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All Journal Reaktor International Journal of Science and Engineering (IJSE) TEKNIK METANA Jurnal Ilmu Lingkungan Teknotan: Jurnal Industri Teknologi Pertanian Jurnal Teknik Kimia USU JURNAL TEKNOLOGI KIMIA DAN INDUSTRI Seminar Nasional Teknik Kimia Kejuangan Journal of Engineering and Technological Sciences Jurnal Riset Industri agriTECH Jurnal Kelautan Tropis Communications in Science and Technology Jurnal Abdi Masyarakat Indonesia Jurnal Teknik Kimia USU

I Nyoman Widiasa

Chemical Engineering Dept., Faculty Of Engineering, Universitas Diponegoro Jl. Prof. Soedarto SH Tembalang Semarang Telp./Fax. (024)7460058 / (024)76480675

Author-ID : 415527

Agriculture, Biological Sciences & Forestry Humanities Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Computer Science & IT Control & Systems Engineering Economics, Econometrics & Finance Education Energy Engineering Environmental Science Industrial & Manufacturing Engineering Materials Science & Nanotechnology Public Health Other

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Fouling Analysis on Polysulfone/Peg400/ZnO Membrane during Textile Wastewater Treatment Putu Teta Prihartini Aryanti; Febrianto Adi Nugroho; Gatra Buana Winiarti; Ghina Shofi Pratiwi; I Nyoman Widiasa
Reaktor Volume 21 No.4 December 2021
Publisher : Dept. of Chemical Engineering, Diponegoro University

Fouling has become the main problem in long-term application of ultrafiltration (UF) membrane for water and wastewater treatment, significantly reducing membrane productivity. In this paper, fouling on polysulfone-based membrane was analyzed using Hermia’s model during textile wastewater treatment. The UF membrane has been prepared by blending polysulfone (PSf), acetone, and PEG400 in DMAc, with ZnO nanoparticles at a concentration of 1% by weight of polymers (PSf and PEG400). The influence of polysulfone concentration (18 and 20 wt.%) and PEG400 (0 - 25 wt.%) on fouling mechanisms was investigated. It was found that the increase of polysulfone from 18 to 20 wt.% reduced permeate flux from 54 to 25 L.m-2.h-1. Vise versa, the increase of PEG400 concentration enhanced the permeate flux. More stable flux was achieved when 18 wt.% of polysulfone was used to prepare the UF membrane. The fouling type in the UF membrane depends on the characteristics of the membrane. A significant flux decline occurred when used 20 wt.% of polysulfone without the addition of PEG400. Smaller membrane pore and higher hydrophobicity due to high polysulfone concentration induced cake layer of fouling on the membrane surface at the first 40 minutes of ultrafiltration. Further increase of operating time, internal fouling was formed due to the movement of pollutants to the permeate side caused by different concentrations. The highest color rejection (86%) was achieved when 25 wt.% of PEG400 was added in 20 wt.% of polysulfone solution.Keywords: fouling, hermia model, ultrafiltration, wastewater treatment.

KOMBINASI ULTRAFILTRASI DAN DISSOLVED AIR FLOTATION UNTUK PEMEKATAN MIKROALGA I Nyoman Widiasa; A A Susanto; B Budiyono
Reaktor Volume 15, No.1, APRIL 2014
Publisher : Dept. of Chemical Engineering, Diponegoro University

