International Research Symposium of UWU-2018

Permanent URI for this collection

https://erepo.lib.uwu.ac.lk/handle/123456789/1304

Browse

Now showing 1 - 20 of 54

Analysis of Slope Stability on Road Cut Slopes; a Case Study at Badulla- Bibile Road and a Cost-Effective Proposal for Future Road Cut Slope Studies
(Uva Wellassa University of Sri Lanka, 2018) Rifkhan, M.N.M.; Jayasinghe, P.; Christopher, W.A.P.
Sri Lanka is frequently affected by hydro meteorological disasters, one of which is slope failure triggered by unusual intense rainfall. Post-disaster inspections reveal the lack of preliminary investigations being carried out on cut slope failures. The first objective, which was a slope stability analysis on proposed cut slopes of Badulla-Bibile road was designed in a three-fold methodology including Preliminary Study, Field Investigation and Laboratory Investigations. Laboratory investigation consisted of Sieve analysis, Liquid limit, Direct Shear and simple pour pile method. The data were interpreted with reference to slope geometry and soil strength. Geometrical interpretation identified that 32.5% of natural and 73.3% of cut slope failures were possible. The soil analysis interpreted using Unified Soil Classification System reveals that silty gravel, Lean Clay, Silt, Silty Sand, Clayey Sand soil types were present. All these soils were known to be cohesion-less and changing the slope angle was identified to be the ideal mitigation. The second objective was to understand the importance of preliminary study in future road cut slope. This proposed method includes geometrical and soil study. Geometrical study is done with three criteria considering the slope angle, slip angle, friction angle, strike of slip and strike slope. The soil analyses are performed using Unified soil classification system considering the Sieve analysis and Liquid limit test. Identified properties of the soil were modeled in Slope W software to check the factor of safety. This method to find the soil properties is cost effective and less time consuming than direct Shear method. This study has considered direct shear as a conventional method and interpreted for a location. Both results were coinciding, and a conclusion can be drawn that the proposed cost effective basic method is economical which can be used as a preliminary study in future road projects in Sri Lanka.
Analyzing Seasonal Variation of Water Quality Parameters of Kelani River
(Uva Wellassa University of Sri Lanka, 2018) Ranathissa, N.P.K.; Sampath, J.K.H.; Attanayake, A.N.B.; Amarakoon, H.A.K.
Raw water quality of a surface water body directly affects the purification process and the final water quality of drinking water. When considering Sri Lanka, the Kelani River plays a vital role in fulfilling people's water necessities, as it provides water for more than 80% of the population of the capital city, Colombo. The current study focuses on the Kelani River in order to identify the models of variation of raw water quality parameters and to investigate patterns and trends of parameter variation. The main objective was to forecast the variation of water quality parameters with special reference to the Kelani River. The water quality was analyzed with different parameters including pH, Turbidity, Electrical Conductivity, Total Colifortn and Escherichia coli, and data gathered for five years (2012 - 2017) at five different intakes. Analysis was carried out by R studio software. Time Series techniques were used to perform the tests, and all decisions were made under p-value of 0.05. ARIMA and SARIMA models were used to identify the best fitting model for the variation of quality parameters with time. Results were forecasted for a 6 month time period using the above fitted models. Based on obtained results, the seasonality of the water quality parameters changed from one intake to another. When analyzing the pH, Ambathale and Biyagama showed seasonality while other three intakes showed non seasonality. Electrical Conductivity had a seasonal variation at Biyagama and Pugoda intakes, while Escherichia colishowed seasonality for Ambathale intake only. Frequent long-term monitoring of physicochemical parameters of surface water resources is vital for the better management of water resources as well as aquatic habitats and the environment. Based on the results of this study, a better prior understanding about the behavior of raw water quality parameters can be obtained, and this prior understanding can be used to manage the water purification process and final water quality.
Assessing the Suitability of Groundwater for Drinking Purpose in Paddanichupuliyankulam, Veppankulam and Nelukkulam in Vavuniya Divisional Secretariat Division
(Uva Wellassa University of Sri Lanka, 2018) Reva, K. V. M.; Premachandra, N. P.
The groundwater is the primary source for drinking purposes in Vavuniya, which is located in northern part of Sri Lanka. Agricultural over application of Nitrogen fertilizers and rapid urbanization are the main causes for the contamination of drinking water supplies. 50 borehole wells located in Veppankulam, Nelukkulam and Paddanichupuliyankulam in Vavuniya Divisional Secretariat Division were assessed for selected physio-chemical parameters such as pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Total Hardness, Calcium, Magnesium, Nitrate (as NO3-) and Phosphate. The objective of this study was to assess the suitability of groundwater for drinking purpose based on the Sri Lanka Standards for potable water of SLS 614: 2013. In this study pH, EC and TDS were measured on the field, the Ultraviolet Spectrophotometric Screening Method was used for the detection of Nitrate and Phosphate concentrations, and Calcium and Magnesium were analyzed using Atomic Absorption Spectrophotometer. Nitrate, EC, TDS, Total Hardness, Calcium and Magnesium exceeded the maximum permissible levels in 70%, 96%, 42%, 80%, 53% and 100% of wells, respectively and the values varied in the ranges of 2.1 — 222 mg L-1, 462 — 8240 𝜇S cm-1, 323 - 7480 mg L-1, 172 1408 mg L-1, 56 - 419 mg L-1 and 114 - 989 mg L-1, respectively. Phosphate concentrations were below the maximum permissible level in all the wells and varied from 0.01 to 0.68 mg L-1. The pH was within the standard range in all the wells and varied from 6.97 to 8.35.
