge exposure, enhanced by small doses of an oxidizing agent, are reduced by 6 times compared to the costs of disinfection by only an electric discharge.
... For potable water supply to Lucknow city, water of river Gomti is pumped from Gaughat, and is sent through a pipeline to Lucknow Jal Sansthan Aishbagh, 4 km away, where water purification is carried out by alum treatment, filtration, and chlorination prior to being released into the drinking water supply [10,11,12]. To investigate the risk of contamination of potable waters by Citrobacter due to defective water distribution systems and insufficient treatment during production, 1 liter of water samples were collected in triplicate for culture free quantitative enumeration at ten sites. ...
The changing global scenario of environmental conditions and altered microbial community has severely deteriorated the quality of water which enforced an elevated health risks on human beings due to unavailability of safe and pristine water. Citrobacter is one of the fecal coliform bacteria of family Enterobacteriaceae. It is an opportunistic pathogen formerly used as an indicator bacterium along with other fecal coliforms namely Escherichia coli, Klebsiella and Enterobacter, but is now known to cause several diseases in human beings. In present study we collected 135 samples from potable water and riverine-systems and confirmed the existence of Citrobacter using the conserved sequence of gnd (6-phosphogluconate dehydrogenate) gene with the application of SYBR green real-time PCR, which demonstrated extremely high specificity, fidelity and stringency in detection strategy. The Citrobacter counts in potable water were in the range of zero to 1.54 x104 ± 572.88 cfu/100ml. The Citrobacter levels in surface water were 2.18 x104 ±848, 1.54 x104 ±462, 3.53 x104 ±1299, 2.57 x104 ±912, 8.78 x103 ±201, 1.28 x104 ±370, CFU/100ml; associated with hydrophytes were 6.24 x104 ±1535, 8.42 x104 ±2711, 1.19 x105 ±4792, 1.12 x105 ±4177, 8.32 x104 ±2329, 8.08 x104 ±2149 CFU/10g and in the sediments the counts were 2.50 x104 ±647, 5.02 x104 ±1852, 3.26 x104 ±1186, 7.65 x104 ±2884, 1.50 x104 ±355, and 2.56 x104 ±737 CFU/10g at sampling site # 1, site # 2, site # 3, site # 4, site # 5 and site # 6, respectively. The present assay could be applied in the detection and regular monitoring of potable water and other environmental samples to check waterborne diseases and outbreaks caused by Citrobacter.
... Since PEM electrolysis uses only deionized water, several filtration steps to attain purity increase the capital cost for PEM. Pure water can be produced by river water treatment using ultrafiltration and reverse osmosis methods [53,54]. In recent years, various techniques for seawater desalination with the removal of charged ions have been developed [55][56][57][58][59][60][61]. ...
Hydrogen, a clean and renewable energy source, is a promising substitute for fossil fuels. Electricity-driven water electrolysis is an attractive pathway for clean hydrogen production. Accordingly, the development of electrolysis cells has drawn researchers’ attention to capital costs related to noble catalyst reduction and membrane degradation by the contaminations. In the literature, polymer electrolyte membranes (PEMs) have been studied on single cations contamination. In this study, we investigated the performance of a PEM on monovalent and divalent cation contamination by feed water. Artificial river water, called soft water, was used to analyze the effect of impurities on the PEM. The results demonstrated that the operating voltage drastically increased and induced cell failure with increasing Mg2+ and Ca2+ concentrations; however, it did not increase for Na+ and K+ after increase in voltage. Therefore, divalent cations have a stronger affinity than monovalent cations to degrade PEM and should be effectively excluded from the feed water.
... An ultrafiltration membrane unit is a unit that can be operated as a single operation which means that the unit does not require pretreatment unless there is a screen filter or operated in combination with other processes such as coagulation and adsorption [2]. In cases where the raw water used has a high level of turbidity or high levels of pollution, the use of conventional water treatment (adsorbs, coagulation, oxidation) at the beginning is very helpful in increasing the efficiency of the performance of the ultrafiltration unit [3]. ...
Raw water with high turbidity requires pretreatment on its ultrafiltration unit to prevent fouling. Based on that, it is necessary to evaluate the ultrafiltration unit’s quality, quantity, and operation in Siwalanpanji’s WTP. The evaluation method compares the design criteria, technical specification, and ultrafiltration with the conventional to see the existing condition. The results of ultrafiltration turbidity and organic substance efficiency removal are about 53% and 18%, it’s not more good than conventional unit efficiency removal, which has 89% for turbidities removal and 37% for organic substance removal. Moreover, the quality of the production water fulfils the standards of Indonesia Health Minister No. 492 of 2010, except for the value of organic substances, which is in this analysis it around 13.69 mg/L meanwhile, in standard, it must not be more than 10 mg/L. Evaluation of the operating performance of each treatment unit related to the membrane unit at the WTP in Siwalanpanji has fulfilled the criteria design. However, using an ultrafiltration unit results in treated water quality is equivalent to a conventional treatment unit. So from this evaluation, it is found that there is a need for recommendations pretreatment, which is better for raw water to treat before ultrafiltration.
... Raw water includes rainwater, groundwater, and water from rivers and lakes. This water is not directly used due to the presence of contaminants, and pre-treatment of raw water is essential (Clever et al., 2000). Aluminium sulfate (Alum) and other coagulants, such as polymers, are generally used to coagulate the fine suspended solids in raw water by forming a mass large enough to settle and enable removal (Matilainen et al., 2010). ...
