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Simulasi pengolahan limbah cair berwarna dengan foto fenton pada sistem kontinyu Lie Hwa; Lieke Riadi
Jurnal Teknik Kimia Indonesia Vol 11, No 2 (2012)
Publisher : ASOSIASI PENDIDIKAN TINGGI TEKNIK KIMIA INDONESIA (APTEKIM)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/jtki.2012.11.2.4

Simulation of Colored Waste Water Treatment Using Photo Fenton in Continuous System Waste water from coffee processing was treated by the Photo Fenton method. Experiments were carried out in a 2 liter batch reactor equipped with ultraviolet lamp for 4 hours. The synthetic waste water was made by dissolving 300 mg instant coffee in 1 liter water. Reagents used are 700 ppm H2O2 prepared from 30 % H2O2, and 15 ppm FeSO4.7H2O. The experiment was carried out at pH= 3. Prior to treatment, the color of the waste water was brownish yellow. After adding the fenton reagent under UV light exposure, the color of waste water changed to pale yellow, and finally became colorless. Absorbance and Total Organic Carbon (TOC) of the sample were measured periodically. The kinetics of organic carbon degradation followed first order reaction towards the TOC concentration. Based batch experiment data, organic degradation was simulated for a single CSTR and four CSTRs in series. The single CSTR with a residence time of 1100 minutes can reduce the organic content from 108 ppm to 10.8 ppm, whereas for the serial CSTR reactors, the residence time was only 100 minutes in each reactor to get the same reduction percentage. Keywords: photo fenton, colored waste water, continuous, residence timeAbstrakPengolahan limbah cair industri pengolahan kopi dilakukan dengan metode Foto Fenton. Kajian menggunakan limbah sintetis berwarna coklat, mengandung kopi 300 ppm. Percobaan dilakukan dalam sebuah reaktor gelas dua liter yang dilengkapi dengan lampu ultra violet. Reagen yang digunakan adalah hidrogen peroksida dengan konsentrasi 700 ppm yang dibuat dari H2O2 30%, dan besi sulfat 15 ppm. Pengolahan limbah dilakukan pada pH=3. Dengan penambahan reagen fenton dan bantuan lampu ultra violet, warna limbah cair berubah secara perlahan dari coklat menjadi kuning dan akhirnya tidak berwarna. Perubahan absorbansi relatif zat warna, kandungan bahan organik total diukur terhadap waktu. Berdasarkan data percobaan secara batch, kinetika degradasi karbon mengikuti orde satu terhadap konsentrasi bahan organik total. Aplikasi untuk sistem kontinyu dibuat menggunakan model simulasi penurunan kandungan organik dalam sebuah reaktor berpengaduk dan 4 buah reaktor berpengaduk yang dihubungkan secara seri. Dengan laju alir umpan tetap, peningkatan volume reaktor akan memperbesar waktu tinggal reaktan dalam reaktor. Hasil simulasi reaktor tunggal menunjukkan bahwa semakin lama waktu tinggal maka semakin tinggi persentase penurunan bahan organik total. Untuk mendegradasi 90% kandungan organik dalam limbah, sebuah reaktor kontinyu seharusnya dirancang dengan waktu tinggal 1100 menit sedangkan empat buah reaktor dirancang dengan waktu tinggal 100 menit.Kata kunci: foto fenton, limbah cair berwarna, kontinyu, waktu tinggal

Characterization of Food Waste from a Campus Canteen as Potential Feedstock for Biogas Production Lieke Riadi; Yunus Fransiscus; Tuani L. Simangunsong; Farida Suhud
Journal of Engineering and Technological Sciences Vol. 52 No. 6 (2020)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2020.52.6.7

Food waste collected from the Ubaya canteen was characterized for its potential for use as anaerobic feedstock. It was collected for 3 weeks on a daily basis and treated with 2 different pretreatments, i.e. mechanic and mechanic-thermal. The result showed that the physical and chemical properties of the food waste in the 3-week time period of collecting were not significantly different for both pretreatments. The VS/TS ratio was around 96.4% to 97.076% and C/N was in the range of 17.295 to 17.813 for the mechanic and mechanic-thermal treatments. Four semi-batch mesophilic anaerobic digesters were used in this study, with 1.215 gVS/L fed once (R1) and twice daily (R3); 2.43 gVS/L fed once (R2) and twice daily (R4). The maximum methane yield was determined to be 64.61 mL/gVS in R1 after 5 days of incubation and 57.41 mL/gVS in R3 after 4 days of incubation. Systems R2 and R4 showed maximum methane yields of 43.15 mL/gVS and 19.1 mL/gVS respectively.

