Judul: Pra – Perlakuan Air Sungai sebagai Air Baku dengan Teknologi Fixed Bed Reactor
Abstrak: Quality of raw water (river water) is decreasing, as result of industrial and domestic wastes discharge into river without any treatment. Therefore, pre-treatment is needed to improve the raw water quality. An alternative for pre-treatment of the raw water is fixed bed reactor (FBR) system, in which organic substances can be removed biologically.In this experiment, an FBR was used to reduce concentrations of organic, ammonia, total suspended solid (TSS), color and turbidity in raw water. Three type of media were used namely honeycomb tube type made of plastic,recycled plastic bottled of drinking water and pumice. The system is equipped with circulator and aerator to support the microorganism growth on the media surface as biofilms.The experiments were conducted at HRT (Hydraulic Retention Time) between 1–4 hours. HRT of 3 hours was found to be optimum for the reactor with recycled plastic bottled of drinking water with removal efficiency of organic, ammonia, total suspended solid (TSS), color and turbidity are 70%, 61%, 66%, 67% and 63% respectively. With the use of fixed bed reactor is able to reduce the need of PAC to 0.07 mL and save production cost on WTP Cihideung for Rp90 720 000.00 /month.
Keyword: 

Judul: Peningkatan kualitas air baku menggunakan teknologi fixed bed reactor dengan media batu apung
Abstrak: The quality of raw water in Indonesia has been in generall decreasing due to incresed environmental pollution. It is becoming a serious problem in processing the raw water into clean water that can later be used as drinking water. Therefore, pre-treatment is in some cases needed to facilitate the production of clean water. An alternative for pre-treatment of the raw water is the fixed bed reactor system, in which organic substances can be removed biologically. This research work is aimed to evaluate the possibilities to pre-treat the raw water using a fixed bed system filled by pumice. The system is equipped with circulator and aerator to support the microorganism growth on the media surface as biofilms. Pumice stone is choosed as the growth media of microorganisms due to its high porosity, availability and stability. The presence of organic and inorganic material in raw water, will be held in the media layer of pumice that formed biofilms.The experimnts were conducted at various contact times. Results show that organic matter and TSS (Total Suspended Solids) can be removed by approximately 33 % and 69%, respectivey. This may result in decreasing chemical consumption in coagulation/flocculation of the raw water.
Keyword: 

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
Keyword: