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"ABSTRAKUpaya menurunkan kadar DO adalah hal yang penting dalam industri seperti diketahui oksigen punya efek oksidatif dan korosif terhadap bahan-bahan lain. Penggunaan : packing tower, mixer settler, chemical additive, & membran merupakan upaya-upaya yang sudah dilakukan selama ini dan yang menjadi unggulan ialah membran karena biaya investasi dan operasional yang lebih rendah, mudah dikombinasikan, mudah di scale-up, operasi kontinu, ramah lingkungan dan save-spacing. Luas permukaan kontak per volume dan pada prosesnya kemungkinan terjadinya foaming dan flooding kecil sebab kontak antar fasa yang minimum menjadi kelebihan performa dibanding metode konvensional. Dari berbagai jenis modul membran, modul membran serat berongga (hollow fiber membrane contactor) adalah modul yang paling banyak digunakan dalam desorpsi oksigen terlarut dari air. Membran yang digunakan adalah membran polipropilen hidrofobik dengan diameter : 0,2 cm. Transfer oksigen terlarut terjadi tiga tahap yaitu: transfer oksigen terlarut dalam air, difusi oksigen terlarut melalui membran, dan difusi oksigen terlarut ke dalam aliran udara gas penyapu. Penelitian ini akan berfokus pada performa pengurangan kadar oksigen dari air pada modul yang sudah dibuat pada 30-40-50 jumlah serat. Performa modul kontaktor diindikasikan dengan parameter nilai bilangan Sherwood dan properti hidrodinamika yang terjadi. Korelasi nilai bilangan Sherwood terhadap faktor geometri dan sifat aliran terlihat pada persamaan perpindahan massa yang mana juga menjadi model persamaan.Dari hasil eksperimen, dihasilkan koefisien perpindahan massa sebesar 0,0022- 0,0066 cm/s dan nilai ini berbanding lurus dengan kenaikan fraksi kepadatan membran pada laju alir linier yang sama. Korelasi perpindahan massa yang terbentuk: Sh ? (0.0106 ? ?1.4169 )(Re0.99 ) dan properti hidrodinamika (penurunan tekanan) yang terjadi menunjukkan perpindahan massa terjadi di daerah laminer. Studi hidrodinamika juga menunjukkan faktor friksi aliran lebih besar 9,5 - 10,7 kali dibanding faktor friksi literatur.

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ABSTRACT

As dissolved oxygen has oxidizing and corroding character if placed next to other material, effort to decrease the dissolved oxygen concentration is a crucial role especially in industry. Until now utilization of packing tower, mixer settler, chemical additive, & membrane are the common way to reach decreased dissolved oxygen number. But membrane has some strong point compared to others, such as: lower cost, easy to scale-up, continuous operation, environmental friendly, & save spacing. Technical advantages of using membrane are its surface area per volume much higher than conventional method and lower opportunity to have flooding and foaming problems because minimum interface contact during process. Holow fiber membrane contactor is the most popular membrane module used in dissolved oxygen problem area. The membrane which is used have diameter of 0,2 cm. Three steps of mass oxygen transfer are : oxygen transfer in the water, dissolved oxygen diffusion into membrane pore, and diffusion of the oxygen to introduced sweeping gas. This research wills focused on dissolved oxygen removal performance using membrane module that have 30, 40, & 50 fibers inside. The performance of the module indicated by Sherwood number and hydrodynamic properties that occur during experiment. And equation model of the module will be developed as it affected by geometry factor of the module and type of the water flow.

As the result, mass transfer coefficient calculated output are 0,0022-0,0066 cm/s and this value are proportional to increase in geometry factor number in equal linear flow rate. Mass transfer corelation that developed is Sh ? (0.0106 ? ?1.4169 )(Re0.99 ) , and the result of dropped pressure during experiment show that mass transfer occur in laminar flow. Further, the hydrodynamic study result show that friction factor of the experiment flow 9,5-10,7 times higher than literature friction factor."

