Judul: Biolistrik pada Microalgae-Microbial Fuel Cell (MMFC) Menggunakan Limbah Cair Pemindangan dan Spirulina Platensis dengan Salinitas Berbeda
Abstrak: Microalgae-microbial fuel cell (MMFC) adalah sistem bioelektrokimia yang mengubah cahaya menjadi listrik berdasarkan reaksi biokatalitik dalam sel mikroba. Teknologi MMFC dapat memanfaatkan energi kultivasi Spirulina platensis dan limbah cair pemindangan menjadi energi listrik. Penelitian bertujuan menentukan kemampuan MMFC 2 bejana dalam menghasilkan bioelektrisitas, menentukan pengaruhnya terhadap perubahan COD, BOD, dan TAN dari limbah pemindangan dan menentukan pertumbuhan Spirulina platensis. Penelitian ini menggunakan kultur Spirulina dengan salinitas 15 ppt (MMFC-A) dan 0 ppt (MMFC-B). Nilai elektrisitas pada MMFC-A menghasilkan tegangan 233 ±17,99 mV, current density 138,004 ± 37,56 mA/m2 , dan power density 31,8 ± 9,00 mW/m2 lebih besar dibanding MMCF-B. Salinitas memengaruhi bioelektrisitas pada sistem MMFC. Pertumbuhan Spirulina pada MMFC-B menghasilkan biomassa kering sebesar 0,251±0,076 g/L. Nilai COD, BOD dan TAN menurun, sedangkan nilai pH meningkat. Sistem Microalgae-microbial fuel cell (MMFC) menunjukkan adanya potensi untuk dikembangkan di masa depan, baik dalam menghasilkan elektrisitas maupun biomassa., Microalgae-microbial fuel cell (MMFC) is a bioelectrochemical system that converts light into electricity based on biocatalytic reactions in microbial cells. MMFC technology can utilize the cultivation energy of Spirulina platensis and fishery wastewater into electrical energy. This study aimed to determine the ability of the MMFC dual-chamber to produce bioelectricity, determine the effect of changes in COD, BOD, and TAN from the fishery wastewater, and determine the growth of Spirulina platensis. This study used Spirulina culture with a salinity of 15 ppt (MMFC-A) and 0 ppt (MMFC-B). The electrical value of MMFC-A produces a voltage of 233 ±17,99 mV, a current density of 138,004 ± 37,56 mA/m2 , and a power density of 31,8 ± 9,00 W/m2 which is greater than MMCF-B. Salinity affects the bioelectricity of the MMFC system. Spirulina growth on MMFC-B produced dry biomass of 0.251±0.076 g/L. The COD, BOD, and TAN values decreased, while the pH values increased. This Microalgae-microbial fuel cell (MMFC) system shows the potential to be developed in the future, both in producing electricity and biomass.
Keyword: Fishery Wastewater, MMFC, Spirulina platensis

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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