UWU Repository :: Browsing by Author "Udagedara, D.T."

Browsing by Author "Udagedara, D.T."

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Algorithmic Aspects of Trees in Graph Theory: Identification and Application
(Uva Wellassa University of Srilanka, 2011) Gamachchige, N.T.S.G.; Udagedara, D.T.
Note: See the PDF Version With the rapid advances of the computer technology, Mathematics and Computer Science have developed into two entirely separate disciplines. Since graphical approach lend themselves naturally as model for a variety of situations, including the hardware of computer and certain aspects of computer software, Graph Theory plays an increasingly important role within Computer Science. In the study of graphs, it soon becomes evident that efficient algorithms are necessary for solving problems of any significant magnitude. It has become fashionable to mention that there are applications of Graph Theory to some areas of Physics, Chemistry, Computer technology, Electrical and civil engineering, Sociology and Economics. Computers have made our daily activities easier with fast and highly accurate outcome. Since we find the applications of Graph Theory in almost all areas, using the computer to solve practical problems makes our task easy. Transforming of our problems into a form that can be understood by the computer is the task of a computer language. Algorithms are used for that purpose. This research consists of Algorithmic aspect of Trees in Graph Theory and is designed to emphasize the close tie between the theoretical and algorithmic aspect of Trees in Graph Theory. Rather than employing a specific computer language for presenting algorithms, the steps were used that are common to many languages. This research has introduced few algorithms, based on properties of Trees in Graph Theory, for practical problems which we often come across. A complexity analysis is also given for each algorithm. The main objective is to recognize the algorithms to solve real world problems using the properties of Trees in Graph Theory and the other objective is to apply these algorithms to solve some problems in day to day life.
A Biological Treatment for Color Removal in Distillery Effluents
(Uva Wellassa University of Sri Lanka, 2013) Dilini, L.M.L.; Premathilake, M.M.S.N.; Udagedara, D.T.
Distilleries are one of the industries generating enormous amount of wastewater which is about 10–15 L of effluent for the production of 1 L of alcohol. The fermentation of carbohydrates present in molasses is carried out by yeasts, which yields ethyl alcohol. The pH of the raw molasses is adjusted to 4 - 4.5 to prevent bacterial growth and then fermented liquor containing alcohol is degasified and alcohol is separated, leaving behind the waste called “spent wash”. The spent wash is the major polluting waste of the distillery, which has very high Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) values. The COD often crosses and BOD reaches7×10 mgL (Goel, 2006).The waste is dark brown in color due to caremalization of some sugar. It also contains nearly 2% of the dark brown recalcitrant pigment called melanoidin, which does not get degraded easily by microorganisms, posing a great difficulty in its removal. Molasses has very high quantity of fermentable sugars. These sugars react with amino acids and undergo Maillard reaction and then polymerize to form melanoidin, which is a major color containing compound in the distillery effluent. Putrescible organics like skatole, indole and other sulfur compounds produces obnoxious smell in the effluent and when it comes in contact with high temperature, becomes more toxic to aquatic biota. The waste has substantial quantities of dissolved solids and suspended solids with high . The pH of spent wash remains in the acidic range varying from 3 to 5.4 (Goel, 2006). The distillery waste also has high quantities of potassium along with sulphates. Melanoidin containing distillery effluents require pretreatment before safe disposal into the environment, because the direct disposal causes serious soil and water pollution by inducing coloration and eutrophication problems in aquatic environments- which leads to reduction of sunlight penetration in water bodies. Additionally, it in turn decreases both photosynthetic activity and DO concentration affecting the normal life cycle of aquatic fauna and flora (Goel, 2006). Further, it causes reduction in soil alkalinity, inhibition of seed germination and damage to vegetation upon land disposal. Treatment of distillery wastewaters by physical or chemical methods was found not feasible due to the high cost and generation of secondary pollutants. But compared to them biological treatments are more economical and environmental friendly. Many fungi species have the ability of removing color from wastewaters. Especially white rot fungi exhibit extensive bioremediation activities that are mainly based upon their capabilities to produce extracellular lignin modifying enzymes (Pant and Adholeya, 2007). In this research we studied several white rot fungi activity towards decolorization of distillery effluents. Methodology Ten polyporusbasidiomycetes white rot fungi species were collected for distillery waste water treatment from Matara area.Effluent was collected from Pelwatte distillery inButtala. Effluent was dark brown in color, semi liquid and a dense material. About 5mm squares were cut from collected basidiocarps and placed on PDA plates and were incubated for 7 days. Among them, five fungal species were selected for the experiment due to their rapid growth. Above efficiently growing five fungal specieswere isolated using streak plate method. Streaked cultures were incubated again for 7 days.Then, using these cultures new plates were prepared by spread plate method incubatingagain for seven days.
