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: 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: Lejeuneaceae Subfamily Ptychanthoideae (Hepaticae) in  West Java
Abstrak: Subfamily Ptychanthoideae of the family Lejeuneaceae (Hepaticae) in West Java is still poorly known. Publications on this subfamily are out of dated and written in the 19th or early of 20th century. The last taxonomic treatment of Ptychanthoideae of West Java was in 1933, many species names have changed since then. Studies on Ptychanthoideae of West Java are urgently needed. Studies on the Ptychanthoideae were based on the specimens collected from West Java. A total number of 361 of specimens deposited in the Herbarium Bogoriense (BO), Herbarium Biotrop (BIOT), Gottingen Herbarium (GOET) and Bangi Herbarium (UKMB) were examined, those are old and several recent specimens collected in West Java. Recent collections were made from Telaga Warna, Ciater, Gunung Halimun Salak National Park, Cibodas Botanical Garden, Bodogol Education Center and Conservation (Gunung Gede Pangrango National Park), University of Indonesia Campus Depok, including several collections from Banten Province. Twenty four species of Lejeuneaceae subfamily Ptychanthoideae are known from West Java, belonging to 8 genera namely Acrolejeunea (Spruce) Schiffn. (2 species), Archilejeunea (Spruce) Schiffn. (1 species), Lopholejeunea (Spruce) Schiffn. (10 species), Mastigolejeunea (Spruce) Schiffn. (3 species), Ptychanthus Nees (1 species), Schiffneriolejeunea Verd. (1 species), Spruceanthus Verd. (2 species) and Thysananthus Lindenb. (4 species). Two new records of Ptychanthoideae: Mastigolejeunea indica Steph. and Thysananthus minor Verdoorn are reported for Java. A determination key to the species is presented including their descriptions and illustrations.
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