Nitrogen is a vital source for the flora as well as the fauna for their metabolic activities. Considering the necessity of nitrogen in agricultural industries, urea is the mostly applied fertilizer to fulfill the nitrogen requirement. But urea is produced under adverse conditions such as under high pressure and high temperature. Moreover, there is naturally occurring nitrogen fixation mechanism, which catalyses by the nitrogen fixing microorganisms. The present study focuses on the nitrogen fixation mechanism by the bacterium Azotobactor. Nitrogen fixation efficiency is defined as the amount of nitrogen fixed in a certain period of time. The rate of fixation is depended on the bacterial growth conditions. Thus, experiments are done by varying the pH of the culture medium. Then, nitrogen fixation is measured with the bacterial state of growth by Acetylene reduction assay.
Tubular photobioreactor for culturing microalgae
Name: Jayawardhana E.P.S.I.
Supervisor / Co-supervisor: Dr. CS Kalpage & Dr. M. Danthurabandara
Consumption of fossil fuels has been increased dramatically during the last century and the current methods of energy production are not sustainable as fossil fuel resources are rapidly depleted. However, various new technologies used in wastewater treatment can be used to remove pollutants while energy is produced. Microbial fuel cell (MFC) is one such method involved in wastewater treatment through a bio-electrochemical reaction while producing the electricity as a byproduct. In this study, domestic wastewater is treated using a dual chamber microbial fuel cell. The anode chamber is maintained under anaerobic condition and methylene blue is used as mediator. Commonly available materials were used to construct and operate the MFC. Saccharomyces cerevisiae was used as the microorganism and carbon rods from pencils were used as electrodes. A ceramic plate (porcelain septum) is taken as the proton exchange membrane (PEM).
Study of Adsorption and desorption of prosperous on biochar
Name: Dissanayake D.A.T.U.
Supervisor / Co-supervisor: Dr. C.S. Kalpage & Dr. D.G.G.P. Karunarathne
Phosphorous is an essential nutrient for the development of living organisms and used for many industries, mostly for fertilizer industry. Because of the population growth, urbanization and development of industries, use of phosphorus is being increased and also the amount of phosphorus in wastewater streams. Due to high concentration of phosphorus in water sources, water quality deteriorates and eutrophication occurs in natural water bodies. Also with the continuation of use of phosphorus reserves on earth reduces which necessitate the need to recover phosphorus from wastewater. In this research, the ability of biochar to adsorb phosphorus from environment and desorb when the environment concentration is law will be studied. Also the dependency of adsorption rates on initial concentration, initial pH and temperature will be investigated. In this study adsorption and desorption capacity of phosphorus onto biochar made from sawdust, paddy husk and guinea grass will be investigated. At room temperature adsorption batch experiments will be conducted to determine the best adsorbent. Kinetic experiments and equilibrium experiments will be conducted on all three biochar at room temperature and for the biochar presenting best adsorbent capability, equilibrium experiments at 30 deg C will be performed. The adsorption with initial solution pH variation will be examined too. C and 40 deg C
Optimization of Cinnamon bark oil production by direct steam distillation method
The percentage yield of Cinnamon bark oil distillation by traditional water and steam distillation method is as low as 1%. In this work, a new process design and operation for steam distillation of essential oils that increases oil yield was developed. During preliminary studies, the percentage yield of Cinnamon bark oil distillation was optimized up to 1.6% using a laboratory scale steam distillation apparatus with a steam flow rate of 12 (kg steam) (kg Cinnamon) -1 h -1 . The high steam flow-rate of 12 cannot be justified environmentally though the yield has increased up to 1.6. The reasons can be high heat loss of the biomass flask and the lack of control of steam flow rate. For further studies, an apparatus was newly designed and fabricated by suppressing heat loss in still and facilitating the option of controlling steam flow rate during extraction tests. A packed bed of raw materials, as opposed to water and steam distillation method was used.
Design and fabrication of a spinning disk reactor for synthesis of Nano particles
Name: Karunarathna N.D.B.G.
Supervisor / Co-supervisor: Dr. D.G.G.P. Karunarathna & Dr. A. Manipura
Calcium carbonate particle size is varying with its operating parameters. Rotational speed, Viscosity of the reagent, Radius of the disc, the reagents feed point of the disc, Number of reagents and the way of they entered to the reactor, seed rate and Ca(OH) 2 concentration, Atmospheric conditions. In this research project, consider how they effect for calcium carbonate Nano-particles.
Biological hydrogen is an alternative method for producing hydrogen as it is cost effective and environmentally friendly process. This is done in dark fermentation by anaerobic bacteria or under light. These basic two methodologies of bio-hydrogen production are already experimented well. However, this research is aimed to get better production rate by combining the two basic methodologies in an optimal way for industrial scale bio hydrogen production.
Bio gas production from food waste for energy recovery
Name: Perera D.I.M.
Supervisor / Co-supervisor: Dr. C.S. Kalpage & Dr. A. Manipura
Nitrogen is a vital source for the flora as well as the fauna, for their growth and metabolism. Considering the necessity of nitrogen in agricultural industries, urea is the mostly applied fertilizer to fulfil the nitrogen requirement. But urea is produced under adverse conditions; under high pressure and high temperature. Moreover, there’s naturally occurring nitrogen fixation mechanism which catalyse by the nitrogen fixers; the microorganisms. The present study focused on the nitrogen fixation mechanism by the bacterium Azotobactor. Nitrogen fixation efficiency is defined as the amount of nitrogen fixed in a certain period of time. Results of the study shows that the rate of fixation depend on the facts that are related to bacterial growth conditions. The experiments are done by varying the pH of the culture medium and N2 fixation is measured with the bacterial state of growth by Acetylene reduction assay.
Synthesis of hydrocarbon fuels using waste plastics
Name: Ranasinghe R.M.W.C.B.