Assessment of Ground Water Salinity in Upparu Lagoon Area in Jaffna with Respect to Salt Water Intrusion
(Uva Wellassa University of Sri Lanka, 2018) Thananjeyan, K.; Perera, M.D.N.D.; Wijethunga, S.; Saravanan, S.
Groundwater is the only source of fresh water that is directly consumed by most inhabitants in Jaffna. However, salinity in ground water has become a serious problem in Jaffna Peninsula and affected to deteriorate the water quality. Further it has been noted that lagoons may be directly responsible for the increased salinity of abandoned agricultural lands in the area. Therefore, this study assessed the extent of the saltwater intrusion in Upparu lagoon which is a major water resource in the Jaffna Peninsula and nearby areas. In this study, 196 sampling points (132 wells in the east bank and 64 wells in the west bank of the lagoon) were selected by using GIS grid net method. Samples were collected along the banks of the lagoon at 1 km intervals and at each selected point, 4 samples were taken; inside the lagoon, 100m, 200m and 500 m away from the lagoon during the time period from August to November 2016. Electrical Conductivity (EC) and pH were tested to find the salinity and alkalinity of water samples. Salinity and pH distribution maps were prepared according the drinking and irrigation water quality standards by using GIS Arc map software. The average EC values in September at the lagoon and at 100 m, 200 m, and 500 m away from the lagoon were 22.44 mS cm-1, 8.47 mS cm-1 5.32 mS cm-1, 3.60 mS cm-1 while in November those were 24.60 mS cm-1, 12.63 mS cm-1, 7.45 mS en ` and 4.94 mS cin-1, respectively. Salinity level of groundwater increased during the dry season due to low rainfall, high temperature with high wind speed and therefore, water in the lagoon may not be suitable for irrigation during dry season. The pH of water in both lagoon and the wells was considerably high. pH in well water, 500 m away from the lagoon, is within the recommended level for drinking. Based on the results, it can be concluded that water in lagoon is not suitable for drinking and irrigation. Saltwater intrusion was increased and groundwater is contaminated with saltwater in dry periods due to the lateral seepage of salt water in Upparu lagoon area. However, well water can be used for drinking and agricultural activities if the distance from the lagoon to wells is increased.
Assessment of Groundwater Contamination at Jaffna Municipal Council Solid Waste Dumping Site
(Uva Wellassa University of Sri Lanka, 2018) Vysshnavi, V.; Weerakoon, W. M. D. S. K.; Attanayake, A.N.B.
Groundwater is the major natural water resource in the Jaffna Peninsula, and it is used for domestic, agricultural and industrial purposes. Disposal of solid waste is increasingly affecting the quality of the limited groundwater resources of this part of the country. This study investigates the groundwater quality around the Kaakkaithivu landfill site in Jaffna in order to assess the impact of leachate percolating into the underlying aquifer. Groundwater samples were collected from fifty dug wells. Various physicochemical parameters including pH, Temperature, Electrical Conductivity (EC), Total Dissolved Solids (TDS), nitrate (NO3-), phosphate (PO43-), heavy metals (Cu, Cd, and Cr) and bacteriological contamination were measured. Their spatial distribution patterns were plotted using ArcGIS software 9.0 - 9.1. The results show that, groundwater of the study area was found to be heavily polluted with Cd. EC, TDS and E- Coli levels are excessively high comparing SLS standards. NO3- and Cr concentrations in 20% of the wells exceed the maximum acceptable levels. It can be concluded that Kaakkaithivu landfill is leading to significant groundwater contamination. Therefore, separation of solid waste method could be an alternative method to solve the landfill leachate issue.
Assessment of the Plant Growth Performances of Vertical Green Walls Developed with Different Plant Types in a Tropical Climate
(Uva Wellassa University of Sri Lanka, 2018) Perera, T.A.N.T.; Halwatura, R.U.; Jayasinghe, G.Y.; Rupasinghe, H.T.