Raw water is a significant resource for industrial water usage, but this water is not directly suitable for use due to the presence of contaminants. Therefore, pre-treatment is essential. The treatment generates water treatment residue (WTR) which consists of silt, clay and undesirable components. Most WTR is conventionally disposed of in landfill. In addition, the presence of iron (Fe) and manganese (Mn) in groundwater can result in a reddish-brown color and undesirable taste and odour. A number of expensive and complex technologies are being used for the removal of such iron and manganese. Due to the high Al2O3 and SiO2 content in WTR, therefore, this research proposes the use of WTR as the source material for geopolymer production for Fe/Mn removal. With the availability of free alkali in the geopolymer framework, the OH⁻-releasing behavior of the WTR-based geopolymer was investigated by the precipitation of Fe(II) ion. The WTR-based geopolymer was calcined at 400 °C and 600 °C to obtain a strong geopolymer matrix with the ability to remove Fe/Mn ions.
The results show that the WTR-based geopolymer has the potential to remove Fe from Fe-contaminated water. Hydroxide ions are released from the geopolymer and form an Fe(OH)3 precipitate. Geopolymer with a calcination temperature of 400 °C provides total removal of the Fe after 24 h of immersion. In addition, the existence of Fe(OH)3 helps to coprecipitate the Mn(OH)2 in the Fe/Mn solution leading to a significant reduction of Mn from the solution. The pH value and retention time play an important role in the final metal concentration. The final pH of the solution is close to 8.5, which is the recommended value for boiler water. This method offers an alternative use of WTR in making a porous geopolymer for groundwater Fe/Mn removal using a simple method.
... As previously reported, wastewater pretreatment by the ultrafiltration (UF) system could reduce its colloids and reduce the permeate flux of the RO system. 13 In the previous study, membrane fouling was alleviated and the overall performance was improved in an RO system due to pretreatment of the UF system. 12 However, hardly any research has been reported for the treatment of paper-making wastewater in a fullscale IC anaerobic reactor combined with A/O and UF-RO membrane system for the purpose of reclamation. ...
BACKGROUND
The paper‐making industry has developed rapidly in recent years. The paper‐making process consumes much water and generates large amounts of wastewater. The reuse of the produced wastewater helps to save water consumption and reduce environmental pollution. Effective methods to treat and recycle paper‐making wastewater are urgently sought.
RESULTS
In this study, the performance of a full‐scale internal circulation–anoxic/oxic (IC‐A/O)–ultrafiltration (UF)–reverse osmosis (RO) membrane system for reclamation and reuse of paper‐making wastewater was investigated. Results showed that the integrated system presented a stable and highly efficient performance. The effluent concentrations of chemical oxygen demand, total organic carbon, biochemical oxygen demand , NH4⁺ nitrogen and total nitrogen were 12, 4, 0.3, 0.5 and 2.9 mg L⁻¹. gas chromatographic–mass spectrometric results showed that the organic composition in each process of the IC‐AO‐UF‐RO system varied significantly. Acute biological toxicity was obviously reduced, with an effluent toxic unit value of 3.11. The results of particle size distribution indicated that anaerobic granular sludge (around 3 mm) was formed in an IC reactor. Anaerolinea, Propioniciclava and Thauera were the main contributors to pollutant removal. Advanced treatment by the UF‐RO system achieved complete removal of suspended solids, silt density index and turbidity with little hardness and conductivity in the final effluent, which allowed for reclamation of paper‐making wastewater.
CONCLUSION
Water reuse and energy recycling were successfully realized in the built‐up IC‐AO–membrane reactor system. © 2020 Society of Chemical Industry
... Recently, UF has an efficient pre-treatment for reverse osmosis (RO) systems [8]. One important to evaluate the costs and benefits of UF operations as pretreatment, especially for high sources of decayed feed water such as surface water, wastewater or open intake sea water [9]. ...
The study aims to utilize Hybrid Membrane Technology (UF-RO) in reducing turbidity, iron and zinc in the liquid waste of the rubber industry. The pre-treatment process used was filtration and adsorption. The filtration process used filter columns containing silica sand and activated carbon, while the adsorption process used an adsorbent column containing bentonite. After the pre-treatment process, it was continued with the application Hybrid Membrane (UF-RO). The variables of the study were operation time of 15 to 90 minutes and flow rates of 7 and 14 L/min. The results showed that the optimum removal percentage of iron and zinc in the Reverse Osmosis Membrane was 84.86% and 96.29% at the feed flow rate of 14 L/min. The optimum removal percentage turbidity of 99.70% was achieved at the feed flow rate of 7 L/min in the Reverse Osmosis Membrane. Finally, rubber industry wastewater treatment using Hybrid Membrane (UF-RO) was able to reduce turbidity, iron and zinc content, and the results were accordanced with the quality standards regarding Water Quality.
... There has been increasing attention in the incorporation of membrane techniques into present water and WWTPs for different causes [1], like to satisfy more strict regulatory needs for reuse and discharge and/or elevate plant capacity [23]. The benefits of membrane filtration upon classical filtration employing granular media comprise superior quality of treated water, small size, low energy consumption, easier maintenance and capacity extension, and the capacity of manipulating large variations in FW quality [24]. MF and UF membranes have also been largely employed in membrane bioreactors (MBRs) [25,26]. ...
Nowadays the humankind is urgently invited to make available for potable use satisfactory quantities of good
quality water to its increasing population. There is a big effort by the water treatment specialists to analyze the solutions the
humankind has at its disposition to respond to these risks. The contribution of water reuse (WR) would be great in the
humankind’s water tomorrow. This review aims to discuss the growing WR technology as a future solution for water supply
issues. WR is broadly applied by industries to decrease the consumption of clean water. WR process should employ treated
wastewater mixed with surface water at a certain proportion depending on the degree of purity of the treated water and assuring
the dilution effect. WR should not employ at any case only wastewater, for safeguard reasons and psychological effects. WR
should be obviously more sophisticated than both water treatment and wastewater treatment since pathogens contamination and
chemicals presence can be there most elevated. Since pharmaceutical products and cosmetics substances at trace levels are found
in tap water, should we assist to a new formulation of water treatment technology? This will be feasible if water
treatment/wastewater treatment/WR would be merged in a super and highly standardized water/wastewater treatment technology,
as a future trend.
