Browsing by Author "Jayawardana, D.T."
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Item Heavy metals and trace element distribution in Eppawala Apatite deposit(Uva Wellassa University of Sri Lanka, 2015) Wickramsinghe, P.C.B.; Udagedra, D.T.; Jayawardana, D.T.In Sri Lanka, the dominant source of drinking water used to supply major urban and rural communities is from wells, tanks, rivers, springs. Although there are no systematic and comprehensive water quality assessment programs in the country, there are increasing indications of water contamination problems in some parts of the country. Causes for water contamination are natural or anthropogenic. Among natural contamination, water-rock interaction is critical but remains hidden for most eyes. No sufficient study has been conducted on heavy metal contamination of drinking water of the Eppawala apatite area in Sri Lanka. The main objective of this paper is to determine the influence of some of the physicochemical parameters and heavy metals and trace elements in drinking water and its distribution of different parts of the Eppawala. Methodology The groundwater was studied around the Eppawala Apatite Deposit (EPD) using tube well and dug wells as the access. Sample size (60) was determined by distribution of the population around the EPD. Samples were collected in wet season and dry season. The electrical conductivity was measured in situ with Orion 3 Star EC meter. The collected water samples were analyzed for seventeen (17) parameters including major cations, anions, heavy metals and trace elements. Cations, heavy metals and trace elements concentration with the Varian SpectrAA AAS facility , Cl and HCO3 were measured using standard methods. The major cations such as Ca, Cu, Fe, K, Mg, Mn, Na, Zn, Cs, Sr, Li, Rb, and major anions such as SO4 2Cl , F and HCO3 were analyzed using the ORIGIN 8 and Surfer software. Results and discussion In terms of electrical conductivity, it ranged from 19.2ms/cm-1.02ms/cm in wet season and , F and Cl are the highly abounded elements in the selected area well water in wet season. That’s value are above the Sri Lankan drinking water strandedItem Investigation of the Effectiveness of Salt Barrages in Jaffna Peninsula: Phase 2(Uva Wellassa University of Sri Lanka, 2013) Suganan, R.; Udagedara, D.T.; Jayawardana, D.T.The Vadamarachchi lagoon and the Upparu lagoon have surface areas of about 77 and 26 km respectively. These lagoons have openings to the sea and are salt water lagoons. However, during the Northeast monsoon, rainwater from their catchment areas also collects in them. The total catchment area of these lagoons is about 50% of the area of the peninsula (Balendran, 1968). Groundwater is the prime source for people in Jaffna peninsula for their drinki ng, domestic and agricultural activities. Even though the households have their own wells, majority of the wells in the study area are affected by salt water intrusion. Thus, as a prevention measure barrages were constructed. The Thondamanaru barrage commenced in 1947, a separation bund between the Vadamarachchi lagoon and Upparu lagoon was constructed along a saddle between the two lagoons. Subsequently Upparu lagoon was incorporated into the scheme by the construction of a semi-circular spill at its outlet at Ariyalai. Thondamanaru barrage was completed in 1953 and Ariyalai barrage in 1955 (Shanmugarajah, 1993). Barrage serves as a salt water exclusion bund to convert the internal salt water lagoon Upparu, to fresh water lake 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 (Balendran et al., 2012).Item Potential of Normalized Difference Vegetation Index Derived from Multispectral Optical Satellite Imagery to Estimate Stand Basal Area and Biomass of Mangroves(Uva Wellassa University of Sri Lanka, 2019-02) Cooray, P.L.I.G.M.; Jayawardana, D.T.Normalized Difference Vegetation Index is one of the frequently employed vegetation index in research which utilizes the information extracts from optical satellite images and often shows significant relationships with many forest structural attributes. The present study was conducted at mangrove forest located in Vidattaltivu nature reserve, Mannar, Sri Lanka to evaluate the suitability of Normalized Difference Vegetation Index to estimate and map vegetation structural attributes of mangroves. A total of forty quadrats (100 m2) were placed at different distances from the seaward side. Diameter at breast height was measured in trees in each quadrat and stand basal area was calculated. Aboveground and below-ground tree biomasses were estimated using already available common allometric equations for