Judul: The Design of Simple Water Reclaim System for Domestic Wastewater (Greywater)
Abstrak: Pertumbuhan populasi, perkembangan industri dan agrikultur, urbanisasi serta faktor kontaminasi dan kekeringan sumber, menjadi tantangan dalam pemenuhan kebutuhan air. Indonesia adalah negara kaya akan sumber air namun seiring dengan perkembangan pembangunan dan perubahan iklim, beberapa kota besar dilaporkan sedang mengalami krisis air dan penurunan kualitas air tanah. Cara kontruktif yang dapat dilakukan masyarakat dalam mendukung perbaikan kualitas sumber air salah satunya adalah usaha mengurangi dan mendaur ulang air limbah. Laporan statistik lingkungan hidup Indonesia tahun 2020 menyatakan lebih dari separuh limbah rumah tangga yang berasal dari mandi, mencuci, kegiatan dapur dialirkan ke selokan atau sungai. Perancangan sistem daur ulang air limbah rumah tangga (greywater) untuk penggunaan kembali dalam ruang lingkup pencucian kendaraan menggunakan tiga tahap secara berurutan yaitu koagulasi menggunakan koagulan alum, filtrasi dengan menggunakan metode multi media filter, dan disinfeksi menggunakan lampu ultraviolet. Pengujian paramer pH, oksigen terlarut, padatan terlarut, padatan tersuspensi dan kadar surfaktan akan dilakukan untuk menentukan kualitas air dengan standar baku yang sesuai dengan tujuan aplikasi air daur ulang. Kata kunci: air, daur ulang air, air limbah, greywater, filtrasi, koagulasi, disinfeksi, ultraviolet., Population growth, industrial and agricultural development, urbanization, and factors of contamination and sources' dryness are challenges in meeting water needs. Indonesia is a country with a lot of water resources. However, in population growth and climate change, several big cities are reportedly experiencing a water crisis and decreasing groundwater quality. One of the constructive ways that the community can support improving the quality of water sources is to reduce and recycle wastewater. The 2020 Indonesian Environmental Statistics report that more than half of household waste from bathing, washing, and kitchen activities goes into sewers, ditches, or rivers. The design of a household wastewater (greywater) reclaim system for application in the scope of vehicle washing uses three sequential stages: coagulation using alum coagulant, filtration using the multi-media filter method, and disinfection using an ultraviolet lamp. Tests for parameters of pH, dissolved oxygen, dissolved solids, suspended solids, and surfactant levels will be carried out to determine the quality of water with standards that are suitable for reclaimed water applications. Keywords: water, water reclaim, wastewater, greywater, filtration, coagulation, disinfection, ultraviolet.
Keyword: water, water reclaim, wastewater, greywater, filtration, coagulation, disinfection, ultraviolet

Judul: Phytoremediation of Greywater Liquid Waste, Chicken Slaughterhouses, and Tofu Factories Using Water Scape (Ipomoea Aquatica Forsk)
Abstrak: Kegiatan masyarakat sehari-hari, pembuangan air limbah industri, dan rumah tangga merupakan faktor-faktor penyebab terjadinya pencemaran lingkungan. Tujuan penelitian ini adalah membandingkan tingkat pertumbuhan tanaman kangkung air (Ipomoea aquatica Forsk) menggunakan limbah cair greywater (domestik), rumah pemotongan ayam, dan pabrik tahu. Proses penanaman tumbuhan secara hidroponik, pengujian kualitas air, dan pengambilan sampel dilakukan di Laboratorium Seameo Biotrop, Kecamatan Bogor Selatan, Kota Bogor dari Desember 2022 hingga Januari 2023. Analisis data berupa perhitungan nilai parameter kualitas air dan perhitungan rata-rata pengukuran vegetatif. Hasil analisis data yaitu penurunan nilai kualitas air (BOD, COD, dan TSS) dan pertumbuhan vegetatif tanaman yang menunjukkan bahwa limbah cair rumah pemotongan ayam dan greywater lebih efisien tingkat pertumbuhannya dibandingkan limbah cair pabrik tahu. Selain itu, hasil perhitungan indeks pencemaran pada limbah cair greywater dan pabrik tahu mengalami penurunan yang signifikan dikarenakan kandungan organiknya sudah menurun akibat proses fitoremediasi dan pengenceran air dan rumah pemotongan ayam mengalami kenaikan sedikit dikarenakan memiliki kandungan amonia., Daily community activities, disposal of industrial and household wastewater are factors that cause environmental pollution. The purpose of this study was to compare the growth rates of water spinach plants (Ipomoea aquatica Forsk) using greywater (domestic) wastewater, chicken slaughterhouses, and tofu factories. The process of growing plants hydroponically, testing water quality, and taking samples was carried out at the Seameo Biotrop Laboratory, South Bogor District, Bogor City from December 2022 to January 2023. Data analysis in the form of calculating the value of water quality parameters and calculating the average vegetative measurements. The results of data analysis, namely the decrease in the value of water quality and plant growth which shows that the liquid waste of chicken slaughterhouses is more efficient in its growth rate compared to greywater wastewater and chicken slaughterhouses. In addition, the results of the calculation of the pollution index in greywater and tofu factory wastewater have decreased significantly because the organic content has decreased due to the phytoremediation process and water dilution and the chicken slaughterhouse has increased slightly due to the ammonia content.
Keyword: Liquid waste, phytoremediation, water quality, water spinach

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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