Supervisor / Co-supervisor: Dr. D.G.G.P. Karunarathna
The plastic consumption rapidly grew during the last few decades due to their ability to be simply formed, its light weight and non-corrosive behavior. These excellent properties of plastic lead to replace of wood and metals by plastics. Disposal of solid waste has become a major environmental issues in Sri Lanka. Land filling was not a suitable option for disposing plastic wastes because of their slow degradation rates. The incineration of plastic waste generates toxics such as dioxins. Therefore, recycling and recovering methods used to minimize the environmental impacts. Waste plastic pyrolysis and conversion in to fuel is one option. The aim of this project is to study fuel oil production from municipal plastic wastes by catalytic pyrolysis process.
Design a steam generating system to reduce heat loss from refinery flare
Name: Samarakoon M.G.C.B.
Supervisor / Co-supervisor: Dr. D.G.G.P. Karunarathna & Ms. Anoma Senevirathne
Steam assisted flare systems are commonly used in petroleum and petrochemical industries to supply required momentum and turbulence to the air and fuel mixture to maintain complete combustion as a result of that reduce the black smoke. Sapugaskanda oil refinery of Ceylon petroleum cooperation has only three water tube steam generating boilers and one is not working. So that steam load is not enough to carry out both electric generations by steam turbines and supply steam to the flare system simultaneously. So that the steam flows to the flare system was limited or cutoff frequently and the environmental issues due to incomplete combustion was neglected. The new design of steam generation system deals with radiation heat transfer from the flare which is usually wasted to the environment without any heat recovery method. So that it is convenient to use flame heat rather than establishing new boiler which is not economically feasible. The existing steam path carries steam all the way from plant to flare with higher amount of heat loss to the environment and the new system generates steam in same place and heat loss can be neglected. The new system contains water pump selection, steam generating coils design, separator drum to separate water vapor and steam, steam injecting nozzle design with measuring and control instrumentation. The economic feasibility analysis and safety analysis can be compared with existing system to check the feasibility of the new design.
Removal of heavy metal from waste water using algae
Water pollution by heavy metals is a serious environmental problem with rapid industrial development. Sources such as textile and tannery industries release these metals to environment and removal of these metals is very important to avoid the hazards associated with them. There are many methods to treat water containing heavy metals. But use of algae is an interesting approach. In this work, an alga, which is locally available, is used to remove two heavy metals from textile industrial wastewater. Here, two methods of alga cultivation are employed. In the first method, alga is grown with known concentrations of selected heavy metals and in the other, once the alga is grown, known concentration of the same metals is introduced to find out which method is effective in removing the heavy metals.
Industrial waste water treatment using photo-oxidation method
Name: Sirisena B.V.M.N.B.
Supervisor / Co-supervisor: Ms. W. Menike & Dr. C.S. Kalpage
Study is carried out to find applicability of Photo Fenton oxidation method for treating textile wastewater and to identify optimum treatment conditions: Ferrous ion concentration, Hydrogen Peroxide concentration, pH value and operating time for having maximum treatment efficiency of color removal and the COD reduction. In preliminary investigation 34% of color revels efficiency was obtained for treatment of a 0.2% methylene blue solution with operating condition of Ferrous ion concentration 80mg/l, Hydrogen Peroxide 200mg/l, pH of 3 and operating time of 1 hour. Detailed investigation will to be carried out according to the response surface methodology for finding optimum operating condition of Photo Fenton oxidation method to be maintained to have maximum treatment efficiency.
Natural fibers as substitutes for asbestos
Name: Wijerathne M.A.P.M.
Supervisor / Co-supervisor: Dr. D.G.G.P. Karunarathna
The exceptional chemical and physical properties of asbestos fibres have led to the development of the use of asbestos fibres in multiple forms of manufacturing numerous widely consumed industries, products and in the construction of building. Though it has a variety of applications asbestos has also been found to be a hazardous material to human health. Many countries, including all European, have banned the usage of asbestos while developing countries are finding substitutes for asbestos. According to WHO the most efficient way to eliminate asbestos related diseases is to stop using all types of asbestos. Several substitutes have been introduced to reduce the consumption of asbestos. Natural fibres are widely used as substitute materials for making roofing sheets at present. In this project, it is expected to manufacture roofing sheets with comparable mechanical properties by using coir fibres and to determine the material properties of coir corrugated sheets.
Investigation of most significant compound for pyro-plasticity of porcelain tiles though an experimental design
Name: Wijesooriya W.A.D.H.P.
Supervisor / Co-supervisor: Ms. W. Menike & Mr. Sumedha Medawala
Pyroplasticity is the tendency of the ceramics to deform under its own weight, during its firing process which affects to reduce the ceramic product quality. The properties of liquid phases formed during the firing process may affect on this deformation of porcelain ceramic products. The properties of the liquid phases formed during firing are varied mainly according to the raw material composition of feldspar, ball clay, silica sand and dolomite and the firing temperature maintained as per literature. Hence this research study Is conducted to find the main affecting factor for pyroplasticity among said factors and to find optimum combination of raw material composition and optimum temperature to be maintained for firing process to have minimum deformation percentage. Experimental design is done according the experimental mixture design procedure.
Design of a evaporation pan for improving the Jaggery making process from Palmyrah/Kithul treackle through efficient heat transfer
Name: Aberathne K.H.A.S.M.W.
Supervisor / Co-supervisor: Dr. M.A. Elangasinghe & Prof. R. Shanthini
The temperature distribution of the pan is an important parameter for consistency of the Jaggery and quality of the Jaggery. Composite evaporation pans improve the uniformity of temperature distribution on surface of the pan. The objectives of this project is to model the temperature distribution of surface of the evaporation pan subjected to a non-uniform heat source for optimizing the materials for composite pan and dimensions of the evaporation pan. The modelling exercise is carried out in COMSOL Multiphysics to observe the temperature distribution of the pan surface for different composites with different thicknesses and shapes of the pan for achieving uniform heat distribution in treacle during evaporation process.
