Judul: Studi Proses Elektrokoagulasi untuk Meningkatkan Kualitas Air Sungai sebagai Air Baku
Abstrak: A river is one of the most important sources of raw water for clean water. The increase of population and the development of various industries resulted in reducing of river water quality that does not meet water quality standards while the human need for clean water is increasing. The low river water quality requires an effective and efficient treatment, such as by electrocoagulation. Electrocoagulation combines coagulation process with electricity without using chemicals. The purpose of this study was to determine the effect of variation of power supply voltage and electrode contact time with the water, and to determine the effect on parameters such as pH, color, turbidity, TSS, and phospate levels (PO4 3-) as an indicator of sewage pollution and get a combination of electrical voltage and contact time best on the electrocoagulation process wastewater pollutant reduction efficiency. Electrocoagulation run on 1 liter of water in a batch system and using stainless steel electrodes. The water taken from Cihideung river with two different times which water stream in sunny and rainy conditions. The results showed that a color reduction of 11% at a voltage of 15 and 5-minute, turbidity of 17% at a voltage of 18 and 5-minute, TSS of 29% at a voltage of 12 and 5–minute, and phospate of 20% at a voltage of 12 and 30-minute could be achieved. With the water in rainy conditions a color reduction of 74% at a voltage of 18 and 60-minute, turbidity of 90% at a voltage of 9 and 60-minute, TSS of 94% at a voltage of 15 and 60-minute, and 70% of phosphate at a voltage of 12 and 25-minute could be achieved. Combination treatment of 9 volts and 5 minutes can be considered as the best condition of treatment.
Keyword: electrocoagulation, river water, raw water, Bogor Agricultural University (IPB)

Judul: Pengurangan Bahan Organik Air Limbah Pemeliharaan Ikan Lele (Clarias sp.) menggunakan Metode Elektrokoagulasi
Abstrak: Metode elektrokoagulasi dapat digunakan untuk mengolahair limbah hasil pemeliharaan ikan. Penelitian ini bertujuan untuk menentukan besar tegangan listrik dan waktu yang efektif dalam pengolahan air limbah pemeliharaan ikan menggunakan metode elektrokoagulasi. Penelitian ini dilakukan menggunakan perlakuan perbedaan besar tegangan (6 dan 12 V) selama 15, 30, 45, dan 60 menit. Hasil yang didapat dari penelitian ini adalah perubahan nilai rata-rata parameter kualitas air dari kondisi awal air limbah. Penurunan ditunjukkan pada tegangan 12 V oleh nilai kebutuhan oksigen kimiawi (COD) selama 60 menit sebesar 82,89%; ortofosfat selama 45 menit (67,49%); kekeruhan selama 60 menit (69,65%); warna selama 60 menit (70,49%); partikel tersuspensi (TSS) selama 15 menit (31,90%); dan partikel terlarut (TDS) selama 60 menit (10,31%). Selanjutnya, peningkatan ditunjukkan oleh amonia bebas pada tegangan 12V selama 15 menit sebesar 291,09%; amonium pada tegangan 12 V selama 30 menit (8,85%); dan pH pada tegangan 6 V selama 60 menit (16%). Perlakuan terbaik yang dapat digunakan dalam mengolah air limbah pemeliharaan ikan adalah perlakuan tegangan 12 V selama 30 menit.
Keyword: Electrical voltage, electrocoagulation, organic compounds, time, water quality, Aquaculture, Waste water treatment, Primary condition, COD, TPS, TSS

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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