"Penelitian ini menggunakan air sebagai senyawa untuk menyerap Terlarut melalui Super Hidrofobik membran kontaktor. Tujuan dari penelitian ini adalah untuk mengetahui kemampuan Super Hyfrophobic membran dalam menyerap Terlarut menggunakan AIR melalui evaluasi perpindahan massa dan hidronamik. Pada penelitian ini, aliran Terlarut mengalir di tube dan air dengan laju alir yang bervariasi mengalir secara berlawanan di shell. Jumlah serat yang digunakan dalam percobaan ini adalah 3000. Hasil penelitian ini menunujukkan bahwa kenaikan koefisien perpindahan massa, flux dan absorpsi terjadi seiring kenaikan laju alir pelarut air.

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This study is using water as a compound to absorb the dissolved through Super Hydrophobic membrane contactor. The purpose of this study was to determine the ability of Super Hydrophobic membrane to absorb the dissolved using water through the evaluation of mass transfer and hydrodynamic study. In this study, the flow of dissolved flowing in the tube and water with varying flow rate flowing in the opposite shell. The number of fiber used in this experiment was 3000. The results of this study indicate that the increase in the mass transfer coefficient, flux and absorption occurs as the increase in the flow rate of the solvent water."

"The combination ofbaffled air flotation and a membrane system for the treatment of palm oil milleffluent (POME) was studied. The POME was obtained from a palm oil factory inPTPN I Tanjong Seumantoh, Aceh, Indonesia. Operation variables and conditions,such as the hydraulic retention time and air flow rates, were varied to findthe optimum process. The air flotation process is able to reduce theconcentration of suspended solids and fats/ oils contained in the wastewater,which increases the performance of the membrane by reducing clogging. Theresults showed that this method was promising for POME treatment. The optimumorganic removal efficiency of the air flotation pretreatment was obtained atHRT = 5 days and at an air flow rate of 11 L/min. The effluent was subsequentlypassed through an anaerobic membrane system to achieve the highest removalefficiency treatment. The removal efficiency of chemical oxygen demand (COD),total suspended solids (TSS), turbidity, mixed liquor suspended solids (MLSS),mixed liquor volatile suspended solids (MLVSS), and fats/oils after passingthrough the membrane system were 97%, 93.9%, 99.8%, 94.5%, 96.2%, and 99.9%,respectively. The results also showed that the pH could be neutralized to 6.18,while a dissolved oxygen (DO) level of 1.60 mg/L could be achieved. A highquality of effluent was obtained, which met the standards for POME effluent."

"The combination of baffled air flotation and a membrane system for the treatment of palm oil mill effluent (POME) was studied. The POME was obtained from a palm oil factory in PTPN I Tanjong Seumantoh, Aceh, Indonesia. Operation variables and conditions, such as the hydraulic retention time and air flow rates, were varied to find the optimum process. The air flotation process is able to reduce the concentration of suspended solids and fats/ oils contained in the wastewater, which increases the performance of the membrane by reducing clogging. The results showed that this method was promising for POME treatment. The optimum organic removal efficiency of the air flotation pretreatment was obtained at HRT = 5 days and at an air flow rate of 11 L/min. The effluent was subsequently passed through an anaerobic membrane system to achieve the highest removal efficiency treatment. The removal efficiency of chemical oxygen demand (COD), total suspended solids (TSS), turbidity, mixed liquor suspended solids (MLSS), mixed liquor volatile suspended solids (MLVSS), and fats/oils after passing through the membrane system were 97%, 93.9%, 99.8%, 94.5%, 96.2%, and 99.9%, respectively. The results also showed that the pH could be neutralized to 6.18, while a dissolved oxygen (DO) level of 1.60 mg/L could be achieved. A high quality of effluent was obtained, which met the standards for POME effluent."

