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All Journal Journal of Engineering and Technological Sciences KOVALEN: Jurnal Riset Kimia MODUS-Jurnal Ekonomi dan Bisnis Hearty : Jurnal Kesehatan Masyarakat FLUIDA Fullerene Journal of Chemistry Jurnal Onoma: Pendidikan, Bahasa, dan Sastra Kumawula: Jurnal Pengabdian Kepada Masyarakat Jurnal Pengabdian Masyarakat Bumi Raflesia Curve Elasticity: Jurnal Pendidikan Ekonomi Journal Serambi Engineering (JSE) Journal of Green Science and Technology
Jayanti, Retno Dwi
Politeknik Negeri Bandung
Humanities Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Decision Sciences, Operations Research & Management Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Environmental Science Industrial & Manufacturing Engineering Languange, Linguistic, Communication & Media Materials Science & Nanotechnology Social Sciences Transportation Other

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Case Study of a Small Scale Reverse Osmosis System for Treatment of Mixed Brackish Water and STP Effluent Widiasa, I Nyoman; Jayanti, Retno Dwi
Journal of Engineering and Technological Sciences Vol 49, No 2 (2017)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (4093.066 KB) | DOI: 10.5614/j.eng.technol.sci.2017.49.2.3

Abstract

A case study on utilizing reverse osmosis (RO) technology to fulfill fresh water needs at a mall and a hotel has been done on Bali Island, Indonesia. A mix of brackish water and sewage treatment plant (STP) effluent was used as feed water in the RO system. The system used 36 membrane elements (CSM RE 8040 BLN) arranged into two stages: 8 pressure vessels (PVs) in the first stage and 4 PVs in the second stage, each loaded with 3 membranes. The objectives of this research were to assess the cleaning effectivity in the plant, to evaluate the cleaning of 1 membrane element using a CIP system, and to assess the use of the membrane for filtration in the pre-treatment system. SEM and FTIR analysis indicated that the foulants on the membrane surface were dominated by organic foulants and inorganic deposits. To clean the discarded membrane the proposed method used NaOH solution (pH 12 and pH 13) and citric acid (pH 2 and pH 3). All membranes displayed a dramatic decline in rejection of about 80%. Based on the rejection tests of SO42-, Cl-, turbidity reduction approached 100%. It can be concluded that an RO membrane that has undergone selectivity decline can be re-used as a filtration membrane in the pre-treatment system.
RANCANG BANGUN SISTEM PENGOLAHAN AIR JERNIH DI KAMPUNG WISATA SABLON Rony Pasonang Sihombing; Agustinus Ngatin; Joko Suryadi; Retno Dwi Jayanti; Yunus Tonapa Sarungu; Robby Sudarman
Kumawula: Jurnal Pengabdian Kepada Masyarakat Vol 5, No 1 (2022): Kumawula: Jurnal Pengabdian Kepada Masyarakat
Publisher : Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/kumawula.v5i1.35907

Abstract

Air bersih yang memadai secara kuantitas, kualitas dan kontinuitas merupakan kebutuhan penting untuk kelangsungan hidup manusia. Oleh karenanya diperlukan suatu instalasi pengolahan air untuk menunjang kebutuhan ini. Air tanah merupakan air yang belum mengalami proses pengolahan dengan kriteria kualitas air yang sudah mendekati air bersih. Metode pengolahan air yang dilakukan menggunakan metode filtrasi fisik dan kimia sebelum digunakan untuk kebutuhan sehari-hari. Jenis filter yang digunakan adalah filter benang ukuran 10 µm, filter polipropilen (PP) 10 µm  dan filter karbon aktif. Berdasarkan hasil rancangan, air yang dihasilkan pada sistem rancang bangun diantaranya adalah air dengan kualitas kesadahan 2.3 NTU, masa pakai filter benang 14 hari/bulan, filter PP 2.4 hari/bulan, dan filter karbon aktif 30 hari/bulan. Untuk kemudahan operasional, sistem rancang bangun untuk filter PP dibuat paralel 3 agar perawatan dapat dilakukan setiap minggu.
Fermentasi Kitin dari Limbah Cangkang Kepiting Menggunakan Jamur Rhizopus Oryzae pada Berbagai Kadar Air Retno Dwi Jayanti; Unung Leoanggraini
Jurnal Kimia Fullerene Vol 5 No 1 (2020): Fullerene Journal of Chemistry
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (458.395 KB) | DOI: 10.37033/fjc.v5i1.144