... There has been increasing attention in the incorporation of membrane techniques into present water and WWTPs for different causes [1], like to satisfy more strict regulatory needs for reuse and discharge and/or elevate plant capacity [23]. The benefits of membrane filtration upon classical filtration employing granular media comprise superior quality of treated water, small size, low energy consumption, easier maintenance and capacity extension, and the capacity of manipulating large variations in FW quality [24]. MF and UF membranes have also been largely employed in membrane bioreactors (MBRs) [25,26]. ...
Membrane fouling has been recognized as a serious barrier in microfiltration and ultrafiltration of secondary effluent. Feed pre-treatment is a frequent use for fouling extenuation. Numerous techniques have been employed to monitor membrane fouling. These include: Pre-treatment of the feedwater, modification of membrane properties, optimization of module configuration and operating conditions, periodic membrane cleaning, evaluation of system performance using pilot plant, and use of predictive models. However, membrane fouling remains complicated task for both technico-economic reasons depending on water characteristics and pre-treatment processes and efficiencies. The large majority of the membranes employed in water and wastewater treatment are produced of polymeric materials. Nevertheless, it has been expected that ceramic membranes will be competitive options in the following years.
... Of the many processes for drinking water treatment and wastewater reuse, low pressure membrane (LPM) treatment, i.e., microfiltration (MF) and ultrafiltration (UF), is an attractive and reliable process for producing high quality drinking water and upgrading the quality of secondary effluent for reuse or safe release to the environment. It has the advantages of small footprint, economic feasibility, high pollutant removal efficiency, easy maintenance and capacity extension (Clever et al., 2000;Guo et al., 2012). ...
The application of low pressure membrane (LPM) technology, i.e., ultrafiltration and microfiltration, for drinking water treatment and secondary effluent reclamation has increased rapidly over the past two decades. A major drawback in the use and operation of LPM processes is fouling due to the deposition of organic matter present in the feedwater on the membranes which leads to reduced water productivity necessitating membrane cleaning, process downtime and eventual membrane attrition. Pretreatment of feedwater using biological processes (particularly slow sand filtration and biological activated carbon) has been investigated as a simple and cost-effective means to control organic fouling of the membrane. In this paper, membrane fouling by the organic matter in drinking water and secondary effluent, the mechanisms of biological treatment systems, and the effectiveness of biological processes for fouling reduction are reviewed. It has been demonstrated that biological processes have great potential for controlling the organic fouling of membranes.
... In the steel sector, electrodialysis and ion exchange have been applied for the treatment of wastewater from rinsing of stainless steel etched in nitric acid and hydrofluoric acid [10]. In addition, the combination of ultrafiltration (UF) and RO has been tested for producing deionised water from surface waters [11]. A more efficient application of RO can be achieved through the combination with a pre-treatment, such as back-washable microfiltration (BMF) [12]. ...
In the steel sector water management aims at improving the sustainability of the production cycle, resulting in resource efficiency benefits and in reduced water demand and costs. To be reused, water needs to be cooled and desalinized to avoid salt concentration in water circulation systems. The presented work includes two case studies carried out in an integrated steelmaking plant, respectively, to evaluate the possible implementation of ultrafiltration and reverse osmosis to reduce salt concentration in water streams and to investigate, through modelling and simulation, a process integration solution to improve water efficiency. Results showed that most salts are removed by reverse osmosis and that its coupling with ultrafiltration allows obtaining very high quality water; reuse of desalinated wastewater resulted in being more suitable and economically viable than its discharge. Moreover, modelling and simulation showed that the considered blowdown could be reused without significant changes in the receiving water network area. The industrial implementation of water recovery solutions can lead to a decrease of fresh water consumption, effluent discharge, and to improvement of product quality and equipment service life. The considered desalination technologies are transferable and easily implementable, and modelling and simulation are very useful in order to evaluate process modifications before real implementation.
... Membrane filtration utilizing microfiltration or ultrafiltration membranes is a well-recognized technology that is used in a variety of industries (e.g. food processing [1][2][3], biotechnologies [4][5][6], wastewater treatment [7][8][9] and pharmaceutical industries [10][11][12]). Membrane technologies are able to provide high quality product water, have a small footprint, and require relatively easy maintenance [13]. ...
... For potable water supply in Lucknow (a major city of northern India) water is pumped from the river Gomti at Gaughat, which is outside the city, and is sent through a pipeline to Lucknow Jal Sansthan, Aishbagh, 4 km away (Figure 1) (Patel et al., 2011), where the water is purified by alum treatment, filtration, and chlorination before being released into the drinking water supply (Clever et al., 2000;Shrivastava et al., 2004;Ram et al., 2008). ...