Correlation of Ground Water Fluoride with Total Hardness and Total Alkalinity in CKDu Prevalent areas in Uva Province
(Uva Wellassa University of Sri Lanka, 2020) Rathnayake, R.M.M.L.; Henagamage, A.P.; Premetilake, M.M.S.N.; Udagedara, D.T.
Chronic Kidney Disease of unknown etiology (CKDu) describes as a multifactorial effect. Thus, postulates on CKDu focus on the cumulative effect of nephrotoxic contaminants which deteriorate the kidney function progressively. This study aimed to determine the influence of total hardness (TH) and total alkalinity (TA) on fluoride (F-) content of groundwater in CKDu prevailing areas in Uva Province. Divisional secretariats of Mahiyangana (MDS), Rideemaliyadda (RDS), Wellawaya (WDS), and Siyambalanduwa (SDS) were selected as CKDu prevailing areas for sample collection. Water samples from 45 dug wells were collected by following a simple random sampling method and the samples were triplicated. Samples were analysed by standard methods of water analysis (APHA 1985). Statistical data analysis was carried out using IBM SPSS 21.0 software. The range of F- contents in MDS (n= 17), RDS (n= 8), WDS (n= 11) and SDS (n=9) were 0.01– 1.80±0.08 mg L-1 , 0.02 – 0.61±0.13 mg L-1 , 0.01±0.01- 5.8±0.1 mg L-1 and 0.17±0.02– 1.42±0.11 mg L-1 respectively. The highest mean value for TH was observed from WDS (156.44±21.53 mg L-1 ) and the least was observed from RDS (116.36±21.95 mg L-1 ). All the mean values for TA were recorded within the permissible level according to WHO guidelines for drinking water and the highest was observed from WDS (336.36±117.58 mg L-1 ). Results of the linear regression analysis on the dependence of Fon TH indicated a positive correlation in MDS, WDS, and SDS as well as a negative correlation (r= - 0.33) in RDS. All the test areas were observed with positive correlations between F- content, and TA. Among the selected DS areas, 44% of the water samples in SDS, 36% of the water samples in WDS, 12% of the water samples in MDS, and 0% of the water samples in RDS exceeded the maximum permissible level for F- defined by WHO. The influence of total hardness and total alkalinity on Fluoride content in groundwater is required to be studied further. Keywords: Fluoride, Total Hardness, Total Alkalinity, CKDu, Uva Province
Feasibility of using Groundwater Geochemistry in Mineral Exploration; A Case Study from Udawalawe, Sri Lanka
(Uva Wellassa University of Sri Lanka, 2019-02) Weerasekara, W.M.B.S.; Udagedara, D.T.
The geochemistry of heavy metals and trace elements in groundwater has been a promising tool for mineral exploration over the well-recognized and practiced geochemical methods such as isotopic techniques, key elements association, rare earth elements association, multi element relationship. This research focused on using heavy metals and trace elements around a known mineral deposit to explore the possibility of their potential in mineral exploration. A total of 31 groundwater and 12 soil samples were collected around Udawalawe serpentinite outcrop exposed at Ginigalpelessa and Indikolapelessa. A combined approach was used to assess the interaction between rock and minerals with groundwater and soil at Udawalawe. The pH and electrical conductivity of groundwater were measured in situ. Concentrations of Na, Mg, K, Fe, Mn, Cu, Cr, Cd, Rb, Sr in groundwater were measured using atomic absorption spectroscopy. The Present study showed Na, K, Mg, Cr, Cu, Cd, Sr and Fe are the highest elevated concentrations in groundwater close to the serpentinite outcrop. Soil samples were analyzed using X-ray diffraction for clay mineral identification. The soils close to the mineral deposit have clay minerals such as serpentine which have directly weathered from the outcrops. The enrichment of heavy metals and trace elements in the groundwater and soil clearly indicate the interaction between the serpentinite and local groundwater regime. This observation proves the feasibility of applying heavy metals and trace elements in groundwater as a tool for uncovering subsurface mineral deposits. In order to strengthen the observation and gain a recognition, it is recommended to precise the same procedure around known mineral deposits.
