Browsing by Author "Attanayake, A.N.B."
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Item Analyzing Seasonal Variation of Water Quality Parameters of Kelani River(Uva Wellassa University of Sri Lanka, 2018) Ranathissa, N.P.K.; Sampath, J.K.H.; Attanayake, A.N.B.; Amarakoon, H.A.K.Raw water quality of a surface water body directly affects the purification process and the final water quality of drinking water. When considering Sri Lanka, the Kelani River plays a vital role in fulfilling people's water necessities, as it provides water for more than 80% of the population of the capital city, Colombo. The current study focuses on the Kelani River in order to identify the models of variation of raw water quality parameters and to investigate patterns and trends of parameter variation. The main objective was to forecast the variation of water quality parameters with special reference to the Kelani River. The water quality was analyzed with different parameters including pH, Turbidity, Electrical Conductivity, Total Colifortn and Escherichia coli, and data gathered for five years (2012 - 2017) at five different intakes. Analysis was carried out by R studio software. Time Series techniques were used to perform the tests, and all decisions were made under p-value of 0.05. ARIMA and SARIMA models were used to identify the best fitting model for the variation of quality parameters with time. Results were forecasted for a 6 month time period using the above fitted models. Based on obtained results, the seasonality of the water quality parameters changed from one intake to another. When analyzing the pH, Ambathale and Biyagama showed seasonality while other three intakes showed non seasonality. Electrical Conductivity had a seasonal variation at Biyagama and Pugoda intakes, while Escherichia colishowed seasonality for Ambathale intake only. Frequent long-term monitoring of physicochemical parameters of surface water resources is vital for the better management of water resources as well as aquatic habitats and the environment. Based on the results of this study, a better prior understanding about the behavior of raw water quality parameters can be obtained, and this prior understanding can be used to manage the water purification process and final water quality.Item Assessment of Groundwater Contamination at Jaffna Municipal Council Solid Waste Dumping Site(Uva Wellassa University of Sri Lanka, 2018) Vysshnavi, V.; Weerakoon, W. M. D. S. K.; Attanayake, A.N.B.Groundwater is the major natural water resource in the Jaffna Peninsula, and it is used for domestic, agricultural and industrial purposes. Disposal of solid waste is increasingly affecting the quality of the limited groundwater resources of this part of the country. This study investigates the groundwater quality around the Kaakkaithivu landfill site in Jaffna in order to assess the impact of leachate percolating into the underlying aquifer. Groundwater samples were collected from fifty dug wells. Various physicochemical parameters including pH, Temperature, Electrical Conductivity (EC), Total Dissolved Solids (TDS), nitrate (NO3-), phosphate (PO43-), heavy metals (Cu, Cd, and Cr) and bacteriological contamination were measured. Their spatial distribution patterns were plotted using ArcGIS software 9.0 - 9.1. The results show that, groundwater of the study area was found to be heavily polluted with Cd. EC, TDS and E- Coli levels are excessively high comparing SLS standards. NO3- and Cr concentrations in 20% of the wells exceed the maximum acceptable levels. It can be concluded that Kaakkaithivu landfill is leading to significant groundwater contamination. Therefore, separation of solid waste method could be an alternative method to solve the landfill leachate issue.Item Characterization of Electrical Properties of Sri Lankan Graphite(Uva Wellassa University of Sri Lanka, 2010) Geethika, A.K.K.; Wijayasinghe, H.W.M.A.C.; Attanayake, A.N.B.; Udagedara, T.Sri Lankan graphite is famous for its high quality which makes it suitable for various technological applications. However investigations on electrical properties of different varieties of Sri Lankan graphite have been very limited. The main objective of this project is to investigate different structural varieties of Sri Lankan vein graphite and characterize their electrical properties with particular attention on examining its applicability in rechargeable battery industry. Graphite is an extensively used carbonaceous material in industries. There are two main types of graphite, synthetic and natural. Various types of vein graphite samples were collected from Bogala and Kahatagaha/Kolongaha mines. The powdered graphite specimens were subjected to