The availability of safe and pristine water is a global challenge when large numbers of natural and anthropogenic water resources are being depleted with faster rate. The remaining water resources are severely contaminated with various kinds of contaminants including microorganisms. Enterobacter is one of the fecal coliform bacteria of family Enterobacteriaceae. Enterobacter was earlier used as an indicator bacterium along with other fecal Coliforms namely Escherichia coli, Citrobacter, and Klebsiella, but it is now known to cause various diseases in human beings. In this study, we have collected 55 samples from potable water and riverine system and proved their presence using their conserved sequences of 16S rRNA and 23S rRNA genes with the help of SYBR green real-time PCR, which showed very high specificity for the detection of Enterobacter. The Enterobacter counts in potable water were found to 1290 ± 32.89 to 1460 ± 39.42 cfu/100 ml. The Enterobacter levels in surface water were 1.76 × 10⁴ ± 492, 1.33 × 10⁴ ± 334, 1.15 × 10⁴ ± 308, 2.56 × 10⁴ ± 802, 2.89 × 10⁴ ± 962, 8.16 × 10⁴ ± 3443 cfu/100 ml; the levels of Enterobacter contamination associated with hydrophytes were 4.80 × 10⁴ ± 1804, 3.48 × 10⁴ ± 856, 8.50 × 10⁴ ± 2074, 8.09 × 10⁴ ± 1724, 6.30 × 10⁴ ± 1738, 3.68 × 10⁴ ± 949 cfu/10 g and the Enterobacter counts in sediments of the river, were 2.36 × 10⁴ ± 703, 1.98 × 10⁴ ± 530, 9.92 × 10⁴ ± 3839, 6.80 × 10⁴ ± 2230, 8.76 × 10⁴ ± 3066 and 2.34 × 10⁴ ± 732 cfu/10 g at the sampling Site #1, Site #2, Site #3, Site #4, Site #5, and Site #6, respectively. The assay could be used for the regular monitoring of potable water and other water reservoirs to check waterborne outbreaks.
... Ultrafiltration process is used in purification, desalting and concentration of macromolecular proteins solutions [19]. Both of ultrafiltration and microfiltration separations are based on size exclusion or particles capture [24]. ...
Efficient strategies for recombinant proteins production are gaining increasing importance as more applications that require high amounts of high-quality proteins reach the market. For example, bacterial hosts are commonly used for the production of recombinant proteins, accounting for 30% of current biopharmaceuticals on the market. Using biotechnological methods, it is possible to clone a gene coding for a protein such as insulin and introduce the cloned fragment into a suitable microorganism using transformation technique, such as E. coli and Saccharomyces cerevisiae. Escherichia coli expression system continues to dominate the bacterial expression systems and remain to be the best system for laboratory research and biotechnological industries. The recombinant microorganism then works as a living machine to produce a large amounts of proteins. For several reasons, bacteria were the first microorganisms to be chosen for use as living factories due to their genetics, physiology and biochemistry. Furthermore, it is easy to culture bacteria in large amounts in inexpensive and simple media. The recombinant bacteria can grow, multiply very rapidly and produce heterologous proteins. Finally, we need to extract and purify the resulted heterologous protein in relatively large quantity for subsequent uses as enzymes, hormones, vaccines, diagnostics tools, single cell proteins and new proteins for bioremediation.
... Additionally, improvements in treatment methods and recent advances in RO technology (Perez-Gonzalez et al., 2012;Malaeb and Ayoub, 2011;Fujioka et al., 2012) including new membrane materials and improvements in membrane modules have decreased operational and investment costs. Microfiltration (MF) and UF have become efficient pre-treatments for RO as RO membranes are very sensitive to fouling, which decreases the resultant permeate flux (Clever et al., 2000). However, the choice of pre-treatment is highly dependent upon the physical, chemical and microbiological qualities of the feed water. ...
Conventional treatment of wastewater from the metal finishing industry is generally based on physical-chemical treatment. Although the effluents from this can be discharged directly there is an increasing interest in industrial wastewater reuse. This requires further wastewater treatment. Here we studied the technical and economic feasibilities of adding an ultrafiltration process as a pre-treatment for removing dissolved and colloidal contaminants > 0.4 μm, and to eliminate membrane fouling before a final reverse osmosis process resulting in permeate that would meet reuse criteria. The results show that the ultrafiltration - reverse osmosis treatment removed between 91.3% and 99.8% of the contaminants from the effluent, such as metal elements, organic, and inorganic compounds. Contaminants such as suspended solids, nickel, ammonium nitrogen, sulphate nitrogen, chemical oxygen demand, and biochemical oxygen demand were completely removed, the concentrations in the permeate being under the detection limits, thus the quality of the ultrafiltration - reverse osmosis process met the reuse criteria. This demonstrates the technological feasibility of wastewater reuse during electro-plating processes and the pre-treatment of powder coating processes. An economic feasibility analysis was performed based on a reuse capacity for 30,000 m3 per year of treated water for two selected production lines at the Gorenje facility at Velenje, Slovenia. Specifically, the current water costs (including the operational costs of wastewater treatment, potable water use for industrial process and pre-treatment, and taxes) were compared with the investment required to implement the ultrafiltration - reverse osmosis processes. Based on the presented scientific results, the analysis shows that there is a potential for implementing this process within the metal finishing industry.
... Res., Vol. 52, No. 3, June, 2014증가한다[1][2][3][4] ...
This study examined the effect of concentration polarization on permeate flux in forward osmosis (FO) membrane process for saline and sucrose solution. The reduction in permeate flux during the FO membrane process is largely due to the formation of concentration polarization on membrane surfaces. The flux reduction due to internal concentration polarization formed on the porous support layer was larger than that due to the external concentration polarization on the active membrane surface. Water permeate flux through the FO membrane increased nonlinearly with the increase in osmotic pressure. The water permeability coefficient was 1.8081×10-7 m/s·atm for draw solution on active layer (DS-AL) mode and 1.0957×10-7 m/s·atm for draw solution on support layer (DS-SL) mode in NaCl solution system. The corresponding membrane resistance was 5.5306×106 and 9.1266×106 s·atm/m, respectively. With respect to the sucrose solution, the permeate flux for DS-AL mode was 1.33~1.90 times higher than that for DS-SL mode. The corresponding variation in the permeation flux (J) due to osmotic pressure (π) would be expressed as J=-0.0177+0.4506π-0.0032π2 for the forward and J=0.0948+0.3292π-0.0037π2 for the latter.
