Abstracts of Undergraduates Dissertations-UWU

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Adsorptive Removal of Ferrous Ion from Aqueous Solution Using Natural Ferrihydrite
(Uva Wellassa University of Sri Lanka, 2012) Mohamed, A.M.A.
Total iron in water is one of major aesthetic problems due to its unpleasant taste, smell and rusty appearance. Iron mainly occurs as ferrous Fe (II) or ferric Fe (III). Fe (II) is soluble and Fe (III) is insoluble and occurs as colloids, in this work we consider all irons in solution phase. Aeration, ion exchanging and adsorption methods are the widely used to remove iron. The adsorption process has many advantages such as low cost of adsorbent, utilization of industrial, biological and domestic waste as adsorbents, low operational cost, ease of operation compared to other processes, capacity of removing heavy metal ions over wide range of pH and to a much lower level, environmentally friendly and cost effective. In this research ferrihydrite is used as a starting material to remove excess iron in potable waters. This method has several advantages; the material is readily available, and can be generated in their presence of excess iron in solution and it is environmentally benign. The major process we are interested is the sorption. Ferrihydrite (Fe5H08.4H20), a poorly crystalline meta stable mineral which is a precursor to the more stable iron oxides such as goethite and hematite. It is commonly formed by rapid oxidation of Fe (II) containing solutions followed by hydrolysis in the presence of crystallization inhibitors (Schwertmann, 1982). One of the most significant roles of ferrihydrite is as an adsorbent for various trace elements due to its coordination-unsaturated surface sites, large surface area, strong adsorptive effects, and high adsorption capacity. In this study, a series of batch laboratory experiments were conducted in order to investigate the feasibility of natural ferrihydrite for the removal of iron, Fe (II) from aqueous solution by the adsorption process. Investigation was carried out by studying the influence of initial solution pH, contact time, adsorbent dosage and initial concentration of iron. All batch experiments were carried out at a constant temperature of 25°C using magnetic stirrer that operated at 120 rpm. The findings indicate that the possibility of applying natural ferrihydrite as an adsorbent to remove ferrous ion with the approximate removal percentage of 99%.
Applicability of Red Earth in Manganese Removal from Groundwater
(Uva Wellassa University of Sri Lanka, 2012) Uthishdiran, S.
Manganese is commonly present in groundwater worldwide. The presence of manganese in the drinking water supply is not harmful to human health, however it is undesirable. Bad taste, discoloration, staining, deposition in the distribution system leading to after growth, and incidences of high turbidity are some of the aesthetic and operational problems associated with manganese in water supplies. Different mechanisms (physical, chemical, and biological) may contribute to the removal of manganese in filters and the dominant mechanism depends on water quality and process conditions applied. Under the commonly applied treatment conditions in manganese removal plants, the oxidation-floc formation mechanism (floc filtration) is commonly believed to be dominant. Adsorption characteristics of manganese onto Natural Red Earth (NRE), have been studied in batch technique to ascertain the effect of pH, ionic strength, initial sorbent and sorbate concentrations, temperature and effect of other cation and anion. Solid suspension (10 g/L NRE) was sufficient to remove Manganese up to 1 Oppm. Manganese adsorption achieved its maximum adsorption of nearly100% at neutral to slightly acidic conditions. The rate of adsorption of manganese was very fast. Manganese adsorption onto NRE was better explained by Langmuir-Freundlich isotherm. These results suggested that the NRE could be effectively used as a low cost candidate for removal of Manganese from environmental water.
Arsenic (V) Removal from Water by Modified Montmorillonite (MMT) from Naturally Occurring clay Deposits in Sri Lanka
(Uva Wellassa University of Sri Lanka, 2017) Rajamanthri, R.R.M.M.