phase, purity, morphology, particle size and chemical analyses. Electrical conductivity of dense graphite pellets were measured by the d.c. four probe method in the temperature range between 25 °C to 100 °C. XRD phase analysis indicates the existences of appropriate phases of these graphite specimens. Further, the electrical characterization reveals the possessing of significant electrical conductivity hence indicating the high potentiality of Sri Lankan graphite for rechargeable battery applications. Key words: Electrical properties, Graphite, ConductivityItem Confirmation of Newly Discovered Area in Eppawala Phosphate Deposit Using Geological, Geochemical and Geophysical Methods(Uva Wellassa University of Sri Lanka, 2018) Kumari, M.M.T.D.M.; Subasinghe, N.D.; Attanayake, A.N.B.; Samaranayake, S.A.Parent rock of the Eppawala apatite deposit is suggested to be a carbonatite in origin and one of the associated minerals of apatite is magnetite. A high concentration of magnetite has been seen within the deposit. A regional ground magnetic survey concluded that the deposit extends to the North further than the formally known boundaries. Also, the studies indicate that the deposit runs along the E-W direction as two ore bodies. Appear in this study, the newly discovered area in Eppawala phosphate deposit was demarcated using geological, geochemical and geophysical methods. Geological studies revealed the presence of carbonatite and apatite outcrops along E-W direction. Representative soil samples were collected during field work for chemical analysis. As the carbonatite is highly weathered anomalous peak of calcium and magnesium should be recorded in the samples collected along the magnetic anomaly, which in turn help to identify the presence of carbonatite bodies within the subsurface. In deeper horizons along E-W direction, the elemental availability is relatively high (High peak values of Ca, Mg in anomalous area is 5000 mg kg-1, 1655 mg kg-1 and in background it is 890 mg kg-1, 720 mg kg-1, respectively) which indicates the possible presence of subsurface carbonatite bodies. Resistivity surveys were carried out in the study area and resulted resistivity signatures show similarity to the known phosphate deposit. Detailed magnetic map resulted from the magnetic survey done by early workers confirmed the boundary indicated in the magnetic anomaly map. Hence existence of the newly discovered deposit in Eppawala along E-W direction was verified by using integrated geological, geochemical and geophysical study.Item Development of Sri Lankan Vein Graphite for Lithium-Ion Rechargeable Battery Anodes by Chemical Oxidation(Uva Wellassa University of Sri Lanka, 2012) Bandara, S.M.J.G; Wijayasinghe, H.W.M.A.C.; Attanayake, A.N.B.Graphite has been used as an anode material in state-of-the art Li-ion batteries due to high capacity (337 mAh/g) and low potential (0.1 — 0.3 V vs. Li+/LI) of its lithium intercalation compound (Li,C6, X=1) (Kurzweil and Brandt, et al., 2009). Reversible intercalation and deintercalation of Li+ ions with graphite are attributed to successful formation of a stable and protecting solid electrolyte interface (SE1) on the graphite surface, which is known to complete in initially few cycles. Previous studies have shown that formation of the SE1 is greatly affected by electrolyte composition, morphology and surface chemistry of graphite (Fu et al., 2006). For this reason, only a limited number of graphite has been found to be suitable for the anode of Li-ion batteries. To use natural graphite that is inexpensive and abundant, many researchers have currently focused on the surface modification of natural graphite (Fu et al., 2006). The graphite surface can be modified by mild oxidation in air and using solution of strong oxidant (Balasooriya, et al., 2006,2007). Mild oxidation induce acidic group on the graphite surface, which act as surface film to produce SEI resulting high reversible capacity. However, in gas-solid inter-phase oxidation reaction, control of the homogeneity of the product is difficult to maintain. Consequently, a liquid-solid interface oxidation reaction has been introduced as the use of chemical oxidant. Nitric acid is well known as a strong oxidant and its standard potential is > I .5V (Wu et al., 2003). Sri Lanka is well known for high quality vein graphite, containing 95-99% of pure carbon (Herath, 1995). They were categorized into four structural types, namely, coarse flakes of radial (CFR) graphite, coarse striated-flaky (CSF) graphite, needle-platy (NPG) graphite and shiny-slippery-fibrous (SSF) graphite, based on the structural and physical characteristics (Touzain, et al., 2010). Recent investigation pointed out that vein graphite