Abstract

Chitin on crab shell waste can be obtained by fermentation process use Rhizopus oryzae. The objective of this research are to determine the optimum of water content on crab shell waste fermentation by Rhizopus oryzae for chitin production. Fermentation process is carried out for 72 hours, 5 of pH, 37oC, and 10% (v/w) of inoculum addition. Water content on fermentation process were varried whithin 40%, 50%, and 60% respectively. Fermentation process were carried out by 40% of water content reported as the optimum based on the deproteinization degree and the solubility in acidic solution.
Pembuatan dan Pengujian Pupuk Organik Cair (POC) dari Limbah Pasar dengan Menggunakan Bioaktivator EM4 Delinda Nirmala Afiyah; Emelia Uthari; Dewi Widyabudiningsih; Retno Dwi Jayanti
Jurnal Kimia Fullerene Vol 6 No 2 (2021): Fullerene Journal of Chemistry
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.37033/fjc.v6i2.325

Abstract

Organic waste from market rubbish can be utilized as liquid organic fertilizer. In general, liquid organic fertilizers contain nutrients such as Nitrogen, Phosphorus, Potassium, and C-Organic that are needed by plants. The objective of this research are to manufacture liquid organic fertilizer through anaerobic fermentation from market rubbish with the addition of an EM4 bio activator and to determine the optimum time. The nutrients content were determined using the Kjeldahl method, UV-VIS Spectrophotometry, and Atomic Adsorption Spectroscopy. Liquid Organic Fertilizer that had the best quality among all types is from non-green vegetable. It has 0,45% of nitrogen, 0,08% of phosphorus, 0,34% of potassium, and 2,8% of C-organic respectively. The optimum time for POC fermentation occurred on the 14th day. The nutrient levels of all types of liquid organic ferilizer produced have not meet the minimum technical requirements of the quality of liquid organic fertilizers based on the Decree of the Minister of Agriculture of the Republic of Indonesia Number 261/Kpts/Sr.310/M/4/2019
Pengaruh Laju Alir Terhadap Penurunan Pengotor Limbah Laundry Metode Elektrokoagulasi Kontinyu Berpengaduk Agustinus Ngatin; Adi Rizki Nugraha; Mukhtar Gozali; Ageng Priyambudi; Tri Hariyadi; Rony Pasonang Sihombing; Yusmardhany Yusuf; Retno Dwi Jayanti; Retno Indarti
Fluida Vol 15 No 2 (2022): FLUIDA
Publisher : Department of Chemical Engineering, Politeknik Negeri Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35313/fluida.v15i2.4040