Montmorillonite (MMT) nano-clay is widely used in many applications. MMT clay has been deposited and enriched in dry zone of Sri Lanka. Identifying the possibilities and methods for use of MMT clay for heavy metal removal was the objective of this research. Mainly naturally occurring clay deposits in Murukkan area were considered. Research focused on arsenic (As) removal by raw MMT clay and modified MMT clay because of the human health problems associated with excessive and long-term exposure to As. The can be either acute and chronic health issues. Purpose of the study was developing suitable and low cost adsorbent materials for arsenic removal. Only the clay particles were used to prepare the samples. Selected MMT samples were characterized using Fourier Transform Infrared Spectroscopy (FTIR) technique. Apart from the identification the samples were modified by FeCl3 and modified clay was used to make small pellets for filter media. The pellets were fired at 500°C - 600°C temperature range in a furnace. FTIR technique was used to identify composition and functional groups present in resulted product as well as raw MMT. Modified filter media and raw samples were treated with As(V) solutions with different contact times and different pH ranges. Then filtrate of all samples were analyzed using Atomic Absorption Spectroscopy (AAS) to determine arsenic concentration and iron concentration of each samples. Results of the test prove that the MMT clay is capable of removing arsenic efficiently.
Arsenic Removal from Water Using Magnetite Coated Quartz Sand Column
(Uva Wellassa University of Sri Lanka, 2012) Gamlath, P.G.R.C.A.
Arsenic has become a major contaminant of concern due to the increase knowledge of its toxicological and carcinogenic effects. This fact has prompted the need to investigate suitable methods for lowering arsenic concentrations in drinking water by rapid, simple and low cost techniques so the process utilizing natural geo materials as adsorbents has been promising. The sorption of As (III) and As (V) onto iron oxides has been studied previously and proven success. In this research Sri Lankan Magnetite coated quartz sand are evaluated as arsenic sorbents due to their high surface area and minimal production of waste. Magnetite coated Quartz was prepared according to literature. Columns with different fillings and operating conditions were set up to evaluate the effect of their combinations on Arsenic removal. Effluent solutions were collected at 1 h interval for each trial and analyzed for residual Arsenic through Atomic Absorption Spectrophotometer. Experiments were conducted separately for Arsenic (iii) and (iv). Magnetite coated Quartz accomplished better Arsenic removal with an iron weight of 14.68 mg el. In this work arsenate was better adsorbed than arsenite. Moreover the experimental results visualized a significant difference in Arsenic removal over the investigated grain size ranges and removal efficiency of As (v) decreased above pH 6 and comparably As (iii) removal efficiency against pH variation demonstrated consistent pattern. The experimental results suggest that the adsorption generally depended on the surface area of the adsorbent and adsorption isotherm results were best fitted with Langmuir model. Further, the maximum adsorption capacity of As (iii) was greater than As (v). The decrease of arsenate removal efficiency in alkaline pH can be explained by the formation of colloids. As for the conclusion, this study demonstrated that Magnetite coated sand could be an effective media for Arsenic removal from water in a fixed bed reactor.
Assesment of Heavy Minerals in Stream sediments of Wellawaya Area
(Uva Wellassa University of Sri Lanka, 2012) Chathurangani, A.S.M.
The study of heavy minerals placer deposits of the stream sediments in Wellawaya in Uva province in Sri Lanka at boundary of Highland Vijayan complexes was carried out; the surface sediment samples from ten locations of different tributaries along the kirindi oya are collected. The main framework of this research is to study the identification of various type of heavy minerals in stream sediments in Wellawaya and analyze grain size distribution in stream profile. The heavy mineral analysis involved separation of sand grains into different sizes; density separation of heavy minerals using heavy liquid, and magnetic separations and identify types of each mineral using transmitted light microscope. Results show that the sediments with 0.125mm grain size dominate in all the samples. Studying stream profile is involved measuring weight of each sieve fractions and they analyze using graphs. Identified heavy minerals in sample locations are Ilmenite, Rutile, Garnet, Sillimanite, Zircone, Monozite, Hornblende, Magnetite, Biotite, Muscovite, and Limonite. Magnetic, Physical, and optical properties of minerals are used to identify types of heavy minerals. There are six stream layers and two of them are gravel layers while others are poorly sorted.
An Assessment of Economic Heavy Minerals Associated with Gem Bearing Gravel Layers in Kiriella Division
(Uva Wellassa University of Sri Lanka, 2012) Perera, S.H.K.