Geochemical Characteristics of Geothermal and Non-geothermal Water at Wahawa Field in Sri Lanka
(Uva Wellassa University of Sri Lanka, 2018) Sajath, M.M.; Udagedara, D.T.; Samaranayaka, S.A.
Hydrogeochemistry of the geothermal and non-geothermal water is highly related to geology in Wahawa geothermal field. The objective of this study is to accumulate all existing geochemical and isotopic data into the water in the Wahawa area, in high grade metamorphic terrain of Sri Lanka. In this study, the C1-SO42—HCO3-, and Na-K-Mg ternary diagrams, stable isotopes were used to characterize the water and estimate the subsurface temperature using AqQA computer code. Twenty two water samples were analyzed. Geochemistry of geothermal water is separate from that of non-geothermal water. Higher contents of Na, K, Cl, F, Br, NO2-, NO3-, PO43-, SO42-, and Total Dissolved Solids in geothermal water are most likely due to the dissolution of feldspar, mica, and sulfide minerals in the granitic and dolerite rocks. Similarly, lower values of Mg, Fe, Cu and Zn suggest less ferromagnesian minerals in the basement. The classification based on major ions reveals a Na-K-SO4 type of geothermal water for Wahawa. Non-geothermal water is dominated by the Na-CaSO4. The water was classified, mixing processes studied and the origin and movement towards the water determined. From the ternary plots, the waters can be classified as groundwater, geothermal water and a combination of the two, with the geochemical diagram which plots close to mature water. The plots also suggest that all the water originates from old systems. In overall, the chemical compositions of geothermal water in this area are determined by the interface between the groundwater (meteoric waters of current hydrological cycle) and the rock environment. The procedure may depend on pH, mineralization, the rate of other ions and temperature. Most of the geothermal water seems to have equilibrated with respect to specific minerals. Geothermal waters in Wahawa are formed by mixing.
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.
Identifying Leachate Plumes Using Geophysical Methods: A Case Study from Open Municipal Solid Waste Dumpsite in Badulla
(Uva Wellassa University of Sri Lanka, 2018) Dulmini, K.K.V.; Samaranayake, S.A.; De Silva, S.N.; Udagedara, D.T.; Bandara, H.M.D.A.H.; Perera, K.V.G.S.
Badulla dumpsite is one of the major open municipal dumpsites in Sri Lanka. However the dumpsite has not been constructed according to the modern engineering techniques and it has no liner to prevent seepage of leachate. Therefore leachate pockets can be built up in the subsurface and they can flow directly to a nearby surface water body (Badulu oya) through surface and subsurface channels, due to elevation difference. Therefore mapping leachate plumes and their flow paths have high interest in the environmental management and prevention of surface water pollution. Hence in this study leachate flow paths were delineated by using resistivity imaging with controlled inversion parameters and magnetic mapping techniques. The geophysical findings of the leachate characters, were supplemented with physico-chemical parameter analysis of collected leachate samples from solid waste dumpsite and leachate drainage channel. Leachate plumes were demarcated by 2D resistivity technique, and a unique correlation was established between ground magnetic results and resistivity imaging. 3D resistivity contour plot synthesized by 2D resistivity imaging profiles, confirms that leachate plumes and their flow paths are confined to near surface, almost throughout the dumping area. Moreover high electric conductivity values of leachate produce unique signature in resistivity image. Chemical parameters such as biochemical oxygen demand, chemical oxygen demand and phosphate are above the tolerance limits for the discharge of industrial wastewater into inland surface waters. This study reveals the appearance of subsurface leachate plumes in Badulla dump site and their flow paths. It is recommended to build a retaining wall in the identified direction of leachate flow path down to the depth of bedrock in order to prevent seepage of leachate to Badulu oya and accumulated leachates should be treated prior to discharge.
