Drinking water production by coagulation-microfiltration and adsorption-ultrafiltration

1998 ◽  
Vol 37 (10) ◽  
pp. 135-146 ◽  
Author(s):  
Akira Yuasa
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
Hollow Fiber ◽  
Cross Flow ◽  
Ceramic Membranes ◽  
Cellulose Acetate Membrane ◽  
Water Recovery ◽  
Dead End ◽  
Iron Manganese ◽  
Gac Adsorption

Microfiltration (MF) and ultrafiltration (UF) pilot plants were operated to produce drinking water from surface water from 1992 to 1996. Microfiltration was combined with pre-coagulation by polyaluminium chloride and was operated in a dead-end mode using hollow fiber polypropylene and monolith type ceramic membranes. Ultrafiltration pilot was operated in both cross-flow and dead-end modes using hollow fiber cellulose acetate membrane and was combined occasionally with powdered activated carbon (PAC) and granular activated carbon (GAC) adsorption. Turbidity in the raw water varied in the range between 1 and 100 mg/L (as standard Kaolin) and was removed almost completely in all MF and UF pilot plants to less than 0.1 mg/L. MF and UF removed metals such as iron, manganese and aluminium well. The background organics in the river water measured as KMnO4 demand varied in the range between 3 and 16 mg/L. KMnO4 demand decreased to less than 2 mg/L and to less than 3 mg/L on the average by the coagulation-MF process and the sole UF process, respectively. Combination of PAC or GAC adsorption with UF resulted in an increased removal of the background organics and the trihalomethanes formation potential as well as the micropollutants such as pesticides. Filtration flux was controlled in the range between 1.5 and 2.5 m/day with the trans-membrane pressure less than 100 kPa in most cases for MF and UF. The average water recovery varied from 99 to 85%.

Effect of operational modes on the removal of a synthetic organic chemical by powdered activated carbon during ultrafiltration

2001 ◽  
Vol 1 (5-6) ◽  
pp. 39-47
Author(s):  
Y. Matsui ◽  
A. Yuasa ◽  
F. Colas
Keyword(s):  
Activated Carbon ◽  
Cross Flow ◽  
Powdered Activated Carbon ◽  
Organic Chemical ◽  
Filtration Cycle ◽  
Dead End ◽  
Synthetic Organic Chemical ◽  
The Cross ◽  
Short Time ◽  
Operational Modes

The effects of operational modes on the removal of a synthetic organic chemical (SOC) in natural water by powdered activated carbon (PAC) during ultrafiltration (UF) were studied, through model simulations and experiments. The removal percentage of the trace SOC was independent of its influent concentration for a given PAC dose. The minimum PAC dosage required to achieve a desired effluent concentration could quickly be optimized from the C/C0 plot as a function of the PAC dosage. The cross-flow operation was not advantageous over the dead-end regarding the SOC removal. Added PAC was re-circulated as a suspension in the UF loop for only a short time even under the cross-flow velocity of gt; 1.0 m/s. The cross-flow condition did not contribute much to the suspending of PAC. The pulse PAC addition at the beginning of a filtration cycle resulted in somewhat better SOC removal than the continuous PAC addition. The increased NOM loading on PAC which was dosed in a pulse and stayed longer in the UF loop could possibly further decrease the adsorption rate.

A New Short–Cut Design Method for Ultrafiltration and Hyperfiltration Cross–Flow Hollow Fiber Membrane Modules

2012 ◽  
Author(s):  
Wan Ramli Wan Daud
Keyword(s):  
Hollow Fiber ◽  
Driving Force ◽  
Hollow Fiber Membrane ◽  
Cross Flow ◽  
Extinction Curve ◽  
Membrane Area ◽  
Transfer Unit ◽  
Dead End ◽  
The Dead ◽  
The Difference