Pemanfaatan Abu Sekam Padi pada Ozonisasi Minyak Goreng Bekas untuk Menghasilkan Biodiesel Lieke Riadi; Lanny Sapei; Yosephine Kristiani; Octovania Sugianto
Jurnal Rekayasa Proses Vol 8, No 1 (2014)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Penggunaan abu sekam padi sebagai katalis pendukung pada ozonasi minyak goreng bekas untuk menghasilkan biodiesel dipelajari pada penelitian ini. Ozonasi minyak goreng bekas termasuk proses yang hemat energi dan ramah lingkungan karena menggunakan minyak goreng bekas sebagai bahan baku biodiesel serta suhu reaksi yang relatif rendah yaitu pada suhu kamar. Proses pembuatan biodiesel dilakukan dengan mereaksikan minyak goreng bekas dan metanol dengan bantuan katalis KOH pada sebuah reaktor. Gas ozon dialirkan secara kontinu dalam reaktor berpengaduk pada suhu 30oC dan tekanan atmosfer. Pengaruh penggunaan abu sekam padi sebagai supporting catalyst terhadap konsentrasi metil ester yang dihasilkan dikaji dalam percobaan ini. Abu yang digunakan adalah abu hitam (pemanasan pada 350oC) dan putih (pemanasan pada 750oC) dengan konsentrasi masing-masing sebesar 0,5 ; 1 ; 1,5% (b/b). Produk metil ester dikarakterisasi menggunakan Gas Chromatography untuk mengetahui jumlah metil ester rantai pendek (SCME) maupun metil ester rantai panjang (LCME). Di samping itu, dilakukan juga uji densitas dan viskositas, abu yang digunakan diuji dengan analisa XRD dan BET. Konsentrasi SCME paling tinggi dihasilkan pada variasi abu putih dengan konsentrasi 1,5%. Namun, penambahan abu tidak berpengaruh secara signifikan terhadap pembentukan LCME. Dengan demikian, abu putih lebih berperan sebagai supporting catalyst dibandingkan abu hitam. Kata kunci: biodiesel, minyak goreng bekas, abu sekam padi, proses ozonasi,metil ester rantai pendek,metil ester rantai panjang Biodiesel is one of the alternatives for the shortage of fossil fuel. In this experiment biodiesel from waste cooking oil which is made using an ozonation process was studied. The process is energy extensive and environmentally friendly because of the use waste cooking oil as a raw material and the experiment was carried out at low reaction temperature which is room temperature. Waste cooking oil was reacted with methanol, KOH as the base catalyst, and ozone that was continually flowed into a stirred reactor at 30oC and atmospheric pressure. The effect of rice hulk ash addition as the supporting catalyst on methyl esters concentrations was observed in this experiment. Two different types of ashes were used, namely black (heating at 350oC) and white (heating at 750oC) with the concentrations of 0.5; 1; 1.5% (w/w). Methyl esters products were characterized using GC apparatus for Short Chain Methyl Ester (SCME) and Long Chain Methyl Ester (LCME) concentrations. They were also analyzed in terms of density and viscosity. The ashes were characterized by XRD and BET. The highest amount of SCME was achieved at the white ash concentration of 1.5%. However, the ash additions seemed not significant on the LCME production. Thus, the white ash was more useful as a supporting catalyst than the black one. Keywords: biodiesel, used cooking oil, rice hulk ash, ozonation process, short chain methyl ester, long chain methyl ester

Response Surface Approach for Optimization of Protein Hydrolysis from Reutealis trisperma Cake as Potential Animal Feedstock Yuana Elly Agustin; Lieke - Riadi; Titie Prapti Utami
Reaktor Volume 20 No.1 March 2020
Publisher : Dept. of Chemical Engineering, Diponegoro University

The conditions for protein hydrolysis were optimized to prepare Reutealis trisperma cake for potential animal feedstock. The cake’s content was 34.03 % protein, 6.32 % moisture, 18.56 % total sugar, 15.58 % lipid and 25.51% others. Other components in cake could be fibre and lignin. The cake is a byproduct of mechanical pressing process of the seeds and contains high protein content (34.03%). It was ground prior the hydrolysis process. A central composite design including concentration of NaOH, ratio of cake to NaOH, time and temperature were used to develop second order model to predict protein content under various experimental conditions. Protein yield was primarily affected by ratio pressed cake to NaOH and concentration of NaOH. Based on the Response Surface Methodology (RSM) model, maximum yield of protein was 11.33% which was obtained at cake/solvent ratio 1: 50; 1.5 % w/v NaOH; 15 minutes of hydrolysis at 40oC. The actual maximum protein yield from the experiment was obtained at cake/solvent ratio 1: 40; 1.5 % w/v NaOH; 20 minutes of hydrolysis at 45oC which was 21.28 %.Keywords: animal feedstock; protein hydrolysis; response surface; Reutealis trisperma

