Judul: Efek Koagulan dari Kitosan dan Abu Tandan Kosong Kelapa Sawit dalam Unit Pra-Pengolahan dari Reaktor Anaerobik-Aerobik Limbah Cair Kelapa Sawit
Abstrak: POME and EFB form the largest by-products of palm oil processing. This study instigates the UASB and IFCS system in ACSt reactor. Additionally, evaluating bio-coagulants chitosan and EFB ash to enhance treatment efficiency. The research aims to improve pollutant removal in ACSt reactor by adding pre-treatment processes with bio-coagulant. Laboratory tests on TSS, COD, TDS, and pH for jar tests, and oil and grease for ACSt reactor operation were conducted. Chitosan (10 mg/L) achieved 18.88% COD and 98.68% TSS removal, while EFB (1500 mg/L) showed 16.98% COD and 98.96% TSS removal. The chitosan:EFB combination (80:20) had the highest removal rates of 19.72% for COD and 99.15% for TSS. Kinetic analysis revealed the highest R, LCKS dan TKKS merupakan produk sampingan terbesar dari pengolahan minyak sawit. Studi ini mengembangkan sistem UASB dan IFCS dalam reaktor ACSt. Selain itu, dilakukan evaluasi terhadap koagulan organik kitosan dan abu TKKS untuk meningkatkan efisiensi pengolahan. Penelitian ini bertujuan untuk meningkatkan penyisihan polutan melalui penambahan pra-pengolahan dengan bio-koagulan. Pengujian laboratorium pada TSS, COD, TDS, dan pH untuk uji jartest, serta minyak dan lemak untuk operasi reaktor ACSt dilakukan. Kitosan (10 mg/L) mencapai penyisihan COD sebesar 18,88% dan TSS sebesar 98,68%, EFB (1500 mg/L) menunjukkan penyisihan COD sebesar 16,98% dan TSS sebesar 98,96%. Kombinasi kitosan:EFB (80:20) memiliki tingkat pengurangan tertinggi yaitu 19,72% untuk COD dan 99,15% untuk TSS. Analisis kinetik menunjukkan nilai R
Keyword: Chitosan, EFB, palm oil mill effluent, pre-treatment, bio-coagulant

Judul: Performance of Modification Hybrid Attached Growth Biofilm on Suspended Media on Anaerobic-Aerobic Unit in Treating Palm Oil Mill Effluent
Abstrak: Produksi minyak sawit mentah (CPO) di Indonesia hingga tahun 2022 telah mencapai 48,3 juta ton dari total produksi dunia sebanyak 75,45 juta ton dan tingginya produksi CPO menyebabkan peningkatan Limbah Cair Kelapa Sawit (LCKS) atau Palm Oil Mill Effluent (POME). Penelitian ini bertujuan untuk efektifitas pengolahan LCKS dengan variasi waktu detensi (HRT) yang berbeda pada Reaktor Anaerobic Contact-Stabilization (ACSt). Penelitian ini juga berfokus pada kajian mengenai parameter biokinetika pada unit Integrated Fixed-Film Contact Stabikization (IFCS) untuk estimasi nilai substrat di efluen. Penelitian terdiri atas tahap persiapan reaktor, aklimasasi, konfigurasi reaktor, dan pengoperasian reaktor, dan analisis data. Berdasarkan penelitian diketahui bahwa perubahan variabel operasional HRT berpengaruh terhadap persen penyisihan substrat sCOD pada pegolahan menggunakan Reaktor ACSt (Variasi 1 = 99,41%, Variasi 2 = 99,17%, Variasi 3 = 99,65%, Variasi 4 = 98,633% dan Variasi 5 = 96,47%). Selain itu, perhitungan parameter biokinetika untuk pengolahan LCKS menggunakan Reaktor ACSt pada unit IFCS memperoleh hasil nilai Kec, Kea, Yc, Ya, μmax-c, μmax-a, Ks-c, Ks-a dengan nilai berturut-turut sebesar 0,04 hari-1, 0,0018 hari-1, 3,51 mgMLVSS/mgCOD, 1,95 mgMLVSS/mgCOD, 2,33 hari-1, 2,09 hari-1, 75,55 mg/L, dan 49,57 mg/L, Production of crude palm oil (CPO) in Indonesia until 2022 has reached 48.3 million tons of the world's total production of 75.45 million tons and the high production of CPO can increase Palm Oil Mill Effluent (POME). This study aims to determine the effectiveness of POME processing with various detention time (HRT) in Anaerobic Contact-Stabilization (ACSt) Reactor. This research also focuses on the study of biokinetic parameters in the Integrated Fixed-Film Contact Stabikization (IFCS) unit to predict the value of the substrate concentration in the effluent. This research starts with reactor preparation, acclimation, reactor configuration, reactor operation, and data analysis. Based on the research, it is known that changes in HRT operational variables affect the percentage of sCOD substrate removal in processing using the ACSt Reactor (Variation 1 = 99.41%, Variation 2 = 99.17%, Variation 3 = 99.65%, Variation 4 = 98.633% and Variation 5 = 96.47%). In addition, the calculation of biokinetic parameters for LCKS processing using the ACSt Reactor in the IFCS unit yielded the values of Kec, Kea, Yc, Ya, μmax-c, μmax-a, K_s-c, K_s-a with consecutive values of 0.04 day-1, 0.0018 day-1, 3.51 mgMLVSS/mgCOD, 1.95 mgMLVSS/mgCOD, 2,33 day-1, 2.09 day-1, 75.55 mg/L, and 49.57 mg/L.
Keyword: Anaerobic Contact Stabilization, bioball, biokinetic, Hydraulic Retention Time, Palm Oil Mill Effluent

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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