Abstrak Mikroalga merupakan mikroorganisme fotosintetik prokariotik atau eukariotik yang dapat tumbuh dengan cepat. Pemanfaatan mikroalga tidak hanya berorientasi sebagai pakan alami untuk akuakultur, tetapi terus berkembang untuk bahan baku produksi pakan ternak, pigmen warna, bahan farmasi (β-carotene, antibiotik, asam lemak omega-3), bahan kosmetik, pupuk organik, dan biofuel (biodiesel, bioetanol, biogas, dan biohidrogen. Studi ini bertujuan untuk menginvestigasi kombinasi ultrafiltrasi (UF) – dissolved air flotation (DAF) untuk pemekatan mikroalga skala laboratorium. Hasil penelitian menunjukkan bahwa penurunan fluks membran UF secara tajam sebagai akibat dari deposisi sel mikroalga terjadi pada 20 menit pertama proses filtrasi. Backwash pada interval 20 menit selama 10 detik dengan tekanan 1 bar memberikan pengendalian fouling yang efektif dalam nilai kestabilan fluks yang layak. Membran UF yang digunakan dapat memberikan selektivitas pemisahan biomassa mikroalga ~ 100%. Kualitas permeat sangat stabil, yaitu kekeruhan < 0,5 NTU, kandungan organik < 10 mg/L, dan warna < 10 PCU. Lebih lanjut, pemekatan retentat membran dengan DAF pada tekanan saturasi 6 bar dapat menghasilkan pasta mikroalga dengan konsentrasi 20 g/L. Koagulan PAC perlu ditambahkan kedalam umpan DAF dengan dosis 1,3–1,6 mg PAC/mg padatan tersuspensi. Kata Kunci: ultrafiltrasi; dissolved air flotation; pemanenan mikroalga; pemekatan mikroalga Abstract COMBINATION OF Ultrafiltration and Dissolved Air Flotation for Microalgae CONCENTRATION. Microalgae is a prokaryotic photosynthetic microorganism or eukaryotic microorganism that proliferate rapidly. Cultivation of the microalgae is not only oriented as natural food for aquacultures, but also developed for animal food, color pigment, pharmaceutical raw material (β-carotene, antibiotic, fatty acid omega-3), cosmetic raw material, organic fertilizer, and biofuels (biodiesel, bioethanol, biogas, and biohydrogen. This study is aimed to investigate the potential of combination of ultrafiltration (UF) and dissolved air flotation (DAF) for concentration of microalgae in laboratory scale. The experimental results showed that fluxes of the UF membrane decreased sharply due to deposition of microalgae biomass during first 20 minutes of filtration. Periodically backwash using the UF permeate (backwash interval = 20 minutes; backwash duration = 10 seconds; backwash pressure = 1 bar) gave an effective fouling control to maintain reasonable stable fluxes. In addition, the UF membrane gave separation of microalgae biomass ~ 100%. Permeate quality is strongly stable in which turbidity < 0.5 NTU, organic content < 10 mg/L, and color < 10 PCU. Moreover, concentration of the UF retentate by DAF under saturation pressure of 6 bars was able to produced microalgae feedstock having 20 g/L dry microalgae. PAC is required for DAF feed with dosage of 1.3–1.6 mg PAC/mg suspended solids.

KARAKTERISTIK INTERAKSI MEMBRAN-FOULANT DAN FOULANT-FOULANT SEBAGAI DASAR PENGENDALIAN FOULING Heru Susanto; Asteria Apriliani Susanto; I Nyoman Widiasa
Reaktor Volume 14, Nomor 1, April 2012
Publisher : Dept. of Chemical Engineering, Diponegoro University

THE CHARACTERISTICS OF MEMBRANE-FOULANT AND FOULANT-FOULANT INTERACTIONS AS THE BASIS FOR CONTROL OF FOULING. Industrial membrane applications for solid liquid and liquid-liquid filtration are limited by fouling and concentration polarization. Because fouling significantly reduces the membrane performance and often changes the membrane selectivity, efforts to overcome the fouling problem are very important from practical applications point of view. This paper presents the basic knowledge required to control fouling and recent development in fouling control including the method developed by the author. Control of fouling can be done by (i) commercial membrane modification (post modification) by photo-graft polymerization, (ii) modification by polymer blending during membrane manufacturing and (iii) integration of a pretreatment into membrane processes. The results showed that all the developed methods can significantly reduce the resulting fouling; however, none of the method could totally remove the occurring fouling. The understanding of the membrane-foulant and foulant-foulant interactions is the key to success in control of fouling.Aplikasi teknologi membran untuk pemisahan padat cair di berbagai industri dibatasi oleh peristiwa fouling yang menyebabkan penurunan laju produk dan perubahan selektifitas membran. Oleh karena itu, pengendalian fouling merupakan upaya yang mutlak harus dilakukan. Makalah ini mempresentasikan pengetahuan dasar yang diperlukan untuk pengendalian fouling dan perkembangan terkini dalam pengendalian fouling termasuk hasil-hasil yang telah dikembangkan oleh penulis. Pengendalian fouling dilakukan dengan (i) modifikasi membran komersial (post modification) menggunakan metode photo-grafting, (ii) modifikasi dengan pencampuran polimer selama proses pembuatan (polymer blend) dan (iii) integrasi unit perlakuan awal (pre-treatment) dengan proses membran. Hasil penelitian menunjukkan bahwa kesemua metode yang dikembangkan dapat mengurangi terjadinya fouling secara signifikan. Namun, tidak ada satu pun metode yang dapat mengurangi fouling dengan sempurna. Pemahaman terhadap interaksi membran-foulant dan foulant-foulant merupakan kunci sukses dalam pengendalian fouling.

