Judul: Aktivitas Isolat Bakteri Aerob dari Lumpur Aktif  Pengolahan Limbah Cair dalam Mendegradasi Limbah
Abstrak: Limbah cair industri mengakibatkan dampak negatif bagi lingkungan. Bioremediasi merupakan salah satu cara untuk mendegradasi limbah dengan menggunakan mikrob. Oleh sebab itu perlu diketahui spesies dan kinerja mikrob dekomposer yang mampu mendegradasi limbah organik. Pada penelitian ini dilakukan isolasi dan identifikasi terhadap bakteri dominan yang berasal dari kolam aerasi PT East Jakarta Industrial Park. Bakteri ditumbuhkan pada media padat selektif dengan komposisi limbah cair dan agar-agar. Bakteri dominan diidentifikasi menggunakan biolog kit. Isolat dan lumpur aktif diinokulasi ke dalam limbah cair pada dua buah wadah berbeda., selanjutnya dilakukan uji chemical oxygen demand (COD), biochemical oxygen demand (BOD), padatan tersuspensi, amonia, nitrat, dan nitrit. Hasil uji parameter tersebut dibandingkan dengan kontrol dan efisiensi ditentukan menggunakan rumus efisiensi.
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Judul: Isolasi dan karakterisasi bakteri anaerobik perombak limbah cair pabrik kelapa sawit
Abstrak: Limbah cair Pabrik Kelapa Sawit (PKS) mengandung bahan pencemar dengan nilai rata-rata BOD 25 000 mg/I. Penelitian ini bertujuan untuk melakukan isolasi, seleksi dan karakterisasi mikroorganisme ·anaerobik yang potensial untuk perom­bakan limbah cair PKS. Isolat mikroorganisme anaerobik diambil dari lumpur aktif kolam anaerobik pada unit limbah cair PKS Keriajaya PTP XI Malingping­Banten, PKS Bekri PTP X Lampung, PKS Betung PTP X Palembang dan rumen sapi. Teknik yang digunakan dalam mengisolasi bakteri anaerobik adalah metode Hungate yang dimodifikasi. Medium yang digunakan untuk pertumbuhan bakteri anaerobik adalah medium basal yang diformulasikan oleh Mann (1967) dan Zeikus (1972). Dari isolasi yang dilakukan diperoleh empat isolat yang terseleksi berpotensi merombak bahan organik lemak, protein dan serat, serta mampu menurunkan nilai COD, BOD, padatan tersuspensi (SS) dan padatan total (TS). Keempat isolat terse­but diberi kode MCL4, MCM!, MCP0 dan MCR2. Dalam perombakan protein keempat isolat mempunyai keunggulan yang sama. Dipihak lain isolat MCR2 merupakan isolat yang paling unggul dalam perombakan serat, sedangkan isolat MCMI paling lemah. Isolat MCL4 dan MCP0 merupakan isolat yang unggul dalam merombak lemak dibandingkan kedua isolat yang lain. Urutan keunggulan isolat dalam menurunkan nilai COD, BOD, TS dan SS adalah MCL4, MCP0, MCR2 dan MCML Isolat MCMI merupakan isolat yang paling lemah dalam merombak limbah cair PKS dibandingkan ketiga isolat yang lain. Efisiensi perombakan BOD oleh keempat isolat MCL4, MCP0, MCR2 dan MCMI adalah 83, 82, 77 dan 73%. Isolat MCR2, MCL4, MCP0 dan MCMl menghasilkan gasbio dengan kandungan metana 12, 10, 9 dan 6 % .
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Judul: The Effects of Variance of Interest rate to Variance of Annuity Future Values
Abstrak: Time value of money is a concept that refers to the difference of the value of money due to time difference. The value of money for present time would not be the same as the value of money in the future. The value of money for present time is called as Present Value (PV) of the money and the value of money for future time is called Future Value (FV) of the money. Determination the value of money, for present and future time, depends on the time and rate of return. The value of money is determined by several factors such as inflation, fluctuation of interest rates, and government policy in securities and taxation. Due to fluctuation of the value of money we need a FV formulation, it is useful for knowing whether an investment can be profitable or not, and this information is useful also in budget analysis. Annuity is defined as a series of payments made for a specific period. The payment, fixed or varied, can be made at the beginning or at the end of the period. Annuity paid at the beginning of the period is called annuity-due and annuity paid at the end of the period is called immediate annuity-certain. The accumulated value of the annuity after few years later is called as a final value or a future value. Burnecki et al. (2003) have discussed about the FV of a fixed-rate annuity in which payments are made according to the arithmetic or geometric series. They have also examined FV for annuities in which payments are made according to arithmetic or geometric series with random rates of interest. This paper examines FV for annuity-due in which payments are made according to arithmetic or geometric series with interest rates as a random variable, which is normal distribution ,  . Future value formula is expressed in recursive form. FV for annuity-due which payments are made according to the arithmetic or geometric series with random rates of interest is calculated by theoretical way and simulation way. The random rates of interest is denoted as k k i  i  , where k i an independent random variable; i is a constant and k  is a random variable which has normal distribution ,  . By using the determined parameters, a sequence of random rates of interest are generated for theoretical calculation. Meanwhile for the simulation, the random rates of interest is generated 1000 times for the simulation. The generated data give mean value, variance, and standard deviation. Moreover, error of mean value, variance, and standard deviation from the theoretical and simulation results are calculated. Error calculation uses Symmetric Mean Absolute Percentage Error (SMAPE). The smaller the value of SMAPE is the more accurate the simulation. The interest rate variances are varied from 0.000036 to 0.0001 to study the relationship between variance of rates of interest and variance of future value. The theoretical and simulation results show that when the variance of random rates of interest increases, then the variance of FV increases linearly. FV of the annuity-due in
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