from Bogala mine have sufficient electrical conductivity to be used as potential candidate for Lithium ion rechargeable batteries (Geethika, et al., 2010) and chemical oxidation in (NH4)2 5208 increase the reversible capacity (Balasooriya, et al., 2006,2007). The present study aims to chemical oxidation of natural vein graphite in nitric acid in order to upgrade the quality of vein graphite as anode material for lithium ion rechargeable batteries.Item Erosive Wear Resistance of Sri Lankan Rocks Used for Flooring(Uva Wellassa University of Srilanka, 2011) Ruwanpura, U.D.M.N.; Wijayasinghe, H.W.M.A.C.; Attanayake, A.N.B.NOTE: see the PDF version Varieties of floor tiles are amongst many of the specialties in ancient Sri Lankan architectural wonders. Even today floor tiles in Sri Lanka claim a high regard in world export market being one of the biggest equity grosser in commodities. Stone floors are admired for their splendid appearance as well as for higher durability. Natural stones such as slate, granite, gneisses and marble are commonly used for interior designs and flooring. Stone floor tiles being materials which are always in physical contact with moving objects are prone to wear, although at a comparatively slower rate. Therefore, the durability of tiles should also be of concern in addition to their aesthetic appearance. However, wear resistance of stone floor tiles has not been attracted adequate attention in material testing. Hence, it is essential to ascertain tribological properties, including resistant to wear, when selecting the most suitable flooring material. This research aims at investigating and documenting the wear resistance of commonly used Sri Lankan rocks in flooring.Item Fabrication of Supersand for Water Purification(Uva Wellassa University of Sri Lanka, 2018) Thennakoon, R.S.; Weerasooriya, R.; Kumarasinghe, A.R.; Attanayake, A.N.B.; Ritigala, H.M.T.S.Fluoride is an essential constituent for both human and animal health that depends on concentration in the medium. The sand is conventionally used in water treatment plants to control water turbidity. This project is aimed at improving its performance using a chemical modification to remove other water contaminants as well. Thus improved substrate is designated as "Super sand". Super sand has proven to be a better adsorbent for the removal of certain heavy metals and dyes from water. Among several treatment technologies applied for fluoride removal, adsorption process has been explored widely and offers satisfactory results especially with mineral-based and/or surface modified adsorbents. Graphene Oxide was synthesized using the modified Hummer’s method. Super sand was synthesized by heating a mixture of sand and graphene oxide/deionized water in an oven for two hours. The process was repeated five times for multiple coating. Graphene oxide and super sand were characterized using Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectrometry (EDS), Fourier Transform Infrared Spectroscopy (FT-IR) analysis and X-Ray Diffraction (XRD). The applicability of the synthesized material in the water industry for fluoride removal was studied utilizing sand, GO-sand and GO multiple coated sand at varying pH conditions. These results are to be confirmed by conducting further scientific studies.Item Geochemical Influences on Sri Lankan Bottled Water(Uva Wellassa University of Sri Lanka, 2012) Pelpitiya, I.P.S.K.; Udagedara, D.T.; Attanayake, A.N.B.Sri Lanka is one of the renowned countries to have abundant sources of clean natural water resources. There are numerous discovered or undiscovered natural water bodies that contain clean water which can be used as drinking water without any treatment. They can be categorized according to the origin as artesian water, spring water, well water, prepared water or surface water. However, currently Sri Lanka is experiencing an unprecedented development which does not assure clean natural water anymore. At this scenario, bottled water plays a major role as a source of clean drinking water. Bottled water, which is used for human consumption may contain minerals and carbon dioxide, naturally occurring or intentionally added; but shall not contain added sugars, sweeteners, flavorings or other foods that are packaged in plastic or glass bottles and sizes range from small PET bottles to large gallons. There are number of bottled water brands which contain treated or untreated spring water, well water, or river water which are bottled and distributed in various districts. This bottled water may contain different chemical components according to their natural source, different treatment methods or with the requirements. A research on investigating the chemical