Investigating the impact of water content and rotational speed upon quality of sesame oil produced using response surface methodology
Sesame oil contains oleic (up to 38.84%), linoleic (up to 46.26%), palmitic (up to 8.58%), steric (up to 5.44%). Oleic and linoleic have double bonds. That’s why sesame oil is unsaturated oil. Storage life (peroxide value and oxidative stability) of crude sesame oil significantly depends on the initial moisture content of sesame seed. High moisture content increases the peroxide value and reduces the oxidative stability, and therefore storage life is reduced. If sesame seeds has 12.7 % (wet basis) moisture, then it can be extracted maximum amount of oil. When the rotational speed is high in the screw expeller, yield of oil becomes low. Research hypotheses is sesame oil quality (peroxide value-PV, total phenolic content-TPC, 1,1-diphenyl-2-picrylhydrazyl –DPPH) and yield vary with seed moisture content and rotational speed. Overall aim is extracting oil with good quality and high yield. Specific objectives are extracting oil with seeds of different moisture contents (5 to 20% wb), extracting oil at different rotational speeds (30 to 50 rpm), determining the antioxidant activity ( TPC, DPPH )of sesame oil extracted, determining the yield of sesame oil extracted, and using response surface methodology to determine the relationship among quality parameters, yield, moisture content and rotational speed. Foin-Ciocalteau regent (FCR) volume, Na2CO3 concentration and time duration of optimum values were calculated using Minitab analyzing. There are 1.866 ml, 24.575% and 30 min.
Sesame oil is a healthy food for human body due to its ability of prevention aging and increasing energy in human body. Though sesame oil contains more unsaturated fatty acids, it is a food which has high resistance to oxidation due to presence of phenolic antioxidant compounds. Recent studies have investigated that oil oxidation is a temperature and time dependent process. It is important to investigate the optimum heating temperature and heating time of sesame oil because sesame oil is basically used in cooking. Therefore aim of this project is to find out the temperature and heating time that sesame oil gives the optimum antioxidant activity. Best method for extracting phenolic compounds from sesame oil was obtained by carrying out total phenolic content (TPC) for different extraction methods. Four tests including TPC and peroxide value(PV), free fatty acids(FFA) and 2,20-diphenil- 1-picrhlhydrazyl (DPPH) will be carried out in future to find out antioxidant activity of sesame oil heated in different heating temperatures and times.
Use of paddy husk ash in production of garden tiles
Name: Chandrasiri L.C.M.
Supervisor / Co-supervisor: Dr. M. Danthurebandara
Rice husk ash (RHA) is a residue of burning of rice husks. As RHA has very effective pozzolanic properties they can be used as construction materials. In this study, RHA resulted from a boiler used in power generation has been evaluated for optimal level of replacement of sand and cement in garden tile production. Results obtained in the preliminary testing indicate that high carbon content in RHA could have adverse effect on the compressive strength of the specimens.
Removal of some basic dyes from artificial textile wastewater by adsorption on paddy husk charcoal
Name: Ilangarathna D.C.N.
Supervisor / Co-supervisor: Ms. S.M.W.T.P.K. Ariyaratne & Dr. M.A. Elangasinghe
All synthetic dyes in the effluents from textile industry activities can result many environmental hazardous to the aquatic system. Though there are several methods to treat such effluent, capital and the operational cost of them, limits the application. So, this is high time to search an advance treatment method like adsorption and low cost adsorbant. Paddy Husk Ash (PHA) is identified as freely available and hypothesised as a good adsorbant. Feasibility of using PHA is studied and the optimization of variables in adsorption is being studying at the moment.
Feasibility study of fluoride adsorption onto apatite powder/clay filter
Name: Manchanayake M.D.A.S.
Supervisor / Co-supervisor: Dr. M.A. Elangasinghe & Ms. N.I.K. Ekanayake
Excess fluoride in drinking water creates many problems to human health. Adsorption is most commonly used method for defluoridation. This study investigates feasibility of apatite or brick powder as fluoride adsorbents in a filter column. The fluoride removal efficiency of these powders as a function of pH level of the fluoride solution, contact time, initial fluoride concentration and apatite dosage are investigated. When the two powders are compared brick powder is found to be having high fluoride removal efficiency compared to apatite powder. Further studies are carried out in designing a filter column for home usage.
Design optimization of PET bottle through regression modelling & CAD simulations
Name: Perara L.T.S.
Supervisor / Co-supervisor: Dr. M.A. Elangasinghe & Mr. Ivan Dassanayake
The quality of a carbonated beverage essentially depend on the amount of carbon dioxide available in the beverage throughout its shelf-life. The fizziness caused by the presence of carbon dioxide gives a distinct taste as well as a sense to the particular beverage. Therefore, it is important that the fizziness is maintained throughout the shelf-life of the beverage. Hence, this study investigate whether the present design of Polyethylene terephthalate (PET) bottle, serves its purpose and, what modifications could be done in order to improve the design of the PET bottle. The bottle thickness at different zones of the bottle, as well as the pressure of carbon dioxide inside the bottle have been considered as model variables to be optimized using COMSOL Multiphysics software.
Manufacturing a geo-textile using fabric off-cuts
Name: Rathnasiri K.A.T.S.
Supervisor / Co-supervisor: Dr. M. Danthurebandara & Mr. Ranil Kularathna
With growing attention to environmental pollution due to improper solid waste management strategies, the textile l industry has expanded its efforts to reduce disposal of textile waste in landfills and also at the same time about finding alternative methods for the disposal of this textile waste. Hence considering the waste issue and textile industry demands, manufacturing a geotextile from fabric off cuts was considered in this study. Considering resource availability, non- woven methodology was considered for web forming and both thermal and chemical bonding methods were suggested as approachable bonding methods.
Micro algae farming in the wastewater as a treatment technology
Name: Sandaruwan B.L.P.
Supervisor / Co-supervisor: Dr. M. Danthurebandara
Generation of massive amounts of wastewater from industries and households is a big issue in the world. Treatment of wastewater before discharging them into inland surface waters is essential to minimize the related environmental problems. Current treatment methods needs higher costs and energy. Using microalgae in wastewater treatment is a promising low cost treatment technology which incurred more benefits compared to conventional treatment processes. Wastewater can be treated at low cost from one hand and the harvested microalgae can be used in various other applications such as production of biodiesel and biogas on the other.
