Judul: The Influence of Honeycomb Biofilter Application in Organic Wastewater Treatment of A Combined Anaerobic and Aerobic System (Case Study : Waste of Tofu and Fermented Soybean Cake Industry)
Abstrak: The objective of this study are to assess the influence of honeycomb biofilter application in degrading organic pollutant at combined anaerobic and aerobic system, and also to assess the possibility for applicating this technology in tofu and fermented soybean cake industry. This study was carried out in tofu and fermented soybean industry at Semanan, west Jakarta, that have around 800 small industries which has been operated since 1992. The total amount of wastewater produced from that area is about 846 m3/day, and is collected in wastewater lagoon nearby. Wastewater treatment of a combined anaerobic-aerobic system is a secondary wastewater treatment after physical treatment. Basically this wastewater treatment relies on bacteria in degrading pollutants. The use of honeycomb biofilter is to increase specific surface of media for attachment of bacteria. The Biofilter is made of plastic, 28 cm x 25 cm x 30 cm, very light and easy to clean. The system consist of two reactors that is made of 8 mm glass, and the volume of each reactor is 140 liter (so total volume of reactors is 280 liter). The reactor is equipped with two circulating pump and blower in the aerobic zone. It takes 14 - 25 days for seeding. The reactors run in four different resident times, namely 7 days, 5 days, 3 days and 1 day. The raw water used in this experiment is wastewater from tofu and fermented soybean cake industries that have 8005 around 300 - 500 mg/I. The water for physical and chemical analysis is sampled weekly. It took from raw water and each colum of reactor. Bacteria analysis was also carried out to investigate the presence of bacteria using carbohydrate and protein as main component of wastewater. Bacterial population decreased significantly at the end of the proses. The results from 1,872 physical and chemical parameters from 144 water samples showed that the reactors using biofilters have better performance than the reactors without biofilters. The Efficiency process in decreasing 8005 value is up to 90.24%, COD 74.43%, ammonia 98,68%, nitrite 87.64%, nitrate 94.76%, sulfide 100%, and total phosphate 97 .60%. Besides such a good relatively high efficiency, the hydraulic loading is around 0,48 - 3,33 m3/m2 of surface biofilter media each day and BOD loading is around 0, 20 - 0,43 kg BO05 / m3 of biofilter media each day. Economic assessment of small industry that used 100 kg soybean as raw material, need investment Rp. 5 562 000,- and operation cost Rp. 68 440,- every month or equivalent with Rp. 463,-/m3 wastewater.
Keyword: Biofilm, Organics, Sewage, Biofilter, Wastewater Treatment, Anaerobic and Aerobic Reactors, Organic Waste, Waste of Tofu, Fermented Soybean, Cake Industry

Judul: Kajian Pemanfaatan Tanaman Eceng Gondok (Eichornia crassipes (Mart) Solms) dan Kiambang (Salvinia molesta) Untuk Menurunkan Kadar Nutrien Pada Limbah Cair Tahu.
Abstrak: Tofu industry is producing waste water in large volume and being disposed to natural water. Biological treatment using aquatic plants can be used to remove tofu waste water. Aquatic plants such as Water Hyacinth and Kariba-Weed have rapid growth and resistance to any critical condition. The objective of this research was to determine effectiveness of nutrients removal by Water Hyacinth (Eichornia crassipes (Mart) Solms) and Kariba-Weed (Salvinia molesta) and as a result the effluent of tofu industrial waste water can be disposed safety to the environment. Experiment was divided into two stages. In the beginning of experiment, Water Hyacinth and Kariba-Weed were cultivated with several dilutions. There were 1:0, 1:1, 1:2, 1:3, 1:4, 1:5, and 1:6 in every pond. The best result covered visual research and DO (Dissolve Oxygen) will be used for the main experiment where their nutrient will be analyzed. The nutrients cover total nitrogen, phosphate, nitrate, ammonia, TSS (Total Suspended Solid), COD (Chemical Oxygen Demand), and pH. The result showed that Water Hyacinth with dilution 1:2 has the highest ammonia (NH3) removal that was from 10,4 mg/l becomes 1,45 mg/l with the percentage was amount of 38,52%. Reducing nitrate (NO3) was from 0,339 mg/l becomes 0,178 mg/l with the percentage was amount of 37,19 %, total nitrogen was from 24,6 mg/l becomes 9,8 mg/l with the percentage was amount of 35,58 %, and phosphate (PO4 3-) was from 0,259 mg/l becomes 0,015 mg/l with the percentage was amount of 78,11%. In Kariba-Weed with the dilution 1:2 has removed total nitrogen from 24,6 mg/l becomes 12,55 mg/l and percentage 23,10 %, ammonia removal was from 10,4 mg/l becomes 2,4 mg/l and percentage 31,68 %, nitrate removal was from 0,339 mg/l becomes 0,191 mg/l and percentage 36,29 %, also the phosphate removal was from 0,259 mg/l becomes 0,026 mg/l and the percentage 76,38 %. The effectiveness of nutrient absorption happens until the twelfth day, after it the effectiveness of nutrient is not significant anymore. Along with the amount of nutrient removal by Water Hyacinth and Kariba-Weed, it also happens to TSS and COD removal while the increasing of DO value and pH also happens. The highest TSS and COD removal received by Water Hyacinth with dilution 1:2 which removed TSS from 37 mg/l becomes 10,5 mg/l and removed COD from 670 mg/l becomes 96,52 mg/l. The highest increasing of pH value received by Kariba-Weed with dilution 1:2 which increased pH from 6 becomes 9,3 while Water Hyacinth increased DO from 0,505 mg/l becomes 0,471 mg/l. Designing of tofu processing waste water with the combination of Water Hyacinth and Kariba-Weed in laboratory plant removed high nutrient contents with 8 day of hydraulic retention time. Industrial plant design with 8 day of hydraulic retention time used anaerobic digester and Water Hyacinth and Kariba-Weed pond with 18,3 m x 3,7 m x 0,6 m of dimension to accommodate the amount of waste water as much as 5000 liters. Anaerobic digester was designed with 5 m3 holding capacity of tofu waste water, 0,75 m of digester radius, and 2,8 m of height. After treatments, the
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Judul: Konstruksi aritmetika kurva eliptik F(2m) supersingular dan non-supersingular untuk skema kunci publik ElGamal
Abstrak: Algoritme ElGamal adalah salah satu algoritme kunci publik dengan aritmetik modular p yang mempunyai struktur grip siklik Z(p). Tingkat keanaman algoritme ini terletak pada pemecahan masalah logaritme diskret dari Z(p). Akan tetapi, tingkat keamanan tadi tahun ke tahun semakin menurun yang disebabkan kemampuan pemecahan algoritme diskret semakin meningkat. Untuk memenuhi tingkat keamanan yang memadai dibutuhkan p yang cukup besar yang menyebabkan proses enkripsi dan dekripsi menjadi lambat.
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