composition and its relationship with the bed rock geochemistry of the source area has not been conducted in Sri Lanka. Thus, this research aims at assessing the geochemical conditions of Sri Lanka's bottle water sources by analyzing samples collected from different areas of the country. Where the sources of bottled water are dug wells, springs or tube wells they can easily be used for the groundwater monitoring purposes. It is attempted to recognize the real quality of the bottled water and to evaluate the quality compliance with the standards. In Sri Lanka there are two specific standards given for the bottle water by the Sri Lankan Standards Institution. Those are SLS 1038:2003 and SLS 894:2003 which define the requirements for high quality bottled water product.Item Geophysical Techniques and Geochemical Analysis for Identification of Potable Groundwater — A Case study from Morawewa Area(Uva Wellassa University of Sri Lanka, 2018) Arangajanan, S.; De Silva, S.N.; Attanayake, A.N.B.; Samaranayake, S.A.Appropriate accessibility to drinking water is a major concern throughout the world. Having access to safe drinking water leads to improvements in health of communities while achieving local (SLS) and international (WHO) Standards, which is a basic measuring-yard of the development of a nation. Dry-zone of Sri Lanka has recently suffered due to lack of drinking water availability and this trend is set to be climbed for damaging heights, as time passes. This study was carried out selecting Morawewa as a sample area, which is situated in the North Central part of Sri Lanka and adjoining the Trincomalee district, bounded by latitude 8° 35' 0" - 8° 38' 0" North and the longitude of 80° 50' 0" - 81° 04' 0" East. The present study aims to detect the groundwater potential in Morawewa area of Trincomalee District, Sri Lanka using electrical measurement and geochemical analytical methods. Electric resistivity data interpretation was carried out by using Schlumberger configuration with electrode spacing (AB/2) of 100 m distance. The resistivity curves were analyzed with curve matching techniques along with the help of RESIST Software. The results of quantitative interpretation of geophysical data indicated that the layer system having minimum of two layers to a maximum of three layers in the area and the maximum depth to the bedrock was 17.9 m. Hence based on the range of resistivity values and graph trending, the weathered and fractured zones were interpreted. The contacts between certain saturated and dry formation zones having different resistivity values were identified from the interpreted resistivity curve and the range of resistivity value. Moreover, geochemical analysis revealed phosphate contamination in the dug well water samples.Item Hardness Removal Using Graphite-based Nano Materials(Uva Wellassa University of Sri Lanka, 2018) Kularathne, K.A.M.; Weerasooriya, R.; Kumarasinghe, A.R.; Attanayake, A.N.B.Water hardness creates substantial issues both in health sector and in industry. In regulatory agencies hardness in drinking water is often categorized as a secondary contaminant in that its regulation is not mandatory. However, high hard waters are not palatable. The hardness in the water is defined as the presence of di- and trivalent cations. However the removal of hardness from water is no easy task. Ion exchange resins were commonly used to control drinking water hardness which creates reject water enriched with monovalent cations. The methods based on sorption offers several advantages as such they are economical and do not require high technology. Further most of the adsorbents are readily available. The major limitation of the method is its efficiency. This project aimed at determining developing substrate to remove divalent cations from drinking water using nano Grapheneoxide (GO). GO was synthesized from natural vein graphite of Sri Lanka. Grapheneoxide (GO) was synthesized using the modified Hummer's method. Results showed that the suitable pH for calcium removal was pH 10 but there is a Calcium removal below pH 8 (pH 5.5 to 7) and the optimal concentration was 50 ppm. Equilibrium isotherms have been analyzed using Langmuir and Freundlich isotherm models. The adsorption data were fitted well in Langmuir isotherm than Freundlich isotherm for GO. GO was characterized using Scanning Electron Microscope (SEM),Energy Dispersive X-ray Spectrometry (EDS), Fourier Transform Infrared Spectroscopy (FT-IR) analysis and X-ray Diffraction (XRD) and the results were in good agreement with the literature. Calcium adsorption isotherms were also prepared to assess its applicability for water industry.Item Investigation of the Effectiveness of Salt Barrages in Jaffna