I Nyoman Widiasa
Program Studi Teknik Kimia, Fakultas Teknik, Universitas Diponegoro Jl. Prof H Soedarto Kampus UNDIP Tembalang 50275.Telepon/Fax (024)7460058/(024)76480675

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PEMISAHAN FAT, OIL, AND GREASE (FOG) DARI LIMBAH FOODCOURT DENGAN DISSOLVED AIR FLOTATION Utama, Bayu Satria; E. Simorangkir, Maria; Widiasa, I Nyoman
JURNAL TEKNOLOGI KIMIA DAN INDUSTRI Volume 1, Nomor 1, Tahun 2012
Publisher : Jurusan Teknik Kimia, Fakultas Teknik, Universitas Diponegoro,

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Abstract

Oil waste water is the source of pollution that is often found in everyday life. Oil as a pollutant that is contained in the water must be separated so that oil can be utilized, and its existence as a pollutant can be removed. In this research study will be conducted to find the most suitable parameters of the pressure to separate the fat, oil, and grease from waste water foodcourt with Dissolved flotation. The variables used in the separation pressure is 4.5; 5; 5.5; and 6 bar. Separation results obtained will be analyzed by using analysis of total suspended solids. Data analysis results obtained are total suspended solids in the feed of 40,000 mg / L, after the water is separated using flotation Dissolved respectively obtained at a pressure of 4.5 bar total suspended solids of 3000 mg / L, at a pressure of 5 bar can get the total solids suspension of 2500 mg / L, at a pressure of 5.5 bar total suspended solids obtained at 1500 mg / L, and at a pressure of 6 bar obtained total suspended solids of 500 mg / L.
PENGOLAHAN AIR LUMUT DENGAN KOMBINASI PROSES KOAGULASI DAN ULTRAFILTRASI Arinaldi, A; Ferdian, F; Widiasa, I Nyoman
JURNAL TEKNOLOGI KIMIA DAN INDUSTRI Volume 2, Nomor 2, Tahun 2013
Publisher : Jurusan Teknik Kimia, Fakultas Teknik, Universitas Diponegoro,

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Air berlumut adalah air yang mengandung lumut yang terlarut di dalamnya. Lumut yang terlarut dalam air dapat menyebabkan gangguan. Pada penelitian ini, digunakan proses koagulasi dan flokulasi, yang kemudian dilanjutkan dengan proses ultrafiltrasi untuk memisahkan lumut dari air berlumut. Pralakuan koagulasi-flokulasi pada umpan membran dilakukan untuk memperpanjang umur membran dan meningkatkan kinerja pemisahan membran ultrafiltrasi dalam pengolahan air berlumut ini. Koagulan yang digunakan adalah tawas dan PAC, variabel pH antara 5 ? 8, dan konsentrasi koagulan antara 50 ? 250 ppm. Umpan berupa air berlumut memiliki kekeruhan 75 ? 100 NTU. Didapatkan hasil bahwa pH optimum untuk proses koagulasi dengan kedua jenis koagulan adalah pada pH netral (6,5 ? 7,5). Konsentrasi koagulan tawas optimum adalah 100 ? 200 ppm, sedangkan konsentrasi PAC optimum adalan 50 ? 100 ppm. Dari penelitian ini juga dapat disimpulkan bahwa pralakuan koagulasi sebelum proses ultrafiltrasi pada pengolahan air berlumut akan mengurangi beban kerja membran ultrafiltrasi.
PENYISIHAN KEKERUHAN PADA SISTEM PENGOLAHAN AIR SUNGAI TEMBALANG DENGAN TEKNOLOGI RAPID SAND FILTER Pamularsih, Catur; Choanji, Dera; Widiasa, I Nyoman
JURNAL TEKNOLOGI KIMIA DAN INDUSTRI Volume 2, Nomor 4, Tahun 2013
Publisher : Jurusan Teknik Kimia, Fakultas Teknik, Universitas Diponegoro,

