Judul: Pengelolaan Air Asam Tambang Melalui Rawa Buatan Berbasis Bahan In Situ di Pertambangan Batu Bara (Studi Kasus di Site Pertambangan Sambarata PT. Berau Coal, Kabupaten Berau, Provinsi Kalimantan Timur)
Abstrak: Acid mine drainage (AMD) is the main problem in open pit mining due to extremely low pH and high solubility of metals. Metal solubility can be reduced biochemically in an anaerobic condition. Wetland is typical ecosystem having anaerobic conditions and characterized by low potential redox (Eh). Low Eh can be achieved if the wetland has enough quantities of organic matter. This research was aimed to design an artificial wetland that was constructed using locally available materials, and test it for AMD treatment, to identify AMD remediation process within artificial wetland, and to identify biomass production of artificial wetland plants. An artificial wetland of 1.028 m2 has been constructed. It’s composed of two organic walls, two growing ponds, and one collecting pond. Each component separated by a dike. Each organic wall was placed next to growing pond that were planted by Typha sp. and Cyperus sp. Collecting pond was planted by Eichornia crassipes. Artificial wetland was incubated until redox potential (Eh) of inundated water was less than 100 mV. Operation of artificial wetland started after incubation was done. Result showed that during incubation Eh of inundated water has decreased to below 100 mV after 5 days. Reduction and precipitation has occured during AMD remediation process. Sulphate, iron and manganese were accumulated in the root of each plant. Typha sp. has better growth rate than other plants and potentially to produce a higher biomass.
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Judul: Kajian Bioreaktor Untuk Pengolahan limbah Air Asam Tambang Dengan Menggunakan Bakteri Pereduksi Sulfat
Abstrak: Coal mining industry is one of the industries which has potency to produce acid mine drainage. Sulfide compound exposed with air will oxidized which produce sulphate compounds. If it react with water, it will generate acid mine drainage containing sulphate. Natural acid can trigger the form of reactive metals on his ion form, thereby will generate contamination of metal at water environment. To reduce contamination of acid mine drainage effect an appropriate technology is required. Biotechnology is an alternative method to threat acid mine drainage, in which a microbe is used as agent for sulphate reduction. The main objectives of this research are: 1) studying bioreactor ability using D. orientis ICBB 1220 to reduce sulphate and dissolved metal of acid mine drainage at various time of biofilm formation; 2) studying bioreactor ability using D. orientis ICBB 1220 to reduce sulphate and dissolved metal of acid mine drainage at vaious time of waste retention time; 3) determine the optimum biofilm formation time and retention time in the bioreactor using D. orientis ICBB 1220 to reduce sulphate and dissolved metal of acid mine drainage. This research has done in a bench scale in the laboratory of environmental biotechnology at Indonesian Center for Biodiversity and Biotechnology (ICBB) Bogor. This research was camed out from October 2006 until October 2007. Research results shown that 5 hours of retention time at 14 days of biofilm formation could be considered as an optimum condition to improve pH from 2.85 to 6.98 and for sulphate reduction from 721.75 to 226.679 (68.59%) and each dissolved Fe and Mn reduction 10.82 to 0.17 (98.43%) and from 13.79 to 3.65 (73.52%).
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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