Planting on roofs and walls seems to be a modern and swiftly developing strategy towards sustainable environmental constructions. Covering building with vegetation enhance the city environment in terms of contributing to urban biodiversity, growing thermal comfort by buffering building temperature and mitigation of the Urban Heat Island (UHI). The study observed the significance of urban vegetation cover with the objectives of selecting suitable plant types for selected medium on vertical green wall panel by investigating the different plant physiological parameters. Fabrications of green wall panels were done in the premises of Department of Civil Engineering, University of Moratuwa by using timber frames (60 x 30cm) filled with coir dust growing medium for 2.5 cm thickness and fixed with wire mesh. Few holes at the bottom of the panel was prepared to facilitate water drainage. Each panel was irrigated three times per week with 0.5 liter of water per each panel. Nutrient solution prepared by dissolving 0.5 g of Albert's mixture in 500 ml of water for each panel and applied two times per week. Experimental design was Completely Randomized Design (CRD) with 3 replicates from each plant species. The nine plant species (treatments) were placed in green wall panel. Each panel (replicates) held eight plants of each species. Desmodium triflorum, Roheo spathacea, Centella asiatica, Axonopus fissifoliu, Axonopus compressus, Elusine indica, Dieffenbachiae spp, Tectaria spp, Bigonia spp were the selected plant species for the study. Plant health was rated for all plants using a 3 point scale. 1 = thriving, 2 = alive, but with signs of pest, disease or other stresses, 3 = dead. Plant height and leaf area were measured along with visual assessments of plant development stages and pest/disease incidence. Roheo spathacea, Elusine indica, Axonopus fissifolius displayed the greatest survival (100%) and coverage on an extensive green wall. Increment of Leaf Area Index of nine species over the eight weeks was significantly different (P < 0.05) among each species. Highest LAI obtained from Roheo spathacea (3.99) followed by Axonopus compressus (0.99), Elusine indica (0.76), Axonopus fissifolius (0.44),) over the trial period. In terms of actual performance, Roheo spathacea, Elusine indica, Axonopus fissifolius displayed the greatest survival and coverage on an extensive green wall.
Avifauna at Warathenna-Hakkinda Declared Environmental Protection Area (EPA) in Kandy, Sri Lanka
(Uva Wellassa University of Sri Lanka, 2018) Thilakarathne, K.G.D.D.; Lakkana, P.H.T.; Hirimuthugoda, G.N.; Kumburegama, N.P.S.
Sri Lanka has vast diversity and endemicity of both flora and fauna. The Mahaweli River is the longest river and it originates from the central highlands and flows through the wet, intermediate and dry zones of the country. It helps sustain a rich biological diversity. However, large extents along the river are yet to be explored for its rich biodiversity. One such area along the Mahaweli River at Gatambe, Warathenna in the Kandy District appears to harbor a rich biodiversity and hence recently declared as an Environmental Protection Area (EPA). The present study was carried out to investigate and prepare a comprehensive checklist of the avifauna in this declared EPA which may be used for future conservation efforts. The study was carried out from June 2016 to May 2017 along an approximately 2 km stretch of the Mahaweli River in the declared EPA starting from the Gatambe main bridge (7° 27213’N, 80° 60463’E) to Dodangwela Suspension Bridge (7° 287915’N, 80° 608630'E). Field sampling was carried out once a week during the study period in the declared EPA and sampling was conducted to encompass all habitat types. A point count method was carried out along 100 m transect to identify the birds and a maximum of 30 minutes was spent at each point. Birds were identified using direct observations with the aid of a 10 x 42 binocular and through birdcalls. Bird guides were used to confirm the identifications. A total of 74 bird species belonging to 61 genera were encountered from the study site. Among these, seven species were endemic while seven were migratory. Five percent of the birds recorded were raptors and most of them were canopy and sub canopy dwellers associated with riverine forests and islands. Most of the birds encountered use this area as their roosting and nesting areas. According to the National Red List (2012), 62 of the species recorded during the study are categorized as “Least Concerned”, two species as “Vulnerable” (Sri Lanka wood pigeon, Sri Lanka Hill mynah), three as “Near Threatened” (Oriental dwarf kingfisher, Cinnamon Bittern and Black crown night heron), one as “Endangered” (Alpine swift) and another as “Critically Endangered” (Rock Pigeon) in their natural habitats. According to the Global Conservation Status, 72 of the species recorded during the study are categorized as “Least Concerned” while one species as “Vulnerable” (Sri Lanka wood pigeon) and one as “Near Threatened” (Sri Lanka Hill mynah). These habitats along the Mahaweli River at Warathenna appear to aid in sustaining a rich bird community so future conservation of this declared EPA will help create a safe haven for the avifauna.
Baseline Survey of Sediments from Galle Harbor Basin
(Uva Wellassa University of Sri Lanka, 2018) Jayasekara, M. A. D. D.; Asanthi, H. B.; Kumara, P. B. T. P.