mangroves. Multi-spectral image of Landsat 8 Operational Land Imager was obtained and the image was radiometrically corrected. Subsequently, Normalized Difference Vegetation Index was computed and regression models were developed. Best fit models were selected to estimate and map stand basal area, aboveground biomass and below-ground biomass of mangroves. Field sampling method resulted average values of 22.25±9.06 m2 ha-1, 205.18±98.66 t ha-1 and 86.54±39.26 t ha1 while remote sensing method generated average values of 22.64±3.75 m2 ha-1, 197.46±37.81 t ha-1 and 85.54±14.99 t ha-1 for stand basal area, above-ground biomass and below-ground biomass respectively. Maps generated through remote sensing method manifested their potential in interpreting mangrove structural attributes effectively and efficiently with respect to field based techniques where the sampling process is rather a difficult task with relatively high time and monetary demands.Item Sedimentological and Mineralogical Investigations of Heavy Mineral Sand Deposits in Mahaweli River Alluvial Fan(Uva Wellassa University of Sri Lanka, 2013) Janajeewa, W.M.C.; Cooray, J.T.; Jayawardana, D.T.Most of the economically important offshore heavy mineral sand deposits in Sri Lanka including Koddiyar bay is not fully investigated and there are very limited studies available in literature. Koddiyar Bay is the Mahaweli River discharging area. Detailed investigation on heavy mineral sand deposits is vital before extracting them. This paper presents the results of a sedimentological and mineralogical investigation of Koddiyar Bay heavy mineral sands deposit with the view of identifying its economic potential. More than ninety percent of Sri Lankan terrain is underlain by metamorphic rocks with meta - sedimentary or meta-igneous origin. Meta-sediments consists of quartzites, quartz schists, fine to medium grained acidic gneisses and granulites, calc gneisses, crystalline limestones, dolomites, sillimanite gneisses and silimanite-garnet-graphite rocks (Fernando, 1986). During the ice age, the present inner harbor area of Koddiyar Bay might have had the normal ridge and valley topography as we find in present day inland. With the rise of the sea level the present inner harbor area has submerged gradually and it has opened up rapidly due to wave and current actions with time (Wijayananda, 1985). Rock fragments are flown to Mahaweli River mainly during rainy season from catchment areas. Heavy mineral particles are derived from these detrital materials. Heavy mineral grains are subjected to abrasion during this transportation. Grains with higher hardness like ilmenite, rutile and garnet do not change their shape during the course of transportation. Moderately hard grains like magnetite are changed slightly their shape and they tend to form round grains. Low hardness grains like monazite and zircon are changed slightly their size and shape also tend to well roundness. Then this heavy and light mineral grains move with combination of sea waves and tidal forces. Then sedimentation occurs along coastal stretch in Koddiyar bay. This processes are not continue throughout the year. During monsoon period deposition layer thickness is higher than dry season.Item Selective Removal of Iron Oxide in Sri Lankan Laterite(Uva Wellassa University of Sri Lanka, 2019) Goonetilleke, W.A.I.A.T.; Jayawardana, D.T.; Ratnayake, A.S.Fe-rich laterite uses as the main alumina source in cement manufacturing process. The high iron content in laterite increases the limestone consumption. Therefore, this study is focused to investigate the effect of pH, temperature and sonication time for Fe removal. The Fe removal from laterite was examined along with Cd and Mn. The loss of mass on ignition (LOI), moisture, pH, elemental and mineralogical characterization of raw and treated laterite were determined by using Atomic absorption spectroscopy, X-ray diffraction (XRD) and Fourier-transform infrared instruments. The particle size (63 µm) and the solid-to-liquid ratio (1:10) were constant, for the whole experiment. The pH range was prepared using HCl acid and NaOH at 300 K for 1800 s, while the temperature and sonication time were examined with 313, 333, 353 and 373 K for 3600 s and 600, 900, 1800, 2700 and 3600 s at 300 K, respectively. The pH, moisture, and LOI of raw laterite were 5.69, 15.80% and 16.56%, separately. The Fe and Mn removal efficiencies were increased when the pH from 5 to 1 and the efficiency was negligible when pH 6-10. Cd removal efficiency was increased when pH 1-10. All elements removal efficiencies were increased 313-373 K. Fe and Mn got high efficiency at 900 s and Cd was