Although ultrafiltration and hyperfiltration have replaced many liquid phase separation equipment, both are still considered as “non–unit operation” processes because the sizing of both equipments could not be calculated using either the equilibrium stage, or the rate–based methods. Previous design methods using the dead–end and complete–mixing models are unsatisfactory because the dead–end model tends to underestimate the membrane area, due to the use of the feed concentration in the driving force, while the complete–mixing model tends to overestimate the membrane area, due to the use of a more concentrated rejection concentration in the driving force. In this paper, cross–flow models for both ultrafiltration and hyperfiltration are developed by considering mass balance at a differential element of the cross–flow module, and then integrating the expression over the whole module to get the module length. Since the modeling is rated–based, the length of both modules could be expressed as the product of the height of a transfer unit (HTU), and the number of transfer unit (NTU). The solution of the integral representing the NTU of ultrafiltration is found to be the difference between two exponential integrals (Ei(x)) while that representing the NTU of hyperfiltration is found to be the difference between two hypergeometric functions. The poles of both solutions represent the flux extinction curves of ultrafiltration and hyperfiltration. The NTU for ultrafiltration is found to depend on three parameters: the rejection R, the recovery S, and the dimensionless gel concentration Cg. For any given Cg and R, the recovery, S, is limited by the corresponding flux extinction curve. The NTU for hyperfiltration is found to depend on four parameters: the rejection R, the recovery S, the polarization β, and the dimensionless applied pressure difference ψ. For any given ψ and R, the recovery, S, is limited by the corresponding flux extinction curve. The NTU for both ultrafiltration and hyperfiltration is found to be generally small and less than unity but increases rapidly to infinity near the poles due to flux extinction. Polarization is found to increase the NTU and hence the length and membrane area of the hollow fiber module for hyperfiltration. Key words: Ultrafiltration; hyperfiltration; reverse osmosis; hollow fiber module design; crossflow model; number of transfer unit; height of a transfer unit

scholarly journals Membran Separasi Serat Berongga untuk Hemodialisis

2019 ◽  
Vol 7 (1) ◽  
pp. 27-36
Author(s):  
Krisna Lumban Raja
Keyword(s):  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Salt Water ◽  
Cross Flow ◽  
Polymer Chains ◽  
Current Status ◽  
Separation Membranes ◽  
Fiber Separation ◽  
Dead End ◽  
Wide Range

Polimer mempunyai aplikasi luas. Campuran heterogennya membentuk struktur fasa terpisah menjadi membran untuk membuat perangkat medis. Fungsi membran melakukan penghalangan selektif dengan aspek keragaman : tebal, struktur, diameter pori, muatan listrik, perpindahan partikel. Grup. Membran separasi adalah membran sintetis untuk pemisahan. Membuat membran separasi polimerik dibutuhkan kriteria polimer berdaya rekat rendah, berdaya tahan pembersihan tinggi, berkarakteristik rantai polimer saling cocok, harga murah, serta mudah diperoleh. Sifat kimia permukaan membran memberi konsekuensi pembasahan atau pencemaran yang mempengaruhi daya tahan membran. Konfigurasi membran separasi adalah silang aliran dan dead-end.Hukum Darcy merumuskan pemodelan yang pokok pada membran separasi dead end. Serat membran morfologinya keropos dan gaya pendorongnya perbedaan konsentrasi. Aliran nya silang dan modulnya menampung hingga 10.000 serat berdiameter 200 μm sampai 2500 μm. Pada dialisis, aliran darah dan dialisat berlawanan, agar pengeluaran zat-zat beracun maksimal. Aplikasi membran serat berongga untuk hemodialisis karena gagal ginjal kronis. Hakekat dialisis adalah memindahkan zat-zat racun dari metabolisme dan memperbaiki keseimbangan garam, air dan asam dalam darah. Status iptek terkini membran hemodialisis adalah pada ginjal buatan dari bahan hidup selain peralatan hemodialisis yang dapat berpindah-pindah, dibawa, dikenakan di badan, dan ditanam dalam tubuh.Kata kunci : Membran, Sintetis, Separasi, Hemodialisis, Serat berongga.AbstractPolymers have a wide range of uses. Their heterogenous blends form separated phase structures to become membranes for making medical devices. Membranes serve as selective barriers with various classifications such as thickness, structure, pore diameter, electric charged, particle transport, and in groups. A separation membrane is synthetically created for separation purpose. To make polymeric separation membranes require polymers that are low binding affinity, withstand the harsh cleaning conditions, suitable with properties of polymer chains, reasonable pricing, and easily obtainable. Two flow configurations of separation membranes are cross flow and dead-end filtrations. Darcy’s law formulates the main modeling equation for the dead end filtration. Hollow fiber separation membranes have porous morphology and driving force of concentration gradients. They have cross flows and their modules can contain up to 10.000 fibers ranging from 200 to 2500 μm in diameter. In dialysis, blood travels in the opposite direction with the dialysate to maximize the excretion of poisonous substances. A hollow fiber membrane application is for hemodialysis of chronic renal failure that causes physiological derangements. Actually dialysis is to remove toxic end-products of nitrogen metabolism and improve the balance of the salt, water, and acid-base derangements in blood. The current status of hemodialysis are the bio-artificial kidneys along with the development of mobile, portable, wearable and implantable hemodialysis devices.Keywords : Membrane, Synthetic, Separation, Hemodialysis, Hollow-fiber.