Galle Harbor has been operating as one major economic harbor in Sri Lanka since 1873. Long-term contamination of sediments due to harbor operations may pose a great threat to marine biota. Baseline assessment of sediment quality is important to record the sediment state. The aim of the study was to investigate the sediment quality of Galle Harbor basin. Thirteen sediment samples were collected from Galle Harbor with three replicates, covering both inner and outer harbor areas. Air dried samples were sieved using mechanical sieve set and grain size distribution curves were plotted, followed by particle size analysis and coefficient of uniformity (Cu ) and coefficient of curvature (Cc) were calculated. Samples were digested in Kjeldhal digestion system and Pb, Ni, Cu, Zn concentrations were determined using Atomic Absorption Spectrometer. The concentration of heavy metals was assessed against the Background Assessment Concentrations (BACs) and Effects Range Low/Effects Range Median (ERL and ERM) concentrations. Sediment organic matter content was determined by using loss on ignition (LOI) method according to the CRIMP protocol. According to the results, all samples were composed of a major portion of silt, very fine sand and fine sand. Sediment particle in all samples, were poorly graded (Cu < 4 and Cc~1). Zn was the most prominent trace metal in majority of sampling stations. Except Ni in some stations, metals did not exceed the Effective Range Median concentration. Sediment organic matter percentage was not significantly (P > 0.05) varied between inner harbor and outer environments and it ranged between 1.6 ± 0.3% to 41.0 ± 2.8%. According to the standards of US EPA, all sediment samples were in intermediate to high organic carbon levels. Overall results highlighted that the marine environment in Galle Harbor basin is exposed to low and moderate contamination levels of assessed metals and intermediate to high organic matter.
Comparative Life Cycle Analysis of Environmental Impact from Micro and Small Scale Cassava Chip Production Using Raw Cassava Roots
(Uva Wellassa University of Sri Lanka, 2018) Minna, M.M.F.; Somendrika, M.A.D.; Wickramasinghe, I.
Cassava chips are produced from fresh cassava root and the market for chips has increased over recent years. The aims of the analysis were to assess the environmental impact of cassava chips manufacturing and to identify the hotspots in the life cycle of cassava chips manufacturing. Three separate but interrelated components: inventory analysis, impact assessment and interpretations were performed for the cassava chips life cycle using SimaPro software 8.4.0.0 faculty version. Inventory data were collected through the use of structured questionnaires and personal communication. Data were collected on cassava farming, chips manufacturing, packaging, transportation and waste management. The scenario combining machinery use, LPgas and polythene showed higher environmental impact than the scenario combining no machinery use, LP gas and polythene. Higher contribution was associated with the electricity used in machineries. Cassava cultivation and cassava chips processing stages contributed to a higher impact on the environment and transportation of raw cassava root, raw material and cassava chips contributed to a lesser impact on the environment. The impact categories most affected by cassava cultivation were stratospheric ozone depletion 78.2%, Human non-carcinogenic toxicity 67.1%, land use 68.6% and mineral resource scarcity 76.4%. The impact categories most affected by cassava chips processing were fine particulate matter formation 80.7%, human carcinogenic toxicity 99.5%, terrestrial acidification 78.2%, marine ecotoxicity 75%, freshwater ecotoxicity 83.8%, fossil resource scarcity 84.9% and ozone formation 80%. No machinery use in cassava chips processing stage contributed to lesser environmental impact compared to the machinery use. Transportation of raw cassava root, raw material and cassava chips contributed to lesser impact on the environment. Cassava cultivation and cassava chips processing stages contributed a higher impact on the environment.
A Comparative Study on Water Vapour Permeability of Surface Treated Paperboards with Keratin and Gammalu (Pterocarpus marsupium) Latex
(Uva Wellassa University of Sri Lanka, 2018) Uduwerella, H. M. I. A.; Ranasinghe, M. K.; Amarasinghe, A. R. P. C. C. J.
Chicken processing industries produce a high amount of feathers as a wastage, which cause disposal problems. Chicken feathers contain a high percentage of keratin; a protein, which shows good resistance towards water. Gammalu latex is a naturally available resource in Sri Lanka, which has high barrier properties. Extracted keratin and Gammalu latex can be applied as a coating on the surface of paperboards for biodegradable packages in order to improve the barrier properties against water vapour permeability, while preventing the environment pollution caused by thermoplastic polymers. Thus, the present studies mainly focused on the extraction of keratin from chicken feathers and develop a coating to paperboards, and compare the properties of that with a coating made of Gammalu latex. Pretreated chicken feathers were subjected to a feather dissolving, protein precipitation, protein purification and film preparation process. Paperboard (0.25 g cm-2) coated with 2% (v/v) Glycerine with Keratin and 2% (v/v) Glycerine with Gammalu latex were used as treated samples. Non-coated paperboards used as the control sample. All samples were stored in a climatic chamber at controlled environment. Water vapour permeability was evaluated under constant temperature (35 C) and relative humidity (65%) for three weeks. Data were analyzed using two-way ANOVA technique in Minitab 17. Results showed significant deference (P < 0.05) amongst the treated samples while keratin showed least water vapour permeability followed by Gammalu latex coated paperboards. This study revealed that keratin coated paperboards could be used as an effective packaging material with low water vapour permeability.