"Pemisahan oksigen terlarut dari dalam air sangat diperlukan untuk beberapa industri khususnya industri pembangkit tenaga listrik, semikonduktor dan industri obat dan makanan. Proses pemisahan secara konvensional telah dibuktikan memiliki banyak kekurangan sehingga proses perpindahan massa yang terjadi tidak dapat optimal. Proses pemisahan alternatif untuk desorpsi oksigen terlarut adalah dengan menggunakan kontaktor membran serat berlubang. Kontaktor membran memberikan luas permukaan perpindahan massa yang lebih besar daripada kolom konvensional dan memiliki keunggulan karena tidak terdapatnya kontak antar fasa sehingga mengurangi kemungkinan terjadinya foaming dan flooding. Luas permukaan membran adalah faktor yang penting di dalam penggunaan modul kontaktor membran serat berongga ini; luas permukaan membran yang besar memberikan luas permukaan kontak antar fasa yang besar sehingga proses perpindahan massa semakin baik. Penggunaan luas permukaan membran yang besar melibatkan lebih banyak jumlah serat membran yang digunakan, sehingga hal ini dapat menyebabkan perbedaan tekanan dalam selongsong modul yang tinggi dan biaya pemompaan fasa cair menjadi besar sekali. Terdapat kondisi optimum pada system membran kontaktor ini, yaitu saat jumlah biaya pemompaan fasa cair dan biaya membran untuk sejumlah perpindahan massa tertentu pada jenis diameter serat yang sama adalah yang paling rendah. Setiap variasi diameter serat membran, diameter selongsong modul dan debit air memiliki jumlah serat tertentu yang harus digunakan. Jumlah serat ini meningkat dengan bertambah besarnya diameter selongsong dan debit air untuk diameter serat membran yang sama. Penggunaan diameter serat membran yang lebih besar menurunkan jumlah serat yang digunakan dalam selongsong yang sama. Jumlah serat terhitung sebelumnya akan digunakan untuk menghitung biaya pemompaan dan biaya membran yang akan digunakan dalam uji sensitivitas untuk penentuan kondisi optimum modul. Kondisi optimum modul direpresentasikan dalam diameter selongsong tertentu yang besarnya bertambah seiring dengan penggunaan diameter serat membran yang semakin besar. Penggunaan diameter selongsong modul yang optimum ini diharapkan dapat mengurangi biaya operasi desorpsi oksigen terlarut dari dalam air.

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Dissolved oxygen desorption from water is needed in a few industries especially in the steam power generator plant, semiconductor and food and drugs industries. Conventional separation processes have been proved to be un-efficient so that the mass transfer process can not be optimal. Alternative separation process for dissolved oxygen removal is the application of hollow fiber membrane contactor. Membrane contactor gives higher surface area for mass transfer than conventional column and has the advantage of not having dispersed phases so that the possibility of foaming and flooding to be happened can be reduced. The membrane surface area is an important factor in using hollow fiber membrane contactor; large surface area gives large area for phases to be contacted therefore the separation process is better. The use of large membrane surface area include the use of many number of fibers, so it can cause high pressure drop along the module shell which lead to high pumping cost. There is an optimum condition in this membrane contactor system. This condition is defined as a condition at which the total cost for pumping and membrane for a specified mass transfer reach the lowest point for a given fiber diameter. Every variation of membrane fiber diameter, module diameter and water flowrate has a certain number of fiber to be used. This number of fiber is increased with the increase of module diameter and so with water flowrate for a certain membrane fiber diameter. The use of wider fiber diameter decrease the number of fiber used in the same module. The previous calculated number of fiber will be used to calculate the pumping cost and the membrane cost which are used in a sensitivity test to determine the module optimum condition. The module optimum condition is representated as a specific optimum value of module diameter which value will increase as the use of membrane fiber diameter is increased. By using this optimum modul diameter, a decreased operation cost for dissolved oxygen removal from water can be obtained."

