Browsing by Author "Nawarathna, T.N.T.K."

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    Equilibrium Isotherm Analysis of Methylene Blue Adsorption by Natural Sri Lankan Ball Clay
    (Uva Wellassa University of Sri Lanka, 2019-02) Nawarathna, T.N.T.K.; Kalpage, C.S.
    Synthetic dyes are used in the textile industry production as raw materials. Excess and dye-containing wastewater are released to the environment without proper treatments. Consequently, textile wastewater creates environmental hazards. In Sri Lanka, textile industry cannot release their wastewater without treating upto industrial discharge limits stipulated by Central Environmental Authority. The main objective of this study was to Sri Lankan ball clay has been investigated as low cost and eco-friendly adsorbent for the removal methylene blue from aqueous solution. The powder X-ray diffraction (XRD) analysis was carried out to find the structure and the type of clay mineral present in the bulk clay sample. Batch system experiments were carried observing an effect of the adsorbent dosage, contact time and initial concentration. Equilibrium isotherm of the clay materials was studied Freundlich and Langmuir model. According to the results of the influence of adsorbent dose, the removal percentage and adsorption capacity almost became constant at the dose of 6.8 g/100 ml. Therefore, it was considered the best dosage of adsorbent. As a result of contact time, it was found that the adsorption tends to attain the equilibrium in near 270 min (4.5 h). It was considered the saturation time. The results indicated that increasing adsorption capacity with increasing concentration. The equilibrium of the ball clay was found the Freundlich isotherm model was more suitable than the Langmuir model. Since the high value of the Freundlich correction coefficient (R2 = 0.9730) than the Langmuir correction coefficient (R2 = 0.9266). A conclusion is Sri Lankan ball clay can be employed as the low-cost alternative for removing the dye from industrial wastewater.
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    Water pollution study in Nalanada Lake to improve the Water quality of Naula Water Treatment Plant
    (Uva Wellassa University of Sri Lanka, 2015) Nawarathna, T.N.T.K.; Makehelwala, M.
    Water is the largest natural resources of Sri Lanka although only a relatively low percentage of total population is getting safe and clean water for daily use. Water is using for Drinking, bathing, washing, and cleaning. Beside it is used for agriculture, industrial, hydropower generation. The Nalanda reservoir located in Naula, Matale district is the main water source of Naula Water Treatment Plant of National Water supply and Drainage Board (NWSDB). On the other hand NWSDB faces a big problem in the dry season because pumping water had a less amount of Dissolved Oxygen (DO) and occurring black color in pumping water. The dissolved oxygen (DO) concentration is a primary measurement of a stream’s healthiness. The dissolved oxygen concentration responds to the biochemical oxygen demand (BOD) load. Investigators have continuously studied the dissolved oxygen uptake characteristics in stream water in relation to different sinks and sources in order to develop mathematical models describing the DO consumption. In this reservoir percent high amount of Algae due to high nutrients content such as nitrate and phosphorous and change that algae type seasonally. One of the objectives of this research study is that Nitrate and Phosphorus variation in reservoir. And Main Objective was identification of the Dissolved Oxygen (DO) Variation in Nalanda reservoir. Methodology In this study six sampling location points were selected and studied the variation of nitrate, phosphorous and DO of these sampling points for four weeks of time. These data were collected in rainy and dry season. Samples were collected from the different distances from the intake of Naula Water Supply System. Totally 24 samples were collected from the upstream of the reservoir. Basically, the selected pollution points are surrounding point of the reservoir. Samples were taken from different morphological units of the reservoir. DO was analyzed at the sample collected points and COD and BOD also analyzed using the Standard laboratory procedures. Finally DO concentration variation was analyzed by using mathematical model called Streeter- phelps. Results and discussion Eutrophication of water body is occurred under high nutrients. The nutrients such as nitrate and phosphate distribution within selected pollution points in Nalanda reservoir is shown in figure 1. The recommended phosphate level for maintaining healthy water to minimize algae growth is 0.1 mg/L and nitrate level is 10 mg/L (USEPA). The results shown below indicated that the nitrate level was within required limit and phosphate level was exceeded limit. Therefore, phosphate consuming algae species can occur in Nalanda reservoir during this period.
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    Water Pollution Study in Nalanda Lake to Improve the Water Quality of Naula Treatment Plant
    (Uva Wellassa University of Sri Lanka, 2014) Nawarathna, T.N.T.K.
    Matale District in central province has a lot of Natural water resources. And also compare to other area that water have a high amount of Dissolved Oxygen (DO) concentration. National Water supply and Drainage board in Naula pumping Nalanada reservoir water for their treatment plant. But Water board faces a big problem in the dry season because pumping water had a less amount of Dissolved Oxygen (DO) and occurring Black color. Five points were selected in the upstream from the water pumping inlet. Samples were collected within four weeks. Therefore 25 samples were collected. Initial DO was measured the sample collected points. And after five day BOD was measured. And also Total Nitrogen and Total phosphate were measured. According to the results TN and TP devour an inverse relationship. It can be vary with the season wise. Main objective of this research is developed the mathematical model for recognize the influence of the polluted point to the water pumping inlet. Therefore major conclusion was not any effect that polluted points were inside the 1750m ahead the pumping point.