ULTRAFILTRATION AS PRETREATMENT OF REVERSE OSMOSIS: LOW FOULING ULTRAFILTRATION MEMBRANE PREPARED FROM POLYETHERSULFONE–AMPHIPHILIC BLOCK COPOLYMER BLEND Heru Susanto; Luqman Buchori; Siswo Sumardiono; Berkah Fajar; Titik Istirokhatun; I Nyoman Widiasa
Reaktor Volume 12, Nomor 4, Desember 2009
Publisher : Dept. of Chemical Engineering, Diponegoro University

This paper demonstrates the preparation of polyethersulfone (PES) ultrafiltration (UF) membranes via wet phase inversion method using either poly(ethylene oxide)-b-poly(propylene oxide)-b- poly(ethylene oxide) (Pluronic®, Plu) or polyethylene glycol (PEG) as hydrophilic modifier. Their effects on membrane structure as well as the resulting membrane performance and their stability in membrane polymer matrix were systematically investigated. The investigated membrane characteristics include surface hydrophilicity (by contact angle), surface chemistry (by FTIR spectroscopy) and water flux measurement. Visualization of membrane surface and cross section morphology was also done by scanning electron microscopy. The membrane performance was examined by investigation of adsorptive fouling and ultrafiltration using solution of bovine serum albumin as the model system. The stability of additive was examined by incubating the membrane in water (40oC) for up to 10 days. The results show that modification effects on membrane characteristic and low fouling behavior were clearly observed. Further, amphiphilic Pluronic generally showed better performance than PEG.

Application of the Fenton Process in the Petroleum Refinery Spent Caustic Wastewater Treatment Riang Anggraini Rahmanisa; I Nyoman Widiasa
Reaktor Volume 20 No.2 June 2020
Publisher : Dept. of Chemical Engineering, Diponegoro University

Spent caustic wastewater is produced from the scrubbing process using a caustic solution to absorb contaminants in the oil stream (hydrocarbon). Indonesia’s Petroleum Oil Refinery produces spent caustic wastewater from LPG and kerosene processing unit. Spent caustic wastewater has the characteristic of a strong odor with very high pH (12-14), containing dangerous pollutants such as phenol, aldehydes, mercaptans, and thiols that can be harmful to the human and environment. The Fenton process is used to treat spent caustic before being discharged to the environment. The Fenton process is one of AOPs (Advanced Oxidation Process) using Fe2+ as a catalyst and H2O2 as an oxidant to oxidize organic contaminants in wastewater. This study aims to determine the operating conditions of the Fenton Process with the target characteristics of treated spent caustic meet the WWTP (Waste Water Treatment Plant) inlet specifications and to make the design process of spent caustic treatment with the Fenton Process capacity of 10 m3/day. By operating at the H2O2/Fe (II) ratio of 1.8, the final target was achieved with COD of 810 ppm, ammonia of 22.84 ppm, sulfide of 60.93 ppm and phenol of 14.56 ppm. Total Capital Investment (TCI) for the design is US$ 2146701.89 whereas Total Manufacturing Cost of US$ 2089740.75.Keywords: spent caustic; refinery wastewater; Fenton process

Studi Tekno Ekonomi Desalinasi Air Laut Skala Kecil Dengan Sistem Reverse Osmosis Linda Aliffia Yoshi; I Nyoman Widiasa
Reaktor Volume 16 No.4 Desember 2016
Publisher : Dept. of Chemical Engineering, Diponegoro University

Penelitian ini bertujuan untuk mendapatkan desain dan keekonomian desalinasi air laut di Indonesia yang mempunyai suku bunga bank 12-14%, tarif listrik Rp 1.300-1.800 per kWh, dan pajak air bawah tanah. Penggunaan sistem desalinasi SWRO di Indonesia pada umumnya dibuat skala kecil. Studi ini berdasarkan studi kasus di Pulau Bali dengan tarif listrik adalah Rp 1.335,29/kWh dan pajak air bawah tanah adalah Rp 4.950/m3. Evaluasi tekno-ekonomi dianalisa untuk kapasitas 150-1000 m3/hari, recovery sistem 40% dengan salinitas air laut 32.000 ppm, suku bunga 13%, dan jangka waktu pinjaman 10 tahun. Harga jual air desalinasi pada tahun pertama 24,300/m3. Berdasarkan hasil evaluasi ekonomi yang meliputi NPV dan IRR dapat disimpulkan bahwa investasi layak dilakukan.

