Judul: Analisis Kecepatan Aliran Air Pada Filter Flow Up dan Filter Flow Down
Abstrak: Penggunaan system Recirculating Aquacultur System (RAS) diterapkan di daerah yang memiliki sumber air yang terbatas. Sistem tersebut merupakan konsep pemanfaatan air bersih yang disaring dan diresirkulasi untuk berbagai jenis manfaaat salah satunya untuk akuakultur. Aliran air yang terdapat pada sirkulasi juga memiliki kecepatan alir yang mengikuti bentuk sistem. Penelitian ini bertujuan mendapatkan analisa kecepatan aliran sistem filtrasi flow up dan flow down. Pengukuran pada pipa yang besar, mengakibatkan kecepatan aliran air juga semakin besar, kemudian skema dengan bentuk pipa flow up mendapatkan nilai debit aliran air yang lebih besar dibandingkan skema bentuk pipa flow down. Filter yang digunakan juga berpengaruh terhadap nilai kecepatan aliran air dimana nilai kecepatan alirnya lebih besar dibandingkan sebelum menggunakan filter. Penelitian ini diharapkan dapat memberikan referensi bagi pemilihan jenis filter flow up dan flow down, pemilihan ukuran pipa untuk skema resirkulasi air pada akuakultur, dan cara menganalisis debit pompa terhadap kesesuaian skema sirkulasi kolam ikan., The use of the Recirculating Aquaculture System (RAS) is applied in areas that have limited water sources. This system is a concept of using filtered and recirculated clean water for various types of benefits, one of which is for aquaculture. The water flow contained in the circulation also has a flow rate that follows the shape of the system. This study aims to obtain an analysis of the flow velocity of the flow up and flow down filtration systems. Measurements on large pipes result in a greater velocity of water flow, then the flow-up pipe scheme obtains a greater water flow rate than the flow-down pipe scheme. The filter used also affects the value of the velocity of the water flow where the value of the flow rate is greater than before using the filter. This research is expected to provide a reference for selecting flow up and flow down filter types, selecting pipe sizes for water recirculation schemes in aquaculture, and how to analyze pump discharge for the suitability of fish pond circulation schemes.
Keyword: Aquaculture, Discharge, Filters, Flow Up and Flow Down Pipes, Water Flow Velocity

Judul: Optimization of Effluent Water Quality in Recirculating Aquaculture System Based on Variations in Pre-Treatment Configurations of Nanofiltration Membrane Technology
Abstrak: Teknologi membran nanofiltrasi (NF) yang diterapkan pada sistem resirkulasi akuakultur (RAS) memiliki kekurangan berupa terjadinya fouling. Fouling dapat direduksi dengan adanya unit pra-pengolahan seperti unit filter multimedia (FMM) serta filter karbon aktif (FK). Oleh karena itu, penelitian ini dilakukan pengaturan konfigurasi pada RAS menggunakan FMM, FK, dan membran NF90-4040 agar diketahuinya pengaturan sistem pengolahan terbaik dalam mereduksi kontaminan pada air limbah akuakultur. V1 (FMM-FK-NF) merupakan konfigurasi dengan nilai total efisiensi tertinggi dalam menurunkan konsentrasi kontaminan amonia sebesar 97,5% dan nitrit sebesar 100%. Unit FMM pada V1 dapat mereduksi amonia 36,25% dan nitrit 35,48% serta unit FK dapat mereduksi amonia dan nitrit sebesar 86,27% dan 10%. Selain itu, unit NF dapat mereduksi amonia sebesar 71,43% dan nitrit sebesar 100%. Reaktor RAS optimal dalam bekerja mereduksi nitrat dan TSS pada V1 sebesar 100%. V1 memiliki fenomena penurunan nilai fluks dan peningkatan resistensi yang lebih kecil daripada kondisi V2 (FMM-NF) dan V3 (FK-NF). Pengembangan model konsentrasi permeate memiliki kemampuan yang sangat baik dalam menggambarkan dan memprediksi proses filtrasi menggunakan membran NF dengan nilai Aw, Bs, dan X berbeda-beda pada setiap variasi., The nanofiltration (NF) membrane technology implemented in the recirculating aquaculture system (RAS) suffers from fouling issues. Fouling can be reduction by incorporating pre-treatment units such as the multimedia filter unit (FMM) and activated carbon filter (FK). Therefore, this study aims to investigate the configuration optimization of the RAS using FMM, FK, and NF90-4040 membrane to determine the most effective treatment system for reducing contaminants in aquaculture wastewater. Configuration V1 (FMM-FK-NF) demonstrated the highest overall efficiency in reducing ammonia concentration by 97.5% and nitrite by 100%. The FMM unit in V1 reduced ammonia and nitrite levels by 36.25% and 35.48% respectively, while the FK unit reduced ammonia and nitrite levels by 86.27% and 10% respectively. Additionally, the NF unit reduced ammonia by 71.43% and nitrite by 100%. The optimized RAS reactor achieved 100% reduction in nitrate and TSS in V1. Furthermore, V1 exhibited a smaller decline in flux value and resistance increase compared to V2 (FMM-NF) and V3 (FK-NF) conditions. The developed permeate concentration model showed excellent ability to describe and predict the filtration process using NF membranes with varying values of Aw, Bs, and X for each variation.
Keyword: flux, pre-treatment configuration, nanofiltration membrane, RAS

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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