Peninsula(Uva Wellassa University of Sri Lanka, 2012) Balendran, S.; Udagedara, D.T.; Attanayake, A.N.B.The Jaffna Peninsula which is the northernmost tip of Sri Lanka has its groundwater source in the subsurface limestone layer. Due to over exploitation of groundwater for agricultural needs, most wells in the region have become brackish. Therefore, a supply source to replenish the wells to meet the increasing demand for fresh water is of paramount importance. Converting the two internal saltwater lagoons, Vadamarachchi and Upparu, to fresh water lakes is expected to improve the water resources of the peninsula, both in recharging the underground storage with additional surface storage and desalinating the lands fringing the lagoons. Making these lands suitable for cultivation and fresh water prawn farming in the banks of the lagoon are also expected (Shanmugarajah, 1993). The Upparu lagoon with surface area of about 26 km2 has opening to the sea towards the south and is mainly a saltwater lagoon. During the north-east monsoon rain water fills up the lagoon lowering its salinity. Saltwater barrages have been erected in the mid-1900s to convert the lagoon into a fresh water lake (Rajasooriyar et.al., 2002). However, the barrages have not functioned properly and have allowed the salt water to intrude. Repair and replacement of these barrages were completed in October 2009. Currently the effectiveness and the efficiency of the Ariyalai barrage of Upparru lagoon is monitored by the Irrigation Department by observing the salinity of surface water in five locations every month. This research focuses on evaluating the effectiveness of the Ariyalai barrage by delineating the saltwater intrusion pattern and groundwater flow pattern within the area extending from the fringe of the lagoon into the land for 2 km. The larger area coverage is expected to provide a more realistic picture of the saltwater intrusion patterns and hence a correct assessment of the effectiveness of the barrages.Item An Investigation on Iron Enrichment in Groundwater in Ampara District(Uva Wellassa University of Sri Lanka, 2012) Litheepan, G.; Udagedara, D.T.; Attanayake, A.N.B.Ground water is the major source to drinking purpose in the world, because usually its quality is good. Public of Sri Lanka also rely on groundwater as a drinking water source and also for other purpose. Naturally occurring groundwater quality problems are typically associated with high hardness, high salinity and elevated concentrations of iron, manganese, ammonium, fluoride, and occasionally methane, hydrogen supplied, nitrate, and arsenic. A high concentration of iron is by far the most common water quality problem associated with groundwater Excess iron problems have been reported from two villages in Ampara district of Sri Lanka, namely, Naavithanvely and Savalakadai. As per the previous studies above locations are containing more than 0.3mg/L iron in ground water. This research intends to investigate the distribution of iron in groundwater of this particular area. First the location in Ampara district was investigated based on the information from previously published data. The groundwater quality was analyzed from different sources like lake, ponds, dug wells, tube wells and holes in the two villages.50 water samples were collected into glass bottles in linear pattern from land to river based on groundwater flow in selected areas. The temperature and pH were also measured at the site. GPS coordinates were recorded. Standard sampling methods were followed. Iron concentrations were measured using atomic absorption spectrometric method. It is apparent that high iron concentrations are reported in groundwater samples close the river. The land use patterns in the area are paddy fields on the west, lagoon on the east and forest area on the northwest corner of the map. Highest concentrations are observed in the middle of the map, while most other concentrations are higher than the maximum permissible levels.lt was observed that the total iron concentration is decreasing from land toward the river. There are two areas where high total iron concentrations are recorded. Most of these locations have iron concentrations which exceed maximum permissible levels imposed by the WHO. The actual source for these high iron concentrations is yet to be identified.Item Microbial Aided Leaching of Potassium from Sri Lankan Feldspar(Uva Wellassa University of Sri Lanka, 2012) Dissanayake, D.M.S.; Wijesekara, K.B.; Attanayake, A.N.B.Potassium is an essential major plant nutrient and also a non-renewable resource. It plays a vital role in plant nutrition. Majority of the soils of the world are too low in available potassium for production