Judul: Optimasi Penggunaan Koagulan Terhadap Rancangan Unit Koagulasi, Flokulasi, dan Sedimentasi pada Pengolahan Air Limbah Laboratorium
Abstrak: Laboratories wastewater of Bogor Agricultural University (IPB) Dramaga is one of the parties who contribute environmental pollution. Waste Water Treatment Plant (WWTP) located in front of the Veterinary Medicine Faculty serves to treat wastewater in order that appropiate with the treshold. The systems which is used in WWTP IPB is coagulation, flocculation, sedimentation, filter system (sand filters and carbon filters), and disinfection. The objective of this research is to analyze the characteristics of laboratiories wastewater, optimization of using coagulants, and designing coagulation-flocculation and sedimentation units, along with making the mass balance. This study done in two stages, the first stage was primary and secondary data collecting and the second stage was wastewater characteristics analyzing, doing jar test, and design units. Based on the results, the parameters pH, N-NO2, NH3, H2S has met quality standards but TDS, COD, BOD, oil and grease do not meet the threshold . The final concentration of TDS, COD, BOD, and oil and grease in a row at 11273 mg /L, 3300 mg/L, 442 mg/L, and 181 mg/L. The optimum dose of coagulant that can be used for wastewater treatment lab was 6250 mg/L PAC + 62500 mg/L alum. The mass balance indicates that TSS concentration at efluent already under the threshold that is 93 mg/L, whereas BOD was still above the threshold which was 331.77 mg / L. On coagulation and flocculation unit, stirrer speed does not meet the criteria. On sedimentation unit, BOD can be reduced up to 48 % and TSS reduction can be up to 70 %.
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Judul: Evaluation of Coagulation Performance and Optimization of Coagulant Dose in WTP of PT XYZ
Abstrak: Salah satu unit yang berperan penting dalam penjernihan air adalah koagulasi. Penambahan koagulan pada unit koagulasi seringkali tidak sesuai dengan kebutuhan yang menyebabkan air menjadi keruh dan bau pada outlet. Penelitian ini bertujuan mengevaluasi kinerja unit koagulasi serta menentukan koagulan yang efisien dan ekonomis. Metode penelitian yang digunakan adalah pengamatan kondisi lapangan dan penentuan dosis optimum menggunakan Jar test. Koagulan yang digunakan adalah Alumunium Chlorohydrate (ACH), Poly Aluminium Chloride (PAC), dan tawas. Evaluasi kinerja unit koagulasi dilakukan pada nilai gradien kecepatan (G) dan waktu pengadukan (td). Berdasarkan hasil perhitungan diperoleh nilai G sebesar 2448,73/detik dan td sebesar 25,63 detik. Walaupun waktu pengadukan tidak memenuhi SNI 6774:2008, kenyataan di lapangan unit koagulasi masih berjalan dengan baik dan memiliki efisiensi sebesar 93,67%. Pada optimalisasi dosis optimum diperoleh ACH adalah 10 mg/l, PAC 12% adalah 20 mg/l, dan tawas adalah 30 mg/l. Dosis tersebut bekerja cukup stabil untuk memenuhi Peraturan Menteri Kesehatan No. 429 Tahun 2010. Kata kunci: Baku mutu, jar test, kinerja, koagulan, koagulasi
Keyword: Coagulant, coagulation, jar test, performance, standards

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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