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.
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).
INVESTIGATION OF THE EFFECTIVENESS OF UPPARU SALT BARRAGE IN JAFFNA PENINSULA (3 Stage)
(Uva Wellassa University of Sri Lanka, 2015) Rupathasan, N.; Udagedara, D.T.; Jayawardhane, D.T.
The Jaffna Peninsula is located in the northern Sri Lanka. The total area of the Jaffna Peninsula is and demarcated three internal lagoons such as Thondamanaru, Upparu and Valukiaru. The first two lagoons comprise of an area of 77.6 km and 25.9 km . They are connected to the sea and drain an area of 518 km . Majority of the local community of the area is depending on agriculture and fishing. Groundwater is the main source for people in Jaffna Peninsula for domestic and agricultural activities. According to the field observations even people having their own wells, majority of them are affected by salt water intrusions. Therefore, they depend on the common water supply given by the government for drinking purposes, whereas some people still depend on groundwater sources. Recently, barrage was constructed as a salt water exclusion bund to convert the salt water in lagoon Upparu to fresh water lake. This is expected to improve available water resources of the peninsula, both in recharging the underground storage (Sukanya, 2012). This research is focus of the area from the fringe of the lagoon into the land extending around 2 km. Major aim of the research is to evaluate the effectiveness of the barrage by delineating the salt water intrusion pattern especially in the west and northwest areas of the lagoon. Methodology Existing aquifer types, geology and topography were studied with the help of available resources and monitoring was done in the area. Wells were selected in a circle to the fringe of Upparu lagoon. The areas coming under study are parts of Nallur, Kopay and Chavakachcheri divisional secretariat divisions. Electrical conductivity (EC) of the groundwater was measured during wet and dry seasons. The wells in which EC show a sudden change was selected for further chemical analysis (sodium and chloride). In addition, both wet and dry season sixty eight (68) shallow well samples were selected for sampling. Water samples were collected in PETF bottles, acidified and capped tightly. Water samples were analyzed for Na using Varian Atomic Absorption Spectrometer (AAS 240 series) facility available at the Uva Wellassa University. Chloride was measured with argentometric method. Spatial distribution of the chemical & physical parameters in the groundwater was interpolated using Inverse Distance Weighted method available in Arc GIS 9.3 software. Results and Discussion Results of this study show that EC values for groundwater in the study areas varies between 574 µS/cm and 23,470 µS/cm in wet seasons and between 544 µS/cm and 22,810 µS/cm in dry seasons. Element chloride values range between 449.8mg/L and 7,197.7 mg/L in wet seasons and between 949.7 mg/L and 4,098.7 mg/L in dry seasons. Sodium values vary in between 38.3 mg/L and 802.9 mg/L in wet seasons and between 26.7 mg/L and 648.4mg/L in dry seasons.
Investigation of the Effectiveness of Upparu Saltwater Barrage in Jaffna Peninsula, Sri Lanka (4th Stage)
(Uva Wellassa University of Sri Lanka, 2016) Muraly, K.; Jayawardhane, D.T.; Udagedara, D.T.