of good yields. Potassium containing agrochemicals remains relatively expensive and supplementing potassium deficiency with agro fertilizers is costly. The uses of alternative indigenous resources such as feldspar and mica which are potassium rich naturally occurring minerals are gaining importance against costly agro fertilizers (Badr et al., 2006). Certain groups of microorganisms including bacteria such as Bacillus mucilaginosus and fungi like Aspergillus niger are known to solubilize potassic minerals into soluble form which can be utilized by the plants (Lin et al. 2002; Han, and Lee, 2006). Microbes can enhance mineral dissolution rate by producing and excreting metabolic by products that interact with mineral surface (Barker et al., 1998). Combination of potassic rock minerals with potassium solubilizing microorganisms could constitute a biofertiziler which provides a sustainable solution to improve plant nutrition and production. This study investigates the potassium solubilizing effect of Bacillus mucilaginosus, Bacillus cereus, and Aspergillus from Sri Lankan potassic rock mineral feldsfar.Item Modeling Groundwater Contamination by Agro Nutrients(Uva Wellassa University of Sri Lanka, 2012) Vasan, S.; Attanayake, A.N.B.; Udagedara, D.T.Well water is an important source which provides drinking water supply especially to dry zone of Sri Lanka. Therefore considering the quality of groundwater is essential to ensure the health of human and other living things. However the quality of groundwater varies place to place, mainly depending on its geological origin even though. it is become deteriorated by various anthropogenic activities. Nowadays in Sri Lanka this is especially due to the extensive use of agro chemicals. In this content, this study was carried out regarding the groundwater contamination by agrochemicals. The study was focused on 10 Km' area encircled the paddy land associated with Vavuniya Tank. Topographic map of the study area was grasped deeply for the site visit to acquire hydrogeological features. Flow direction was roughly assumed by investigating hydrogeological features. In this area 68 well water samples were collected for the water quality analysis.Item Production of Lubricant using Sri Lankan Graphite(Uva Wellassa University of Sri Lanka, 2013) Dissanayake, V.N.W.W.; Cooray, J.T.; Attanayake, A.N.B.Graphite is a polymorph of carbon that possesses high electrical conductivity. Most of the industrial applications of graphite exploit this physical property. The loose coupling among the graphite sheets contributes to another industrially important property that enables it to be used as a dry lubricant (Jie, 2012). Graphite has advantages in situations where wet lubricants might not be practical and also in lubricating porous substances such as wood. Graphite has the natural ability to conduct heat and electricity and is chemically inert. So it can be used as a conductor while lubricating the surfaces. Graphite lubricant enhances load carrying capacity and solves sliding friction problems where conventional lubricants fail to perform and produces better bonding strength. Graphite, being naturally hydrophobic, resists rain, water, snow, and mud and aids in reducing the development of corrosion and rust on valuable equipment (Jie, 2012). Viscosity is the most important parameter in selecting a lubricant. It changes lubricating properties at different temperature ranges. Therefore it is important to define a temperature range in which the lubricant can be practicable. Sri Lanka has reputation for its high quality vein graphite. Bogala and Kahatagaha are the main graphite mines in Sri Lanka Kahatagaha graphite is said to be 99% pure crystalline vein graphite. This research focuses on producing a lubricant using Sri Lankan graphite at low cost particularly with the aim of productive utilization of graphite mill waste in future. It investigates the optimum composition of the lubricant compound by testing various materials combinations and concentrations that produce the best lubricity of graphite. Methodology Various weight ratios between finely-ground Kahatagaha graphite powder (75µm) and coconut oil, toluene and carbon tetrachloride were used (5% to 60%) as the testing compounds. Viscous graphite/organic liquid mixtures were stirred and blended in fast mill. Viscosity of each mixture was measured by Brookfield Viscometer. The best organic liquid used to produce graphite lubricant was identified based on higher viscosity and the optimum concentration of that compound suitable for industrial applications was determined.Item Quality of Sea Sand vs. River Sand(Uva Wellassa University of Sri Lanka, 2012) Sripranavan, S.; Attanayake, A.N.B.; Cooray, J.T.Over