Although Sri Lanka is world famous for its abundance of gem minerals, a scientific study on other economically important minerals associated with gem bearing sediments has not been conducted. During the gravel washing, the sediments which have the grain size higher than around 2 mm remain in the panning bucket, while rest finer portion fills into the panning pit. This study was focused on assessment of economic minerals associated with Kalu Ganga gem bearing sediments in Kiriella Division, Ratnapura. The wash dirt which represents the gem bearing layer was used for the assessment. In order to determine the economically important heavy minerals present in the wash dirt and the relationship between the grain size and the heavy mineral content, selected grain size fractions of wash dirt (1 mm +500 p,m), (-500 pm +250 pm), (-250 pm +125 pm) and (-125 i_tm +75 pm) were undertaken for heavy mineral separation by magnetic separation and bromoform separation. Petrographic microscope analysis reveals that the wash dirt is essentially composed of ilmanite, garnet, zircon, magnetite, spinel, and sillimanite, with trace amount of rutile, pyrite, monazite and corundum. Statistical analysis of data reveals that the panned gem bearing gravel layer contained 31.58% of average magnetic heavy minerals and non¬magnetic heavy minerals, and have an inverse relationship between the grain size and the weight percentage of heavy minerals. As well as the weight percentage of the magnetic heavy minerals increases as the grain size decreases, the weight percentage of non-magnetic heavy minerals is decreasing, as the grain size is decreasing, and the total heavy mineral (magnetic heavies and non-magnetic heavies) weight percentage is increasing while the grain size is decreasing. The highest heavy mineral accumulation is in the northern part of the study area with a decreasing trend from high-elevated area to low. The observed variation in the distribution of heavy minerals in the study area and the roundness of the grains showed that the sediments have been transported from a same source at high-elevated area. It was showed that wash dirt does not have the required "Concentration Factor" and grade to mine them economically. Therefore, the economical feasibility for extraction of heavies from wash dirt is not much effective.
Characterizing of Vein Quartz Occurrences in Sri Lanka
(Uva Wellassa University of Sri Lanka, 2012) Piumalee, W.D.H.
This research focused on suggesting a suitable and more reliable model for vein quartz occurrence along Highland/Vijayan (H/V) boundary. Detailed studies that were conducted by the Geological Survey and Mines Bureau at well known vein quartz occurrences along the H/V boundary; Mahagama, Randeniya and Ilukipalessa were considered for this study. Based on geological, textural and mineralogical data suggest of Randeniya that quartz veins bear evidence of single stage crystallization. Randeniya field observations are exhibits fast cooling history which can be occurred due to high temperature disparity of country rock and hot aqueous solution. In many instances, vein quartz ridges are mainly associated with part of outer calc-gneissic rim clearly visible in these locations. Vein quartz occur as narrow concordant or discordant bodies as dykes, lenses, pods and veins in high-grade metamorphic rocks. In sense of geology extension of the vein quartz ridges are almost aligned to the strike direction of the regional geology. Field observations reveals that cross-cutting field relationship of large vein quartz deposits is hardly visible in Randeniya. The flat nature of the 1-D resistivity curve over 1000f1m resistivity range is an indicative for subsurface extension of vein quartz occurrences. Two- D image profiling are used for interpret lateral extension of quartz. In order to most reliably assess the subsurface vertical extension of vein quartz core drilling was necessary for quantitative (depth of extension). Dissimilarities of mode of the occurrence , cooling history and characterizing changes of vein quartz in Central Highland and H/V boundary is clearly distinguish to achieve a clue. Existing most acceptable model of vein quartz occurrence suggested pegmatitic origin, where quartz may have been separated from the hydrothermal solution at later stages of crystallization from magma. According to above explanation suggesting the presence of a root for each and every sporadic vein quartz occurrence is very improbable when the lateral extent of the studied deposits is taken in to consideration. This study and other previous studies on vein quartz lead to the conclusion that the subsurface extension of vein quartz is very limited although the main occurrence is balk in appearance.
Chemical Removal of Fluoride from Drinking Water Using Gypsum
(Uva Wellassa University of Sri Lanka, 2012) Kumari, K.E.D.K.W.