Conversion of Waste Polypropylene into Hydrocarbon Fuel — Analysis of the Effect of Set Temperature on Reaction Time and Liquid Yield
(Uva Wellassa University of Sri Lanka, 2018) Rohan, E.P.; Sumith, B.; Srimal, L.K.T.
Plastic waste and management is a serious environmental issue. The methods available to date such as incineration, land filling etc., are cost intensive. Attention is thus being given to new recycling methods which are more environmentally attractive. Pyrolysis is one such promising method for the treatment of mixed and contaminated plastic wastes. In pyrolysis, plastics are thermally degraded to produce liquid hydrocarbons. Pyrolysis of waste plastics was investigated in a reactor system which consists of a semi batch reactor, a condenser and a liquid-gas separator. Developed reactor system is capable of converting waste plastics (polyethylene, polypropylene and polystyrene) into hydrocarbon fuel at a maximum conversion rate of 99%. Liquid yield and gas yield at optimum conditions are 66% and 31% respectively. Liquid fuel obtained by the process was found to consist of light and middle distillates in the range of C5 to C12 hydrocarbons with higher concentrations of C7, C8 and C9 fractions. Non-condensable gas obtained was chemically equivalent to the LP (liquid petroleum) gas. Polypropylene waste samples of 3000 g by weight were used for the experiments carried out to investigate the effects of set temperature on reaction time and liquid yield. The reaction time was found to decrease from 390 min to 115 min and the liquid yield was found to decrease from 68.2% to 39.2%, when the set temperature of the reactor increases from 375 °C to 475 °C. The solid residue left in the reactor was also observed to be decreased from 19.1% to 0.4%, during the experiments. Low set temperatures such as 400, 375 °C were found to drastically increase solid residue amount and reaction time at an approximately same liquid yield. High set temperatures such as 450, 475 °C were found to decrease liquid yield and reaction time at an approximately same solid residue amount. Waste plastic pyrolysis process is affected by many process parameters such as pressure, batch size, set temperature, heating rate, reactor design etc. Optimized process parameters lead to obtain high liquid yield at a minimum input energy in a comparatively small reaction time.
Degradation of Cellulose and Pectin in Organic Wastes by Selected Fungal Strains
(Uva Wellassa University of Sri Lanka, 2018) Hennayake, H.M.C.R.K.; Singhalage, I.D.
Solid waste management is becoming more complicated due to rise in population, industrialization and changes in life styles. In nature, microbial diversity exhibits wide range of activity, association and interaction with each other and with their environment. Microbes releasing pectinolytic and cellulolytic enzymes are playing a major role in degradation and decomposition of organic compounds. This study aimed to investigate the degradation of cellulose and pectin in organic waste by fungi. A total of 10 fungal species were isolated from waste samples collected from municipal waste dump near Vincent Dias stadium in Badulla. Pectinolytic and cellulolytic activity of isolates were tested by standard plate assays and best strains to degrade cellulose and pectin were selected (F3, F6A, F6B, F8 and F10). Selected fungal species were inoculated to particles (> 1 cm diameter) of corn cobs, banana peduncle and jack fruit axis and incubated under laboratory conditions. Weight loss percentage (WL %), sugar production and Fourier Transform Infrared (FTIR) spectroscopy data were gathered from samples within 5 days interval for 50 days. Experiment was conducted by following complete randomized design with three replicates. The highest weight loss percentage was obtained in F10 treated corn cobs sample (WL% = 1.3). Weight loss percentages and sugar analysis values with respect to the time started to be static after 45 days. It may be due to the fact that the microbial growth has entered a stationary phase' since available nutrients have decreased in the medium. According to the FTIR data, the F3 and F6B treated corn cob samples and F8 treated banana peduncle samples had significantly high (p < 0.05) absorbance in polysaccharide window (900 — 1200 cm-1) at the fifth day of incubation. In conclusion, all fungi stains used in the study have the ability to degrade organic waste efficiently.
Development of Electrochemical Method to Remove Nitrogenous Compounds from Prawn Industry Wastewater
(Uva Wellassa University of Sri Lanka, 2018) Kirujika, K.; Kreshaanth, S.; Gunathilake, C. A.; Udagedara, D. T.; Manipura, A.