the years, with increasing development activities of the country, demand for sand has reached to an exceptionally high level. Yet river sands and sea sands are virtually the main industry raw material source. Indiscriminate mining and extraction of river sand has led to severe environmental degradation. Therefore it is necessary to explore for alternative sources. The collected river and sea sand samples were tested for moisture content, organic matter content, pH value (acid demand), mechanical grain size analysis and specific gravity value. Comparison was made between the properties of the two sand varieties. The result that Specific gravity determination of samples value are between 2.62 — 2.74. This indicates that the Specific gravity determination of the tested dune sand sample is within that oft normal sands and therefore sands are suitable for construction purposes. From the Sieve analysis test, over 90% of the sand samples are between 1.18 mm to 0.15 mm sieve size, while some 1% is coarse particles, and 3% is very fines (silt and clay). With the majority sand samples consisting of sandy particles. Therefore sands are for suitable for construction purpose. All the engineering properties of the sea sand closely match with river sand used in construction. Therefore use of sea sand will help mitigate the environmental degradation caused by excessive river sand extraction.Item Removal of Fluoride from Drinking Water using Gypsum(Uva Wellassa University of Sri Lanka, 2012) Kumari, K.E.D.K.W.; Attanayake, A.N.B.; Udagedara, D.T.Excess amount of fluoride in drinking water causes detrimental health impacts such as dental and skeletal flurosis. According to the World Health Organization (WHO), the maximum acceptable concentration of fluoride in drinking water is 1.5 mg/L (Darchen et al, 2010). According to Sri Lanka Standards desirable and permissible levels of fluoride is 0.6 mg/L and 1.5 mg/L respectively. In tropical countries like Sri Lanka, the lowering of the fluoride regulatory limits in drinking water is required due to high consumption of water by the people living in the regions with high natural fluoride concentrations. Therefore, excess fluoride in drinking water must be removed to the permissible level. There are several techniques available to remove excess fluoride from drinking water based on adsorption, precipitation, ion exchange and membrane separation. (Dou et al, 2012). However, most of these methods are highly specialized and cost intensive in that they cannot be implemented successfully at community level. In this research we propose to utilize gypsum, a ubiquitous mineral in nature, to mitigate excess fluoride from drinking water based on precipitating common ion effectsItem Synthesizing Electro - conductive grease using graphite(Uva Wellassa University of Sri Lanka, 2015) Christopher, W.A.P.P.; Cooray, J.T.; Attanayake, A.N.B.Graphite as we all know is well renowned for its ability to conduct electricity as well as its lubricant nature. The carbon atoms in graphite are sp2 hybridized. Each carbon atom bonds with three other carbon atoms via the three sp2 hybridized atoms to form a sheet of carbon atoms lying in a hexagonal pattern or a honey comb structure and carbon atoms are bound together by strong covalent bonds. And each of these sheets of carbon is bound together by weak van der Waals bonds. The fourth electron in a p orbital is left free and its these electrons that contribute towards the electrical conductivity of graphite. Grease is a semi solid lubricant widely used in the industrial world to reduce ware and tare. Grease is made of three principal components known as a base oil, thickener and additives. Thus combining graphite with grease would preferably transfer the electro-conductive nature of graphite to grease forming an electro-conductive grease. Usage of such a product would be, grounding static discharges, providing electrical continuity between irregular or pitted surfaces, ensuring electrical contact between loose or vibrating parts and small gaps, application to ball bearings in computer equipment where it allows static discharge to pass through the bearing instead of building up and arcing. Synthesizing such a graphite based grease product was the main objective of this study. Materials and methodology Natural vein graphite was used to make graphite powder under 75 microns. Basic grade grease was used as the substrate. Different weight ratios of both graphite and grease were mixed by blending to generate the sample series. The samples were tested for electrical conductivity using the impedance analyzer. A standard cell was made to hold the sample. The conducting length was kept to a minimum