Judul: Isolasi dan Optimasi Flokulasi Bakteri Penghasil Bioflokulan dari Sumber Perairan di Daerah Bogor
Abstrak: Penggunaan flokulan sintetik yang digunakan di beberapa industri diketahui mengandung resiko terhadap kesehatan manusia dan kelestarian lingkungan karena sifatnya yang neurotoksik dan karsinogen kuat serta tidak mudah didegradasi oleh bakteri. Eksplorasi bakteri dari sumber alami yang dapat menghasilkan bioflokulan merupakan salah satu solusi untuk mendapatkan bahan flokulan alternatif yang lebih aman bagi manusia dan ramah terhadap lingkungan. Penelitian bertujuan mengisolasi bakteri dan melakukan optimasi flokulasi terhadap isolat yang mampu menghasilkan bioflokulan. Penelitian dimulai dengan melakukan isolasi bakteri kawah dan air asin dari Gunung Pancar, perairan limbah tapioka, dan kolam Kebun Raya Bogor. Kemampuan flokulasi diperoleh dengan pengujian menggunakan suspensi kaolin yang ditambah FeCl3 0.05%. Berdasarkan hasil penelitian ditemukan sebanyak lima isolat bakteri penghasil bioflokulan dari kawah Gunung Pancar dan perairan limbah tapioka. Isolat tersebut memiliki aktivitas flokulasi yang tinggi masing-masing KH-3 (78.04%), K-P (73.52%), KH-1 (71.77%), LT-6 (71.38%), dan LT-5 (68.92%). Hasil identifikasi menunjukkan bahwa KH-1, KH-3, dan K-P berasal dari genus Bacillus, LT-6 adalah Citrobacter koseni, dan LT-5 adalah Chromobacterium violaceum. Hasil optimasi menunjukkan semua isolat memiliki pH optimum yang berbeda-beda dan bersifat termostabil. Kation AlCl3 0.05% bekerja paling efektif dan sangat membantu dalam proses flokulasi. Keefektifan isolat yang didapat lebih tinggi dibanding Pseudomonas aeruginosa dan uji flokulasi isolat pada beberapa limbah dan pengolahan air belum bekerja secara optimal.
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Judul: Produksi Bioflokulan dari Lumpur Aktif Industri untuk Air Sungai dan Air Limbah Industri
Abstrak: Bioflocculant is a natural flocculant from secretion product of microorganism that is polysaccharide, protein, glycoprotein, and nucleic acid. Source of bioflocculant used in this study is activated sludge from soy sauce industry PT. XXX. This study aims to analyze produce bioflocculant from industrial activated sludge with the isolation microb method and polysaccharide synthesis using acid method. The isolation microb method revealed that there are potential isolates that could floculate the suspension of kaolin by more than 60% in ten minutes which is isolates CMC-1 (78.36%). Isolate CMC-1 is identified as cellulolytic bacteria. Bioflocculant production using acid to catch polysaccharide resulted in only 53.92% flocculation effectivity but it is lower cost, more quickly, and easy to apply in industry. The selected bioflocculant is then tested for water and wastewater treatment. Research results showed the bioflocculant flocculation effectivity of 43.49% for river water and of 29.93% for wastewater. Addition of coagulant with specific dose can help bioflocculant increase flocculating effectivity.
Keyword: Bogor Agricultural University (IPB), flocculating efectivity, bactery isolation, coagulant, bioflocculant

Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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