Judul: Kinetic Analysis of Mixing Coagulants and Floculants for White Water Paper Industry Wastewater Treatment
Abstrak: Upaya meningkatkan efisiensi penurunan parameter total solid (TS), turbiditas, dan COD dilakukan dengan memanfaatkan proses koagulasi-flokulasi untuk pengolahan air limbah industri kertas berjenis white water. Kombinasi koagulan yang digunakan yaitu alum, poliamin, serta flokulan anionik poliakrilamida. Analisis kinetika pada mekanisme koagulasi-flokulasi dilakukan dengan persamaan laju reaksi orde satu, dua, dan tiga. Selain analisis kinetika, hasil eksperimen dibandingkan dengan model prediksi Gompertz untuk melihat potensi kesesuaian antara data eksperimen dan prediksi serta melihat proses adsorpsi berdasarkan model isoterm adsorpsi (Langmuir, Freundlich, dan Temkin). Proses koagulasi dan flokulasi dapat menurunkan konsentrasi polutan maksimum untuk TS, kekeruhan, dan COD berturut-turut 84%, 99%, dan 17%. Pada penelitian ini, persamaan laju reaksi orde tiga menunjukkan hasil yang paling sesuai dengan mekanisme koagulasi-flokulasi. Prediksi berdasarkan model Gompertz menghasilkan data yang baik pada eksperimen menggunakan koagulan tunggal. Analisis adsorpsi membuktikan koagulan PA memiliki kapasitas adsorpsi yang baik pada ketiga model isoterm.
Keyword: flokulasi, isoterm adsorpsi, koagulasi, kinetika, pemodelan

Judul: Determination of Sedimentation Unit Design Parameters Based on the Settling Type Model of Coagulation-Flocculation Process Results in Paper Industry Wastewater
Abstrak: Teknologi pengolahan koagulasi-flokulasi merupakan opsi teknologi yang sering digunakan untuk pengolahan limbah kertas. Unit koagulasi dan flokulasi membutuhkan unit sedimentasi untuk mengendapkan flok berupa padatan tersuspensi dan material organik. Parameter yang diamati pada penelitian ini adalah Total Solid (TS) dan Chemical Oxygen Demand (COD). Dalam perancangan unit sedimentasi, empat tipe pengendapan digunakan untuk analisis sedimentasi, yakni tipe discrete settling, tipe flocculant settling, tipe hindered settling, dan tipe compression settling. Analisis empat tipe pengendapan akan menghasilkan parameter desain unit sedimentasi seperti surface overflow rate (SOR), kecepatan pengendapan, solid loading rate dan waktu detensi. Pada hasil analisis, nilai efisiensi penyisihan partikel TS pada setiap sampel berkisar antara 35-80%. Nilai SOR pada bak pengendapan diketahui berkisar antara 3-11 m3/m2∙hari. Kecepatan pengendapan berkisar antara 0,002-0,006 m/menit dan waktu detensi menghasilkan nilai sebesar 22-69 menit. Nilai parameter tersebut kemudian akan dianalisis menjadi nilai dimensi unit sedimentasi berdasarkan sampel yang memiliki nilai penyisihan TS paling besar., The coagulation-flocculation treatment is a technology that often used for paper and pulp wastewater treatment. The coagulation and flocculation unit requires a sedimentation unit to precipitate the floc in form of suspended solids and organic matter. Observed parameters in this study were Total Solid (TS) and Chemical Oxygen Demand (COD). It is necessary to analyze the four types of sedimentation, such as discrete settling, flocculant settling, hindered settling, and compression settling. The analysis of settling types will be resulting in parameters of the sedimentation unit design such as surface overflow rate, settling velocity, solid loading rate and detention time. In the analysis results, it is known that the efficiency of TS particle removal in each sample ranges from 35-80%. For the surface overflow rate in the settling basin ranges from 3-11 m3 /m2 ∙day. Settling velocity values ranged from 0,002-0,006 m/min and detention time parameter produces a value of 22-69 minutes. These parameter values will be analyzed into the design values in form of sedimentation unit design based on the sample with the largest TS removal value.
Keyword: coagulation, flocculation, particle, sedimentation, settling

Judul: Mitochondrial DNA Gene Organization and Phylogenetic Relationship of Naja siamensis
Abstrak: Naja siamensis is one of Asiatic cobra in the Family of Elapidae, known as a cryptic snake. It has many morphological variations that lead to misidentification. Misidentification can cause the wrong concept in developing antivenom types due to high snakebite cases occur in Thailand. Thus, an accurate species identification using a molecular approach is crucially required. Mitochondrial DNA has been used widely in snake molecular studies. These studies were aimed to determine the arrangement of the N. siamensis partial mitochondrial genes using reptile-oriented primers and to reveal the phylogenetic relationship among other species of Asian cobra. DNA extraction was carried out based on the standard DNA salting-out protocol and was conducted by bioinformatics analysis using BLASTn and MEGA 6 software. Gene annotation was performed against N. kaouthia complete genome. A total of 3121 bp of N. siamensis mtDNA genes were sequenced consisting of partial of six regions: 16S rRNA, ND1, tRNA-Ile, CRII region, tRNA-Leu, tRNA-Gln, and COI genes. The mtDNA gene organization of N. siamensis was predicted to has a similar pattern with the common Elapidae mtDNA gene organization. This study showed that there is a monophyletic form in Naja genus and N. kaouthia is the closest species with N. siamensis based on partial 16S rRNA and ND1 gene.
Keyword: 16S rRNA, Elapidae, ND1, phylogenetic relationship