A COMPARATIVE STUDY OF YARN DYED WASTEWATER USING FENTON’S REAGENT AND OZONATION : REMOVAL EFFICIENCY AND ECONOMIC ANALYSIS Lieke Riadi; Richard Wisanto; Arief Rachmat Herlambang; Sasmita Mirifica Vania; Andy Widyasayogo
Reaktor Volume 16 No.4 Desember 2016
Publisher : Dept. of Chemical Engineering, Diponegoro University

This study makes a comparison between Fenton and Ozonation processes treatment methods to examine the removal of COD in yarn dyed wastewater with initial concentration of 525 ppm. Results indicated that the COD degradation efficiency was in order of Fenton > Ozone. In Fenton method, the ratio of Fe2+/H2O2 used was 1 :10, the concentration of H2O2 was 10.2 gram/L. In ozonation, the ozone concentration used in the study was 5.8 % mol, and the agitation was 400 rpm. The effect of operational parameters including, initial pH and time were studied in both processes. The results indicated that it was 86.2 % COD were removed, when the pH was about 3 using Fenton’s reagent and 83.06 % COD removal in ozonation for one hour experiment. To achieve the standard requirement for allowable parameters in wastewater to be discharged, there is only 15 minutes needed for Fenton process to remove COD by 84.8 %, while the ozonation needs 30 minutes for 81 %removal. Fenton process is more economic feasible compare to ozonation which is almost one-tenth of the operation cost for 1 liter of wastewater being process. Though both processes can demonstrate the high removal efficiency to achieve the allowable COD concentration in the wastewater to be discharged, Fenton process is favor to ozonation.

PENGOLAHAN PRIMER LIMBAH TEKSTIL DENGAN ELEKTROKOAGULASI Lieke Riadi; Whenny Ferydhiwati; Liok Dimas Sanjaya Loeman
Reaktor Volume 15, No.2, OKTOBER 2014
Publisher : Dept. of Chemical Engineering, Diponegoro University

Limbah industri tekstil di area pinggir kota Surabaya mempunyai karakteristik perbandingan COD dan BOD = 5.57. Limbah jenis ini sulit untuk dibiodegradasi. Studi ini mempelajari tekonologi elektrokoagulasi untuk mengolah limbah tekstil dengan menurunkan intensitas warna, Total Suspended Solid (TSS) dan Chemical Oxygen Demand (COD). Percobaan batch pada suhu kamar dilakukan untuk mempelajari pengaruh pH, jarak elektroda terhadap penurunan warna,TSS dan COD dan membandingkan biaya operasinya jika menggunakan pengolahan kimia.Effisiensi penurunan tertinggi untuk warna (91.96%), TSS (49.17%), dan COD (29.67%) terjadi pada pH awal 4.0 dan jarak elektroda 2 cm dengan elektroda Al/Al. Waktu optimum penurunan intensitas warna dalah 10 menit. Laju penurunan COD adalah : -dC/dt = 0.0053 C +0.056 , dengan C adalah konsentrasi COD. Jumlah sludge yang dihasilkan daripengolahan elektrokoagulasi 3.4 % lebih kecil dibandingkan menggunakan bahan kimia. Biaya yang digunakan untuk pengolahan dengan elektrokoagulasi 52.35 % lebih murah dibandingkan jika menggunakan koagulasi dengan bahan kimia ( tawas). Kata kunci : elektrokoagulasi, penurunan warna, penurunan TSS, laju degradasi COD, imbah tekstil Abstract Waste water from textile industry which is located in one suburb of Surabaya city as characteristic which the ratio of COD to BOD was 5.57. This type of waste water is difficult to be biodegraded. This study investigated elektrokoagulasi technology to treat textile waste water by removing color, total suspended solid, and Chemical Oxygen Demand. Batch experiment at room temperature was carried out to study the effect of pH, electrode distance for color, TSS and COD removal. This study also tried to compare the operation cost between elektrokoagulasi and chemical processes. The best removal efficiencies by Al electrodes was 91.96 % for color, 49.17 % for TSS and 29.67 % for COD which were under initial pH 4.0 and electrodes distance 2 cm. The optimum operation time for color removal was found 10 minutes.The COD degradation rate was - dC/dt = 0.0053 C +0.056, with C= COD concentration. Sludge result from elektrokoagulasi was 3.4 % less than that by chemical treatment.The operation cost for elektrokoagulasi is 52.35 % less than that for chemical coagulation.