Investigation of therapeutic properties of Aegle Marmelos (Beli)
Ayurvedic plants have healing powers against many common and powerful diseases. Anti-bacterial activity is one among them. Sri Lankan Aegle Marmelos (Beli) leaves were screened to find out their anti-bacterial property using two extraction methods, solvent extraction and steam distillation. Hexane, Methanol and Ethanol were used as solvents. When Hexane act as the solvent, the extracted oil amount was 3% from powdered leaves. Standard strains of Staphylococcus aureus (ACTT 25123), Pseudomonas aeruginosa (ACTT 10662) and Escherichia coli (ACTT 25922) were used to examine the anti-bacterial property in crude extracts, using Agar diffusion method. Highest antibacterial properties were shown for E.Coli as 2mm inhibition diameter. Minimum Inhibition Concentration (MIC) will be found for the bacteria that it shows highest antibacterial activity. A product (an anti-bacterial cream) will be developed using this minimum inhibition concentration.
Bio gas generation from yeast sludge at the distillery plant, Pelwatte
Recently, there has been an increasing interest in using anaerobic fermentation to produce bio gas as an alternative energy source. Commonly used substrate for biogas production includes industrial waste and agricultural waste. Three major wastes generates in the sugar industry were considered in this study. The objective of this research is to study the feasibility of biogas generation by spent wash discharge from the distillery plant at the sugar industry with , kitchen waste generate in the factory residences and filter mud from the same plant. The biochemical methane potential of distillery spent wash, distillery spent wash with filter mud and
distillery spent wash with kitchen waste were determined in laboratory scale.. In determination of bio methane concentration, the volumes of the gas were obtained using the liquid replacement method (LRM) and the compositions of the collected samples were analyzed using gas chromatography. Spent wash with filter mud was identified as the best combination for biogas generation. The optimized ratio of the combination will be investigated with ongoing experiments
Valorization of paddy husk ash through silica extraction
Name: Wijerathne A.M.L.C.K.
Supervisor / Co-supervisor: Ms. S.M.W.T.P.K. Ariyaratne & Dr. M. Danthurebandara
Paddy husk has been identified as a potential and sound source for power generation. But, the ash generation in paddy husk combustion is high comparing to other fuels. Therefore, Paddy Husk Ash (PHA) generates in the power plants is a considerable waste and has become an issue in dumping sites. Therefore a proper utilization of PHA through value addition is essential.
Bleaching earth is an adsorbent used in edible oil refinery process. After using bleaching earth, the residues are called spent earth. The spent earth has no proper disposal method rather than landfilling which results severe environmental problems. In this study use of spent earth in production of garden tiles has been examined. Two experimental series have been suggested: use of spent earth as an alternative for (i) sand and (ii) cement. Measuring compressive strength and water absorption capacity is suggested to determine the quality of the produced garden tiles.
Modelling and Simulation of Sekku Performance Using Sesame as the Model Material and Experimental Verification
Name: Ranathunga R.M.K.S.C.
Supervisor / Co-supervisor: Prof. R Shanthini & Prof. K.S. Walgama
Oil extracted by means of traditional method; Sekku has comparatively greater demand than the oil extracted using other modern devices due the high quality and taste of Sekku extracted oil. But this methodology is not so efficient in terms of operating speed, capacity, etc. and this is a major drawback that experience by the Sekku owners. Moreover, it can affect the future of this traditional technology. Performance of current system should be understood through careful analyses so that new improvements can be suggested based on the shortcomings of the current system. The minimum power requirement can be identified as the power which is sufficient just to overcome the frictional resistance of the system. And, it can be calculated by solving the system of force acting on the different components of the Sekku which contribute in the grinding operation. Temperature of model material will increase during the operation and this temperature variation cannot really be investigated through a pure experimental approach. Thus, the best way to understand the temperature profile of the study material is application of a suitable graphical analysis approach.
Analysis of therapeutic components in Sri Lankan sesame oil
Name: Rathnayake R.M.M.S.B.
Supervisor / Co-supervisor: Prof. R. Shanthini & Ms. W. Menike
Study was carried out to compare the sesamin and sesamolin contents of white sesame seed oil. Preliminary experiments were carried out by analysing oil samples with high performance liquid chromatography (HPLC) and Spectrophotometric methods. In HPLC peaks were obtained at 290 nm. Absorbance of roasted oil samples and normal oil samples were measured between the range 200 nm to 400 nm in spectrophotometer. The roasted oil samples showed higher absorbance than normal oil samples around 290 nm. This could either represent higher percentage of sesamin and sesamolin or presence of another chemical components formed due to dissociation of sesamin and sesamolin. Further investigation is required in determining the identity of these components in roasted sesame oil.
In silico modeling of MgO nanocarrier pharmacokinetics and tumor delivery - influence of surface charge
Nanocarriers are novel tools for malignancy treatment, reducing the hindrances of conventional medication. Consequently, the drug distribution efficacy of the nanocarriers is low owing to the lack of acquaintance in nano-bio synergies, and the surface charge of the nanoparticle (NP) addresses it a permissive tendency to crawling in the biological barriers. Amid the numerous NPs, inorganic MgO NPs facile vector in the living organism diminishing extended boundaries in NP conveying. The research was carried out with the positively charged MgO NPs including 12 parameters bearing to NP, tumor, and individual physiological characteristics. The in-silico modeling renders a comprehensive study in a spacious series of variables and the sensitivity
analysis is employed to discover the uncertainty of the variabilities within which limit. We concluded the nominally charged particles with 50 nm radius and 2g/cm3 were numerously productive than the MgO particles for NP accumulation in the tumor interstitium. Additionally, the NP radius, degradation rate, tumor blood viscosity are the essential parameters, and NP surface charge, the area fraction of spleen vascular owned by splenic macrophages, blood flow rate, pore radius, and the hematocrit in the plasma are moderate factors of the proximity of the drug delivery..
Air quality improvement in Colombo, Sri Lanka: Is it merely due to COVID 19 related travel restrictions?