The prawn-farm industry is one of the fastest growing export-oriented industries in Sri Lanka. Wastewater originating from prawn-farms contains an excessive amount of nutrients that becomes a serious environmental issue. Currently, there is no proper wastewater treatment method to remove nitrogenous compounds in Sri Lanka. Thus, the study aimed to develop an electrochemical method to remove nitrogenous compounds from simulated prawn-farm wastewater. Further, this method investigated the effect of control factors such as pH, retention time, current, and surface area of the electrodes using Taguchi method which identifies proper control factors to obtain the optimum results in the removal of nitrogenous compounds by using carbon and aluminum electrodes with KCl salt bridge. Results indicate that with carbon electrodes the maximum (50%) removal efficiency was obtained in 16 hours constant retention time and changing pH, DC, and surface area, respectively, about 4, 350 mA at 22.4 V, and 10 cm2. Our results are comparable to the results obtained with Taguchi method where the optimum level was obtained under following conditions where pH = 4, DC = 450 mA at 22.4 V, retention time = 16 hours, and surface area = 40 cm2. In aluminum electrodes the maximum (54%) removal efficiency was obtained by changing retention time, pH, DC, and surface area with controlling parameters of 4 hours, 2, 450 mA at 22.4 V, and 10 cm2, respectively. Results are comparable to results obtained with Taguchi method where optimum level have obtained under following conditions where pH = 2, DC = 250 mA at 6.8 V, retention time = 4 hours, and surface area = 40 cm2. Therefore, the results concluded that aluminum electrodes are better than carbon electrodes to remove nitrogenous compounds even though carbon electrodes can be used due to its low cost, simplicity, and easily renewable surface. The electrochemical method could be a potential method to remove nitrogenous compounds due to its high efficiency, low cost and ease in handling.
Development of Micro-Propagation Protocol for Aponogeton dassanayakei
(Uva Wellassa University of Sri Lanka, 2018) Hettiarachchi, H.D.B.K.; Coswatte, A.C.W.W.M.C.L.K.; Senaratne, M.M.D.J.; Krishnarajah, S.A.; Kaliyadasa, P.E.
Aponogeton is a genus of freshwater aquatic plants and there are five Aponogeton species native to Sri Lanka with three endemic members. They have a high demand as an ornamental aquarium plant, food source and medicinal herb. Due to these reasons over exploitation of plants from natural habitats is common with poor attention on conservation. Aponogeton dassanayakei is a newly identified Aponogeton species from Sri Lanka. This study was carried out to develop a micropropagation protocol for newly identified Aponogeton dassanayakei. Treatments included full strength Murashige and Skoog (MS) solid basal media supplemented with combinations of 6-benzylaminopurine (BAP) (0.00, 1.00, 2.00 mg L-1) with 0.10 mg L-1 Indole-3-acetic acid (IAA) and without IAA for both shoot initiation and multiplication in seed culture. Ten replicates obtained per each treatment. During shoot initiation seed germination rate, seedling height and number of leaves per seedling were taken as the response variables and shoot multiplication stage plant height and number of leaves were considered. Application of hormones showed significant effect (p < 0.05) on both number of leaves and seedling height but not on seed germination rate in shoot initiation. Hormones supplemented in solid media during shoot multiplication were shown significance difference (p < 0.05) in plant height but not in number of leaves. According to the study, MS medium supplemented 1.00 mg L-1 BAP is the best for shoot initiation. MS medium containing 2.00 mg L-1 BAP is best for shoot multiplication. The study demonstrated that micro-propagation could be useful for large scale propagation of Aponogeton dassanayakei while conserving the plant in natural habitat.
Diurnal Behavioral Patterns and Substrate Use of Endemic Endangered Frog Fejervarya greenii in Horton Plains National Park (HPNP)
(Uva Wellassa University of Sri Lanka, 2018) Prabhath, M.C.; Jayasekara, E.G.D.P.; Mahaulpatha, W.A.D.
With the objective of providing important data through studying diurnal behavioral patterns and substrate use for the conservation of endemic endangered frog Fejervarya greenii the study was conducted in and around five lentic waterbodies in HPNP for three consecutive days per month from January to December 2016. Time periods were selected as 06:00 hrs — 09:00 hrs, 09:00 hrs - 12:00 hrs, 12:00 hrs 15:00 hrs, 15:00 hrs - 18:00 hrs and 18:00 hrs - 20:00 hrs. Possible substrate types were recorded as submerged plant cover, bare water cover, short plants and shrubs cover, grass cover, decaying plant matter and leaf litter cover, sand, mud, gravel and rocks. Locomotion, feeding, resting, refuge use, alert, calling, courtship and swimming were identified as distinct behaviors of F.greenii. The behavior of both mature and immature individuals were recorded in 30 second intervals for 20 minutes in each time period. The utilized substrate in each behavioral pattern was recorded. Individuals tend to rest between 06:00 hrs - 09:00 hrs. They were moderately active during 09:00 hrs - 12:00 hrs and mature individuals used to call most of the time. F. greenii was mostly inactive during the time period of 12:00 hrs - 15:00 hrs. They tend to rest, call and exhibit courtship behaviors during 15:00 hrs 18:00 hrs. They were most active during 18:00 hrs - 20:00 hrs. Each distinct behavior was recorded in submerged plant cover. Swimming was restricted to bare water cover. Calling and courtship behaviors were restricted to submerged plant substrate. Gravel and rocks were not utilized. Relatively inactive behavior during the time period of 12:00 hrs - 15:00 hrs was probably a behavioral adaptation to avoid high desiccation during this hottest time. Calling and courtship behaviors were observed in each month which indicates that this species breeds continuously throughout the year. This study identifies the submerged plant cover associated with lentic water bodies as the breeding habitat of this endangered frog population.