An excess amounts of fluoride in drinking water cause detrimental health effects 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. According to Sri Lanka Standard desirable and permissible levels of fluoride are 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 these regions. 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, membrane separation. Most of these methods are highly specialized and cost intensive in that they cannot be implemented successfully at community level. In this research fluoride removal ability was investigated using gypsum based on precipitate common ion effects. Gypsum was separated in to different particle sizes (mesh sizes: 500 j.im, 250 1.1m, 125 63 i.n). The definite (10 ppm) fluoride solutions were prepared and study the fluoride removal ability of the gypsum under different particle size, pH levels and variation of the dose. The residual fluoride concentration is decreased with the particle size of the gypsum and the maximum fluoride removal is obtained the gypsum particles which have diameter below 63 gm. The pH for maximum removal of fluoride was around 8. The residual fluoride concentration in solution decreased with the addition of gypsum. When gypsum content is in excess, the residual fluoride concentration has decreased showing an optimal value at 2.50 g gypsum. Gypsum can be used to mitigate fluoride in drinking water. The particle size effect on fluoride removal efficiency was accounted for to increase in specific surface area.
Delineate Vein Quartz and Bedrock with the aid of 2D Resistivity Technique Compared with Ground Truths
(Uva Wellassa University of Sri Lanka, 2012) Zufra, M.H.
Sri Lanka consists of four major lithotectonic divisions. And nine-tenths of the island is underlain by Precambrian crystalline rocks, the rest being made up mainly of Miocene Limestone and Quaternary deposits along the north-western and northern regions. Principally, mineral resources are highly confined to the Highland/Vijayan boundary zone. One of the main mineral resources along this zone is vein quartz, predominantly south and southeastern part of the island. Mahagama and Randeniya are two major occurrences which were investigated in detail including 1D resistivity survey and 2D resistivity profiling by the Geological Survey and Mines Bureau (GSMB). Generally vein quartz boulders are confined to elongated ridges along strike direction displaying a weather resist nature. Both the vein quartz and bedrock resistivity values are in the same dynamic range and advanced processing techniques have to be identified to screen out vein quartz from the bedrock. The field survey was performed using ABEM Terameter (300-c SAS) and AGI (Advanced Geosciences, Inc.) Mini-sting system. The terrain condition only permits to perform resistivity soundings and profiles parallel to the ridges. 1D data was processed using Resist freeware package while maintaining RMS (Root Mean Square) error below 5%. 2D data was processed via EarthImager licensed software by introducing terrain files to compensate terrain undulations and applying resistivity ranges 100m-3000K2m and 250m-30000m for Mahagama and Randeniya respectively. 2D resistivity sections obtained from various profiles in the area reveal that quartz has high resistivity range with differential weathering and bedrock corresponds for the similar resistivity range with concentric weathering. Therefore, it clearly defines the sharp contact between the vein quartz and the bedrock with different weathering patterns as the key to delineate the two entities.
Designing Prototype Portable Particle Size Separator for Pure Ilmenite Separation
(Uva Wellassa University of Sri Lanka, 2012) Rusiyanthan, S.
Designing prototype portable particle size separator for pure ilmenite (FeTiO3) particle size separation is giving a good phenomenon to further know about particle size distribution and their elementary analysis. Ilmenite has magnetic property that can be feasible to separate the ilmenite due to percentage of Fe2+ percentage on each particle. Separator design has several adjustments for best performance and concentration was analyzed to know success of this research. Sri Lanka has huge beach sands deposit including high amount of ilmenite which are spread over eastern costal of Sri Lanka specially pulmoddai and there is a plant which does ilmeinte separation ,the product of separation export as bulk without any valuation but foreign countries are using ilmenite for nono technology, abrasive purpose and synthetic process, those technologies based on particle size of ilmenite there for perfect analysis of particles based on elementary distribution gives value addition process of ilmenite. When Ilmenite grade is low separator can upgrade the ilmenite also, therefore portable particle size separator can feasible for particle size analysis of ilmenite. Particle size separator outlook is rectangular box shape and in front side of the design has all processing apparatus which are primary coil, secondary coil, feed hopper, conveyor belt, chutes, splitter and switches but inside of this instrument has designed with all circuits, transformer and gear system with motor and bridge circuit. Each apparatus was fixed with systematically for proper separation, after designing Ilmenite was fed through feed hopper and conveyor belt toward the separation point where primary and secondary coils are fixed. Due selective magnetic flux, particle size separation was occurred and concentrate and tailing were dropped into separate bins through chutes. Selective flux rate was changed by current regulator for each deferent particle size distribution output because each ilmenite particle has different amount of Fe2+ which concern by selective magnetic flux density to capture the particles.In low current passage, flux density is low therefor particle size distribution has lot of large grains with low ilmenite grade but when increase the flux density particle size distribution has low amount of large grain and medium size grains with high amount of small particles and distribution can be contained high amount of titanium ion. This separator has high efficiency but recovery is low, to increase the recovery rate feasible magnetic coils are needed.