scholarly journals Pengolahan Air Tanah di Kawasan Politeknik Negeri Bandung menjadi Air Minum dengan Metoda Ultrafiltrasi

2018 ◽  
Vol 2 (2) ◽  
pp. 55
Author(s):  
Emma Hermawati Muhari ◽  
Ayu Ratna Permanasari ◽  
Fitria Yulistiani
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Ground Water ◽  
Hollow Fiber ◽  
Vinylidene Fluoride ◽  
Hollow Fiber Membrane ◽  
Drinking Water Treatment ◽  
Dead End ◽  
Long Time ◽  
Total Dissolved Solid

Di Indonesia, khususnya di sekitar Politeknik Negeri Bandung, sebagian besar sumber air berasal dari air tanah. Air tanah di lingkungan Politeknik Negeri Bandung memiliki pH asam (< 6), coliform > 2.400, dan colitinja positif. Proses pemanasan air kurang efektif untuk mengolah air tanah karena memerlukan waktu yang relatif lama, energi besar, dan tidak dapat meningkatkan pH air agar memenuhi standar air minum sebagaimana tercantum dalam Permenkes Nomor 492/MENKES/PER/IV/2010. Untuk mengolah air tanah di lingkungan Politeknik Negeri Bandung, telah dibuat alat pengolahan air minum portabel dengan menggunakan konsep aliran dead-end filtration. Membran yang dipakai merupakan membran hollow-fiber, berjenis membran ultrafiltrasi berbahan dasar PVDF (Poly Vinylidene Flouride), ukuran pori 0,1μm, panjang membran 15cm, jumlah membran sebanyak 148 buah, dan dapat dioperasikan pada daya isap normal manusia.  Permeat yang dihasilkan sesuai dengan standar PERMENKES No. 492/MENKES/PER/IV/2010 dari parameter fisika, kimia, dan biologi. Lifetime membran diamati melalui jumlah permeat yang dihasilkan dari awal pemakaian membran hingga membran tersebut rusak. Lifetime pada alat pengolah air minum portabel ini adalah 38,879 L. Pengolahan air tanah menggunakan alat ini  dapat menaikkan pH sebesar 12,78%, menurunkan konduktivitas sebesar 39,31%, dan menurunkan Total Dissolved Solid (TDS) 13,72%. Dari segi ekonomi, penggunaan alat ini dapat menghemat biaya 50% dibandingkan dengan pembelian air minum kemasan 600 ml.In Indonesia, especially around the Bandung State Polytechnic, most of the water sources come from ground water. Ground water in the Bandung State Polytechnic environment has acidic pH (<6), coliform> 2,400, and positive colitis. The process of water heating is less effective for treating ground water because it requires a relatively long time, large energy, and can not increase the pH of the water to meet drinking water standards as stated in Permenkes No. 492 / MENKES / PER / IV / 2010. To treat ground water in the Bandung State Polytechnic, portable drinking water treatment equipment has been made using the concept of dead-end flow filtration. The membrane used is a hollow-fiber membrane, a type of ultrafiltration membrane made from PVDF (Poly Vinylidene Fluoride), pore size of 0.1μm, membrane length of 15cm, membrane number of 148 pieces, and can be operated on normal human suction. The permeate produced is in accordance with PERMENKES No. 492 / MENKES / PER / IV / 2010 from physical, chemical and biological parameters. Lifetime membranes are observed through the amount of permeate produced from the beginning of the use of the membrane until the membrane is damaged. Lifetime of this portable drinking water treatment device is 38,879 L. Ground water treatment using this tool can increase pH by 12.78%, decrease conductivity by 39.31%, and reduce Total Dissolved Solid (TDS) 13.72%. From an economic standpoint, the use of this tool can save 50% costs compared to the purchase of 600 ml of bottled water.