... Whereas in drinking water treatment, UF is becoming competitive pretreatment system for RO, where the feed water is not too high in terms of organic content. And UF has become the preferred alternative to conventional technology to remove water borne pathogens in the preparation of drinking water [Clever et al., 2000;. Consistently, UF seems to efficiently achieve current water regulation values for turbidity, Giardia and virus removal. ...
... These are phenomena controlled by diffusion, which require usually large operations times. Moreover, final metal recovery requires additional treatments, which makes the process even more complicated (Clever et al., 2000). Membranes are used to obtain effluents without contaminants, to recycle process water, and to recover valuable products, which can be reused in the process itself or in other applications (Shahalam et al., 2002). ...
A B S T R A C T Keywords: This article describes the preparation and characterization of a porous ceramic multilayer ultrafiltration mem-brane and its performance on indigo carmine and heavy metals removal. The first step of elaboration consists in preparing a high quality macroporous support from Moroccan clay. The microporous interlayer is prepared by slip casting from zirconia commercial powder suspension. The active ultrafiltration toplayers are obtained by sol-gel route using ZnAl2O4 and TiO2 mixed sols. The performance of the ultrafiltration membrane (TiO2 (50 %)-ZnAl2O4 (50 %)) was evaluated by water permeability, thickness, pore diameter and molecular weight cut off (MWCO). The water permeability measured for this composite membrane is 9.42 l/(m 2 ·h·bar), the thickness is less than 700 nm, the pore diameter is centred near 5nm and the MWCO was about 4500 Da. The final part of this study consists in studying the efficiency to remove Cr(NO3)3, Ni(NO3)2, Cd(NO3)2 and indigo carmine colorant from wastewater.
... On the other hand, a process water production from river water, including prefiltration, UF and RO, has been tested. The combination of UF and RO can produce deionised water from surface waters and avoids the waste formation (Clever et al., 2000). Nevertheless some of them need to be tested and applied for the salts elimination in the water streams of the steel industry, in particular for water streams coming from specific plant, such as HSM and BF. ...
Reverse osmosis is the most popular membrane-based desalination process that accounts presently for more than half the worldwide desalination capacity. However, the complex involvement of a variety of factors in this process has hindered the efficient assessment of the process performance such as accurately determining the membrane flux. It is therefore indispensable to search for reliable and flexible tools for the estimation of membrane flux in reverse osmosis such as machine learning. In this study, for the first time, nine different machine learning algorithms, ranging from simple white box models to complex black box models, were investigated for the accurate prediction of membrane flux in reverse osmosis using a large dataset of 401 experimental points retrieved from literature with 8 distinct features. The investigation has shown superior predictive performance for ensemble models over single models. In addition, extreme gradient boosting stood out as the best-performing ensemble model for the prediction of membrane flux due to having the lowest statistical errors (MAE = 1.78 LMH, MAPE = 8.88 %, and RMSE = 2.32 LMH) and strongest correlations with R 2 = 98.2 %, IA = 99.55 %, and KGE = 98.84 %, in the test dataset. The Unified Shapley Additive Explanation technique was also employed to determine the influence of the input features, and the most impactful parameters were found to be the feedwater flow rate and applied pressure. The results of the present study suggest that machine learning algorithms, especially ensemble ones, are powerful tools in forecasting the membrane flux of the reverse osmosis process.
In the TRITIUM project, an on-site monitoring system is being developed to measure tritium (3H) levels in water near nuclear power plants. The quite low-energy betas emitted by 3H have a very short average path in water (5 μm as shown by simulations for 18 keV electrons). This path would be further reduced by impurities present in the water, resulting in a significant reduction of the detection efficiency. Therefore, one of the essential requirements of the project is the elimination of these impurities through a filtration process and the removal of salts in solution. This paper describes a water treatment system developed for the project that meets the following requirements: the water produced should be of near-pure water quality according to ISO 3696 grade 3 standard (conductivity < 10 μS/cm); the system should operate autonomously and be remotely monitored.
Water treatment processes requires low cost readily available adsorbents of high capacity with efficiency adsorption that are biologically degradable. In this study, modified olive leaves powder has been used as a cheap biosorbent for the removal of widespread consumer dyes including an acidic azo dye, as Methyl Orange (MO) and a basic dye, as Methylene Blue (MB). The optimum conditions of biosorption was obtained and the isotherms and kinetics of adsorption have been investigated.
Olive leaf was collected from Roodbar (north of Iran)
and was modified in three ways: cold leaching, hot leaching and in carbonized form. The results indicate that the process of adsorption reaches equilibrium after a maximum of 120 minutes. The optimal maximum leaf adsorbent is 4 g/L, and for activated carbon, one tenth of this value is reported.
The optimum temperature of dye adsorption was determined to be 25 °C for leaf powder and 55 °C for activated carbon powder. MB and MO adsorption process is strongly influenced by the solution pH, so that acidic pH increases adsorption of MO while substantially decreasing MB adsorption. According to the correlation coefficient (R2), the kinetics of the adsorption is best described by pseudo-second order kinetics model and the Langmuir isotherm best fits the experimental results. Based on the results of this study olive leaf powder serves as an effective, accessible and natural adsorbent to attract MB
and MO in water solutions.
Background and purpose: Hypoxemia and hypotension are important complications of hemodialysis in patients with chronic renal failure that are linked to several factors, including the type of filters used. The aim of this study was to compare the effect of simple filtration hemodialysis and ultrafiltration hemodialysis on blood pressure and blood arterial oxygen level.