This paper presents, time series analysis of atmospheric concentrations of particulate matter less than 2.5 micrometre (PM ) measured in a coastal site of Colombo, Sri Lanka to understand whether there is an improvement 2.5 in air quality as a results of reduction in human movement due to Easter bomb attack in 2019 and COVID-19 related travel restrictions in 2020 and 2021. When time series data from 2018 to 2021 are analysed a clear reduction in PM2.5 concentration at the study site located in Galle Road is observed. When the trend of PM concentration over the 2.5 years 2018 to 2021 is calculated using Theil-Sen method it suggest a decrease of PM concentration at a rate of 9.74 mg/m3 per year (with a confidence interval of 7.37 - 11.89 mg/m3 per year). Colombo, Sri Lanka is a coastal city which is greatly affected by southwest monsoon. When monthly pollution rose diagrams were analysed, a clear diurnal variation of wind pattern is observed with increasing of stormy weather during southwest monsoon season from May to September over the years 2018 to 2021. To exclude the fact that the reduction in pollutant concentration is due to the increase in wind speed during the monsoon season, a cluster analysis technique has been used to separate the effect of dilution of pollutants due to the gusty winds during the monsoon season from non-monsoon seasons. The cluster analysis has been performed on the concentration polar plot drawn for the whole data set from 2018 to 2021 and two clear clusters were identified. Cluster-1 represented data during the monsoon season from May to September and cluster-2 represented the data during non-monsoon season. Cluster-1 clearly showed an inverse relationship between wind speed and observed PM concentration suggesting the dilution effect of 2.5 concentration with the increasing wind speed. Cluster-2 clearly showed a directly proportional relationship which suggests that pollutants from the city are transported to the study site with increasing wind speeds. When trend analysis is performed on the two clusters both clusters showed a decreasing trend. Final results of the study suggests that due to the increasing stormy weather during monsoons over the years have reduced the PM 2.5 concentration in the study site at a rate of 10.02 mg/m3 per year (with a confidence interval of 7.05-12.07 mg/m3 per year). Due to the reduction in human travel that caused a reduction in traffic related air pollution over the years has reduced the PM2.5 concentration in the study site at a rate of 6.83mg/m3 per year (with a confidence interval of 4.65-10.03 mg/m3 per year). This technique can be used to analyse the air pollution and meteorological data collected on a routine basis in different cities to extract important information related to atmospheric pollutant concentrations
Understanding Exposure to Air Pollution while Commuting in Different Transport Modes.
The annual death rate of humans has been dramatically increase over the past few years due to cardiovascular and respiratory diseases. One of the main reasons for these types of diseases to increase can be as a result of suspended particulate matter (PM) being inhaled by people. This exposure to particulate matter can occur while people are both indoors and outdoors. Very high, short term and long term exposure is seen in many industrial environments. However many studies have found the exposure to particulate matter while commuting inside vehicles. This study reveals the results of average PM 2.5 and PM 10 exposure concentrations while travelling in four methods such as motorbike, three wheeler, car and bus, under similar ventilation mode that is all windows open while traveling in each vehicle for seven days, one hour each day for each vehicle at the peak time of the day). The result indicates that the PM exposure concentration particularly dependent on the mode of transportation. The commuters were exposed to the lowest concentration of PM 10 and PM 2.5 was the motorbike (47.5 μg/m3 and 21.1 μg/m3 ). The highest PM 10 was recorded from the three wheeler (71.9 μg/m3 ) and the highest PM 2.5 level wasrecorded from the bus (33.5 μg/m3).
Modeling an Electrochemical Cell for Electrosynthesis of Hydrogen Peroxide Using Hydrogen and Oxygen gases
Hydrogen peroxide is a strong oxidant that can be synthesized electrochemically using hydrogen and oxygengases in a more environmentally friendly manner despite its conventional production method which is very energy-intensive. Such electrochemical cell consisting of flow field plates, gas diffusion layer electrodes with catalyst layers and a porous solid electrolyte layer sandwiched by an anion exchange membrane and a cation exchange membrane is modeled here. The main consideration is given to predict reversible voltage, concentration overpotential, activation overpotential and ohmic losses where the governing equations used are Nernst equation, convective mass transfer and Fick's law equation, Butler-Volmer equation and ionic and electrical resistivity equations respectively. The results of the model indicate that reducing ohmic losses through reduced solid electrolyte layer thickness and improved conductivity of solid electrolyte are effective towards improved H2O2 yield, whereas increasing half-cell pressures leads to reduced activation and concentration overpotentials. Further negligible cell performance variation is observed with in the temperature range of 20- 40°C.
Critical Review on Cassava Starch Modification Techniques
Cassava starch is broadly used in industries such as textile, pharmaceuticals, oil drilling, paper andpackaging, gum and adhesives, chemical and household products manufacturing, battery, drinks and beverages, foods and so on. The world production of cassava in 2012 was estimated to be 263 million tons with the top producers being Nigeria, Indonesia, Brazil, and Thailand (Zhu, 2015).Starch is not suitable in the native form for most of the above mentioned industrial applications because native starches generally have limitations such as poor solubility, high hydrophilicity, high viscosity, not resistant to high temperature of heating and gel forming ability etc. Hence, they needto be modified to eliminate these shortcomings and to enhance their physicochemical and functional properties. The current review mainly presents the effects of several starch modification techniqueson the changes in the starch multi-scale structure including molecular structure, crystallinity, lamellae structure, and morphology characteristics. Those various methods have been discovered under three broad areas; chemical, physical and enzymatic. It was observed that environmentally friendly technologies have potential to be used for starch modification. Pasting properties of the modified cassava starch showed high peak viscosities (420 - 488 RVU) compared to low peak viscosity(392.33 RVU) of the native starch. The modified starch was characterized with low set back viscosities (57 - 64 RVU) in relation to native starch with high set back viscosity (66.58 RVU). Similarly, the modified starch was characterized with low gelatinization time (3.45 - 3.36 min) compared to the native starch with high gelatinization time (3.5 min). Modified starch showed high swelling power (9.5 - 13) and solubility indices (11.3 - 15.6%) compared to native starch with low swelling power (8.9) and solubility index (3.1%).