Abstract

Limbah laundry dapat menjadi masalah serius bagi lingkungan jika dibuang tanpa pengolahan. Masalah yang timbul diantaranya nilai Chemical Oxygen Demand (COD), fosfat, dan kekeruhan yang tinggi. Tujuan penelitian yaitu mempelajari pengaruh laju alir terhadap efisiensi penurunan kadar kekeruhan, COD, dan TSS, serta menentukan kondisi optimalnya dengan alat elektrokoagulasi kontinyu berpengaduk. Reaktornya adalah reaktor berkapasitas 10 L dilengkapi pengaduk 180 rpm, pompa peristaltik, rectifier dan 3 pasang elektroda Alumunium dengan ketebalan 0,3x15x15cm yang disusun secara monopolar. Percobaan variasi laju alir (115mL/menit, 170 mL/menit, 340mL/menit) dilakukan dengan rapat arus tetap (70 A/m2), dengan waktu operasi 60 menit untuk setiap variasi. Hasilnya menunjukkan bahwa pada laju tinggi (340 mL/menit) dan laju rendah (115 mL/menit) menghasilkan efisiensi penurunan pengotor yang rendah dan laju alir terbaik ditunjukkan pada 170 mL/menit. Kondisi optimal terjadi pada laju alir 170 mL/menit pada rapat 70 A/m2 menghasilkan efisiensi penurunan kekeruhan, COD, dan TSS berturut-turut 89,35%, 73,33%, dan 99,26%. Laundry waste can be a serious problem for the environment if it is disposed of without treatment. Problems that arise include the value of Chemical Oxygen Demand (COD), phosphate, and high turbidity. The aims of the research were to study the effect of flow rate and current density on the efficiency of reducing turbidity, COD, and TSS levels, and to determine the optimal conditions using a continuous stirred electrocoagulation device. The reaktor used is a reaktor with a capacity of 10 L equipped with a 180 rpm stirrer, a peristaltic pump, a rectifier and 3 pairs of aluminum electrodes with a thickness of 0.3x15x15cm arranged in a monopolar manner. The flow rate variation experiment was carried out with a constant current density (70 A/m2), and the current density variation experiment was carried out with a fixed flow rate (170 ml/minute) with an operating time of 60 minutes for each variation. The results of the flow rate variation showed that at a high rate (340 ml/min) and a low rate (115 ml/min) resulted in a low impurity reduction efficiency, the best flow rate was shown at 170 ml/min. The results of the current density variation show that the increase in impurity reduction efficiency occurs as the current density increases, the best results occur at a current density of 70 A/m2. Optimal conditions occurred at a flow rate of 170 ml/min at a rate of 70 A/m2 resulting in the efficiency of reducing turbidity, COD, and TSS respectively 89.35%, 73.33%, and 99.26%.
Evaluasi Kinerja Operasi Unit Koagulasi Flokulasi Dalam Sistem Instalasi Pengolahan Air Limbah Endang Kusumawati; Rivaldo Rofie Fauzi Budiman; Rizky Setianto; Tifa Paramitha; Retno Dwi Jayanti
Jurnal Serambi Engineering Vol. 9 No. 4 (2024): Oktober 2024
Publisher : Faculty of Engineering, Universitas Serambi Mekkah

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

The coagulation and flocculation processing units represent a series of processing units that employ physical and chemical methods. The objective of this research is to ascertain the impact of coagulant type on process parameters, including turbidity, TSS, and pH, within the coagulation-flocculation processing unit integrated within the WWTP system. This research employs the use of raw water in the form of an artificial wastewater with characteristics closely resembling those of domestic wastewater, with a particular focus on process parameters such as turbidity, total suspended solids (TSS), and pH. The coagulants employed in the coagulation process are polyaluminum chloride (PAC) and aluminum sulfate/alum (Al₂(SO₄)₃.18H₂O). The operation of the wastewater treatment plant (WWTP) is conducted with a coagulation stirring speed of 150 rpm, while flocculation is performed at 60 rpm. A jar test was conducted to ascertain the optimal dose and pH of the coagulant. The results demonstrated that the optimal dose of PAC was 50 ppm, with an optimal pH of 7. In contrast, the optimal dose of alum was 60 ppm, with an optimal pH of 8. The findings revealed that the dose obtained through the implementation of the jar test in the WWTP unit with a stirring speed of 150 rpm yielded the most effective PAC coagulant results, with a TSS value of 10.53 mg/L, turbidity of 4.01 NTU, and pH of 6.74, accompanied by a TSS efficiency value of 94.86%. The velocity gradient and residence time in the coagulation and flocculation units do not align with the specified design criteria. However, both the residence time and overflow rate in the sedimentation unit meet the prescribed design criteria.
Evaluasi dan Modifikasi Alat Penukar Ion dengan Penambahan Kolom Adsorpsi Karbon Aktif untuk Menurunkan Kesadahan : Evaluation dan Modification of Ion Exchange Equipment with the Addition of Activated Carbon Adsorption Column to Reduce Hardness Endang Kusumawati; Retno Dwi Jayanti; Lestari Herlianti Putri; Nurul Annisa; Paramitha, Tifa
KOVALEN: Jurnal Riset Kimia Vol. 10 No. 1 (2024): April Edition
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2024.v10.i1.16556

