Judul: Efektifitas Kitosan dan Biofilter Eceng Gondok (Eichornia crassipes (Mart) Solm) dan Kijing Taiwan (Anodonta woodiana) Sebagai Adsorben pada Pengolahan Limbah yang Mengandung Logam Hg, Cd dan Pb
Abstrak: Environmental problems need attention, because many activities in residential, agriculture, mining, and industry sectors can produce waste water that is discharged into the environment. Waste processing was generated by various sectors must be processed before being discharged into the environment. Various kinds of methods are used to process the waste. One of the methods can do developed for the waste processing which contains Hg, Cd and Pb Metals is done waste absorption method by chitosan solution then followed by biofilter of mussel Anodonta woodiana and water hyacinth. Chitosan solution can absorb Pb metals for 46,65%, Hg for 78,64%, and Cd for 53,52%. The use of biofilter can decrease Pb levels of waste for 98,05%, Hg for 98,88%, and Cd for 97,86%. The use of these biomaterials has three types of these biomaterials. These are easy to find in the environment, so these can be used more optimal in the process of waste processing.
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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: Kajian frieze groups untuk klasifikasi dan konstruksi desain berdasarkan simetri pada pola
Abstrak: Frieze groups adalah konsep matematika untuk mengklasifikasikan desain pada dua dimensi permukaan yang berulang-ulang dalam satu arah berdasarkan simetri pada pola. Frieze groups merupakan grup yang mempertahankan bentuk pola. Pergerakan bentuk pola terdiri dari translasi, refleksi dan rotasi 180o. Tujuan dari karya ilmiah ini adalah mengkaji sifat Frieze group, mengkaji penggunaan Frieze group dalam mengklasifikasikan simetri pada pola dan mengkonstruksi pola dengan menggunakan software tesselmania. Hasil yang telah diperoleh, bahwa jenis Frieze groups merupakan subgroup dari grup pergerakan pola. Selain itu dapat dilihat dari sifat isomorfik berbagai jenis Frieze groups. Untuk mengkonstruksi sebuah bentuk pola dapat menggunakan salah satu software untuk membentuk sebuah pola bidang datar (dua dimensi) yaitu tesselmania.
Keyword: Frieze groups, Simetri, Pola