Groundwater is the prime source of water for the people in Jaffna Peninsula. Saltwater intrusion into aquifers has been a persistent issue caused by excessive extraction of freshwater. In order to overcome the groundwater scarcity and quality issues, a barrage has been constructed as a saltwater exclusion bund expecting to convert the saltwater lagoon into a freshwater lake. Major aims of this study are to evaluate the effectiveness of the barrage by delineating the salt water intrusion patterns in groundwater and to study the variation of groundwater types recorded after the barrage construction. Electrical conductivity (EC) and water level of the wells were measured in the field. Groundwater samples were collected from 66 wells during the wet season. Water samples were analysed using Atomic Absorption Spectrometer (AAS) and Spectrophotometer to determine the concentrations of sodium, magnesium, calcium, potassium, chloride, sulphate and bicarbonate. Results indicate that EC of groundwater varies between 403 — 20760 tS/cm. Chloride, sodium, calcium, potassium, magnesium and bicarbonate concentrations are between 7 — 497 ppm, 0.09 — 986 ppm, 0.6 371 ppm. 0.86 —125 ppm, 0.52 —167 ppm and 10 — 1464 ppm respectively. Spatial distribution of the groundwater composition shows that the fringe of the Upparu lagoon which is far from the barrage is having better quality water than the groundwater close to the barrage. Availability of groundwater has significantly increased after barrage construction. It has been noted that if barrage function properly the groundwater in the fringe of the lagoon will become freshwater soon. Comparing with the results of past analyses it can be concluded that barrage system is slowly recovering to produce freshwater. Keywords: Saltwater barrage, Upparu Lagoon, Saltwater intrusion
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.
Isotherm Models for Aqueous Manganese (II) Adsorption by Bamboo Wood Based Activated Carbon
(Uva Wellassa University of Sri Lanka, 2020) Pathirathne, I.S.; Herath, D.C.; Weerasekara, L.; Weargoda, S.K.; Udagedara, D.T.
The adsorption is considered the most effective technology for the removal of contaminants from water. The production of low cost, efficient and eco-friendly adsorbents is a growing concern, and activated carbon is considered a viable solution. In this study, bamboo which is an abundant and inexpensive material was used to prepare activated carbon, and adsorption of Mn (II) onto bamboo wood activated carbon (BAC) was investigated. BAC was prepared by chemical impregnation with KOH at a 1:1 ratio followed by pyrolysis at 800 °C for 2 hours. Adsorption isotherm of the Mn (II) onto BAC was determined and correlated with Langmuir and Freundlich isotherms. A Commercial Activated Carbon (CAC) was used as a reference. The experimental data at optimum conditions (pH=6-7, adsorbent dose = 5g/L, contact time - 5 hours) for BAC shows a better fit with Langmuir model (R2=0.9960) than Freundlich model (R2=0.9740), whereas CAC shows a better fit with Freundlich model (R2=0.9815) than Langmuir model (R2 = 0.9720). The Langmuir constant (KL) and adsorption capacity (Qm) were calculated with graphical data. KL is 0.2940 mg−1 for BAC and 0.7740 mg−1 for CAC, which implies BAC has a higher affinity than CAC between adsorbent and adsorbate. Qm was 0.9620 mg g−1 for BAC and 2.259 mg g−1 for CAC. For Freundlich model experimental data, the Freundlich constant (KF) and adsorption intensity (1/n) was calculated and it results in KF of 0.5350 mg g−1 for BAC and 2.929 mg g−1 for CAC. The 1/n values are 0.4358 and 1.162 for BAC and CAC respectively which BAC indicates more favourable adsorption than CAC. Mn (II) is found to adsorb strongly on the surface of activated carbon and adsorption behavior is described by a monolayer, homogeneous Langmuir type isotherm. The present investigation showed that bamboo can be effectively used as a raw material for the preparation of activated carbon for the removal of Mn (II) from aqueous solutions. Keywords: Bamboo, Activated Carbon, Langmuir, Freundlich, Manganese
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.
The Potential Use of Reverse Osmosis Concentrate as Water Source for Irrigation
(Uva Wellassa University of Sri Lanka, 2020) Godage, G.I.T.; Udagedara, D.T.; Ritigala, H. M. T. S.
