Judul: Lokasi dan Luas Sistem Lahan Basah Buatan di Area Bekas Tambang DAS Sekayan, Provinsi Kalimantan Utara
Abstrak: Air asam tambang muncul pada kegiatan penambangan terbuka batu bara sebagai polutan bagi lingkungan. Sistem lahan basah buatan merupakan salah satu cara memperbaiki kualitas air sebelum dialirkan menuju sistem jaringan sungai. Penentuan kesesuaian lokasi sistem lahan basah buatan menggunakan metode pembobotan dari enam parameter yaitu elevasi, kemiringan lahan, penggunaan lahan, posisi sub daerah tangkapan air, jarak dari saluran/kanal, dan jarak dari kolam pemantauan. Sedangkan kebutuhan luas sistem lahan basah buatan ditentukan oleh perhitungan debit limpasan dari data curah hujan. Hasil analisis menyatakan kelas sesuai (kelas 4) dan sangat sesuai (kelas 5) seluas masing-masing 43,96 ha (47,93%) dan 9,20 ha (10,03%). Besarnya debit limpasan adalah 0,41 m3 dtk-1, dengan ketinggian genangan setinggi 0,6 m, kebutuhan panjang dan lebar sistem lahan basah buatan masing-masing adalah 171,99 m dan lebar 115,97 m, menghasilkan angka kebutuhan luas sebesar 1,98 ha. Hasil penelitian diharapkan menjadi informasi awal perancangan sistem lahan basah buatan yang diintegrasikan dengan rencana dan kondisi terkini area tambang oleh perusahaan.
Keyword: Artificial wetland system, Acid mine drainage, Runoff discharge, Weighting method

Judul: Pengelolaan Air Asam Tambang Melalui Rawa Buatan Berbasis Bahan In Situ di Pertambangan Batu Bara (Studi Kasus di Site Pertambangan Sambarata PT. Berau Coal, Kabupaten Berau, Provinsi Kalimantan Timur)
Abstrak: Acid mine drainage (AMD) is the main problem in open pit mining due to extremely low pH and high solubility of metals. Metal solubility can be reduced biochemically in an anaerobic condition. Wetland is typical ecosystem having anaerobic conditions and characterized by low potential redox (Eh). Low Eh can be achieved if the wetland has enough quantities of organic matter. This research was aimed to design an artificial wetland that was constructed using locally available materials, and test it for AMD treatment, to identify AMD remediation process within artificial wetland, and to identify biomass production of artificial wetland plants. An artificial wetland of 1.028 m2 has been constructed. It’s composed of two organic walls, two growing ponds, and one collecting pond. Each component separated by a dike. Each organic wall was placed next to growing pond that were planted by Typha sp. and Cyperus sp. Collecting pond was planted by Eichornia crassipes. Artificial wetland was incubated until redox potential (Eh) of inundated water was less than 100 mV. Operation of artificial wetland started after incubation was done. Result showed that during incubation Eh of inundated water has decreased to below 100 mV after 5 days. Reduction and precipitation has occured during AMD remediation process. Sulphate, iron and manganese were accumulated in the root of each plant. Typha sp. has better growth rate than other plants and potentially to produce a higher biomass.
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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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