"Desorpsi oksigen menggunakan kontaktor membran serat berongga polivinil klorida dilakukan dalam penelitian ini. Penelitian ini bertujuan untuk mengevaluasi penggunaan kontaktor membran berdasarkan studi perpindahan massa dan hidrodinamika, serta menganalisis struktur morfologi membran PVC dan kesesuaiannya untuk desorpsi oksigen. Penelitian ini dilakukan dengan mengalirkan air pada selongsong, sedangkan udara vakum dalam serat, dengan memvariasikan laju alir air (1-5,25 liter/menit) dan jumlah serat (50, 60, 70 serat). Berdasarkan studi perpindahan massa diperoleh fluks oksigen sebesar 0,037 – 0,15 g/m2.h, koefisien perpindahan massa sebesar 1,118x10-6 m/s – 4,311x10-6 m/s, dengan korelasi Sh=(0,0015φ2-0,0319φ+0,338)Re(0,0014φ2-0,0499φ+1,086). Parameter performa perpindahan massa, kLa mencapai 0,00124 s-1 (tiga kali lebih besar dari kontaktor konvensional). Berdasarkan studi hidrodinamika, friksi terbesar mencapai 40 kali lebih besar dibandingkan friksi pipa halus, dengan korelasi f=(10,645φ2-216,1φ+1125,9)Re(-0,0086φ2+0,145φ-1,176). Berdasarkan uji FESEM, membran PVC memiliki struktur permukaan selimut yang kompak yang menghasilkan stabilitas mekanik dan ketahanan terhadap fouling yang baik serta memiliki banyak pori yang meminimalkan tahanan perpindahan massa.

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Oxygen desorption with PVC hollow fiber membrane contactor is done in this research. The purpose of this research is to evaluate application of membrane contactor based on mass transfer and hydrodynamic study and to analyze structure of PVC membrane and its compatibility to desorp oxygen. This research applied by flowing water in shell side, while gas in lumen side is vacuumed by varying water flow rate (1-5.25 litre/min) and number of fibers (50, 60, 70 fibers). According to mass transfer study, oxygen flux achieved is 0,037 – 40,15 g/m2.h, mass transfer coefficient achieved is 1,118x10-6 m/s – 4,311x10-6 m/s, with correlation of Sh=(0.0015φ2-0.0319φ+0.338)Re(0.0014φ2-0.0499φ+1.086). Mass transfer performance’s parameter, kLa reaches 0.00124 s-1 (three times higher than conventional contactor). According to hydrodynamic study, the largest friction is 40 times higher than friction in smooth pipe, with correlation of f=(10.645φ2-216.1φ+1125.9)Re(-0.0086φ2+0.145φ-1.176). From FESEM test, PVC membrane has compact structure which leads to better mechanic stability and resistance toward fouling and high-pore structure which decreases mass transfer resistance."

"Desorpsi oksigen menggunakan kontaktor membran serat berongga polivinil klorida dilakukan dalam penelitian ini. Penelitian ini bertujuan untuk mengevaluasi penggunaan kontaktor membran berdasarkan studi perpindahan massa dan hidrodinamika, serta menganalisis struktur morfologi membran PVC dan kesesuaiannya untuk desorpsi oksigen. Penelitian ini dilakukan dengan mengalirkan air di dalam serat, sedangkan udara vakum dalam selongsong, dengan memvariasikan laju alir air (0,2 – 0,5 liter/menit) dan jumlah serat (50, 60, 70 serat). Berdasarkan studi perpindahan massa, diperoleh fluks oksigen sebesar 0,04 – 0,13 g/m2.h, koefisien perpindahan massa sebesar 1,3×10-6 – 3,8×10-6 m/s, dengan korelasi Sh=0,138Gr0,395. Parameter performa perpindahan massa, kLa mencapai 0,0012 s-1 (tiga kali lebih besar dari kontaktor konvensional. Berdasarkan studi hidrodinamika, faktor friksi mencapai 1,9 kali lebih tinggi dari faktor friksi pada pipa halus, dengan korelasi f=3,71Re0,028φ-0,9. Karakterisasi membran dengan FESEM menunjukkan struktur membran PVC mendukung operasi desorpsi oksigen karena struktur selimut yang kompak menghasilkan stabilitas mekanik dan ketahanan terhadap fouling yang baik sedangkan struktur tebal serat yang berongga meminimalkan tahanan perpindahan massa.