Reverse Osmosis (RO) membrane technology is one of the promising techniques used to provide safe drinking water to the community, particularly chronic kidney disease of unknown etiology (CKDu) affected areas in the dry zone of Sri Lanka. The rejected water from the RO plant is known as the RO concentrate, which is generally released to the environment without any beneficial use. The main objective of this study was to identify the potential use of RO concentrate as irrigation source water. Therefore, water samples were collected from different capacities of RO plants varying from household to commercial, and the selected area was the North Central province and North Western province, the total number of RO plants were fifty. The essential irrigation water quality parameters for agriculture were tested to determine the characteristics of RO concentrate. pH, electrical conductivity, total dissolved solids, alkalinity, carbonate, bicarbonate, nitrate, and phosphate were measured. Furthermore, the concentration variation maps were plotted (using ArcGIS 10.5) to identify the spatial variation of RO concentrate. Finally, the findings were compared with existing irrigation water quality standards provided by the United States Food and Agriculture Organization (FAO), and Agriculture Department of Sri Lanka. As the obtained results average values of, pH was 7.25, electrical conductivity was 1.48 dS m-1 , total dissolved solid was 725.4 mg L-1 , alkalinity was 104.66 mg L-1 as CaCO3, bicarbonate was 1.05 meq L-1 , nitrate was 1.78 mg L-1 , phosphate was 0.96 mg L-1 and carbonate was not identified. According to the results, this study revealed that RO concentrate water quality complies with the requirement of both water quality standards for agriculture, and there is a potential of using the RO concentrate as a water source for irrigation. Keywords: Reverse osmosis, RO concentrate, Irrigation, Agricultural water
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 effects
Salinity Distribution of Groundwater in Trincomalee Coastal Region
(Uva Wellassa University of Sri Lanka, 2013) Richardson, V.P.S.; Udagedara, D.T.
Groundwater is the prime source for people living in dry zone of Sri Lanka, especially duringdry season for their drinking, domestic and agricultural activities. Groundwater has been exploited from earliest times in Sri Lanka mainly for domestic use and where readily available for irrigation as well. Almost 80% of the rural population in Sri Lanka relies on groundwater for their domestic needs today, because of its excellent natural quality and sustained availability throughout the year (Panabokke, 2007). Groundwater is frequently contaminated due to anthropogenic activities. However, some natural phenomena too are responsible for making groundwater unsuitable for drinking. Seawater intrusion is one such prominent process of groundwater contamination. This study focuses on seawater intrusion of groundwater regime along a 22 km long coastal region of Trincomalee, fromKinniya to Nilaweli by evaluating the salinity distribution of groundwater. Groundwater plays a significant role as the major source of freshwater for Trincomalee district during the dry season. The main aquifer type in Trincomalee coastal region is called ‘shallow aquifer in coastal sand’. This aquifer is well marked in Nilaweliarea (Water Resources Board 1999-2001). People consuming water from the wells near the sea are highly affected by the salt (saline) water and undesirable properties of the water. Seawater intrusion has not only been affecting the groundwater, but also has changed the soil condition making it unsuitable for agricultural uses. Therefore, most of the farming lands are converted into fallow lands. After the tsunami in 2004 seawater intrusion has exacerbated more than the past. Therefore, seawater intrusion becomes a serious issue and has to be controlled for the future demands both water and land resources. Seawater mainly consists of cations like sodium, magnesium, calcium and major anion known chloride, which induce salinity and high el ectrical conductivity.Therefore, measuring the conductivity of groundwater may help identify any saltwater intrusion. Methodology Initially, existing data including aquifer types, geology and topography were studied with the help of previous researches and monitoring carried out in the area. Wells were selected along a profile perpendicular to the coastal region until the electric conductivity (EC) value became very low close to the drinking water standards. Water samples were collected in plastic bottles and capped tightly for subsequent laboratory analysis. Finally, 32 shallow well samples were selected for chemical analysis from the area of 22 km coastal belt from Kinniya to Nilaweli. Well locations were identified using GPS. On the spot measurement for EC of the water samples was carried out with Orion 3 Star EC meter. Water samples were analysed for Cl by using Silver Nitrate Titration method. Na was determined by Varian SpectrAA AAS facility available at the Uva Wellassa University. Spatial distribution of the chemical and physical parameters in the groundwater was plotted and interpolated using Inverse Distance Weighted method aided by ArcGIS 9.3 software to visualize the data.
Saltwater Intrusion into Freshwater Lagoons in Jaffna Peninsula
(Uva Wellassa University of Sri Lanka, 2019-02) Gajenthiran, A.; Udagedara, D.T.; Gamachchige, N.T.S.G.