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Design of rapid sand filters differ from one place to another because it has the distinction of influent. Therefore in order to obtain the optimal, effective and efficient design for water treatment tembalang river so that the effluent can be used around the community. The purpose of this study is to get a pattern of rapid sand filter operation with water from  Tembalang river. Variables used in this study is the loading rate (10, 11, 12 gpm/ft2), high media filter (60 and 100 cm), and the addition of coagulant. The result of study showed 85% reduction of turbidity by using a loading rate of 10.2 gpm/ft2 at height of 100 cm filter media. At loading rate 11.75 gpm/ft2 removal turbidity by using a coagulant will be more effective when compared to not using coagulants.
MODIFIKASI KARBON AKTIF SEBAGAI ADSORBEN UNTUK PEMURNIAN BIOGAS Susanto, Heru; Wijaya, Wishnu; Widiasa, I Nyoman
TEKNIK Volume 34, Nomor 1, Tahun 2013
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1130.21 KB) | DOI: 10.14710/teknik.v34i1.4811

Abstract

The use of biogas as an environmentally friendly fuel is limited by the presence of CO2 and water vapor asimpurities. Therefore, biogas purification for CO2 and water vapor removal is very important step during biogasapplication. This paper presents a process for biogas purification by means of adsorption using either modifiedor unmodified activated carbon as an adsorbent. The modification was performed by passing a pure ammoniagas into activated carbon in a quartz reactor. The results showed that the adsorption process using modifiedactivated carbon decreases CO2 content in biogas up to 67.5% whereas for unmodified activated carbon was of43%. Further, the modification increased CO2 adsorption capacity from ~28 to ~38 mg CO2/g adsorbent. Theincrease in feed temperature decreases CO2 adsorption capacity.
STUDY ON TREATMENT OF SLAUGHTERHOUSE WASTEWATER BY ELECTRO-COAGULATION TECHNIQUE Budiyono, B.; Widiasa, I Nyoman; Johari, Seno
International Journal of Science and Engineering Vol 1, No 1 (2010)
Publisher : Chemical Engineering Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (227.985 KB) | DOI: 10.12777/ijse.1.1.25-28

Abstract

Electro-coagulation (EC) is well known as a technique for removing suspended solids as well as oils and greases from wastewater. The aims of this research are to study the performance of the EC technique to treat a high strength wastewater from slaughterhouse in batchwise mode. The effect of various process variables such as number and electrode material, initial pH, suspended solid (SS) content, and operating time was investigated The electrolytic cell (electro-coagulator) used was a 600 ml cylinder glass reactor with working volume 400 ml and equipped by magnetic stirrer without temperature control. Cast iron (Fe) and aluminum (Al) cylinder were used as anode/cathode pair. The number of electrode was varied 1 and 2 pairs. The effective area of the electrode pair was 6.28 cm2. The DC power supply was controlled by a voltmeter and be adjusted constant at 125 A/m2 for each test runs. The initial SS concentration were varied from 1250, 2100, 3000, and 4000 mg/L by diluting wastewater. It is found that effluent temperature depends on SS and increases up to 98 °C when SS content was 4000 mg/L. One and two pairs of Fe-Al electrode will give SS removal efficiency are 97.2 and 99.6 %, respectively. However, the higher electrode number will need the shorter time to get certain removal efficiency of SS.  Number of electrodes didn?t give the significant impact to the final pHs. With initial pH 7.05 both two pair of electrode will give the final pH relatively constant to 7.80. Further work will be conducted to optimize the CD and charge loading to avoid the excessive temperature increase
TECHNO ECONOMY ANALYSIS A SMALL SCALE REVERSE OSMOSIS SYSTEM FOR BRACKISH WATER DESALINATION Widiasa, I Nyoman; Yoshi, Linda Aliffia
International Journal of Science and Engineering Vol 10, No 2 (2016)
Publisher : Chemical Engineering Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (960.918 KB) | DOI: 10.12777/ijse.10.2.51-59

Abstract

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

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (336.104 KB) | DOI: 10.14710/reaktor.12.4.203 – 210