Pemanfaatan Abu Sekam Padi pada Ozonisasi Minyak Goreng Bekas untuk Menghasilkan Biodiesel Lieke Riadi; Lanny Sapei; Yosephine Kristiani; Octovania Sugianto
Jurnal Rekayasa Proses Vol 8, No 1 (2014)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.5020

Penggunaan abu sekam padi sebagai katalis pendukung pada ozonasi minyak goreng bekas untuk menghasilkan biodiesel dipelajari pada penelitian ini. Ozonasi minyak goreng bekas termasuk proses yang hemat energi dan ramah lingkungan karena menggunakan minyak goreng bekas sebagai bahan baku biodiesel serta suhu reaksi yang relatif rendah yaitu pada suhu kamar. Proses pembuatan biodiesel dilakukan dengan mereaksikan minyak goreng bekas dan metanol dengan bantuan katalis KOH pada sebuah reaktor. Gas ozon dialirkan secara kontinu dalam reaktor berpengaduk pada suhu 30oC dan tekanan atmosfer. Pengaruh penggunaan abu sekam padi sebagai supporting catalyst terhadap konsentrasi metil ester yang dihasilkan dikaji dalam percobaan ini. Abu yang digunakan adalah abu hitam (pemanasan pada 350oC) dan putih (pemanasan pada 750oC) dengan konsentrasi masing-masing sebesar 0,5 ; 1 ; 1,5% (b/b). Produk metil ester dikarakterisasi menggunakan Gas Chromatography untuk mengetahui jumlah metil ester rantai pendek (SCME) maupun metil ester rantai panjang (LCME). Di samping itu, dilakukan juga uji densitas dan viskositas, abu yang digunakan diuji dengan analisa XRD dan BET. Konsentrasi SCME paling tinggi dihasilkan pada variasi abu putih dengan konsentrasi 1,5%. Namun, penambahan abu tidak berpengaruh secara signifikan terhadap pembentukan LCME. Dengan demikian, abu putih lebih berperan sebagai supporting catalyst dibandingkan abu hitam. Kata kunci: biodiesel, minyak goreng bekas, abu sekam padi, proses ozonasi,metil ester rantai pendek,metil ester rantai panjang Biodiesel is one of the alternatives for the shortage of fossil fuel. In this experiment biodiesel from waste cooking oil which is made using an ozonation process was studied. The process is energy extensive and environmentally friendly because of the use waste cooking oil as a raw material and the experiment was carried out at low reaction temperature which is room temperature. Waste cooking oil was reacted with methanol, KOH as the base catalyst, and ozone that was continually flowed into a stirred reactor at 30oC and atmospheric pressure. The effect of rice hulk ash addition as the supporting catalyst on methyl esters concentrations was observed in this experiment. Two different types of ashes were used, namely black (heating at 350oC) and white (heating at 750oC) with the concentrations of 0.5; 1; 1.5% (w/w). Methyl esters products were characterized using GC apparatus for Short Chain Methyl Ester (SCME) and Long Chain Methyl Ester (LCME) concentrations. They were also analyzed in terms of density and viscosity. The ashes were characterized by XRD and BET. The highest amount of SCME was achieved at the white ash concentration of 1.5%. However, the ash additions seemed not significant on the LCME production. Thus, the white ash was more useful as a supporting catalyst than the black one. Keywords: biodiesel, used cooking oil, rice hulk ash, ozonation process, short chain methyl ester, long chain methyl ester

Soluble phosphorus rich compost by aerobic solid-state fermentation of chicken bone-containing food waste with Aspergillus niger Ong, Lu Ki; Angelio, Ricardo; Indrayani, Clarissa; Riadi, Lieke
Jurnal Rekayasa Proses Vol 19 No 1 (2025): Volume 19, Number 1, 2025
Publisher : Jurnal Rekayasa Proses

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.16629

Food waste has become a concern in solid waste management due to its high bulk volume and production rate. Without good management, food waste piling may result in foul odor, global warming by methane emission and even an epidemic. Composting is a method usually employed to process food waste. However, this method often took a long period and selective to organic waste such as leafy materials or fruit waste. Bone is a food waste that is rich in phosphorus, a chemical substance that is required to make various useful products such as fertilizer, battery, detergent, etc. This study investigates the characteristics of food waste compost containing chicken bone and various domestic organic food waste that was processed through aerobic solid-state fermentation using Aspergillus niger. The composting process was monitored over a 28-day period at 28°C. The resulting compost was characterized under various physicochemical parameters, including pH and nutrient composition. The findings demonstrated that Aspergillus niger effectively released phosphorus from bone while degraded organic matter in just a week, resulting in significant reductions in unprocessed waste volume and the production of a stable, nutrient-rich compost in a short time. Additionally, the compost was successfully induced better growth on corn seed compared to the food waste pile and naturally composted food waste. These results suggest that Aspergillus niger-mediated aerobic solid-state fermentation is a viable and efficient method for converting food waste into high-quality compost, promoting sustainable waste management and agricultural practices.