Abstract

Ion exchange is one of the water treatment methods used to reduce hardness. To improve the performance of the ion exchange columns, modification can be done by adding an activated carbon column placed after the ion exchange column to adsorb ions that were not exchanged by the resin so that the treated water met boiler feed water quality standards. The purposes of this study were to determine the best flow rate to reduce hardness in the configuration of the ion exchange and activated carbon columns, determine the saturation time of each column, and determine their exchange/adsorption capacities. The steps of this study included modifications and repair of equipment, leak tests, and configuration system performance tests. Performance tests were conducted by varying the feed flow rates by 0.2; 0.4; 0.6; 0.8; 1 GPM and analyzed the efficiency of hardness reduction. The results of this study showed that the best flow rate to reduce the initial hardness of 499 mg/ L CaCO3 was a flow rate of 0.6 GPM or 2.2 LPM. The efficiency of hardness reduction in the configuration system was 100%. The conductivity of the effluent of anion column and activated carbon column decreased compared to the conductivity of the effluent of cation column with an average decrease of 33.17% in the anion column and 18.35% in the activated carbon column. The saturation time of the configuration system was 168 minutes in cation resin, 46.4 minutes in anion resin, and 159 minutes in activated carbon. Furthermore, the adsorption capacity of cation resin, anion resin, and activated carbon were 35.28 mg/g, 43.98 mg/g, and 9.61 mg/g, respectively. The addition of activated carbon in the configuration system lowers the conductivity of the effluent and decreases hardness.
PENGARUH ANALISIS INTERNAL DAN EKSTERNAL TERHADAP KINERJA USAHA KECIL MENENGAH Novie Wijaya; Rafi Ohorella; Meilya Suzan Triyastuti; Retno Dwi Jayanti
Curve Elasticity: Jurnal Pendidikan Ekonomi Vol 6 No 2 (2025): Curve Elasticity: Jurnal Pendidikan Ekonomi
Publisher : Universitas Nias Raya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.57094/jpe.v6i2.2657

Abstract

Budo Village, as one of the coastal areas, possesses considerable economic potential, particularly through the activities of Small and Medium Enterprises (SMEs) managed by the local community. Various types of businesses have developed in this village, ranging from fisheries and marine product processing to service and trade sectors. The growth of SMEs in Budo Village is influenced by both internal and external environmental factors, which help shape the direction and quality of local economic development. This study aims to analyze the influence of internal and external environmental factors on competitive advantage and business performance within the community. The research employs a quantitative approach with data collection techniques using questionnaires distributed to 100 respondents who are SME actors. Data analysis was conducted using validity tests, reliability tests, t-tests, and F-tests. The results show that all variables studied internal environmental factors, external environmental factors, and competitive advantage are proven to be both valid and reliable. Furthermore, these three variables have a positive and significant influence on improving business performance. These findings indicate that strengthening both internal and external supporting factors is crucial to enhancing competitiveness and fostering the growth of SMEs in coastal regions such as Budo Village.
Cross-Cultural Pragmatics: An Investigation into Speech Act Realization on The Ship Limbong, Sunarlia; Palayukan, Novianty; Chandra, Ade; Jayanti, Retno Dwi; Riwu, Willyam Raimond
Jurnal Onoma: Pendidikan, Bahasa, dan Sastra Vol. 11 No. 1 (2025)
Publisher : Universitas Cokroaminoto Palopo

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30605/onoma.v11i1.4492

Abstract

This study, titled "Cross-Cultural Pragmatics: An Investigation into Speech Act Realization on the Ship," aims to explore the influence of cultural backgrounds on the realization of speech acts among crew members in the Indonesian maritime industry. Specifically, it identifies the patterns and challenges associated with cross-cultural pragmatics on ships. Utilizing a descriptive qualitative design, the research was conducted on KM Lambelu, employing field notes, interviews, and observations as data collection instruments. The findings reveal that cultural backgrounds significantly influence how speech acts are realized by crew members, particularly regarding politeness, directness, and respect for hierarchy. The study highlights that while cultural diversity enriches interactions among crew members, it can also create communication barriers if not properly managed. The research further emphasizes that politeness strategies are deeply rooted in cultural norms, with a strong emphasis on seniority in hierarchical maritime settings.
PERBEDAAN PENGARUH WORKLOAD DAN WORK ENVIRONMENT TERHADAP JOB SATISFACTION YANG DIMEDIASI OLEH WORK STRESS PADA KARYAWAN INDUSTRI SEPEDA MOTOR DI JAKARTA UTARA Retno Dwi Jayanti; Wiwik Robiatul Adawiyah
Modus Vol. 35 No. 2 (2023): Vol. 35 No. 2 (2023): MODUS
Publisher : Faculty of Business and Economics Universitas Atma Jaya Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24002/modus.v35i2.7799

