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: The Effect of Pressure Variations on the Application of Nanofiltration Membranes in Aquaculture Recirculating Systems
Abstrak: Penggunaan membran nanofiltrasi dengan pengoperasian jangka panjang sebagai unit pengolahan menimbulkan fouling yang tak terhindarkan akibat adanya proses polarisasi konsentrasi pada permukaan membran. Konsentrasi terpolarisasi dan kenaikan tekanan osmotik juga penyebab penurunan fluks permeate. Penelitian bertujuan menganalisis pengaruh tekanan yang diterapkan pada sistem resirkulasi akuakultur dengan teknologi membran nanofiltrasi terhadap konsentrasi kontaminan permeate. Penelitian ini dilakukan pada bulan Maret – Juli 2023 yang berlokasi di Laboratorium Terpadu Departemen Teknik Sipil dan Lingkungan, Fakultas Teknologi Pertanian, Institut Pertanian Bogor. Penelitian ini menggunakan tiga variasi tekanan yang berbeda yakni tekanan 5, 6, dan 7 bar. Variasi 7 bar memiliki nilai efisiensi penolakan kontaminan amonia dan nitrit sebesar 100%. Pemodelan dilakukan untuk estimasi konsentrasi kontaminan nitrit di permeate membran nanofiltrasi. Hasil uji validasi dengan regresi linear menunjukkan pengembangan pemodelan sangat baik dalam mengestimasi konsentrasi kontaminan permeate membran nanofiltrasi karena memiliki indikator nilai R square mendekati satu., The use of nanofiltration membranes with long-term operation as a treatment unit causes unavoidable fouling due to the concentration polarization process on the surface of the membrane. Polarized concentrations and increased osmotic pressure also cause a decrease in permeate flux. The aim of this study was to analyze the effect of pressure applied to the aquaculture recirculating system with nanofiltration membrane technology on the concentration of permeate contaminants. This research was conducted in March – July 2023 located at the Integrated Laboratory of the Department of Civil and Environmental Engineering, Faculty of Agricultural Technology, Bogor Agricultural University. This study used three different pressure variations, namely 5, 6, and 7 bar. The 7 bar variation has an efficiency value of 100% for rejecting ammonia and nitrite contaminants. Modeling was performed to estimate the concentration of nitrite contaminants in the permeate nanofiltration membrane. The results of the validation test with linear regression showed that the development of modeling was very good in estimating nanofiltration membrane permeate contaminant concentrations because it had an indicator value of R square close to one.
Keyword: estimasi konsetrasi, fluks, membran nanofiltrasi, tekanan

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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