Materials and methods: In this clinical trial, we studied 68 patients who underwent dialysis in Semnan Kosar Hospital in November and December 2019. Clinical information, including heart rate, blood pressure, and arterial oxygen saturation, and pulse oximeter reading for oxygen saturation level were recorded before and after every dialysis. The patients were randomly divided into two groups. One group received simple filtration hemodialysis in first month followed by ultrafiltration dialysis in next month, while other patients had ultrafiltration dialysis in first month followed by simple filtration hemodialysis in next month. Data analysis was carried out in SPSS V23.
Results: In ultrafiltration hemodialysis, arterial oxygen saturation at sessions two (P=0.037), five (P=0.002), and 11 (P>0.001) were found with significantly smaller changes compared with the first session. Also, in this type of filtration, changes in systolic blood pressure at sessions 12 (P=0.003) and 13 (P=0.034) were significantly smaller than the first session compared with the simple filtration dialysis.
Conclusion: Compared with simple filtration hemodialysis, ultrafiltration hemodialysis provides more oxygen stability and less hypotension and can minimize the side effects of dialysis.
The global demand for clean and potable water continuously increased due to expanding population and pollution. Water contamination by anionic compounds, heavy metals, and other pollutants is growing globally and needs to be investigated to find proper strategies leading to improve water quality and reduce water scarcity. Several processes have been used to purify and renew water, but they each have limitations. Processes using membranes for water purification are promising. They found uses for environmental applications as molecular filters. This review aims to show the performance of molecular dynamics (MD) simulations in membrane technologies to increase the knowledge of membrane-based water purification purposes. Through MD simulations, dynamic and static features of membrane separation systems can be evaluated on the atomic scale. This paper reviews recent developments in membrane-based wastewater treatment giving insights obtained from MD simulations. Also, the basics of MD, properties, mechanisms, and its limitations were discussed.
Raw water is significant resources for industrial water usage, but this water is not directly suitable for use due to the presence of contaminants. Therefore, pre-treatment is essential. In addition, the presence of iron (Fe) and manganese (Mn) in groundwater can result in a reddish-brown colour and undesirable taste and odour. The treatment generates water treatment residue (WTR) which consists of silt, clay and undesirable components. Most WTR is conventionally disposed of in landfill. A number of expensive and complex technologies are being used for the removal of such iron and manganese. Due to the high Al 2 O 3 and SiO 2 content in WTR, the use of WTR-based geopolymers for Fe/Mn removal is proposed in this study. With the availability of free alkali in the geopolymer framework, the OH-releasing behaviour of the WTR-based geopolymer was investigated by the precipitation of Fe(II) ion. The WTR-based geopolymer was calcined at 400°C and 600°C to obtain a strong geopolymer matrix with the ability to remove Fe/Mn ions. The results show that the WTR-based geopolymer has the potential to remove Fe from Fe-contaminated water. Hydroxide ions are released from the geopolymer and form an Fe(OH) 3 precipitate. A calcination temperature of 400°C provides total removal of the Fe after 24 h of immersion. In addition, the existence of Fe(OH) 3 helps to coprecipitate the Mn(OH) 2 in the Fe/Mn solution leading to a significant reduction of Mn from the solution. The pH value and retention time play an important role in the final metal concentration. The final pH of the solution is close to 8.5, which is the recommended value for boiler water. This method offers an alternative use of WTR in making a porous geopolymer for groundwater Fe removal using a simple method.
In any membrane filtration, the prediction of permeate flux is critical to calculate the membrane surface required, which is an essential parameter for scaling-up, equipment sizing, and cost determination. For this reason, several models based on phenomenological or theoretical derivation (such as gel-polarization, osmotic pressure, resistance-in-series, and fouling models) and non-phenomenological models have been developed and widely used to describe the limiting phenomena as well as to predict the permeate flux. In general, the development of models or their modifications is done for a particular synthetic model solution and membrane system that shows a good capacity of prediction. However, in more complex matrices, such as fruit juices, those models might not have the same performance. In this context, the present work shows a review of different phenomenological and non-phenomenological models for permeate flux prediction in UF, and a comparison, between selected models, of the permeate flux predictive capacity. Selected models were tested with data from our previous work reported for three fruit juices (bergamot, kiwi, and pomegranate) processed in a cross-flow system for 10 h. The validation of each selected model's capacity of prediction was performed through a robust statistical examination, including a residual analysis. The results obtained, within the statistically validated models, showed that phenomenological models present a high variability of prediction (values of R-square in the range of 75.91–99.78%), Mean Absolute Percentage Error (MAPE) in the range of 3.14–51.69, and Root Mean Square Error (RMSE) in the range of 0.22–2.01 among the investigated juices. The non-phenomenological models showed a great capacity to predict permeate flux with R-squares higher than 97% and lower MAPE (0.25–2.03) and RMSE (3.74–28.91). Even though the estimated parameters have no physical meaning and do not shed light into the fundamental mechanistic principles that govern these processes, these results suggest that non-phenomenological models are a useful tool from a practical point of view to predict the permeate flux, under defined operating conditions, in membrane separation processes. However, the phenomenological models are still a proper tool for scaling-up and for an understanding the UF process.
In this study, an internal circulation-anoxic/aerobic (IC-A/O) process followed by ultrafiltration (UF) and reverse osmosis (RO) system was applied for paper wastewater reclamation. The IC-AO system presented a stable and efficient performance, achieving high removal of chemical oxygen demand (COD), total organic carbon (TOC) and total nitrogen (TN) with methane production rate of 132.8 mL/d. Acute toxicity to Daphnia magna (D. magna) was reduced significantly (83.2%) and the spearman's rank correlation analysis indicated that the toxicity of effluents from each reactor were positively correlated with COD and TOC. Hexadecanoic acid, octadecanoic acid and benzophenone were the main toxic contributors for biological effluent. Microbial community revealed that Anaerolinea was significantly related with organic pollutants. The UF-RO system further removed pollutants and toxicity with the final effluent COD, TOC, ammonium nitrogen (NH 4⁺ -N) and TN of 32.6, 18.8, 0.3 and 9.2 mg/L, respectively, which proved that it was feasible for paper wastewater reuse. This study presented an efficient, practical and environmentally competitive system, and paved a foundation for the treatment and reuse of paper wastewater.