SACCHARIFICATION OF NATIVE CASSAVA STARCH AT HIGH DRY SOLIDS IN AN ENZYMATIC MEMBRANE REACTOR I Nyoman Widiasa; I Gede Wenten
Reaktor Volume 12, Nomor 3, Juni 2009
Publisher : Dept. of Chemical Engineering, Diponegoro University

This study is aimed to develop a novel process scheme for hydrolysis of native cassava starch at high dry solids using an enzymatic membrane reactor (EMR). Firstly, liquefied cassava starch having solids content up to 50% by weight was prepared by three stage liquefactions in a conventional equipment using a commercially available heat stable a-amylase (Termamyl 120L). The liquefied cassava starch was further saccharified in an EMR using glucoamylase (AMG E). By using the developed process scheme, a highly clear hydrolysate with dextrose equivalent (DE) approximately 97 could be produced, provided the increase of solution viscosity during the liquefaction was precisely controlled. The excessive space time could result in reduction in conversion degree of starch. Moreover, a residence time distribution study confirmed that the EMR could be modelled as a simple continuous stirred tank reactor (CSTR). Using Lineweaver-Burk analysis, the apparent Michaelis-Menten constant (Km) and glucose production rate constant (k2) were 552 (g/l) and 4.04 (min-1), respectively. Application of simple CSTR model with those kinetic parameters was quietly appropriate to predict the reactor’s performance at low space time.

SYNTHESIS AND CHARACTERIZATION OF POLYIMIDE-ZEOLITE MIXED MATRIX MEMBRANE Budiyono Budiyono; Tutuk Djoko Kusworo; Ahmad Fauzi Ismail; I Nyoman Widiasa; Seno Johari; Sunarso Sunarso
Reaktor Volume 12, Nomor 4, Desember 2009
Publisher : Dept. of Chemical Engineering, Diponegoro University

Biogas has become an attractive alternative energy source due to the limitation of energy from fossil. In this study, a new type of mixed matrix membrane (MMM) consisting of polyimide-zeolite was synthesized and characterized for biogas purification. The MMM consists of medium concentration of polymer (20% wt polyimide), 80% N-Methyl-2-pyrrolidone (NMP) and 25% zeolite 4A in total solid were prepared by a dry/wet phase inversion technique. The fabricated MMM was characterized using SEM, DSC, TGA and gas permeation. Post treatment coating procedure was also conducted. The research showed that surface coating by 3% silicone rubber toward MMM PI 20% gave the significant effect to improve membrane selectivity. The ideal selectivity for CO2/CH4 separation increased from 0.99 for before coating to 7.9 after coating for PI-Zeolite MMM, respectively. The results suggest that PI-Zeolite MMM with good post treatment procedure will increase the membrane selectivity and permeability with more saver polymer requirement as well as energy saving due to low energy for mixing.

KARAKTERISASI FILM KOMPOSIT ALGINAT DAN KITOSAN Nur Rokhati; Bambang Pramudono; Nyoman Widiasa; Heru Susanto
Reaktor Volume 14, Nomor 2, Oktober 2012
Publisher : Dept. of Chemical Engineering, Diponegoro University