Abstract

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.   
BWRO DESALINATION FOR POTABLE WATER SUPPLY ENHANCEMENT IN COASTAL REGIONS Widiasa, I Nyoman; Paramita, Vita; Kusumayanti, Heny
JOURNAL OF COASTAL DEVELOPMENT Vol 12, No 2 (2009): Volume 12, Number 2, Year 2009
Publisher : JOURNAL OF COASTAL DEVELOPMENT

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Abstract

Most of coastal regions in Indonesia have experienced water scarcity where water resources are becoming more and more threatened due to the rapid growth of population, aquaculture industries and agricultures. Brackish water reverse osmosis (BWRO) desalination may be used to overcome the supply potable water problem in the coastal regions. Brackish water having total dissolved solids (TDS) content in the range of 1,000?10,000 ppm can be desalinated at a reasonable cost. This work was aimed to find valuable technical data for plant design and operation. Cost analysis also was conducted to obtain specific water cost. The results show that stable system performance was achieved. Based on a case study of small scale BWRO with capacity of 50 m3/day, specific water cost was around of IDR 6,100/ m3.
PENYISIHAN AMONIAK DAN KEKERUHAN PADA SISTEM RESIRKULASI BUDIDAYA KEPITING DENGAN TEKNOLOGI MEMBRAN BIOFILTER Fauzzia, Malida; Rahmawati, Izza; Widiasa, I Nyoman
JURNAL TEKNOLOGI KIMIA DAN INDUSTRI Volume 2, Nomor 2, Tahun 2013
Publisher : Jurusan Teknik Kimia, Fakultas Teknik, Universitas Diponegoro,

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Crabs are one of the economically valuable commodities. Barriers that often occur in crab farming in ponds is limited land and water. Crab aquaculture activities can not be apart from the waste generated, which can cause water quality degradation, especially of food remains, feases and the metabolism of the crabs. Waste produced as ammonia is toxic at high concentrations and high turbidity can cause death in the crabs. Alternative technologies are used to decrease the production of crabs due to lack of availability of  land and water degradation are water recirculation system using a membrane biofilter. Membrane biofilter is used to maintain the water quality is to eliminate ammonia to levels not exceeding 0.1 ppm, and removing turbidity to <30 NTU.  Biofilter  is used to eliminate ammonia by nitrification and denitrification process using aerobic and anaerobic mikrroorganisme. Membranes which is used to reduce turbidity is ultrafiltration membranes. Flux on the membrane will determine the performance of the membrane. If  the flux decreased 85% from the initial flux, indicating the occurrence of fouling on membrane. This fouling can be overcome by washing. One of  it is the backwash. Using biofilter can reduce of ammonia from 4,41 mg/L up to 1,48 mg/L during 7 days. Turbidity can be reduced by using ultrafiltration membrane. In the Ultrafiltration membrane fouling control can be done by backwash 30 minutes 15 seconds. This is indicated by the high flux of the membrane.
Tekno-Ekonomi Sistem Membran Terintegrasi untuk Pengolahan Air Baku Campuran Air Payau dan Efluen STP Widiasa, I Nyoman; Susanto, Asteria A.
Prosiding Seminar Nasional Teknik Kimia "Kejuangan" 2016: Prosiding SNTKK 2016
Publisher : Prosiding Seminar Nasional Teknik Kimia "Kejuangan"

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Recently, portable water supply is one of crucial problems in the world, including Indonesia because water is not a cheap natural resource. Saline waters such as brackish water, seawater, and wastewater have been used as alternative raw water sources to fulfil domestic and idustrial water demands. Water price higher than IDR 15,000 clearly indicate that treatment of brackish water and/or wastewater reuse is effective from cost point of view. This work is aimed to perform in-situ pilot test by involving user and investor directly. Moreover, technical and cost are analysed based on a case study, i.e. average production of 220,000 m3/year; water price of IDR 14,500/m3 that increase IDR 2,000 every two years. This water treatment plant requires capital cost of 3.5 billions rupiahs. The capital comes from bank loan with interest of 13% per annual. It is found that with contract duration of 10 years, net present value (NPV) is positive so that this investment is feasible.