Ecosystem Carbon Sequestration of Different Land-uses of the Lowland Wet Zone: A Case Study from Waga Area, Kalutara District, Sri Lanka
(Uva Wellassa University of Sri Lanka, 2018) Kuruppuarachchi, K.A.J.M.; Madurapperuma, B.D.; Seneviratne, G.
This study examines plant above-ground carbon and soil carbon stocks of different land-use types with the same climate and geology in Waga area i.e., natural forests (NF), home gardens (HG), coconut plantations (CP), pine and Araucaria mixed plantation forest (PAP), rubber plantation (RP), rambutan plantation (RAP), pineapple plantation (PP) and tea plantation (TP). Five representative sampling sites viz., 20 m x 20 m were selected in each land-use for floristic survey and to make composite soil core sampling (20 samples mixed together) up to a 30 cm depth. Plant parameters, such as DBH, height and physicochemical properties of soil samples were evaluated. The normalized difference vegetation index (NDVI) was calculated using 2017 Landsat 8 image at 30 m spatial resolution, which was acquired during leaf-on season (i.e. mid January to mid March), to recognize the vegetation health. The study revealed ecosystem carbon and soil C densities in the order NF (625 and 52 t C ha-1),PAP (290 and 38 t C ha-1) HG (199 and 21 t C ha-1), RP (188 and 17 t C ha-1), CP (167 and 25 t C ha-1), RAP (167 and 28 t C ha-1), PP (40 and 38 t C ha-1) and TP (15 and 15 t C ha-1), respectively. NDVI values of the land-uses were RP (0.623), HG (0.618), NF (0.615), CP (0.611), PP (0.592), TP (0.576), RAP (0.562), and PAP (0.556). The highest soil moisture accumulation was reported in NF (17.7%) and RP (16.38%). Soil pH values were mainly acidic (< 5) for all land-uses. High total soil N concentrations were observed in both NF (0.18%) and PAP (0.14%). Higher amounts of soil nitrate were recorded in RAP (15.55 𝜇𝑔 g-1 soil), NF (11.45 𝜇g g-1 soil) and PP (9.32 𝜇g g-1 soil). Soil total P concentrations were relatively low in NF (0.041%), PAP (0.042%) and RP (0.045%), and it is an obvious fact for tropical land-uses with perennial vegetation. This study revealed that the land-use types, such as NF, PAP, HG and RP were good carbon reserves in tropical lowland wet zone of Sri Lanka. Further investigations on micro carbon cycles of each land-use are recommended for better understanding of ecosystem carbon footprint.
Effect of Some Selected Plant Species in Ameliorating Indoor CO2 Concentration
(Uva Wellassa University of Sri Lanka, 2018) Madumalil, K.A.A.D.; Senaratne, R.; Seneviratne, G.; Lekamge, C.; Wijesundara, D.S.A.
In view of increasing migration from rural to urban areas and inadequacy of suitable accommodation in towns, many people and students in urban areas live in highly congested, ill-ventilated and abodes. Such conditions have resulted in deterioration of indoor air quality, including increased concentration of CO2 which have posed issues such as Sick Building Syndrome (SBS), reduced productivity and undue fatigue. Therefore, studies were carried out to evaluate the effectiveness of some selected CAM plant species, namely Zamioculcas zamiifolia, Sansevieria trifasciata and Kalanchne spp., in improving indoor air quality. Plants of comparable age and size of the said species were selected and placed in air-tight containers (4500 cm3) one each in 3 replicates. CO2gas (0.1 ml) of 1000 ± 250 ppm was injected into each container and gas samples were collected at the beginning of the experiment (7.00 hours) and at four hourly intervals 11.00, 15.00 and 17.00 hours and were analyzed for CO2 concentration by gas chromatography using a capillary column. Inter-specific variation in CO2 absorption was evident which was highest in Kalanchoe spp. (176.76 ppm.g.hr-1) followed by Zamioculcas zamiifolia (94.94 ppm.g-1.hr-1) and Sansevieria trifasciata (43.16 ppm.g-1.hr-1). Preliminary studies showed a considerable interspecific variation in reducing CO2 concentration in indoor spaces. Therefore, there are prospects for improving indoor air quality of particularly congested and ill-ventilated abodes using plants effective in absorbing elevated CO2, concentration.
Effects of Rainfall on Plant Survival in Restored and Unrestored Pine Stands in Lower Hanthana, Sri Lanka
(Uva Wellassa University of Sri Lanka, 2018) Lakmali, S.M.M.; Jayawardhane, J.; Gunaratne, A.M.T.A.; Nawarathna, L.S.
