Judul: Penentuan Kriteria Variabel Operasional Unit Sedimentasi Limbah Cair Industri Kertas Berdasarkan Tipe Pengendapan Lumpur Aktif
Abstrak: Secondary sedimentation unit in activated sludge is often used due to high concentration of biomass as an effect from organic material degradation with biological process. The sedimentation process is divided into four types of, there are discrete particle settling, flocculant settling, hindered settling and compression settling. The study of sedimentation types is for determining operational variables criteria of secondary sedimentation unit and give a recommendation about unit capacity in the field scale. This study use three variation of HRT in order to know it’s impact to particles characteristic and settling velocity. The result of this study show that particles in paper mill wastewater has an ability to turn into floc naturally and increase the settling velocity, although flocullant and coagulant still needed to maximize TS reduction. In order to fulfill requirements of the optimum area, lowest cost instalation, and the optimum efficiency, then the operation of activated sludge secondary sedimentation was carried out with HRT of 6 hour, SLR limit of 102,46 kg/ m2.day, and an HLR of 42,16 m3/ m2.day., Unit sedimentasi sekunder di dalam lumpur aktif diperlukan karena tingginya konsentrasi biomassa akibat degradasi material organik limbah cair industri kertas secara biologis. Proses pengendapan di dalam sedimentasi sekunder terbagi menjadi empat tipe pengendapan, yaitu discrete particle settling, flocculant settling, hindered settling dan compression settling. Penelitian keempat tipe pengendapan bertujuan untuk menentukan kriteria variabel operasional unit sedimentasi sekunder dan memberi rekomendasi kapasitas pengolahan limbah cair untuk skala lapangan. Penelitian ini dilakukan dengan menerapkan 3 variasi HRT, yaitu HRT 6 jam, 8 jam, dan 12 jam untuk mengetahui pengaruh perubahan HRT terhadap karakteristik partikel dan kecepatan pengendapan. Hasil penelitian menunjukkan bahwa partikel limbah cair industri kertas memiliki kecenderungan untuk membentuk flok secara alami dan meningkatkan kecepatan pengendapan, meskipun pembubuhan flokulan dan koagulan tetap dibutuhkan untuk memaksimalkan reduksi TS. Sebagai upaya memenuhi kebutuhan luas area optimum, biaya instalasi terendah, dan efisiensi unit terbaik, maka operasional unit sedimentasi sekunder lumpur aktif dijalankan dengan HRT 6 jam, SLR 102,46 kg/m2.hari, dan HLR sebesar 42,16 m3/m2.hari.
Keyword: compression settling, discrete particle settling, flocculant settling, hindered settling

Judul: Estimation of Biokinetic Parameters of Activated Sludge Process for Paper Mill Industry Wastewater in Unsteady State Conditions
Abstrak: Industri kertas menghasilkan polusi air dalam kuantitas yang cukup besar sehingga membutuhkan unit pengolahan lumpur aktif untuk mereduksi kandungan pencemar pada air limbah. Penelitian ini bertujuan untuk memperoleh hubungan biokinetika terhadap kinerja unit lumpur aktif sehingga memperoleh nilai efisiensi terhadap peningkatan kualitas efluen. Penelitian ini diawali dengan tahap konfigurasi reaktor lalu menganalisis parameter kualitas air limbah sehingga dapat digunakan untuk mencari pemodelan biokinetika yang presisi. Berdasarkan penelitian ini, persentase nilai removal chemical oxygen demand (COD) pada waktu detensi (HRT) 6, 8, dan 12 jam berturut-turut sebesar 56,64%; 64,92%; dan 70,80%. Pengaruh biokinetika terhadap unit pengolahan lumpur aktif tidak hanya untuk memprediksi pengolahan air limbah, tetapi juga merancang, mengoperasikan, dan mengendalikan sistem pengolahan. Nilai biokinetika terpilih berdasarkan analisis statistika dalam kondisi unsteady state tanpa inhibitor yaitu Persamaan Ming pada HRT 12 Jam dengan nilai Ke¸Y, μmax, dan Ks masing-masing sebesar 0,084/hari; 1,39 mgMLVSS/mgCOD; 2,12/hari; dan 26.279 mg/L. Selain itu, biokinetika terpilih dengan mempertimbangkan inhibitor nitrit yaitu Persamaan Jerusalimski pada HRT 8 jam dengin nilai nilai Ke¸Y, μmax, dan Ks berturut-turut sebesar 0,896/hari; 2,488 mgMLVSS/mgCOD; 2,01/hari; dan 57,57 mg/L. Maka dari itu, modifikasi unit pengolahan lumpur aktif perlu mempertimbangkan kondisi lingkungan agar nilai parameter biokinetika yang diperoleh lebih baik., The paper mill industry produces water pollution in large quantities that it requires an activated sludge to reduce the pollutant content in wastewater. This study aims to obtain a biokinetic relationship to the performance of the activated sludge so as to obtain an efficiency value for improving effluent quality. This research begins with the reactor configuration and then analyzes the wastewater quality parameters so that it can be used to find precise biokinetic modeling. Based on this study, the percentage of chemical oxygen demand (COD) removal at 6, 8, and 12 hours detention time was 56,64%; 64,92%; and 70,80%. The effect of biokinetics on activated sludge is not only to predict wastewater treatment, but also to design, operate and control treatment systems. Selected biokinetic values based on statistical analysis in unsteady state conditions without inhibitors is the Ming Equation at 12 Hours HRT with Ke¸Y, µmax, and Ks values of 0,084/day; 1,39 mgMLVSS/mgCOD; 2,12/day; and 26.279 mg/L. In addition, biokinetics was selected taking into account the nitrite inhibitor, namely the Jerusalimski equation at 8 hours HRT with the values of Ke¸Y, µmax, and Ks respectively 0,896/day; 2,488 mgMLVSS/mgCOD; 2,01/day; and 57,57 mg/L. Therefore, Modification of activated sludge treatment needs to consider environmental conditions so that the obtained biokinetic parameter values are better
Keyword: Biokinetika, Lumpur aktif, Industri kertas

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