CHARACTERIZATION OF ALGINATE AND CHITOSAN COMPOSITE FILM. Due to the specific characteristics of (thin) films, the use of polymer films in various aplications has singnificantly increased. Alginate and chitosan are natural polymers, which have potential as a raw material for the manufacture of composite films. This paper presents the preparation and characterization of alginate, chitosan and chitosan-alginate composite films. The film characterization included permeability test, degree of swelling, mechanical property, morphology (by SEM), and surface chemistry (by FTIR). The results showed that alginate films have a higher permeability and degree of swelling (DS) than chitosan films. Both permeability and DS decreased with increasing concentration for both alginate and chitosan films. DS experiments showed that the films have the highest DS in water followed by ethanol 95% and ethanol >99.9%, respectively. The mechanical strength of chitosan films was larger than alginate films. Alginate-chitosan composite films prepared by layer by layer method showed better characteristics than the composite films prepared by blending of alginate and chitosan solutions. Meningkatnya aplikasi film polimer di berbagai industri tidak terlepas dari keunggulan yang dimiliki. Alginat dan kitosan merupakan polimer alam yang mempunyai potensi sebagai bahan dasar pembuatan film komposit. Pada penelitian ini dilakukan pembuatan dan karakterisasi film komposit berbasis alginat dan kitosan. Karakterisasi film yang dilakukan meliputi uji: permeabilitas, derajat swelling, mekanik, morfologi (dengan SEM), dan struktur kimia permukaan (dengan FTIR). Hasil penelitian menunjukkan bahwa film alginat mempunyai nilai permeabilitas maupun derajat swelling yang lebih tinggi dibanding dengan film kitosan. Baik pada kitosan maupun alginat memberikan fenomena bahwa semakin besar konsentrasi larutan maka semakin kecil nilai permeabilitas maupun derajat swelling, dengan derajat swelling terhadap air adalah yang paling besar kemudian diikuti oleh ethanol teknis (± 95%) dan yang terkecil adalah ethanol PA (> 99,9%). Kekuatan mekanik film kitosan lebih besar dibanding dengan film alginat. Film komposit alginat-kitosan yang dibuat dengan metode layer by layer memberikan karakteristik yang lebih baik dibanding dengan film komposit yang dibuat dengan pencampuran larutan alginat dan larutan kitosan.

TECHNO ECONOMY ANALYSIS A SMALL SCALE REVERSE OSMOSIS SYSTEM FOR BRACKISH WATER DESALINATION I Nyoman Widiasa; Linda Aliffia Yoshi
International Journal of Science and Engineering Vol 10, No 2 (2016)
Publisher : Chemical Engineering Diponegoro University

This study aims to get the design process and the economics of small-scale desalination of brackish water in Indonesia which has interest in the range of 12-14%, electricity cost of $0.09-0.13/kWh, and groundwater tax regulation. The use of BWRO desalination system in Indonesia has been generally done at small scale. This study based on Bali island with electricity cost at $0.1/kWh and water tax at $0.37/m3. Techo economy evaluation was analysed for plant capacity of 150-1,00 m3/day, recovery of 40% with brackish water water salinity of 5,000 ppm. Price of desalted water during first year a case study is $1.31/m3. It can be concluded that economic evaluation based on NPV and IRR shows that it is worthed.

Co-Authors A A Susanto A Ardiansyah A Arinaldi Adina, Alifia Rizki Adyaksa, M. Nur Ahmad Fauzi Ismail Ahmad Fauzi Ismail Ali Djunaedi Ario Budi Kusumo Asteria Apriliani Susanto Ayu Putri Lestari B Budiyono Bambang Pramudono Bayu Satria Utama Berkah Fajar Bernadeta Eka Naftalina Catur Pamularsih Dera Choanji F Ferdian Febrianto Adi Nugroho Gatra Buana Winiarti Ghina Shofi Pratiwi Hasristuti, Nani Hendrik Wijaya Heny Herawati Heny Herawati Heru Susanto I Gede Wenten Izza Rahmawati Jannah, Rizkiyah Fatikhatul Jayanti, Retno Dwi JS, Ikha Rasti Kendri yanto Kendriyanto Kendriyanto Khoiriyah, Lu'luatul Lestari, Amelia Eka Linda Aliffia Yoshi, Linda Aliffia Luqman Buchori Malida Fauzzia Maria E. Simorangkir Michael MGP Simatupang Miranti Budi Kusumawati Nafiunisa, Aininu Nita Aryanti Noer Abyor Handayani Nur Rokhati Priyo Sasmoko Putri, Tanti Nabella Putu Teta Prihartini Aryanti Rahmanisa, Riang Anggraini RATNAWATI Ratnawati Ratnawati Retno Dwi Jayanti Retno Dwi Jayanti Riang Anggraini Rahmanisa Savero Pakavi Zahrudin Seno Johari Seno Johari Seno Johari Seno Johari Seno Johari Siswo Sumardiono Sunarso . Sunaryo Sunaryo Sunaryo Sunaryo Titik Istirokhatun Tito, Adryan Tutuk Djoko Kusworo Wishnu Wijaya Yasmin Nabilah Zakki, Abdurrahman

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