recovered within a short time with sonication. XRD results revealed goethite, hematite and magnetite are main Fe-rich minerals. The effective pH for Fe, Cd and Mn were 1 (17.6 ppm), 7 (0.18 ppm) and 1 (2.05 ppm), respectively. The Fe and Mn removal efficiencies were greatly influenced by hydrogen ion concentration and Cd removal was influenced by hydroxyl ion concentration. The optimal condition of Fe for industrial applications is pH 1 with 333 K temperature or pH 1 with 900 s sonication time. The optimal condition for Mn is pH 1 with 900 s sonication time and Cd can dissolve effectively with basic pH conditions under high temperatures.Item Socio-economic Risk Assessment of Soil Erosion Integrating GIS to Universal Soil Loss Equation; A Case Study from Nillambe Catchment, Kandy(Uva Wellassa University of Sri Lanka, 2018) Perera, E.N.C.; Jayawardana, D.T.Soil erosion is a widespread problem in Nillambe catchment which accommodates a population that is mainly based on agriculture. Consequently, it is important to identify the socio-economic risk in the area in order to carryout necessary mitigation measures to minimize the potential risk. This study attempts to categorize socio-economic risk levels of soil erosion. Based on Universal Soil Loss Equation (USLE), geo-spatial input data representing rainfall, soils, land slopes and land use were used to model soil erosion hazard. A selected set of socio-economic vulnerability and coping capacity indicator variables were spatially modeled based on AHP (Analytical Hierarchical Process) and the outcomes of hazard, vulnerability and coping capacity measurements were further modeled using GIS based Disaster Risk Equation to obtain the socio-economic risk index for Nillambe catchment. The study revealed that approximately 25% of the catchment is in moderate to extremely high socio-economic risk to soil erosion. Furthermore, it indicates that the majority of such lands are covered with moderately managed tea and a slope greater than 10% (slope of the catchment varies between 0 - 36 degrees) with a moderately high rainfall erosivity level between 16 - 27. The maps identifying the socio-economic vulnerability, coping capacity and the risk levels to soil erosion can be utilized to identify areas with different vulnerabilities and coping capacities to promote necessary mitigation actions and strengthen socio-economic capacities of the community involved which would eventually minimize the socio-economic risk for soil erosion in the area.Item Structural and Geochemical Characteristics of Limonite ore in Dela Sri Lanka(Uva Wellassa University of Sri Lanka, 2013) Weerakoon, W.A.P.; Balasooriya, N.W.B.; Jayawardana, D.T.Limonite (FeO.OH (H2O)) is hydrated, amorphous, and non-crystalline form of iron oxide. Limonite contains around 52.86% of iron. In Sri Lanka hydrated iron oxide is present as boulders, hill capping and near-surface deposits, classified as supergene deposits, around Dela- Noragolla (Jayawardena, 1984). The objective of this research is to identify the chemical compositions, weathering grade, weathering pattern, decomposition, and provenance of Dela Limonite. There are only a limited number of detailed geochemical and mineralogical studies carried out up to date. Therefore, present research focuses on filling the gap in knowledge by identifying geochemistry with mineralogical characteristics of the limonite deposit. Each sample was homogeneously crushed. Fresh crushed samples were powdered using mortar and pestle and sieved into < 63 µm size. wave number. The most representative limonite sample (SLDL 01) was analyzed at 25 °C room temperature, obtained with 2Th/Th radiation, operating at 40 kV, 30 mA and diffraction data were compared with references. XRF analysis was carried out using Brucker hand held XRF S1 TITAN instrument for forty (40) selected major and trace elements by having 0.4008 average errors. Results and Discussions , 1100 cm , and 800 cm wave numbers showing water group, P-H bond, organic sulfate, P=O and silicate iron (Coates, 2000; Stringfellow et al, 1993). In XRD analysis minerals were verified as limonite, goethite, quartz and hematite present in the deposit. Measured XRF data are summarized in Figure 2. By comparing with UCC value, it was clearly identified that the Fe2O3, P2O5, and MnO are enriched in this deposit (Figure 3). MgO, TiO2, Cl, Co, and Ce slightly deviate from the UCC value. Al2O3, SiO2, K2O, CaO, S, V, Cr, Cu, Zn, Rb, Sr, Y, Sn have fewer amounts compared to the UCC value. Less amounts of Al2O3, SiO2, K2O, and CaO represent that insignificant amount of feldspar. Low percentage of silica in the deposit revealed that