Judul: Peningkatan Kualitas Air Baku Perusahaan Air Minum dengan Proses Biofiltrasi Menggunakan Media Plastik Tipe Sarang Tawon:
Abstrak: In big cities, quality of raw water (source: river water) are decreased, as result of industrial and domestic waste water are discharged to river, without any treatment. Existing concentrations of organic, ammonia and detergent of raw water of PDAM TKR Tangerang respectively are 19.2 mg/l, 3.8 mg/l, and 0.9 mg/l, which are above threshold limit value of raw water for drinking water. A biofiltration process is use as one alternative to reduce concentrations of organic, ammonia, detergent and total suspended solid (TSS) in raw water. In this treatment, biofilter reactor is use with plastic of Honeycomb tube type as media. Operational condition of treatment is variation of HRT (Hidrolisis Retention Time) between 1–4 hours and air supply between 0–30 l/min. The selected operational condition of treatment found at HRT of 2 hours and air supply of 20 l/min, with removal efficiency of concentration of organic, ammonia, detergent and TSS are 68%, 65%, 64% and 74% respectively. From this experiment, it was found that linear regression equations between removal efficiency and organic loading as yo = -5.98xo + 81.16, between removal efficiency and ammonia loading as ya = -91.19xa + 77,12, linear regression equation between removal efficiency and detergent loading as yd = -301.25xd + 71.53, linear regression equation between removal efficiency and TSS loading as yt= -0.84xt + 83.26.
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Judul: Peningkatan Kualitas Air Menggunakan Biofiltrasi dengan Media Pasir Kuarsa dan Botol AMDK
Abstrak: Biofiltration is a process that can be used to improve the quality of the raw water biologically. This study aimed to determine the effectiveness of biofiltration using media of quartz sand and drinking water bottles, as well as to evaluate the effect of ammonium loading on the ability of biofilters to reduce ammonium, nitrate, phosphate, organic compounds, pH changes, color and turbidity. Based on testing characterization raw water and according to PP. No. 82 / 2001 that raw water quality belong to the groups II. Acclimatization is a process of microorganisms in the press biofiltrasi. . Biofiltration using sand medium test reduced ammonium from 60,48 into 25,45 mg/L, nitrate from 1,8 to 1,74 mg/L, phosphate from 0,36 to 0,29 mg/L, organic compounds from 9,79 to 6,36 mg/L, the color from 30 to 24 PtCo, TSS from 17 to 8 mg/L and turbidity from 17 to 13 FTU. Whereas, biofiltration using drinking water bottles media reduced ammonium from 60,48 into 35,56 mg/L, increasing nitrate from 1,8 to 2,4 mg/L, reduce phosphate from 0,36 to 0,34 mg / L, reduce organic compounds 9,79 to 5,72 mg/L , the color of 30 to 18 PtCo, TSS from 17 to 6 mg/L, and turbidity from 17 to 8 FTU. Biofiltration process could lower the water quality fluctuation and save coagulant material costs. The application of the medium sand biofiltration reactor capable of coagulant material savings of Rp 1.588.673.986 per year, while media Rp 1.418.311.317 bottles of drinking water per year. The use of the medium sand biofiltration reactor is recommended for use in water treatment plants IPB Dramaga, Bogor
Keyword: raw water, quartz sand, drinking water bottled, biofiltration

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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