assuming that in real world applications (12 millimeters). The cell electrodes were designed in such a manner that two over rings were placed to ensure that the effective conducting length was kept constant throughout the sample series tested. Three measurements were taken with each generating a graph of imaginary part of impedance versus the real part of it. And the resistance of the sample was determined by the point where the curve seemed to make contact with the x axis of the graph. And the capacity of the particular sample can be determined by finding out the frequency of the peak point of the semicircle.Item Toxic Metal Absorptivity to Agriculture Soil(Uva Wellassa University of Sri Lanka, 2015) Chamara, M.A.N.; Cooray, J.T.; Attanayake, A.N.B.Soil contamination has increased by several folds within the recent past due to various man made activities. Various types of toxics involve in the processes of making contaminated soil profiles. There are many toxic metals and chemical complexes which contaminate soils. When toxic agents contact with soils they may absorb or adsorb in to the soil structure depending on their structural and physical properties. One of the major sources of contaminant is agrochemicals. Due to expansion of agricultural practices and over use of agrochemicals (pesticides, weedicides, insecticides, fungicides and others) the effect has become adverse. Sri Lanka is covered with versatile range of soils with highly contrast physical properties. In this study, soil samples from different agricultural areas in Badulla district have been used to determine their quantity of toxic metal absorptivity quantitatively. Method Five areas were selected where there are many types of agricultural activities. Uncontaminated samples were collected from these farms (Mirigama, Passara, Badulla Bandarawela and Welimada). Soil properties like moisture content, soil pH, bulk density, hydraulic conductivity, soil porosity were studied in order to categorize the soil types. Soil columns were made for these samples and metal absorptivity was studied by adding Roundup pesticide (which is heavily used agrochemical in the area). Concentration of the agrochemical was kept at its normal dosage. Original agrochemical was fully studied with ASS to identify the containing metal ions and the obtained leachates were also measured for the same set of metal ions to confirm their soil absorptivity under specific time period. Obtained AAS results interpreted to identify the correlations between soil properties and toxic metal absorptivity.Item Water Quality Index Calculation and Management System(Uva Wellassa University of Sri Lanka, 2012) Jayasinghe, H.M.B.N.; Attanayake, A.N.B.; Udagedara, D.T.Water quality data recording and manipulation has always been a manual procedure in local water resource management agencies. The Water Quality Index Calculation and Management System was developed as a partial solution for these shortcomings. It calculates water quality index automatically after entering the basic data into the system. It can accurately generate necessary reports daily, monthly and yearly. Web- based online system has been chosen to facilitate the Water Quality Index Calculation and Management System. Open source PHP and SQL were used to develop a comprehensive design program for a waste water treatment plant.With the use of powerful problem solving feature of the HTML this system was developed. The program can also be used to check the design details of an existing plant to know the expansion works needed for increased hydraulic and organic loadings occurring in future.The purpose of this study is to present the development of a modular online system package for simulating the performance of the selected treatment.The computer program for the design of water treatment plant was test-run and the results were compared with those of the existing plant. The program is interactive. The program has been fed with relevant input data for each unit of treatment plant and executed. Data are entered as and when necessary as per the guidance obtained from the program.Major output of this system is giving a final conclusion about the treated water in a water treatment plant. Also it calculates values for the water quality parameters like turbidity and total water hardness etc. Different user can get customized details and information from the system.The proposed system benefits to all the people who use water quality reports by increasing the efficiency and mobility in an effective manner. Also waste water treatment plants play a major role in the system. The main goal of the Water Quality Index Calculation and Management System is to popularize it among water professionals.