Judul: Biodesulfurisasi batubara Bukit Asam menggunakan Thiobacillus ferrooxidans
Abstrak: Coal is a very important non-renewable energy resource in Indonesia and many industries depend on this resource. In coal burning process, coal produces hazardous waste contains high sulfuric compound that harmful for environment as well as human. In order to reduce sulfur content in the coal, several methods could be applied. One of them is biodesulfurization of coal using T. ferrooxidans. Main objectives of this research are: 1) to know the most effective strain of T. ferrooxidans in order to reduce sulfur content in coal, and 2) to know ability of T. ferrooxidans in order to reduce sulfur content in a bioreactor. The experiments consisted of three main steps, that are: 1) Stock culture rejuvenation, 2) Strain selection, and 3) Coal desulfurization in a bioreactor. Medium that used in this research is according to Leathen et al. (1956). The result of this research show that T. ferrooxidans ICBB 9100 is the most effective strain for coal desulfurization. T. ferrooxidans strain ICBB 9100 can reduce sulfur content 77.53% within 12 days. By treatment of the coal in bioreactor, sulfur content was reduced 62.89% within 2 days by T. ferrooxidans strain ICBB 9100. Key words: coal, biodesulfurization, T. ferrooxidans
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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: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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