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Oxygen desorption on water with PVC hollow fiber membrane contactor is done in this research. The purpose of this research is to evaluate application of membrane contactor based on mass transfer and hydrodynamic study and to analyze structure of PVC membrane and its compatibility to desorp oxygen. Water flows inside the fiber (lumen side) while gas in shell side is vacuumed. Process variables are number of fibers (50, 60, and 70) and water flow rate (0.2 – 0.5 L/min). According to mass transfer study, oxygen flux is in range of 0,04 – 0,13 g/m2.h, mass transfer coefficient is in range of 1,3×10-6 – 3,8×10-6 m/s, while empirical correlation is Sh=0,138Gr0,395. Mass transfer performance’s parameter, kLa reaches 0.0012 s-1, three times higher than in conventional contactor. According to hydrodynamic study, friction factor is to be 1.9 times higher than friction factor inside smooth pipe, with correlation of f=3,71Re0,028φ- 0,9. Membran characterization using FESEM shows structure of PVC membrane is appropriate to conduct oxygen desorption process because its low-pored shell structure produces high resistance toward fouling while its sponged-like structure between two shells decreases mass transfer resistance in membrane."

"ABSTRAKDalam proses bioremediasi air yang terkontaminasi minyak bumi, Azolla microphylla berinteraksi dengan bakteri. Pada proses tersebut perlu dilakukan adanya pengontrolan terhadap faktor-faktor pertumbuhan Azolla microphylla dan bakteri serta hubungannya dalam degradasi minyak bumi. Penelitian ini bertujuan untuk mengetahui pengaruh kadar oksigen terlarut dan amonia terhadap pertumbuhan Azolla microphylla dan bakteri, penyisihan minyak, serta untuk mengetahui hubungan pertumbuhan azolla dan bakteri dalam bioremediasi. Penelitian eksperimen ini dilakukan dengan menggunakan 3 kepadatan azolla yaitu 250, 300, dan 350 g/m2. Air yang terkontaminasi disimulasikan dari 400 ml air tanah dan minyak bumi dengan 2 konsentrasi yaitu 0,05 dan 0,1 v/v. Selama 15 hari penelitian diperoleh bahwa oksigen terlarut memiliki pengaruh yang terhadap pertumbuhan azolla, pertumbuhan bakteri, dan penyisihan minyak dengan rentang persentase secara berturut-turut: 7,1-13,2 ; 6,3-46,2 ; dan 3,1-13,8 . Amonia memberikan pengaruh yang bernilai positif terhadap azolla, bakteri dan penyisihan minyak dengan persentase pengaruh: 2,1-12,5 ; 7,2-33,6 ; dan 50,0-69,7 . Efisiensi penyisihan minyak bumi optimum pada hari ke-3 dengan persentase penyisihan untuk konsentrasi minyak 0,05 pada densitas Azolla 250, 300 dan 350 g/m2 secara berturut-turut adalah 40,7 , 47,4 ; dan 42,4 . Sementara untuk konsentrasi minyak 0,1 memiliki persentase penyisihan minyak sebesar 50,1 ; 59,6 ; dan 61,9 . Pertumbuhan azolla berbanding lurus dengan pertumbuhan bakteri dengan persentase pengaruh sebesar 16,1-30,7 .

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ABSTRACTIn the process of bioremediation of water contaminated with crude oil, Azolla microphylla interacts with bacteria. It is necessary to control the growth factors of Azolla microphylla and bacteria and their relationship in oil degradation. This study aims to determine the effect of dissolved oxygen and ammonia levels on the growth of Azolla microphylla and bacteria, oil removal, and to determine the relationship of azolla and bacteria growth in bioremediation. This experimental study was conducted using 3 azolla densities of 250, 300, and 350 g m2. Contaminated water is simulated from 400 ml of ground water and petroleum with 2 concentrations of 0.05 and 0.1 v v. During the 15 days of the study it was found that dissolved oxygen had an effect on the growth of azolla, bacterial growth, and removal of oil by a successive percentage range 7.1 13.2 6.3 46.2 and 3.1 13.8 . Ammonia has a positive effect on azolla, bacteria and oil removal with percentage range 2.1 12.5 7.2 33.6 and 50.0 69,7 . Optimum oil removal efficiency on day 3 with percentage of removal for 0.05 oil concentration at Azolla 250, 300 and 350 g m2 densities were 40.7 , 47.4 , respectively and 42.4 . Meanwhile, for oil concentration 0.1 has a percentage of oil removal of 50.1 59.6 and 61.9 . The growth of azolla is directly proportional to bacterial growth with the effect percentage of 16,1 30,7 . "