Hasil Pencarian  ::  Simpan CSV :: Kembali

Abstrak :
Pemodelan fisik penjalaran pencemar menggunakan seepage tank yang sudah dilakukan oleh Herlambang (2012) dan Triandhika (2013) sudah bisa memvisualisasikan adveksi dari penjalaran pencemar namun belum bisa memvisualisasikan fenomena adveksi dan dispersi yang mengalami refaksi. Tujuan penelitian ini adalah untuk mengembangkan protokol alat seepage tank untuk mampu memvisualisasikan penjalaran pencemar pada perched aquifer. Media berpori yang digunakan adalah pasir dengan dua jenis yang berbeda nilai konduktivitas hidroliknya. Pasir dialiri air hingga jenuh dan dibiarkan dalam kondisi pengaliran steady lalu pencemar dialirkan ke lapisan pasir dan dilihat visualisasi penjalarannya. Hasil dari penelitian ini berupa protokol yang merupakan pengembangan protokol sebelumnya. Pengembangan dari protokol sebelumnya adalah (1) penetapan kondisi batas kedap air pada bagian tepi kiri dan kanan kolom pasir di dalam seepage tank, (2) pengaturan debit inflow menjadi sekecil mungkin sehingga permukaan pasir tidak tergerus, (3) penggunaan jarum infus sebagai pengganti injektor, dan (4) pengaturan debit aliran pencemar sebesar 0,005 mL/detik. ...... Previously, Herlambang (2012) dan Triandhika (2013) were able to visualize contaminant advection with physical modeling using seepage tank However contaminant transport through heterogeneous systems, according to Freeze and Cherry (1979), they refract as passes from one medium to another with different values of hydraulic conductivity. The purpose of this study was to develop a protocol for the seepage tank and to visualize contaminant transport flow through perched aquifer. Porous media in seepage tank consist of sand with two different types of hydraulic conductivity values. Sand was saturated and the flow was in steady conditions, thencontaminantwas discharged into sand layers. Visualization of contaminnant advection and dispersion is recorded and analized. Result of this research is a protocol that is an improvement from the previous protocol; (1) setting impermeable condition on left and right of sandbox inside seepage tank, (2) controlling pump inflow as low as possible to prevent scouring on top of sandbox, (3) replacing injector into infuse needle, and (4) setting contaminant loading 0,005 mL/s.

Abstrak :
This textbook employs a technical and quantitative approach to explain subsurface hydrology and hydrogeology, and to offer a comprehensive overview of groundwater-related topics such as flow in porous media, aquifer characterization, contaminant description and transport, risk assessment, and groundwater remediation. It describes the characterization of subsurface flow of pristine and polluted water and provides readers with easily applicable tools for the design of water supply systems, drinking-water source protection, and remediation interventions. Specific applications range from groundwater exploitation as a drinking water supply to the remediation of contaminated aquifers, from the definition and safeguarding of drinking-water sources to the assessment of human health risks in connection with groundwater contamination events. The book represents an ideal learning resource for upper-undergraduate and graduate students of civil engineering, environmental engineering, and geology, as well as practitioners in the fields of water resource management and environmental protection who are interested in groundwater engineering and technical hydrogeology.

Abstrak :
Aliran air tanah mengalir disebabkan oleh perbedaan tinggi hidraulik. Dalam menurunkan persamaan, massa jenis sering diasumsikan konstan. Persamaan ini dapat dan sering diaplikasi di tempat yang jauh dari wilayah pantai. Namun, persamaan tersebut tidak dapat diaplikasikan di wilayah/akuifer pantai karena massa jenis merupakan sebuah fungsi dari konsentrasi. Air laut yang mengandung garam NaCl menginduksi air tanah sehingga menyebabkan perubahan massa jenis. Peristiwa ini disebut transpor pencemar. Perbedaan massa jenis menyebabkan perubahan tinggi hidraulik. Dalam kondisi aliran tidak berubah menurut waktu (steady), transpor pencemar tidak terlalu berpengaruh terhadap perubahan tinggi hidraulik. Sebaliknya, dalam kondisi aliran yang berubah menurut waktu (unsteady), transpor pencemar sangat berpengaruh. Hal ini menyebabkan terjadi aliran air tanah didorong oleh perbedaan massa jenis (driven density). Untuk memodelkan masalah ini, digunakan metode numerik beda hingga dan diterapkan pada spread sheet program Microsoft Excel. ......Groundwater flow caused by hydraulic head. In term of governing equation, density often assumed as a constant value. This equation often used far away from coastal area. However, those equation can?t be used in coastal area/aquifers because density is a function of concentration. Saltwater which is containing salt (NaCl) induces freshwater so that causing changes in the density of water. This phenomenon called contaminant transport. The changing of density caused changes in the hydraulic head. At steady condition, contaminant transport does not significantly affect to the hydraulic head. Otherwise, contaminant transport significantly affect to the hydraulic head. This is caused driven density groundwater flow. To solving this problem, is used numerical method (finite difference method) and applied to the spread sheet of Microsoft Excel.