Judul: Effect of Different CO2 Sources on Microalgae-Microbial Fuel  Cell Design on Bioelectricity and Growth of Spirulina platensis
Abstrak: Microalgae-Microbial Fuel Cell (MMFC) merupakan integrasi kultur mikroalga dalam sistem MFC untuk menghasilkan energi listrik dari proses metabolisme mikroorganisme seperti bakteri elektrogenik. Penelitian ini bertujuan membandingkan elektrisitas, pertumbuhan S. platensis, dan karakteristik limbah cair pemindangan dari dua desain MMFC yang berbeda, yaitu desain MMFC dua chamber dengan selang aliran CO2 (MMFC-1) dan desain MMFC dua chamber dengan aerator (MMFC-2). Penelitian dilakukan dengan mengintegrasikan kultur S. platensis dengan campuran lumpur aktif dan limbah pemindangan pada perbandingan 1:10. Sumber CO2 yang berbeda memberikan pengaruh nyata terhadap elektrisitas, tetapi tidak berpengaruh nyata terhadap nilai OD dan biomassa kering S. platensis. Desain MMFC-2 memiliki elektrisitas lebih tinggi dibandingkan MMFC-1 dengan nilai tegangan 703,33 ± 38,21 mV, kuat arus 3,66 ± 0,36 mA, rapat daya 85,01 ± 6,29 mW/cm2, serta biomassa kering S.platensis lebih tinggi (0,17 ± 0,09 g/L). Kedua kondisi pada MMFC dapat menurunkan COD sampai 9,79%, BOD 31,12%, TAN 78,01% dan CO2 terlarut 67,69%., Microalgae-Microbial Fuel Cell (MMFC) is an integration of microalgae culture in the MFC system to produce electrical energy from the metabolic process of microorganisms such as electrogenic bacteria. This study aims to compare the electricity, growth of S. platensis, and characteristics of boiled fish processing wastewater from two different MMFC designs, namely the design of a two-chamber MMFC with a CO2 flow hose (MMFC-1) and a two-chamber MMFC design with an aerator (MMFC-2). The research had conducted by integrating the culture of S. platensis and a mixture of activated sludge and boiled fish processing wastewater in a ratio of 1:10. Different CO2 sources have a significant effect on electricity but have no significant effect on the OD value and dry biomass of S. platensis. The MMFC-2 design has a higher electrical than MMFC-1 with a voltage value of 703,33 ± 38,21 mV, a current of 3,66 ± 0,36 mA, a power density of 85,01 ± 6,29 mW/cm2, and biomass dry S. platensis was higher (0,17 ± 0,09 g/L). Both conditions in MMFC can reduce COD up to 9,79%, BOD 31,12%, TAN 78,01%, and dissolved CO2 67,69%.
Keyword: Limbah perikanan, Mikroalga, MMFC

Judul: Bioelectricity in Microalgae-Microbial Fuel Cell  (MMFC) using Different Ratios between Activated Sludge and Fish Processing Wastewater
Abstrak: Sistem microalgae-microbial fuel cell (MMFC) dilakukan dengan memanfaatkan proses fotosintesis Spirulina platensis dan reaksi metabolisme bakteri yang terdapat dalam lumpur aktif untuk menghasilkan energi listrik dan biomassa mikroalga. Penelitian bertujuan menentukan pengaruh rasio lumpur aktif dengan limbah pemindangan ikan dalam menghasilkan bioelektrisitas pada MMFC, menentukan kurva pertumbuhan dan biomassa S. platensis serta menentukan perubahan kualitas air limbah pada MMFC. Rasio lumpur aktif dan limbah pemindangan yang digunakan, yaitu 1:10 (MMFC-1), 2:10 (MMFC-2), dan 3:10 (MMFC-3). Perbedaan rasio berpengaruh terhadap elektrisitas yang dihasilkan. Perlakuan MMFC-1 menghasilkan elektrisitas tertinggi (rata-rata tegangan 577,03±18,71 mV; arus 3,16±0,17 mA; dan power density 55,35±4,45 mW/cm2 ), perlakuan MMFC-3 menghasilkan pertumbuhan S. platensis tertinggi (optical density 0,55±0,04) serta MMFC-1 dapat menurunkan chemical oxygen demand sebesar 4,89%; biological oxygen demand 31,12%; dan total ammonia nitrogen 28,79% sedangkan nilai pH dan total plate count mengalami kenaikan. Sistem MMFC berpotensi untuk dikembangkan dalam menghasilkan elektrisitas, menurunkan beban polutan, dan menghasilkan biomassa., Microalgae-microbial fuel cell (MMFC) system is carried out by utilizing the photosynthesis process of Spirulina platensis and metabolic reactions with bacteria contained in activated sludge to result in electrical energy and biomass microalgae. The study aims to determine the effect of the ratios of activated sludge to boiled fish processing wastewater in producing bioelectricity in MMFC, determine the growth curve and biomass of S. platensis, and changes in wastewater quality at the MMFC process. The ratios of activated sludge and wastewater used in the study were 1:10 (MMFC-1), 2:10 (MMFC-2), and 3:10 (MMFC-3). The difference in ratios affected to resulting electrical power. The MMFC-1 treatment produced the highest electrification (average voltage 577.03±18.71 mV; current 3.16±0.17 mA; and power density 55.35±4.45 mW/cm2 ), MMFC-3 resulted in the highest growth of S. platensis (optical density of 0.55±0.04) and MMFC-1 system can reduce chemical oxygen demand 4.89%; biological oxygen demand 31.12%; and total ammonia nitrogen 28.79% while pH and total plate count values increased. The MMFC system has the potential to be developed both in producing electrical power, reducing pollutants, and producing biomass.
Keyword: activated sludge, biomass, pollutant, power

Judul: Truncated Stop Loss as a Optimal Solution of Reinsurance Agreement in One-Period Model
Abstrak: Reinsurance is one of risk management efforts of an insurance company, which is called the cedent. Similar with insurance, reinsurance constitutes the cedent to pay the premium. We consider one-period reinsurance model and derive a rule which minimizes the ruin probability of the cedent for a fixed reinsurance premium. Therefore, it is needed to construct an optimal reinsurance agreement for the cedent. The premium is calculated according to four different principles, i.e. economic, generalized zero-utility, Esscher, and mean-variance principles. Stop loss is a reinsurance contract which protect the insurance company for losses that exceed a certain amount. The result of this research shows that a truncated stop loss is an optimal agreement in the class of all reinsurance contracts with various premiums calculated using above mentioned principles.
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