Perbandaran pesat dan pertumbuhan penduduk di Malaysia telah membawa kepada peningkatan permintaan air yang tinggi. Ia juga menyebabkan peningkatan dalam tahap pencemaran, terutamanya kepada jasad air yang bertindak sebagai sumber bekalan air. Penggunaan sistem penapisan tebing sungai (RBF) sebagai kaedah pra-rawatan di loji rawatan air telah menjadi semakin penting dalam beberapa tahun kebelakangan ini. Disebabkan proses peyingkiran semula jadi penapis dan penyerapan oleh pelbagai jenis media penapis, RBF mempunyai potensi yang cerah untuk digunakan sebagai penapis bahan cemar. Dalam kajian ini, batu kapur digunakan sebagai media penapis dalam sistem RBF skala makmal. Ciri-ciri fizikal dan kimia batu kapur telah ditentukan terlebih dahulu sebelum dan selepas eksperimen dengan menggunakan kaedah pengimbasan mikroskopik pengimbasan (SEM) dan X-Ray Fluorescence. Dua rentang saiz batu kapur, 1.18 mm-2 mm dan 2.36 mm- 4.75 mm digunakan sebagai media berliang dan sampel air diambil dari Sungai Kerian, Lubok Buntar, Perak sebagai tapak kajian kes. Kecekapan penyingkiran parameter air terpilih iaitu pepejal terampai, jumlah coliform, E. coli, UV254, warna dan kekeruhan ditentukan dalam tempoh 15 hari eksperimen. Saiz zarah dan morfologi media juga ditentukan dengan menggunakan kaedah SEM. Keputusan SEM ini, ia menunjukkan bahawa kapur terdiri daripada belahan rhombohedral dan gabungan kristal saiz mikron bersama-sama dengan saiz liang kecil. Batu kapur yang digunakan dalam kajian ini adalah dari jenis kalsit. Kalsit mengandungi 52.93% kalsium oksida (CaO) dan 0.66% magnesium oksida (MgO). Hasil daripada kajian turus menunjukkan bahawa penyingkiran zarah dan jumlah pepejal terlarut (TDS) tidak dapat ditentukan kerana larutan batu kapur yang terlepas sebagai tapisan. Batu kapur dengan saiz 1.18mm-2.0mm dan 2.36mm-4.75mm menunjukkan perbezaan ketara dalam kecekapan penyingkiran jumlah coliform, pepejal terampai, E. coli, kekeruhan, UV254 dan warna. Kesan penyingkiran yang diperolehi untuk parameter pepejal terampai (SS) , jumlah coliform, E. coli, UV254, warna dan kekeruhan adalah masing-masing 91% -97%, 82% -93%, 93% -98%, 28% -40% , 60% -83% dan 78-83%, bagi kedua-dua turus. Tiada terobosan yang diperhatikan dalam tempoh 15 hari eksperimen. Batu kapur yang bersifat alkali telah meningkatkan nilai pH dari 6.19 sebelum tapisan kepada 6.53 dan 6.57 efluen untuk kedua-dua turus.
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The rapid urbanization and growth of the population in Malaysia have led to increase demand for water. It has also caused an elevation of pollution level, especially in water bodies which acts as a water source. The use of riverbank filtration system (RBF) as pre-treatment method in the water treatment plant has become a common interest in recent years. Due to natural attenuation process of filtration and sorption by various types of filter media, RBF has high potential to filter contaminants. In this study, limestone was used as a filter media in a laboratory scale RBF system. The physical and chemical characteristics of limestone were first determined before and after the experiment by using scanning electron microscopy (SEM) and x-ray fluorescence (XRF) methods. Two difference ranges of limestone sizes, 1.18 mm-2 mm and 2.36 mm- 4.75 mm were used as a porous media and the sample of water was taken from Sungai Kerian, Lubok Buntar, Perak as a case study site. The removal efficiencies of selected water parameters namely suspended solids, total coliform, E. coli, UV254, colour and turbidity were determined within 15 days of the experiment. The sizes of particles retained and the morphology of media were also determined by using particle analyzer and SEM machine, respectively. From the SEM results, it showed that the limestone was made of rhombohedral cleavage plane and the combination of micron-size crystal along with the small size of pores. The limestone used in this study was mainly made up of calcium carbonate (CaCO3) and categorized as calcite. The calcite contains 52.93% of calcium oxide (CaO) and 0.66% of magnesium oxide (MgO). The result from the column study showed that the removal of particles and total dissolved solids (TDS) using limestone could not be determined due to the leaching of limestone which added the impurities into the water. Limestone with size 1.18mm-2.0mm and 2.36mm-4.75mm did show a significant difference in the removal efficiencies of total coliform, suspended solid, E. coli, turbidity, UV254 and colour. The removal efficiencies obtained for the following parameters suspended solids (SS), total coliform, E. coli, UV254, colour and turbidity were 91%-97%, 82%-93%, 93%-98%, 28%-40%, 60%-83% and 78-83%, respectively for both column. No breakthrough was observed within 15 days of the experiment. The addition of limestone has increased the pH of the water sample from 6.19 before filtration to 6.53 and 6.57 for the final pH at effluent in column 1 and column 2 respectively.
Removal of solids, total coliform, e.coli, uv254, colour and turbidity using limestone filter in riverbank filtration / Siti Nur Aishah Mohd Yusoff