Judul: Estimation of Leachate Effluent  Quality in Stabilization Contact Unit Based on Biokinetic Parameters stabilization  process
Abstrak: Kandungan polutan organik yang terkandung pada air lindi melebihi baku mutu berdasarkan Permen LHK Nomor P.59/MENLHK/Setjen/Kum.1/7/2016 tentang Baku Mutu Air Lindi Bagi Usaha dan/atau Kegiatan Tempat Pemrosesan Akhir Sampah. Pengolahan biologis kontak stabilisasi dirancang untuk mendegradasi kandungan polutan organik air lindi. Penelitian ini bertujuan mengestimasi efluen air lindi berdasarkan parameter biokinetika unit stabilisasi. Prosedur penelitian skala laboratorium dilakukan dalam empat tahap, antara lain tahap persiapan, tahap pengambilan sampel, tahap pengujian reaktor pada kondisi tidak tunak, dan tahap analisis laboratorium. Persamaan umum biokinetika yang digunakan antara lain Monod, Contois, Blackman, dan Chen-Hashimoto. Berdasarkan hasil perhitungan dan uji validasi, parameter biokinetika terpilih diperoleh melalui persamaan Blackman dengan nilai Ke, Y, μmax, Ks sebesar 2,05 hari-1 ; 32,88 mgMLVSS/mgCOD; 0,57 hari-1 ; 24,38 mg/L. Konsentrasi efluen rata rata yang diperoleh melalui persamaan Blackman berdasarkan variasi waktu detensi 4 – 6 jam berturut-turut sebesar 208,46 ± 23,35 mg/L; 173,39 ± 54,03 mg/L; 146,83 ± 30,46 mg/L., The content of organic pollutants contained in leachate exceeds the quality standard based on the Minister of Environment and Forestry Regulation No. P.59/Menlhk/Setjen/Kum.1/7/2016 concerning Leachate Water Quality Standards for Business and/or Activities of Waste Final Processing Sites. The stabilizing contact biological treatment is designed to degrade the organic pollutant content of leachate. This study aims to estimate the leachate effluent based on the biokinetic parameters of the stabilization unit. The laboratory-scale research procedure is carried out in four stages, including the preparation stage, the sampling stage, the reactor testing stage under unsteady-state conditions, and the laboratory analysis stage. The general biokinetic equations used include Monod, Contois, Blackman, and Chen-Hashimoto. Based on the results of calculations and validation tests, the selected biokinetic parameters were obtained through the Blackman equation with the values of Ke, Y, μmax, Ks of 2.05 day-1 ; 32.88 mgMLVSS/mgCOD; 0.57 day-1 ; 24.38 mg/L. The average effluent concentration obtained through the Blackman equation based on the variation of detention time 4 – 6 hours in a row was 208.46 ± 23.35 mg/L; 173.39 ± 54.03 mg/L; 146.83 ± 30.46 mg/L.
Keyword: Air lindi, biokinetika, kontak stabilisasi, Biokinetics, leachate, stabilization contact

Judul: HYDRAULIC RETENTION TIME EFFECT OF STABILIZATION UNIT IN TREATING LEACHATE USING CONTACT STABILIZATION PROCESS
Abstrak: Konsentrasi bahan organik pada lindi TPA Galuga lebih tinggi dari baku mutu air limbah yang dikeluarkan oleh Kementerian Lingkungan Hidup dan Kehutanan. Pertumbuhan penduduk yang tinggi di Indonesia menjadi permasalahan sosial yang berdampak pada produksi lindi dan ketersediaan lahan pengolahan lindi. Penelitian ini dilakukan untuk membuktikan potensi stabilisasi kontak untuk menurunkan konsentrasi COD yang tinggi di daerah yang terbatas. Penelitian difokuskan untuk menentukan nilai parameter biokinetik dan mempelajari hubungan antara parameter biokinetik dan termodinamika untuk memahami performa biologis. Parameter biokinetik ditentukan dengan menggabungkan persamaan kesetimbangan massa dan kesetimbangan substrat dengan persamaan Jerusalimski dan Hinshelwood. Penentuan parameter biokinetika dilakukan dengan VBA Solver Microsoft Excel. Penentuan model terbaik dilakukan dengan beberapa analisis statistik, seperti RMSE, A_f, B_f, dan Korelasi Pearson. Analisis sensitivitas dengan Simulasi Monte Carlo juga digunakan untuk mengetahui kontribusi masing-masing parameter biokinetik terhadap varians. Model Hinshelwood dapat diterima sedangkan Jerusalimski tidak dapat diterima untuk estimasi kualitas efluen proses stabilisasi di unit stabilisasi. Efek kombinasi terbaik dalam model Hinshelwood ditunjukkan oleh efek kombinasi amonia, nitrit, pH, dan suhu. Model terbaik memberikan informasi kinerja biologis dengan nilai parameter biokinetik, seperti laju pertumbuhan maksimum (μmax) sekitar 4,28 hari-1, setengah konsentrasi sekitar (K_s) 18,25 mg/L, koefisien produksi sintesis sel (Y) sekitar 25,28 mgVss/mgCOD, dan angka kematian sekitar (K_e) 5,52 hari-1. Kinerja biologis berkaitan dengan analisis termodinamika, terutama untuk mengetahui pengaruh perpindahan panas terhadap pertumbuhan mikroba di unit stabilisasi. Salah satu reaksi katabolik di unit stabilisasi adalah oksidasi amonia dalam proses pembentukan mikroorganisme baru. Perhitungan entalpi reaksi menunjukkan bahwa reaksi oksidasi amonia dapat melepaskan panas ke luar sistem dan mempengaruhi pembentukan mikroorganisme baru di unit stabilisasi., Concentration of organic material in the Galuga landfill leachate is higher than the quality standard for wastewater issued by the Ministry of Environment and Forestry. High population growth in Indonesia has become a social issue that gives an impact to leachate production and the availability of leachate treatment areas. The research is carried out to prove the potential of contact stabilization for degrading high COD concentration in limited areas. The research is focused on determining the biokinetic parameters value and learning the relationship between biokinetic parameters and thermodynamic studies for understanding the biological performance. Biokinetic parameters are determined by combining the mass balance and substrate balance in the stabilization unit with the Jerusalimski and Hinshelwood equations. Determination of biokinetic parameters is carried out by VBA Solver in Microsoft Excel. Determination of best model is carried out by some statistical analysis, such as RMSE, A_f, B_f, and Pearson Correlation. Sensitivity analysis with Monte Carlo Simulation is also used to know the contribution of each biokinetic parameter to variance. The Hinshelwood model could be acceptable while Jerusalimski is likely unacceptable to estimate the effluent quality of the stabilization process in the stabilization unit. The best combination effects in the Hinshelwood model are shown by the combination effect of ammonia, nitrite, pH, and temperature. The best model provides the biological performances information by the value of biokinetic parameters, such as maximum growth rate (μmax) is around 4.28 day-1, half concentration is around (Ks) 18.25 mg/L, cell synthesis production coefficient (Y) is around 25.28 mgVss/mgCOD,
Keyword: contact stabilization, enthalpy reaction, Hinshelwood equation, Jerusalimski equation, leachate

Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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