Detection and Identification of Bacteriological Contamination and Some Heavymetals (Fe, Mn & Zn) Contamination of Groundwater in Gurunagar Area, Jaffna Peninsula
(Uva Wellassa University of Sri Lanka, 2012) Sriskantharaja, A.
Jaffna Peninsula is mainly depends on groundwater sources because other fresh water sources are not available. Groundwater contaminated with microbiological and heavy metals constituents can cause a variety of water related diseases. Groundwater intended for human consumption should be safe, palatable and aesthetically pleasing. Coliform group has been extensively used as an indicator of drinking water quality and historically led to the public health protection concept. The aim of the present study were carried out to determination and identification of bacterial species of groundwater and to determine the concentrations of heavy metals (Fe, Mn, Zn) in groundwater at gurunagar located in Jaffna compare the results with guidelines from WHO. Seventeen sampling points were collected from different places in Gurunagar area. Sixty one Water samples were collected from these sampling points. Most Probable Number (MPN) method has been currently used for assessment of the microbiological quality of drinking water. Bacterial identification was carried out using biochemical tests. Water samples were analyzed by Flame Atomic Absorption Spectroscopy for their heavy metals concentration. A total of bacterial species: Escherichia coli, Klebsiella spp, Salmonella, Shigella and Enterobacter were identified form groundwater samples. The bacteria belonging to the family enterobacteriaceae (coliforms) showed the maximum occurrences in water samples. The high total coliforms count 2400 MPN index/100 ml in groundwater samples. Different selective media like Eosine Methylene Blue (EMB) and MacConkey were used to isolate bacteria rather than one increased the chances of successful isolation/identification. The identified bacteria were reconfirmed through the use of biochemical (IMViC) tests made for this purpose. The average abundance order of trace element contents in groundwater samples are: Fe > Mn > Zn, respectively. The maximum determined concentrations of Fe, Mn and Zn are 0.0339, 0.0100 and 0.0017 mg/l.
Determination of the Raw Water Quality Parameters and Examine the Reasons for the Failures in Hanthana Sewerage Treatment Plant
(Uva Wellassa University of Sri Lanka, 2012) Ritigala, H.M.T.S.
Sri Lanka faces a number of water and wastewater issues and water related health hazards. These problems arise primarily due to the increasing level of qualitative and quantitative depletion of water resources owing to over- utilization and continuous discharge of wastewater. Sewerage treatment plants (STP) have been constructed in most places to reduce the degradation of water quality and to ensure a healthy environment. The present study has been undertaken to evaluate the raw water quality parameters and find out the reasons for failures and defect identification in Hantana STP.The Hantana sewerage treatment plant is operating on biological treatment method (Suspended growth process and attached growth process) and main treatment units are imhoff tanks and trickling filters. Raw wastewater samples were collected and analyzed for the major water quality parameters, such as biological oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS) and pH. The obtained results were very much useful in identification and rectification of operational and maintenance problems as well as the future expansion to be carried out in the plant to meet the increased hydraulic and organic loadings. This research will further discuss on the treatment process of Hantana STP along with the findings from the study.
Determining the Source Rock of Gem Deposits Found in Halangoda Lake at Diyathalawa
(Uva Wellassa University of Sri Lanka, 2012) Wimalasuriya, K.M.D.C.M.