the rock formation was in mafic environments. Having very fewer amount of S and Chalcophile elements trace elements represent that there is no sulphide mineral is a source to form this deposit. Geochemically Ce, and Y are the traces, which were representing formation of apatite as a heavy mineral. By enrichment of P2O5, and fewer amount of Ca, Cl, OH, Ce and Y indicated that the apatite was present as a gangue mineral in this deposit. Item Study of Applicability of Kaolin to Remove Heavy Metals (Cr, Mn, Cu, Fe and Cd) from Textile Sludge(Uva Wellassa University of Sri Lanka, 2019-02) Hewage, I.; Jayawardana, D.T.; Udagedara, D.T.Synthetic dyes (metal complex, direct, azo, vat etc.) heavily used in the dyeing process in textile industry are toxic as they contain a wide variety of poisonous chemical compounds including carcinogenic heavy metals that cause adverse effects on all forms of life. In textile wastewater treatment process, most of these chemicals get settled out, ending up in sludge making it hazardous, thus making its management a critical environmental issue. Studying the effective utilization of compost and kaolin mixtures with 0, 10, 20, 30 and 40 wt% kaolin to compost mass ratios on textile sludge (in the form of a slurry) treatment and to analyzing their efficiencies at specified heavy metal(s) removal under ion exchange and absorption processes is the primary objective of this research. In the study adsorption characteristics were provide by adding kaolin and compost for boosting Cation Exchange Capacity (CEC) of filter media(s). Major physical changes were observed in the media after 50 days at which filtering process was terminated. Higher average values for all analyzed parameters; Cr, Mn, Cu and Cd in textile sludge used for the experiment was reported. Wide ranges of removal efficiencies in all heavy metals: Cr (9-67%), Mn (2100%), Cu (6-98%), Fe (1-100%) and Cd (16-95%) was observed where heterogeneous sorption processes were involved. In addition, the statistical analysis revealed that a significant improvement in removal efficiencies of all specified heavy metals can be achieved by adding organic matter to kaolin except for Mn. It was concluded that the filter with 30 wt% kaolin/compost has the best conditions. Furthermore, X-ray diffraction (XRD) analyses indicated that secondary mineral kaolinite as the major mineral responsible for the sorption process. Fourier-transform infrared (FT-IR) analysis of filter media(s) evident active functional groups for sorption.Item Use of Laterite Soil as a Filter Material to Remove Copper from Aqueous Solution(Uva Wellassa University of Sri Lanka, 2018) Mahagodage, S.Y.; Udagedara, D.T.; Jayawardana, D.T.Elevated levels of heavy metals in drinking water are found to have severe impacts on human health. Therefore, effective treatment method is of prime importance. Several techniques are available to remove heavy metals from water. However, all those methods are not cost effective and viable to the environment. Hence, it is important to study alternatives from natural resources. Laterite is a low cost novel adsorbent available in the country. Thus, the aim of the present research is to study the possibility for the use of activated laterite to filter copper from aqueous solution. In the experimental design, acid activated, thermal activated and raw laterite with 2 mm grain size has been used for the adsorbent trials. Experiment was conducted for 15 days continuously and copper removal efficiency was calculated. In addition pH, Oxidation Reduction Potential, Electrical Conductivity and Total Dissolved Solids of filtrates were studied to investigate process of treatment. Results indicate the average Cu removal efficiencies of acid activated, thermal activated and raw laterite is 89%, 98% and 98% respectively for an aqueous solution with 10 ml min-1 flow rate and 2 ppm initial copper concentration. After 15 days, acid activated laterite system has shown higher pH reduction and most of the samples were in pH below 6.5. Other two systems have shown pH within 6.5 - 8.5. Acid activated laterite system has shown positive Oxidation Reduction Potential values and other two systems have shown negative values at the beginning and change to positive values. Both Electrical Conductivity and Total Dissolved Solids curves showed upward trend with time for all three systems. According to the performance of the materials it can be concluded that laterite as an ideal material for removal of copper. Conversely, due to the high cost of activation, raw laterite can be considered as the best filter material for the removal of copper from an aqueous solution.