In the past decade, the high demand and strict legislations regarding pure and potable water production and quality require finding new treatment technologies with higher effectiveness. When compared with conventional treatment technologies, membrane technology is a viable option in water and wastewater treatment due to high performance, ease in implementation, cost-efficiency among other advantages, also, leading to a rapid expansion in use in almost all areas of industry. Polymeric ultrafiltration membranes have been successfully used in various industries since 1969, and in later years they were studied in the water purification sector, mainly as a pre-treatment step to reduce severe fouling that could occur in reverse osmosis filtration stage. Polysulfone (PSf) was the polymer of choice in this study with two concentrations, 25 wt.% and 30 wt.%. Surface SEM morphology, roughness and water affinity were analyzed for the studied membranes. Water from Siret river was used in the permeation tests in order to analyze the retention capacity and anti-fouling ability. The present study revealed higher retention for the 30 wt.% PSf membranes, from the physico-chemical and microbiological point-of-view and lower fouling, also.
In this report, antifouling polyacrylonitrile (PAN) ultrafiltration membranes were prepared from blends of PAN/polyglycidyl methacrylate (PGMA) via phase inversion method followed by the grafting of natural amino acids through epoxy ring-opening reaction. The grafted PAN membranes possessed highly stable hydrophilic surfaces as a result of the grafting of amino acids, which was adequately demonstrated in attenuated total reflectance–Fourier transform infrared spectroscopy (ATR/FTIR), X-ray photoelectron spectroscopy (XPS), and contact angle measurements. The results of tensile strength and scanning electron microscopy (SEM) images further proved that the surface modification had little effect on their mechanical properties, surface, and cross-sectional morphologies. Meanwhile, remarkable resistance against bovine serum albumin (BSA) and lysozyme (Lyz) fouling was observed for the neutral amino acid-based PAN membranes due to the formation of zwitterionic hydration layer on the membrane surface, while PAN membranes grafted with charged amino acids were able to prohibit the approach of like charged proteins with reduced deposition and provide the driving force for oppositely charged protein adsorption. Furthermore, the ultrafiltration and antifouling performance of PAN membranes were investigated by BSA filtration experiments. Compared with the pristine PAN membrane, all the modified PAN membranes exhibited higher pure water flux, better flux recovery ratio, lower rejection, less total permeation resistance, and preferable stability, having potential applications in protein separation and purification.
While the ion concentration polarization (ICP) phenomenon has been intensively researched for a last decade, the complete picture of ions and analytes distributions near the nanoporous membrane has been strongly demanded not only in fundamental nano-electrokinetic studies but also in developing lab-on-a-chip applications. Since direct concentration measurements either by time-consumed collection or microelectrodes were limited due to low throughput (~nL/min in typical micro/nanofluidic device) or Faradaic reaction, respectively, we suggested for measuring the concentration changes of the prefilled solution in each reservoir in this work. As a result, analytes larger than the size of nanopore were completely repelled by the ICP layer, 65% of cations were transported through the nanoporous membrane to sustain ICP phenomenon, and remaining anions were consumed by electrode reaction for electro-neutrality requirement. These combined effects would enables the perfect recovery of target analyte and the removal of unnecessary salts simultaneously. Using the scenario, the novel concept of ink recycler was demonstrated in this work as well, showing that 40% of unnecessary salt which causes serious deterioration of inkjet head were desalted and the concentration of ink molecules were doubled in a single step operation. Therefore, the experimental verification of simultaneous desalting and molecular preconcentration mechanism would be a key operational strategy of various refinery/purification applications of drug discovery and chemical industry, etc.
An autopsy procedure has been carried out on both clean and fouled polysulfone (PSF) UF membranes with prime intention to investigate the relative effect of NOM fouling onto the membrane characteristics and as well as to identify the primary NOM component that possessed the major fouling potential. A PSF membrane has been fouled with feeds of Bekok Dam reservoir and Ulu Pontian river. Results of foulant analyses showed that the membrane was mainly fouled by the organic NOM fraction of hydrophilic character. In fact, the hydrophilic fraction was found to play a more significant role as the primary foulant that were hypothesized to be responsible for the substantial flux decline during membrane water treatment. Comparatively there were distinctive changes in membrane characteristics from the perspective of contact angle, SEM analysis and membrane zeta potential of NOM fouled membrane, thus adequately supporting the evidence of membrane fouling by the responsible foulant. In particular the membrane wettability and surface charge have been found to decrease significantly after being fouled with both NOM source waters, as a matter of fact the Ulu Pontian river showed greater decrement of membrane properties compared to its counterpart the Bekok Dam reservoir. Thus this observation implied that most of the membrane surface has been covered-up by the non-humic component which could possibly be the primary membrane foulant as it was significantly found to adhere most on the membrane surface. ATR-FTIR analysis revealed that hydrophilic components such as the polysaccharides-like substances, alcoholic compounds and aliphatic amide of protein groups as the responsible materials covering the membrane surface.