Sri Lanka has been famous all over the world for its vast potential and vast varieties of gemstones. 25% of the landmass of the country is gem bearing. The studies clearly indicate the vast gem potential of Sri Lanka yet to be unearthed. However, gem deposit exploration in Sri Lanka is still based on more traditional methods than modem technical methods. Application of modern scientific methods in gem exploration is therefore a national requirement for Sri Lanka. Halangoda lake was constructed in the premises of the Sri Lanka Military Academy (SLMA) at Diyatalawa and it consists of gem deposits. The lake was fed by two streams while narrow valleys and hillocks are presented around the lake. Well defined crystal shaped and sub angular gemstones are found from this deposit. The geological mapping procedure was carried out to determine the source rock of this peculiar gem deposits which can be great support to identify same kind of gem deposits in the area nearby. Base map was prepared using 1:10,000 topographic map and satellite images. The road traversing method was selected to perform geological mapping of the lake area. Global Positioning System (GPS) was used to mark precise location of outcrops. The strike and dip of the foliation planes were measured using the Brunton® compass. Their lithological units were named and other special geological features were recorded. The identified three lithological units are Garnet biotite sillimanite gneiss (Khondalite), Garnet hornblende biotite gneiss and Quartzofeldspathic gneiss. Some of Quartzite traces which are not in mappable scale were found. The general strike and dip of foliation of the north eastern part of the map were N 80° E and 30° NW respectively while the general strike and dip of foliation of the south western part of the map were N 40° W and 40° NE respectively. Khondalite is the gem bearing rock type found in this area. Geological, geomorphological and hydrological features also prove the possibility of transportation of gemstones from the khondalite rock in to the lake. Therefore khondalite is the source rock of gem deposits found in Halangoda lake at Diyathalawa.
Development of Sri Lankan Graphite-Silver Composite for Lithium-Ion Rechargeable Battery Anodes
(Uva Wellassa University of Sri Lanka, 2012) Samaranayake, T.B.D.T.
Li-ion rechargeable battery (LIB) is a high end technological application which uses graphite as its anode material 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). However, the present generation of LIBs still has many limitations such as expensiveness and capacity fading. Few studies have focused the environmental condition such as humidity for manufacturing LIBs. The graphite surface is differ from its crystalline structure and consist of edge planes, basal planes, surface functional group and defects (Noel and Suryanarayanan, 2002).Those surface structures are of great importance of electrochemical performance and sensitivity to humidity . Recent studies show that the deposition of ultrafine metals such as Cu and Ag on the surface of the natural graphite lowered the sensitivity of anode material to humidity and improved the cycleability and specific capacity (Nishimura et al., 1997, Wu et al., 2002). This study is focused to develop graphite-silver composite in order to upgrade the quality of vein graphite as anode material for lithium ion rechargeable batteries. Electrical characterization and structural characterization was done by four probe electrical conductivity and Fourier Transformation Spectroscopy (FTIR) respectively. According to the results, the study reveals that Ag-graphite composite can be successfully produced from vein graphite. This method can evidently lower the sensitivity of anode material for humidity. Therefore, vein graphite in Sri Lanka is a promising material for industries to manufacture lithium ion batteries under less critical conditions.
Development of Sri Lankan Vein Graphite for Lithium-Iron Rechargeable battery Anodes by Chemical Oxidative Treatment
(Uva Wellassa University of Sri Lanka, 2012) Bandara, S.M.J.G.
Modification of natural graphite has recently moved into the focus of the preparation of anode materials for lithium ion batteries. It has been reported that, modification of natural graphite by oxidation proved a higher reversible capacity around 330 mAh/g, and its cycling behavior is considerable. Reversible intercalation and de-intercalation of Li+ ions with graphite are attributed to successful formation of a stable and protecting solid electrolyte interface (SEI) on the graphite surface, which is known to complete in initially few cycles. Recent studies on Sri Lankan natural vein graphite indicate that it has sufficient electrical conductivity to use as potential candidate for Lithium ion rechargeable batteries (Geethika, et al., 2010). Chemical oxidation with acids increases the reversible capacity of Bogala natural vein graphite. The study aims to chemical oxidation of natural Bogala vein graphite using nitric acid to improve its surface structure. Different structural varieties of natural vein graphite powder were oxidized with series of nitric acid to improve its surface structure. This oxidation process is accompanied by production of nano channels and microspores, which can act as host sites, inlets and outlets for reversible lithium storage. According to the FTIR data, functional groups of carbonyl, carboxyl and hydroxyl groups were appeared after the mild oxidization. Moreover, the attachment of the functional groups represents the removal of active sites. Consequently, the electrochemical performance is markedly improved (Fu et al 2006). The chemical oxidation with HNO3 slightly modify the graphite surface by forming acidic group which act as surface film to produce SEI resulting high reversible capacity of lithium ion rechargeable batteries. However, chemical oxidation with HNO3 has not significantly change the d,c electrical conductivity.
Devolop the Wastewater Treatment Method for Rubber Industry
(Uva Wellassa University of Sri Lanka, 2012) Gunawardana, W.D.A.K.