Evaluation and analysis of the control measures under COVID-19 using the SIR and SEIR models: A Sri Lankan case study
The COVID-19 pandemic has shown the whole world that effective methods of controlling the spread of the disease is a crucial aspect that needs to be focused on in order to defeat the virus. In this article, the focus is on the control measures taken by the Sri Lankan government and their effects on the country. For this, the country specific data were collected and four experiments were run to test the control measures implemented in the three waves that the country faced and is still facing. Furthermore, to compare the situation with the uncontrolled scenarios, the simple SIR and SEIR models were implemented. Thus, the results showed that the country’s control measures have been quite good at stopping the spread of the virus from being uncontrollable. However, the fourth experiment showed that the control measures haven’t had any effect in controlling the spread of the virus during the second wave.
Study of Fruit and Vegetable Preservation and Analysis of Critical Process Parameters
Fresh fruit and vegetable preservation is a combined study of loss of freshness and freshness preservation techniques. Loss of freshness is a multiple effect factor where temperature, humidity and gas compositions are involved. Prior disinfection is also essential. Preservation techniques discussed are Irradiation, High pressure processing, Modified atmosphere packaging, Control atmosphere storage, Cold storage and Evaporative cooling systems. Analyzing the suitability of these techniques and current fresh produce wastages in supply chain of Sri Lanka, Evaporative cooling technique is proposed as a solution for farmer-level preservation methodology. Research gap in optimizing conditions of Evaporative cooling system is identified. The freshness factors and the preservative techniques were critically analyzed and discovered that the temperature is the most vital controlling factor affecting to the freshness of fruits and vegetables. A case study on weight loss of tomato using Minitab factorial design also concluded that temperature is the significant factor for freshness preservation relative to relative humidity.
Pathway analysis of Pigment production using metabolic Engineering
Chemical synthesis is a well-established method for mass-producing various chemicals, although it still has certain limitations, such as unstable intermediates, multistep reactions, and complicated process con- trol. Bio based production offers an appealing remedy to these issues, but converting cells into effective factories is difficult. Design-construction-evaluation-optimization (DCEO) biotechnology, which includes the ideas and methodologies of pathway design, pathway building, pathway evaluation, and pathway optimization at the sys- tems level, is a crucial enabling technology for developing efficient cell factories. DCEO provides a conceptual and technological framework for identifying prospective paths, modifying current ones, and creating new ones for the most efficient manufacturing of desired compounds. Here, we review current developments in DCEO biotechnology and present instances of its application, as well as recommendations on when, what, and how different tactics should be used. Comparison between parameter optimization and metabolically optimization was discussed. In addition, we discuss DCEO biotechnology's future prospects for the effective creation of bio refineries.
Are ELECTRIC CARS REALLY GREEN?; LIFE CYCLE ASSESSMENT OF COVENTIONAL AND BATTERY ELECTRIC VEHICLES.
Mainly due to environmental pollution and rising oil prices, Battery Electric Vehicles (BEVs) have taken significant attention in transport sector in reason years. Compared to Internal Combustion Engine Vehicles (ICEVs), BEVs seem greener in use phase due to zero emission. Even so, manufacturing and disposal stages are also play an important role when comparing vehicles. Therefore, Life Cycle Assessment (LCA) method is carried out between two technologies. The environmental damages occurred during the LC stages are considered for 18 impact categories. However, the study finds that BEVs powered by average SL electricity mix contribute to environmental pollution as same as the ICEVs in the use phase. Even so, BEVs powered by renewable energy reduce the global warming and other impacts significantly. Burdens from raw materials and production are also high for BEVs for most impact categories including freshwater and marine eco-toxicity. Even so, end of life treatments give environmental benefits.
A Critical Review of Resources, Synthesis and Applications for Zeolite-X
Name: Botheju W. K. T.
Supervisor / Co-supervisor:Dr. C. S. Kalpage, Dr. A. Manipura
This review not only provided a summary of the state of the art with regard to commercially important Zeolite-X technology, but also identified strategies to further promote the uptake of this material in the industry. Waste resources included fly ash, lithium slag, geothermal solid waste, waste sandstone cake, bauxite, and natural resources included kaolin, diatomite. The adsorption capacities of Zeolite-X for Zn(II), CO2(g), NH+4and Sr+2 and crystal violet (CV) dye have been described. A key weakness identified was the lack of compelling economic models in relation to synthesis of Zeolite-X from waste resources or by new methods which produce hierarchical materials. Key areas identified in this review article are scaling-up of new synthesis methods to industrial scale, detailed economic analysis of Zeolite-X synthesis from waste materials as well as from the natural sources, utilization of methods to reduce the cost of zeolite manufacture such as ultrasonics.
Suitability of using Spent Diatomaceous Earth for Concrete Production: A review
In today's world, industries are mostly responsible for environmental pollution. Spent Diatomaceous Earth (SDE) is used to filter beer in the final filtering process. Breweries dump SDE into dumping places, which pollutes the environment. As a result, SDE can be substituted for cement in the concrete manufacturing industry as a solution to this problem. The research on repurposing the SDE for concrete manufacturing is reviewed in this study. In this study, factors impacting concrete quality and attributes, as well as selected criteria that should be maintained to manufacture concrete of the required quality, are discussed. To identify the optimum dosage of SDE that can be used with cements, concrete mixtures with 5%, 10%, 15%, 20%, 30% SDE and control concrete mixtures are considered. It can be concluded that by replacing 15% to 30% of the cementitious material volume with SDE, the compressive strength of concrete can be enhanced. The use of SDE eliminate the negative environmental effects behind the SDE discharge..
SUITABILITY OF REUSING THE SPENT DIATOMACEOUS EARTH FOR BRICK PRODUCTION: A REVIEW
Nowadays industries are mainly responsible for environmental pollution. In breweries, spent diatomaceous earth (SDE), which is used to filter beer in the final filtering process, dispose into dumping areas leads to environmental pollution. Therefore, as a remedy for that problem, SDE can be adulterate with clay to produce bricks. Mixing clay with SDE leads to reduce the quality of the bricks. Nevertheless, usage of SDE in brick production can overcome the negative effects on the environment caused by brick production and SDE waste. This paper reviews research on reusing the spent diatomaceous earth for brick production. Factors affecting the quality of the brick and properties and selected parameters that should be maintained to produce the brick with desired quality are discussed in this paper. For the emphasis of wide production bricks with spent diatomaceous earth, it is recommended to have further research and development, not only on the technical, economic, and environment aspects but also on standardization, government policy, and public education related to SDE recycling and sustainable development.