Skim coconut milk processing by thermal- and ultrasonic-thermal pasteurization Ong, Lu Ki; Sutikno, Kevin Hosea; Jodie, Kennita Alvina; Riadi, Lieke
Jurnal Rekayasa Proses Vol 17 No 1 (2023): Volume 17, Number 1, 2023
Publisher : Jurnal Rekayasa Proses

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.82928

The coconut industry in Indonesia is significant for national income, with the potential for value-added products that could enhance the industry’s expansion. Skim coconut milk, a by-product of virgin coconut oil production, is a healthy substitute for dairy milk that can be consumed by people with lactose intolerance. The low-fat and high-protein content of skim coconut milk makes it a healthier alternative to regular coconut milk and cow milk. This study compares ultrasonic-assisted pasteurization of skim coconut milk to conventional pasteurization technique in terms of contamination reduction efficacy and energy efficiency with minimum product characteristic change. The process consisted of thawing frozen skim coconut milk, homogenization of liquid skim coconut milk and pasteurization in a shaking water bath or ultrasonic bath. Total cell counting was conducted, D-value and z-value were estimated to measure the effectiveness of pasteurization in reducing the number of harmful microorganisms in skim coconut milk. The study found that ultrasonic-assisted pasteurization reduced the number of microorganisms more effectively than conventional pasteurization with a lower energy consumption. The study showed the removal efficiency of ultrasonic-assisted pasteurization and conventional pasteurization at 70°C and 15 minutes were 28.74% and 12.33%, respectively. At that condition, energy consumption for every microbial cell being removed was approximately 3 times lower in ultrasonic-assisted pasteurization than the conventional one (0.13 kWh vs. 0.36 kWh). Skim coconut milk processed by ultrasonic-assisted pasteurization at 75°C for 15 minutes featured homogeneous white liquid with shelf time of 11.2 h, which was 2.65 times longer than the unprocessed coconut skim milk. The research suggests that ultrasonic-assisted pasteurization can be a feasible and sustainable processing technology for skim coconut milk, with potential commercial value for small companies and farmers in Indonesia.

Enhancing Monomeric Sugar Production from Coconut Husk by FeCl3-assisted Hydrothermal Pretreatment and Enzymatic Hydrolysis Wijaya, Candra; Sangadji, Ningsi Lick; Muharja, Maktum; Widjaja, Tri; Riadi, Lieke; Widjaja, Arief
Bulletin of Chemical Reaction Engineering & Catalysis 2025: BCREC Volume 20 Issue 3 Year 2025 (October 2025)
Publisher : Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.20444

Coconut husk (CCH), an abundant agricultural byproduct of the coconut processing industry, holds significant potential as a renewable feedstock for monomeric sugar production. However, efficient fractionation remains a challenge due to its recalcitrant lignocellulosic structure. This study investigates FeCl₃-assisted hydrothermal pretreatment (HTP) as a selective and scalable approach to enhance enzymatic hydrolysis efficiency and sugar recovery. The effects of FeCl₃ concentrations, temperatures, and unified of pretreatment conditions as combined hydrolysis factor (CHF) on biomass fractionation, modeling xylan dissolution, and monomeric sugar production were evaluated. Results indicate that 0.06 M FeCl₃ at 150 °C achieved the highest total monomeric sugar concentration of 7.364 g/L, an 11-fold increase compared to the non-catalyzed control (0.667 g/L) during HTP. This condition also facilitated 81.2% hemicellulose removal while minimizing cellulose and lignin degradation, thereby improving enzymatic digestibility. Furthermore, xylan hydrolysis also successfully developed with high correlation with unified CHF parameter. FeCl₃-assisted HTP CCH coupled with enzymatic hydrolysis further enhanced overall sugar recovery, with a total monomeric sugar yield of 18.4 g per 100 g raw CCH, representing a 4.4-fold increase compared to hydrothermally pretreated CCH without FeCl₃. These findings highlight FeCl₃-assisted HTP as a promising, cost-effective strategy for biomass fractionation, supporting its integration into lignocellulosic biorefineries for bio-based product development. Copyright © 2025 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

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