Plastic tank, 1 mm grain size sand were used to prepare sand filter. Lime and Alum are used to chemical treatment. Lime was used for the pH adjustment and remove. Sand filtration method was used for reduce turbidity, color and order problem. Alum was used for remove suspended solid. 1 g of lime was enough to pH correction. After sand filtration and was added lg of alum to reduce suspended solids. Then Algal treatment was used to reduce nitrate and suspended solids. Alum treatment was started after lime treatment and sand filtration. It was helped to minimize the Alum usage and increase the efficiency of Alum treatment. Most research about rubber waste water based on only biological methods. This research, chemical treatment was used to increase the treatment rate. This was easy to maintain and Chemical cost is low value. In Algae treatment process, Algae was used nitrogen for their metabolism activities. Denitrification microorganism activities also helped to reduce total nitrogen. This research was concerned to evaluate the pH, BOD, COD, TSS, total nitrogen in wastewater and adjust them to desirable limit.
Disinfection & Coagulation Abilities of the Natural Plant Materials for Water Treatment
(Uva Wellassa University of Sri Lanka, 2017) Lakshanuka, K.G.S.
In certain instances chemical compounds are used in water purification plants as disinfectants and coagulants which would cause adverse environmental and health issues. Present study aimed by finding a suitable plant materials as disinfectants and coagulants for both water and wastewater treatment. In disinfection test, leaves of Carica papya, Azadirachta indica, Teminalia arjuna and bark of T. arjuna were used. Plant powder (20 g) of each species was mixed in 70% ethanol (100 mL) separately and 2.5 mL of mixture was used to treat Eesherichia coli suspension. In control, E. coli suspension was treated by 2.5 mL of 70% ethanol. Treated suspensions were incubated (100 rpm, 15 hours), re-cultured in a Nutrient Agar, incubated for 24 hours and number of colonies were counted. In coagulation test, seed powder of Zea mays, Moringa oleifera, C. papaya and Cicer arietinum mixed in water (0.5 g, 1.0 g, and 1.5 g/100 mL) separately and added to 500 mL of raw water and jar test was performed. Turbidity, pH and conductivity were measured in treated water. Complete Randomized Design was followed in both experiments with three replicates. Data were analyzed by ANOVA. According to the results of disinfection test, all treatments showed the reduction of E.coli colony count in comparison to control. C. papaya showed the least colony count. Turbidity and pH of coagulated samples were significantly different (p < 0.05) among treatments. The least turbidity was observed under M oleifera. Zea mays, M. oleifera and C. arietinum maintained the pH of treated water around 7. Carica papaya maintained the basic water pH. Least conductivity was given by C. papaya but not significant (p > 0.05). Effective concentration for turbidity and conductivity maintenance was 0.5 g /100 inL whereas pH was maintained with 1.5g/100 mL concentration. In conclusion, according to the results obtained from the study, the most effective disinfectant and coagulant was powder of C. papaya leaves and M oleifera seeds respectively.
Ecological Purification System Modification of Slow Sand Filter
(Uva Wellassa University of Sri Lanka, 2012) Hewamadduma, A.D.
Unsafe drinking water is a major cause of water-related diseases that predominantly affect people living in developing countries. Today there are many technologies available to treat unsafe water; however, most of these are suited for use with low turbidity source water. The treatment of high turbidity water (>40 NTU) is a challenge that was investigated in this research. Slow sand filtration process is an established rural area water treatment, technology widely used in developing countries to treat low turbidity drinking water. This research investigates modifications to the ecological slow sand filter design to color and turbidity reduction in high turbidity water. During field tests conducted at Doluwa, in Kandy. A modified ecological slow sand filter with lmm grain size sand layer for added filtration and gave condition to grow filamentous algae on top of the sand bed and reduce supernatant water level till half of present water level; achieved the greatest color and turbidity removals, according to these condition. Because of larger grain size (1mm) sand used for filter media, then suspended material was not mostly deposited on top of the sand bed in ecological slow sand filter. The field tests, during April 2012, showed the Ecological slow sand filter was capable of reducing water turbidity by 85%, and color by 90% on average than unmodified slow sand filter. Average filtration rate, before algal mat was growth on top of the sand bed; 0.4014 m3hr-lm2.After algal mat was growth on the top of the sand bed; the average filtration rate was 0.4007m3hr-1m2. So optimize filtration rate was 4007m3hr- The filamentous algae was mainly affected to reduce color and turbidity in water. Modification of ecological slow sand filter in Doluwa, spirogyra was the dominant algae type growth on the top of the sand bed. During photosynthesis process, air bubbles were released by the algae from top of the sand bed. Therefore suspended material was attached with air bubbles and come to the supernatant water. Those suspended material was floated on the supernatant water. Scum was used to remove those suspended material from the ecological filter. So suspended material was not containing on the top of the sand bed.