Mathematical modeling of pesticide distribution in paddy field tank systems
Sri Lanka is a tropical island located in the Indian Ocean consisting of two distinct climate zones: the dry zone and the wet zone. The rain water scarcity of the dry zone for agricultural use has resulted in the development of man-made tank systems referred to as Tank Cascade Systems (TCS) which has over the years integrated with the natural environment of the dry zone. Recently, agrochemicals and other pollutants have come in contact with these traditional water preserving TCSs. As these water systems are used for cultivation and consumption, pollution of these water bodies can cause many health and environmental effects. These systems are studied in qualitative ways in literature but there is a lack of mathematical models to capture, predict and better understand the dynamics of TCS pollution. Therefore, in this work, a time dependent mathematical model for a TCS is developed by considering the interrelations between different environmental components of a TCS. Relevant data is obtained from literature to apply the model to two tanks in the dry zone of Sri Lanka. Simulations were conducted using the Xcos dynamic simulation environment of the open source software Scilab. The water volume and pollutant variations in the Kadirgama and Nawakkulama tank systems are studied. The simulated results are compared against available measured data from the literature and are found to be in good agreement. The developed model in the present work provides a tool to predict how the agrochemicals distribute through a TCS in a selected time period and can be used for further studies in this area.
Assessment of indoor air quality in homes of Kandy urban and suburban areas – A review
Indoor air quality is one of the most important factor for human health. Approximately people spend 74% of their time in houses and indoor air quality in houses directly links with lot of health problems. According to the previous studies, in urban areas mainly vehicular emission has been caused for poor indoor air quality. In suburban areas, indoor burning process has been caused for increasing air pollutants in houses. Among these air pollutants, particulate matters (PM) are one of the most harmful thing for human health. These particles deposit in the deep parts of respiratory system and cause for dangerous health effects such as cancers. And also lung function is decreased due to the deposition of particulate matters. As a another major health problem, cardiovascular problems can be occurred. This study was conducted to using results of previous studies which was approximately similar ones. By assessing those data, how vehicular emission and indoor burning sources (wood and Liquified petroleum gas – LP gas) were affected to the indoor air quality was analyzed. Using information which were taken from analysis conclusion was taken for our study. According to that, higher PM2.5 and PM10 concentrations can be expected in urban houses which were located near a major street. Relatively lower PM concentrations can be expected in urban houses which were located more than 20m away from a major street. In the suburban houses which were used woods for burning processes can be expected higher PM concentration more than in houses which were used LP gas. Previous studies has been shown that higher PM concentration linked with cardiovascular and respiratory health problems. Due to that,
we can conclude households who expose to higher PM concentration have a high health risk. According to this study, in Kandy, urban households who lives near major streets and suburban households who use firewood for cooking purposes expose higher level of PM concentration and they have higher health risk.
Life cycle assessment of different roofing materials in Sri Lanka
Asbestos is used as a common roofing material around the world due to its commercially viable properties. However, many countries have banned or taken actions to ban asbestos due to its bad impact on the health and environment. Though the Sri Lankan government also implemented a ban on asbestos use still, the chrysotile asbestos is widely used in Sri Lanka.Use of clay roof tiles is a possible alternative for asbestos. However, as both the asbestos and clay roof tiles have adverse impacts on the environment, a proper environmental assessment is needed. In this study, comparative Life Cycle Assessment was conducted using SimaPro software to identify the environmental impacts of asbestos and clay roof tiles. The results indicate that modern clay roof tiles have lesser impact than the chrysotile asbestos sheets used in Sri Lanka. A significant burden identified from the extraction phase and the disposal phase of asbestos sheets.
Review on Decolorization of Rhodamine B Dye in Textile Wastewater; Optimization of Photo Fenton Process
Improper discharge of dye effluent of textile indus- try in ecosystems is a subject that should be considered seriously. Dye contaminated wastewater distracts photosynthetic activities by reducing sunlight penetration, dissolved oxygen concentration and water quality. Rhodamine B dye is a highly water-soluble basic organic dye belonging to the xanthene class, which is chemically stable and non-biodegradable. Adsorption, microbial
de-colorization, Photo Fenton process are three major techniques used in Rhodamine B dye removal. Among them, Photo-Fenton which is an Advanced Oxidation Process was identified as easy
handling, more economically efficient, environmentally friendly and rapid technique for Rhodamine B dye decolorization. This study has detailed the effect of chemical parameters such as
initial dye concentration, Fe2+ and H2O2 dosages and physical parameters such as pH and temperature on the decolorization of Rhodamine B dye textile wastewater. The optimum reaction conditions to achieve 98.3% of decolorization were identified to be [Dye] = 1000 mg/L; [H2O2] = 30 mg/L; [Fe2+] = 8 mg/L at pH 3 and 300C of temperature. Among different techniques used for optimizing the system parameters of the Photo Fenton process, Response surface methodology (RSM) coupled with Central Com-posite Rotatable Design (CCRD) was identified as most adequatefor the purpose. . This study will help the researchers to select the most efficient technique and optimum system parameters that should be maintained to obtain the highest decolorization efficiency of Rhodamine B dye contaminated textile wastewater.
Life Cycle Assessment of Strongly Practiced Municipal Solid Waste Management Options in Sri Lanka
The largest percentage of MSW in Sri Lanka is contributed by Colombo district. It is important to analyze the impact of municipal solid waste disposal today and what would be the impact under integrated waste management schemes. Therefore, the aim of this study is to consider different MSW management options from an environmental point of view. In this study, LCA is used to weigh up different treatment scenarios and SimaPro software applied to model scenarios. Four scenarios were considered as alternatives to the current practice waste management options: Aerobic composting with landfilling residue, Anaerobic digestion with landfilling residue, Sanitary landfill with and without energy recovery. The study covers various environmental impacts discussed in ReCiPe Endpoint 2016 (H/A). The results show that it can be reduced the environment impact through energy recovery. Anaerobic digestion is preferable than aerobic composting as a treatment option for biodegradable fraction. An integrated municipal solid waste management approach with a mix of anaerobic digestion and landfill had the lowest overall environmental
impact.
