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: 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: Distribution and Diversity of Ectoparasite Mites on Geckos in Indonesia
Abstrak: Data on the diversity and dispersal of parasitic mites on house geckos in Indonesia are very scarce. In this work, the distribution and diversity of mites living on three species of house geckos, namely Cosymbotus platyurus, Hemidactylus frenatus, and H. garnotii collected throughout Indonesia, has been elaborated. Geckos and mites were captured and immediately preserved in 70% ethanol. Whole mount of the mites was prepared by clearing in lactophenol followed by mounting on polyvinyl lactophenol solutions. The SEM preparation was conducted to examine the detail morphological characters of the mites. The results showed that among 448 individuals of geckos, 221 geckos were infected by Geckobia mites. Prevalences of C. platyurus, H. frenatus, and H. garnotii infested by mites were 14.8%, 50.69%, and 79.6%, respectively. Three different spesies of Geckobia (G1, G2, and G3) could be differentiated; and based on similarities of their morphological characters to ones described in published literatures, Geckobia G2 is Geckobia glebosum and Geckobia G3 is Geckobia bataviensis while G1 could not be identified to the species level. The highest mean intensity of Geckobia G1 infestation was found on H. garnotii (I=7.0), G. glebosum infestation on H. frenatus (I=3.5), and G. bataviensis infestation on H. garnotii (I=11.8). In general, C. platyurus was infested by the least number of mites. Geckobia G1 were found living on the skin folds on the claws, G. glebosum were found mainly on the body and thigh, and G. bataviensis were found on almost all parts of the host’s body. Geckobia mites are distributed randomly throughout Indonesian Archipelago, following the pattern of distribution of their hosts. So it is concluded that Geckobia G1, G. glebosum, and G. bataviensis are sympatric.
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