Efficiency of Constructed Wetland in Treating Small Scale Reverse Osmosis Rejects
(Uva Wellassa University of Sri Lanka, 2017) Selvakumar, M.
Natural ecosystems like water and soil in developing countries are frequently vulnerable to potential health hazardous due to contamination by human waste and other industrial pollutants. Improper waste disposal plays major role and are commonly due to lack of awareness of the proper waste disposal techniques. This is noted specially in small or rural scales related to waste water and water supply systems. Reverse Osmosis have been used as a major treatment technology in small scale treatment plants to remove hardness in ground water in the CKDu vulnerable villages. Unfortunately, treatment of RO rejects has not been implemented yet. The present study was carried out in the premises of pioneer Reverse Osmosis (RO) plant at Madukantha which related to Regional Support Centre (North), NWSDB Vavuniya, Sri Lanka to treat the RO plant rejects using constructed wetland systems. As the first step of this study, a constructed wetland model was created with dimensions of 2m x 0.5m x 0.5m (Length x Width x Depth) and using Typha (Typha Latifolia) as vegetation. Following this the applicability of constructed wetlands for the treatment of the RO rejects was evaluated by diverting part of the RO rejects to the wetland model and water quality examinations were carried out in the inlet and the out let of constructed wetland model to quantify the nutrient removal efficiency. The wetland model was arranged as Horizontal Sub-surface Flow (HSSF) system to evaluate the performance at the Hydraulic Retention Time (HRT) of 4 days. Samples were collected from influent and effluents of constructed wetland system at once in four days over one month period and hardness, Calcium, electric conductivity, Fluoride, Manganese, alkalinity, Total Dissolved Solids (T.D.S), nitrates, phosphates and shulphates were measured. Results shows that average removal efficiencies of hardness, Calcium, electric conductivity, Fluoride, Manganese alkalinity, T.D.S, nitrates, phosphates and shulphates were up to 31.20%, 35.03%, 38.13%, 28.35% , 25.37%, 25.30%, 38.13%, 18.60%, 12.90% and 19.35% respectively. Results indicate the removal efficiencies increasing with the plant growth.
Evaluation of Gem Mineral Bearing Deposits in Upper Part of Kirindi Oya, Wellawaya
(Uva Wellassa University of Sri Lanka, 2012) Thilakaratne, E.J.N.
Normally gem bearing soil (Mama) is washed and large fraction is retained in the washing bucket. During washing of soil nearly 90% soil is removed as fine fraction and that fraction may contain some amount of gem minerals. Evaluation of gem mineral bearing sediments in upper part of the Kirindi Oya at Wellawaya area was done by collecting samples along two tributaries of Kirindi Oya and that has distributed from Highland complex to the Vijayan complex. Kirindi Oya belongs to the Buttala-Okkampitiya —Monaragala area where one of major gem potential region of Sri Lanka. 12 samples were taken for analysis of gem minerals. Here magnetic separator and heavy media separation were used to get heavy fractions of the sample. Still there are not prepared enough gem potential maps of our country with proper scientific background and some prepared gem potential maps are also not giving adequate details. There was not prepared a gem potential map of the study area. As a practice gem potential map of the study area is prepared. Wellawaya area falls in the Monaragala district, Uva province of Sri Lanka and that province is one of the potential provinces for gems and Wellawaya is located between Highland complex and Vijayan complex. According to the results of the studied area garnet, zircon, tourmaline like minerals have accumulated in various amounts within the area. Variation of gem minerals in the studied locations can be caused the mineral content of the source rock beneath the locations of the area. According to the gem potential map of the study area there is high potentiality of gem along the main Kirindi Oya alluvium. Mainly geology, Geomorphology, stream pattern and stream networks are responsible for the deposition of gems.

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