Development of Cellulose Acetate Membranes for Nano–and Reverse Osmosis Filtration of Contaminants in Drinking Water

2012 ◽  
Author(s):  
Darunee Bhongsuwan ◽  
Tripob Bhogsuwan ◽  
Narumol Buangam ◽  
Waneerat Mangkalatas
Keyword(s):  
Cellulose Acetate ◽  
Reverse Osmosis ◽  
Contaminated Water ◽  
Cellulose Acetate Membrane ◽  
Permeate Flux ◽  
Dead End ◽  
Cellulose Acetate Membranes ◽  
Stirred Cell ◽  
Iron Manganese ◽  
Iron And Manganese

Cellulose acetate (CA) membrane was produced from CA powder, formamid, and acetone. Annealing temperature of 80C and evaporation times of 30, 60, and 90 seconds were chosen in preparation of the CA membranes named R530, R560, and R590, respectively. The membranes were tested using a dead-end stirred cell for filtration of NaCl salt, iron, manganese, and arsenic in the laboratory-prepared water and groundwater. Results of the tests using a membrane R530 at 400 psi showed, that the rejection efficiencies for salt, iron, and manganese in laboratory-prepared water with 3000 ppm NaCl , 2.0 ppm Fe, and 2.0 ppm Mn were 87%, 99%, and 92%, respectively, with a permeate flux of 21 Lm-2hr-1. Tests for the groundwater containing 4815 ppm NaCl and 5.48 ppm Mn without acid treatment showed that membrane R530 gave the flux and rejection for salt and manganese at 24 Lm-2hr-1, 85% and 98%, and for iron and manganese at 21 Lm-2hr-1, 93% and 99%, respectively. In the filtration of arsenic, the prepared membrane had a As rejection of 68 - 70% at 300 and 400 psi when the feed was the laboratory prepared 1 ppm As+3 contaminated water but it was found to be more than 82 - 96% when the feed was a natural water. This is probably because the prepared membrane had a higher rejection efficiency for As+5 ions than As+3 ions. Ion selective capability of the CA membrane shows the potential to use the membrane in filtration of selective ions. Key words: Cellulose acetate membrane, reverse osmosis, nano-filtration, contaminated water, dead-end stirred cell

scholarly journals Pilot - Plant Experiments For The Removal of Thms, Haas and Doc from Drinking Water by Gac Adsorption- Galatsi Water Treatment Plant, Athens

2013 ◽  
Vol 5 (3) ◽  
pp. 177-184
Keyword(s):  
Drinking Water ◽  
Organic Matter ◽  
Activated Carbon ◽  
Water Treatment ◽  
Dissolved Organic Matter ◽  
Pilot Plant ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Carbon Surface ◽  
Gac Adsorption

A pilot-plant study was carried out with the water supply to Athens water works filtered through a granular activated carbon (GAC) filter- adsorber. The objective of this study was to evaluate the performance of GAC for the removal from drinking water of the two main groups of disinfection by -products (DBPs), trihalomethanes (THMs) and haloacetic acids (HAAs), as well as of dissolved organic matter. The pilot treatment facility is located at the Water Treatment Plant of EYDAP in Galatsi, Athens, and was operated as a rapid gravity filter - adsorber. It was fed with chlorinated water, coming from the overflow of the sedimentation tanks, and operated continuously in parallel with a full-scale sand filter. At regular time intervals water samples were taken from both filters and analysed for THMs, HAAs and DOC. Other parameters were measured too. The operation of the GAC filter-adsorber continued until the GAC adsorption capacity for THMs and HAAs was almost exhausted. The results of the analyses showed that GAC was more effective in removing the dissolved organic matter than the smaller molecules of THMs and HAAs, fact which is in agreement with the relevant literature. GAC was also proved more effective in removing HAAs than removing THMs. The removal of THMs and the most part of the removal of HAAs and DOC must be attributed to adsorption by GAC, while that of a smaller part of DOC and HAAs may be attributed to biological activity in the filter bed, where chlorine had been totally removed by the catalytic action of the activated carbon surface.