Surface water and groundwater are scares and hence highly demanded resources in the Jaffna peninsula causing the communal water supply is an extreme challenge. In order to ease the burden, barrages were constructed closing fresh water lagoon envisaging the accumulation of rainwater during the monsoon periods. Though the initial expectation was the lagoons to act as freshwater ponds, due to malfunctioning of barrages the anticipation wilted. The barrages were reconstructed expecting the same purpose early this decade. However, the salinity has been unexpectedly high even since then irrespective to the climatic patters viz dry and wet seasons in the peninsula. This research focuses on understanding the behaviour of salinity variation in the Upparu lagoon and in the Thondamanaru lagoon which is under the spot light nowadays. Several investigations of the salinity variations across the Upparu barrage showed that there are subsurface linkages with high saline water from the Jaffna lagoon. In addition to that, the evaporation during dry season increases the salinity away from the barrage toward the mainland. The electrical conductivity (EC), salinity, sodium and chloride concentrations were measured in 58 groundwater wells around the lagoon as the lagoon water recharge the nearby groundwater table. The EC varies between 954 µS cm-1 to 13450 µS cm-1 in the wet season and it is between 673 µS cm-1 to 18570 µS cm-1 during the dry season. The salinity varies from 0.63 to 10.32 in the wet season, where as it is 0.92 to 12.3 in the Dry season. Chloride concentrations vary between 49.70 mg L-1 and 3012 mg L-1 in wet season and between 33.5 mg L-1 and 5538 mg L-1 in dry season. Sodium concentrations vary between 43.1 mg L-1 and 5324.3 mg L-1 in wet season and between 17 mg L-1 and 4124 mg L-1 in dry season. The groundwater quality far from the barrage is comparatively good to the areas closer to the barrage. This observation has been appearing with promising prospectus over last six years. Yet, it is not convinced whether this is due to the less effectiveness of the barrage or subsurface movement of brackish water from the Jaffna lagoon to the south Kopai area. Additionally, the dry period of this year was longer than usual. Thus, it is recommended to continue the research focusing more on south Kopai area.
Social Impacts on Rainwater Harvesting – A Case Study in Anuradhapura and Kegalle
(Uva Wellassa University of Sri Lanka, 2019-02) Rathnayake, K.A.I.L.; Weragoda, S.K.; Weerasekara, W.B.M.L.I.; Udagedara, D.T.
Water scarcity is a global issue with the increasing population. Rainwater harvesting is considered as an environmental friendly, sustainable source of water which can be used for domestic and drinking purposes. Sri Lankan government has framed rules and policies supporting the installation of rainwater harvesting systems, however, implementation and operation of these require the acceptance and willingness of general public. This research focuses on the social impacts on the rainwater harvesting systems installed in dry and wet zones in Sri Lanka. Both, water quality (Physical, Chemical, Bacteriological) and factors affecting it were assessed through the study. The samples were collected from rainwater harvesting systems at Kegalle and Kebithigollewa regions, 30 from each while conducting a questionnaire survey simultaneously. pH values were varied between 5.53- 7.19 in Kebithigollewa and 6.49 – 9.55 in Kegalle, may be due to the reactions in the tank material, ferrocement and plastic. All the tested chemical parameters of rainwater samples were within the limits of SLS 614: 2013 guidelines. Total coliform was detected in 50% of Kebithigollewa samples and 100% of Kegalle samples, which may be due to wrong water quality and quantity management practices. Social survey analysis revealed that microbiological parameters were affected mainly by the cleanness level of roof catchment area and atmospheric conditions, such as dust in the environment. Consumers in Kegalle region hesitate to drink rainwater due to lack of confidence as a drinking source. Harvested rainwater can be of consistently high quality through the selection of appropriate catchment, storage materials and the application of post-cistern treatment. A water safety plan should be implemented on rainwater harvesting systems to identify the risks, to improve the water quality and to mitigate quality degradation. A social awareness programs can be recommended to increase the rainwater consumption and willingness.
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.

Browsing by Author "Udagedara, D.T."

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