Abstract

This study aims to analyze differences in the influence of workload and work environment on job satisfaction mediated by work stress on motorcycle industry employees in North Jakarta. Respondents from this study used a sample size of 155 respondents. Sampling in this study uses non probability sampling method with a purposive sampling approach. Meanwhile, in testing the hypothesis using an analytical tool in the form of a Structural Equation Model (SEM). The results of hypothesis testing in this study indicate that workload has a positive effect on work stress, workload has a negative effect on job satisfaction, work environment has a negative effect on work stress, work environment has a positive effect on job satisfaction, work stress has a negative effect on job satisfaction mediated by work stress, and work environment has a positive effect on job satisfaction mediated by work stress. The implication of this research is that companies are expected to always pay attention to the workload given by the company to employees, maintain a work environment that supports work activities, pay attention to stress levels in employees, and continue to improve existing job satisfaction. Keywords: workload, work environment, work sress and job satisfaction Penelitian ini bertujuan untuk menganalisis perbedaan pengaruh workload dan work environment terhadap job satisfaction yang dimediasi oleh work stress pada karyawan Industri Sepeda Motor di Jakarta Utara. Responden dari penelitian ini menggunakan jumlah sampel sebanyak 155 responden. Pengambilan sampel dalam penelitian ini menggunakan metode non probability sampling dengan pendekatan purposive sampling. Sedangkan dalam pengujian hipotesis dengan menggunakan alat analisis berupa Structural Equation Model (SEM). Hasil pengujian hipotesis dalam penelitian ini menunjukkan bahwa workload berpengaruh positif terhadap work stress, workload berpengaruh negatif terhadap job satisfaction, work environment berpengaruh negatif terhadap work stress, work environment berpengaruh positif terhadap job satisfaction, work stress berpengaruh negatif terhadap job satisfaction, workload berpengaruh negatif terhadap job satisfaction yang dimediasi oleh work stress, dan work environment berpengaruh positif terhadap job satisfaction yang dimediasi oleh work stress. Implikasi penelitian ini adalah diharapkan perusahaan selalu memperhatikan workload yang diberikan perusahaan kepada karyawan, mempertahankan work environment yang menunjang kegiatan kerja, memperhatikan tingkat stres pada karyawan dan terus meningkatkan job satisfaction yang ada. Kata Kunci: beban kerja, lingkungan kerja, stress pekerjaan dan kepuasan pekerjaan  
Co-Authors Adawiyah, Wiwik Robiatul Ade Chandra Adi Rizki Nugraha Ageng Priyambudi Agus Binarto Andrijanto, Eko Chyntia Wahyuni Febryanti Delinda Nirmala Afiyah Della Agustia Marhani Emelia Uthari Endang Kusumawati Euis Sartika Hadiani, Fatmi Haryadi Haryadi I Nyoman Widiasa Kardian Rinaldi Lestari Herlianti Putri Limbong, Sunarlia Maharani, Nine Elissa Meilya Suzan Triyastuti, Meilya Suzan Mukhtar Gozali Ngatin, Agustinus Novie Wijaya Nurul Annisa Palayukan, Novianty Paramitha, Tifa Putri Widad Salsabila Rafi Ohorella Retno Indarti Riniati Rivaldo Rofie Fauzi Budiman Riwu, Willyam Raimond Rizky Setianto Robby Sudarman Saifa Haikal Witcaksono Sihombing, Rony Pasonang Sri Murniati Suryadi, Joko Tri Hariyadi Troskialina, Lina Unung Leoanggraini Widyabudiningsih, Dewi Yohana Fransiska Ferawati Yuliah, Siti Yunus Tonapa Sarungu Yusmardhany Yusuf