Judul: Biodegradasi Amonium Menjadi Nitrit dan Nitrat (Nitrifikasi) Oleh Kultur Mikrob Campuran N-Sw
Abstrak: Degradasi amonia seeara hayati te!jadi melalui proses nitrifikasi dan denitrifikasi. Pada proses nitriflkasi amonia dikonversi secara aerobik menjadi nitrit, kemudian nitrit dioksidasi menjadi nitrat. Adapun pada proses denitrifikasi nitrat dikonversi menjadi gas nitrogen (N,). Proses biodegradasi nitrogen, khususnya amonia dilakukan oleh kultur mikrob eampuran N-Sw. Proses biodegradasi dapat digunakan dalarn pembuatan kultur mikrob nitrifikasi yang mampu diaplikasikan dalam pengolahan limbah cair, terutarna limbah nitrogen.
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Judul: Biodegradasi amonium menjadi nitrit dan nitrat (nitrifikasi) oleh kultur mikrob campuran N-Sw
Abstrak: Degradasi amonia secara hayati terjadi melalui proses nitrifikasi dan denitrifikasi. Pada proses nitrifikasi amonia dikonversi secara aerobik menjadi nitrit, kemudian nitrit dioksidasi menjadi nitrat. Adapun pada proses denitrifikasi nitrat dikonversi menjadi gas nitrogen (N2). Proses biodegradasi nitrogen, khususnya amonia dilakukan oleh kultur mikrob campuran N-Sw. Proses biodegradasi dapat digunakan dalam pembuatan kultur mikrob nitrifikasi yang mampu diaplikasikan dalam pengolahan limbah cair, terutama limbah nitrogen. Pertumbuhan kultur mikrob nitrifikasi ditentukan berdasarkan pada penurunan konsentrasi amonium atau nitrit. Dari hasil konsentrasi amonium dalam media pertumbuhan mengalami penurunan dari 43.90 mg N-NH/L menjadi 4.10 mg N-NH/L (90.66%) selama inkubasi 12 jam dan tidak terdeteksi lagi (100%) setelah inkubasi 24 jam. Penurunan konsentrasi amonium dalam basal media diikuti dengan terbentuknya nitrit (6.32 mg N-NO/L) dan nitrat (24.30 mg N-NO37L), sebagai produk dari proses nitrifikasi. Adanya konversi dari amonium menjadi nitrit mengindikasikan pertumbuhan dan aktivitas bakteri pengoksidasi amonium (Nitrosomonas), sedangkan terbentuknya nitrat di dalam kultur mengindikasikan adanya pertumbuhan dan aktivitas bakteri pengoksidasi nitrit (Nitrobacter). Dari data tersebut dapat disimpulkan bahwa di dalam kultur mikrob campuran N-Sw telah terbentuk populasi mikrob nitrifikasi. Perhitungan efisiensi nitrifikasi ditentukan berdasarkan dua metode, yaitu metode I berdasarkan pada perubahan konsentrasi amonium yang terjadi. Perhitungan ini masih mencakup proses hilangnya amonium oleh faktor lain, misalnya oleh proses pertumbuhan sel, physical air stripping, fisika, dan kimia. Adapun metode II berdasarkan pada terbentuknya nitrit dan nitrat, sehingga lebih mencerminkan aktivitas nitrifikasi. Pada kondisi pH 7, atau pH 8, dan suhu 30 °C aktivitas nitrifikasi mencapai nilai yang optimum. Fakta ini dibuktikan dari hasil efisiensi dan laju nitrifikasi. Nilai efisiensi nitrifikasi dari kondisi tersebut berdasarkan perhitungan dengan metode I diperoleh sebesar 100%, sedangkan berdasarkan metode II diperoleh 84.64% (pH 7), 87.80% (pH 8), dan 81.81% (suhu 30 °C). Adapun nilai laju nitrifikasi dari masing-masing kondisi mencapai 2.057 mg N-NH/L/jam/g biomasa (pH 7), 2.172 mg N-NH4/L/jam/g biomasa (pH 8), dan 2.104 mg N-NH/L/jam/g biomasa (suhu 30 °C).
Keyword: perombakan nitrogen, nitrifikasi, pola degradasi amonium

Judul: Characteristic of Overshooting Top (OT) Based on  Himawari  8  Satellite  as  a  Convective  Cloud  Feature  that  Generates  Extreme Weather in the Java Island Region
Abstrak: Overshooting Top (OT) is a feature at the top of a convective cloud that is associated with extreme weather. Research on OT in tropical Indonesia is still very limited. The existence of geostationary satellites with wide area coverage and fast frequency observations is useful for observing the fast dynamics of the OT life cycle. Therefore, this study intends to analyze the relationship between OT and extreme weather, updraft and thermodynamic conditions of OT when extreme weather occurs, the best objective method for detecting OT in the day time and night time, and the spatiotemporal distribution of OT in the tropical region of Java Island during the 2018-2021 period. Based on visual analysis using visible channel and Himawari 8 sandwich products, 87% of extreme weather events in Java were accompanied by the appearance of OT. It indicates that the presence of the OT pattern is a convection cloud pattern or feature that is closely related to extreme weather events for the Java Island region. The existence of a time lag between the appearance of OT and extreme weather events on Java Island indicates that the OT of convection cloud can be used as a precursor or nowcasting for the appearance of extreme weather. Most of the convective cloud OT features during extreme weather events on Java Island have altitude that were only able to exceed the altitude of the equilibrium level and few were able to exceed the tropopause level of 9 km – 16 km. The difference in atmospheric conditions during extreme weather events on Java Island, which is in the tropics and subtropics, is a strong and unstable convective energy condition characterized by a larger CAPE, as well as unstable KI, LI, SI and TTI values. It is offset by kinematic factors in the form of a weak vertical wind shear (bulk wind shear 0-6 km) and a higher freezing point height. The difference between extreme weather events in the Java Island region and other tropical regions compared to subtropical regions is the strong updraft speed of convection clouds. The IRW Texture COMB algorithm based on the IRW-Texture Gradient modification and the COMB algorithm shows a significant increase in quality for detecting OT and non-OT pixels in Java. Rainy days with rainfall > 50 mm/day are very common in areas with an altitude of > 500 m. On the other hand, the level of convection activity which is indicated by the presence of OT and lightning is significantly reduced in this area. OT of convective clouds appear more frequently during the DJF season and less frequently during the JJA season. OT often appears during the day time and rarely at night time. Most OTs appear in the central part, away from the south and north coasts of Java Island during the day, while OTs that appear near the south and north coasts of Java Island can appear in the morning or afternoon.
Keyword: convective clouds, extreme weather, Overshooting Tops, Himawari 8 Satellite