Life cycle assessment of paper and plastic grocery bags used in Sri Lankan supermarkets
Name: L. M. P. D. Pitawala
Supervisor / Co-supervisor: Dr. M. Danthurebandara
Large-scale use of plastic grocery bags presents a significant burden on the environment, where paper bags
are considered a popular alternative to plastic bags. However, it is important to assess the environmental impacts of both types to avoid adverse consequences of use of alternatives on false sense of benefits. Using
life cycle assessment tool, this research investigates environmental impacts of two types of single use grocery bags (plastic and paper) commonly used in supermarkets in Sri Lanka. The results reveal that, under the framework considered in the study, the overall environmental impact of plastic bags is lower than that of paper bags. However, when considering the individual impact categories, plastic bags are relatively more detrimental for global warming, ionizing radiation, terrestrial ecotoxicity, freshwater
ecotoxicity, marine ecotoxicity, human non-carcinogenic toxicity, mineral resource scarcity and fossil resource scarcity. On the other hand, paper bags yield adverse impacts on stratospheric ozone depletion, ozone formation: human health, ozone formation: terrestrial ecosystems, fine particulate matter formation, terrestrial acidification, freshwater eutrophication, marine eutrophication, human carcinogenic toxicity, and water consumption. Raw material extraction, bag production and end of-life stages are the most influential life cycle stages of both bag types.
Mathematical modeling and simulation of wood particle drying process
Gasification is a technological process that can convert any carbonaceous (carbon-based) raw material such as coal into fuel gas, also known as synthesis gas (syngas for short). Gasification occurs in a gasifierIn gasification process, wood drying is a main step of it.In the process there is a huge energy wastage from half dried wood particals, unaccurate time predictions for drying...etc. Main reason is there isn’t a best type of drying simulations for wood drying. Below about to find a mathematical model and simulation for wood drying time and drying precentages. According to this report, Two block meshes are designed Using openFoam-8 software
considering symmetric foams and Developed the mesh using boundary conditions and control conditions Finally applied the command Foams and collected the results. First mesh is a air flow mesh. Its used to calculate the air velocity around the wood block mesh. Its plotted as the 2nd block mesh. Finally calculate the drying time with different moisture contents using laplacian mass transfer equations. Navier stokes equations is solved to calculate the external flow around the wood particle and fick's second law is solved to calculate internal moisture transport with boundary conditions.
Mathematical modeling and simulation of internal heat and mass transfer during convective drying of food with the introduction of shrinkage
Convective drying of food is a commonly used drying method in domestic and industries with industrial application. It uses the ambient hot air. The aim of this research is to model and simulate the heat and mass
transfer during convective drying of food. For this purpose, the convective drying of a thin cuboidal potato slice is modeled. It is assumed that hot air at temperature 60 oC is supplied above and below a potato slice.
Mathematical models for heat and mass transfer equations are developed. The shrinkage effect of the potato was introduced in the model. For this, a stress equation is used to account for shrinkage. OpenFOAM software is used to simulate the developed mathematical models. The water concentration of the potato is well correlated with the time during the convective heat transfer (R2= 0.9951). The results ofthe simulated model are validated with the available experimental data from other literature.
Pigment Extraction from Plant Materials for Food Related Applications
Name: Thilakarathne K.B.C
Supervisor / Co-supervisor: Prof. Karunaratne D.P.
Pigments have been traditionally used for many applications over the years. Apart from their application in textiles, natural pigments are also used in the coloration of foods and medicines. However, the use of natural pigments has diminished over time due to lack of documentation of precious knowledge. With the discovery of synthetic dyes, the demand for natural pigments was further reduced. Nevertheless, there has been an increasing interest in the use of natural dyes as a result of the environmental standards imposed by many countries in response to the toxic and allergic reactions associated with synthetic dyes. This study involved a literature review on natural plant pigments extraction for food applications covering areas such as; chemical composition of natural pigments, pigment sources, pigment extraction techniques, stability enhancement and quality assurance. It identified solvent extraction, microwave and ultrasound extraction, supercritical fluid extraction and enzymatic extraction as commonly used pigment extraction techniques. They are discussed briefly and compared with respect to pigment yield and color strength to enable the reader to select the most suitable technique for their application. The study further identified that microwave; ultrasound and enzymatic extraction give better pigment yields and high color strengthening characteristics compared to conventional methods. Furthermore, pigment stabilizing techniques such as blanching, alkaline treatment, metal complexion, chemical pretreatment and microencapsulation were discussed briefly and their pros and cons were identified. In order to address the future demand of natural colorants, a combination of applied and theoretical research is further required.
Extraction of Valuable Components; Polyphenols and Antioxidants from Fruit Peels and Process Optimization
The consumption of fruits is associated with the reduced risk of chronic diseases. Due to advanced
technologies used in the food and pharmaceutical industries, there is an increasing fruit production worldwide. Lack of proper utilization practices in fruit processing factories generate high amount of solid fruit waste streams which result in both environmental and economic losses. According to researches, Banana, mango, pineapple and papaya peels are mostly wasted in Sri Lanka. Currently they are either landfilled or used as animal feed but cause high costs. Researches have shown that fruits have
potential antioxidant capacities and several extraction methodologies have been tested so far to extract valuable components like polyphenols and antioxidants. Since it has identified that some fruit peels have antioxidant potential than of their pulp, many of studies have focused on extracting them from wasted fruit peels. From the experimental data analyzed through Taguchi approach, results show that soxhlet extraction is the most efficient method with higher extraction yield. Comparative study done for the selected six fruit peels types; banana; mango; lime; orange; papaya; pineapple shows mango peel exhibit the highest phenolic and antioxidant potential. For banana peel extracts, it exhibits higher yield at 25 0C, 120 min with acetone: water solvent mixture.