Resorcinarene Cavitand Polymers for the Remediation of Halomethanes and 1,4-Dioxane

2019 ◽  
Author(s):  
Luke Skala ◽  
Anna Yang ◽  
Max Justin Klemes ◽  
Leilei Xiao ◽  
William Dichtel
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
High Capacity ◽  
The United States ◽  
Water Sources ◽  
Disinfection Byproducts ◽  
Porous Polymer ◽  
Organic Micropollutants ◽  
Executive Summary ◽  
Regulatory Limits

<p>Executive summary: Porous resorcinarene-containing polymers are used to remove halomethane disinfection byproducts and 1,4-dioxane from water.<br></p><p><br></p><p>Disinfection byproducts such as trihalomethanes are some of the most common micropollutants found in drinking water. Trihalomethanes are formed upon chlorination of natural organic matter (NOM) found in many drinking water sources. Municipalities that produce drinking water from surface water sources struggle to remain below regulatory limits for CHCl<sub>3</sub> and other trihalomethanes (80 mg L<sup>–1</sup> in the United States). Inspired by molecular CHCl<sub>3</sub>⊂cavitand host-guest complexes, we designed a porous polymer comprised of resorcinarene receptors. These materials show higher affinity for halomethanes than a specialty activated carbon used for trihalomethane removal. The cavitand polymers show similar removal kinetics as activated carbon and have high capacity (49 mg g<sup>–1</sup> of CHCl<sub>3</sub>). Furthermore, these materials maintain their performance in real drinking water and can be thermally regenerated under mild conditions. Cavitand polymers also outperform activated carbon in their adsorption of 1,4-dioxane, which is difficult to remove and contaminates many public water sources. These materials show promise for removing toxic organic micropollutants and further demonstrate the value of using supramolecular chemistry to design novel absorbents for water purification.<br></p>

Low-pressure membrane filtration with unconventional coagulation regimes

2005 ◽  
Vol 5 (5) ◽  
pp. 1-8 ◽  
Author(s):  
K.Y. Choi ◽  
B.A. Dempsey
Keyword(s):  
Activated Carbon ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Cross Flow ◽  
Chemical Cleaning ◽  
Sand Filters ◽  
Charge Neutralization ◽  
Floc Size ◽  
Filtration System ◽  
Pre Treatment

The objective of the research was to evaluate in-line coagulation to improve performance during ultrafiltration (UF). In-line coagulation means use of coagulants without removal of coagulated solids prior to UF. Performance was evaluated by removal of contaminants (water quality) and by resistance to filtration and recovery of flux after hydraulic or chemical cleaning (water production). We hypothesized that coagulation conditions inappropriate for conventional treatment, in particular under-dosing conditions that produce particles that neither settle nor are removed in rapid sand filters, would be effective for in-line coagulation prior to UF. A variety of pre-treatment processes for UF have been investigated including coagulation, powdered activated carbon (PAC) or granular activated carbon (GAC), adsorption on iron oxides or other pre-formed settleable solid phases, or ozonation. Coagulation pre-treatment is often used for removal of fouling substances prior to NF or RO. It has been reported that effective conventional coagulation conditions produced larger particles and this reduced fouling during membrane filtration by reducing adsorption in membrane pores, increasing cake porosity, and increasing transport of foulants away from the membrane surface. However, aggregates produced under sweep floc conditions were more compressible than for charge neutralization conditions, resulting in compaction when the membrane filtration system was pressurized. It was known that the coagulated suspension under either charge-neutralization or sweep floc condition showed similar steady-state flux under the cross-flow microfiltration mode. Another report on the concept of critical floc size suggested that flocs need to reach a certain critical size before MF, otherwise membranes can be irreversibly clogged by the coagulant solids. The authors were motivated to study the effect of various coagulation conditions on the performance of a membrane filtration system.

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