Study on the effect of Ca2+ and Fe3+ addition on nitrification-denitrification process in a submerged membrane bioreactor was conducted. The removal rate of total nitrogen and ammonia nitrogen was investigated. The result indicated that the ammonia nitrogen and total nitrogen removal rate increased from 75% to 85% and 55% to 75%, respectively, as the calcium concentration ranging from 0 to 150 mg/L, which indicated that the nitrification and denitrification process were promoted. Ferric ion of 50 mg/L obtained a considerable increase in TN removal from 55% to 70%, with an increase of ammonia nitrogen removal rate from 75% to 83%. However, ferric ion concentration ranging between 100 mg/L and 150mg/L caused a decrease of both total nitrogen and ammonia nitrogen removal efficiency, indicating that the activity of nitrifying and denitrifying bacteria was inhibited.
Removal of natural organic matter (NOM) from drinking water by membrane technology is attracting increasing attention. However, the fouling of the membrane by NOM is one of the biggest obstacles restricting its widespread application. Therefore an anti-NOM fouling polyelectrolyte complex (PEC) membrane was obtained by creating a negatively charged multilayer on a polyacrylonitrile (PAN) supporting membrane using a layer-by-layer assembly method. To improve the stability of the PEC membrane, the electrostatically assembled (poly(ethyleneimine)/poly(sodium 4-styrenesulfonate))n/PAN membranes were crosslinked by glutaraldehyde. It was found that the zeta potential of the membrane surface decreased after chemical crosslinking, which further improved the electrostatic repulsion to NOM and thus improved the anti-NOM fouling property. Results of a 30 day nanofiltration operation showed the crosslinked membrane had good stability and gave a higher rejection of NOM; the permeance of the crosslinked membrane was double that of the uncrosslinked membrane.
In recent years, membrane-based ultrafiltration (UF) and reverse osmosis (RO) have become popular worldwide as possible alternative methods to conventional ion exchange and clarification processes for the production of potable water. The performance of UF and RO membranes was evaluated for treatment of surface and ground water from Prakasam District of Andhra Pradesh, India; namely, jagarlamudi well water (JWW), jagarlamudi pond water (JPW), veerannapalem old pond water (VOPW), and veerannapalem new pond water (VNPW). Pilot-scale UF and RO systems were built indigenously by incorporating commercial hollow fiber polyacrylonitrile UF and thin film composite polyamide RO modules, respectively. Operating parameters such as feed concentration, pressure, and cross-flow velocity were varied to study their effect on membrane performance. Effect of fouling on flux and rejection characteristics of the membrane was evaluated. RO membrane exhibited a rejection of 96.4% for JWW and VOPW feeds with reasonable flux of 42.5 and 48 L m−2 h−1, respectively, whereas, UF experiments with JPW and VNPW feeds revealed corresponding turbidity rejections of 95.6 and 98.2%. A mathematical model was developed for commercial RO system to simulate the process for establishing optimum operating conditions. A comparison of UF and RO processes for this application is presented along with useful details of equipment list, process flow diagram of commercial membrane plant, schematic of compact hollow fiber pilot plant, and detailed estimation of operating costs.
Treatment of Tehran refinery effluent, high in oil and grease (O&G), total organic carbon (TOC), and total dissolved solids (TDS), as boiler feedwater was proposed by a treatment scheme comprising microfiltration (MF), ultrafiltration (UF), and reverse osmosis (RO). To find optimum conditions for each membrane operation, effects of operating parameters such as transmembrane pressure (TMP), flow rate (Q), and temperature on permeation flux and TOC or TDS removal efficiencies were investigated. A tubular ceramic MF (α-Al2O3) membrane module was employed for treatment of oily wastewater before UF. The optimum operating condition was found as TMP of 1.25 bar, Q of 32.5 L min−1, and temperature of 32.5°C. MF reduced turbidity and solid particles content of the wastewater for UF. UF was investigated in this study to reduce turbidity and O&G of the wastewater prior to RO, which was necessary to reduce salinity to an acceptable level for using as boiler feedwater. The optimum UF experiments were found at TMP of 2 bar, temperature of 25°C, and Q of 12 L min−1; using a spiral wound polyacrylonitrile membrane module. UF reduced O&G and turbidity almost completely. Another spiral wound Polyamide RO membrane module was used to finally treat the wastewater. The optimum condition was found as TMP of 15 bar, temperature of 30°C, and Q of 10 L min−1. Analysis of the oily wastewater treated by the MF–UF–RO integrated membrane system exhibited 100% reduction in total suspended solids (TSS), 99.43% reduction in turbidity, 99.87% reduction in O&G, 97.43% reduction in TOC, and 97.93% reduction in TDS. As a result, the effluent of MF–UF–RO integrated membrane system could be recommended as boiler feedwater.
This research details the effects of ozone pretreatment on flux of a reverse osmosis membrane. Initial tests were conducted to determine the effects of ozonation on solids removal, turbidity, and chemical oxygen demand concentrations using various doses on a simulated surface water. These initial tests showed that the best reduction of solids in the 2–5 microns range was at 0.30 mg/L of ozone. Next, a series of bench scale tests was run for 62.5 hours using a standard reverse osmosis system under constant pressure with three pre-ozonation doses and a no ozone baseline dose. Temporal models were developed using the flux data from these tests to determine the effects of operating hours and ozone dosage on flux. It was found that the laboratory data were not linear and followed power law models. Statistical analysis was used to determine the significance of each ozone dose on the four developed models. The change in flux over the 62.5 operating hours with an ozone dosage of 0.30 mg/L showed the lowest flux change. Last, the models were tested using Hermia's filtration models and resistance versus time data to determine the type of membrane fouling that existed. It was concluded that the major fouling was pore blockage. This work demonstrated that ozone pretreatment is effective prior to use with reverse osmosis since it shows a better solid and organic removal rate as well as decreased flux and resistance changes over time.
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