Restoration is crucial to assist the recovery of degraded, damaged or destroyed ecosystems to promote biodiversity and ecosystem services. This study was conducted to identify the relationship between rainfall and plant establishment in an unrestored (UP) and a restored (RP) Pinus caribaea Morelet plantation, in lower Hantana, Sri Lanka. In RP, partial thinning of pines followed by enrichment planting of four broad-leaved tree species and total thinning of pines have been initiated. In both sites fifteen plots (5 m x 5 m) and within each of them three subplots (1 m x 1 m) were demarcated randomly. The number of leaves in plants, height, and diameter at breast height (DBH) in two sites were obtained (seedlings in sub plots and saplings and trees in plots). Effects of rainfall on the species density and survival of plant species in the two sites were investigated. Data were categorized as seedling (< 50 cm), saplings group I (50 - 129 cm in height), saplings group II (129 - 300 in height) and trees (> 300 cm in height). The rainfall data for the study period was obtained from the Meteorology Department, Sri Lanka. Data were analyzed using non-parametric statistical techniques using the SPSS statistical software. When comparing the establishment of woody plant species in the two sites, more species were recorded in the restored site for all categories except for saplings group II. However many plants died within the 6 months of the study period, due to various factors including herbivory damage and over dominance of Alstonia macrophylla. The mortality decreased with the increased rainfall in restored site than the unrestored site. According to Spearman's correlations coefficient of seedlings, the restored site has more powerful negative relationship between rainfall and mortality while mortality comparison with rainfall data shows that when rainfall is high, mortality of trees is tending to be low.
Efficiency Comparison of Three Types of Constructed Wetlands for Treating Reverse Osmosis Rejects
(Uva Wellassa University of Sri Lanka, 2018) Ranathunga, P. G. K. B.; Premachandra, N. P.
Reverse osmosis is a water purification technology that uses a semipermeable membrane under pressure to remove particulate and dissolved contaminants mainly pathogenic microorganisms, organic compounds, hardness and heavy metals. Use of this technology has increased tremendously to treat ground water in the Chronic kidney disease of unknown etiology prevalent areas in Sri Lanka in recent years. However, the need to treat reverse osmosis rejects (concentrated residue stream of reverse osmosis process) before releasing to the environment has not received much concern yet. Constructed wetland is one economical technique to treat reverse osmosis rejects. In this study efficiency of three different types of constructed wetlands were analysed. Three constructed wetlands were prepared, first one (CW1) only with soil, second one (CW2) with plantation of Schcenoplectus grossus (Thunhiriya) on the same soil and the third one (CW3) without soil with Water Hyacinth (Japan Jabara), an aquatic plant. The wetlands were created at a hydraulic retention time of 4 days with dimensions of 0.6 m x 0.3 m x 0.2 m. Removal efficiency of eleven parameters including concentration of nitrate, total alkalinity, total dissolved solids, total hardness, electrical conductivity, pH and heavy metals such as calcium, copper, manganese, magnesium, and cadmium were evaluated in all three wetlands. Results showed that all three types of wetlands have considerable efficiency in removing selected parameters, but CW2 was more prominent in removing the selected parameters except for magnesium, nitrate and electrical conductivity. Removal efficiencies of those three parameters were slightly lower in CW2 than CW1, and the reason could be carrying of nutrients to the CW2 at the plantation step. According to the results, it is, possible to conclude that a constructed wetland including soil and a plant is more efficient in the treatment of wastewater than a wetland which contains only soil or an aquatic plant.
Environmental Risk Assessment of Water Basin in Capital City Area of Sri Lanka
(Uva Wellassa University of Sri Lanka, 2018) Herath, H. M. P. C. K.; Sanjeevan, R.
Metropolitan city Colombo can be polluted by many ways. This study was addressed to analyze canal/lake sediment and water samples in selected locations within the Colombo basin to assess the possible environmental risks and challenges of people in those areas. Sampling was carried out only between 8.00 a.m. to 12.00 noon in order to arrest the similar conditions in terms of tidal variations. A grab sampler was used to collect sediment samples at the bottom surface and water samples were collected from the upper 12 inches of the surface. Sulfate, Chloride and heavy metals of sediment samples and pH, Conductivity, COD, BOD, Heavy Metal, Total & Fecal Coliforms and Oil and Grease content of water samples were analyzed in accordance with BS 1377: 1990 and APHA (2005). Heavy metal content varied as for cadmium in the range of 0.4 to 8.3 mg kg-1, chromium 20.1 to 72.8 mg kg-1, lead 30.2 to 805.3 mg kg-1, arsenic 0 to 3.1 mg kg-1 and mercury 0.7 to 3.0 mg kg-1.Sulfate content of sediment varied within the range of 50 to 439 mg kg1. Chloride content of sediments was from 4 to 48mg kg-1.The pH varied in between 7 to 8.5 and mostly pH was 7.6. Conductivity was distributed within 11.1 to 539 𝜇s cm-1. BOD levels were in the range of 9 to 20. COD values were in between 14 to 60 ppm. Oil and Grease content was somewhat high and it was at 7.3 - 296.8 ppm. Total Coliforms was 230000 to 5400000 MPN per100 ml. Fecal Coliforms was in between 130000 to 490000 MPN per100 ml. From the above studies, we conclude Beira Lake has the highest risk for pollution and Madiwela East Lake reported to be at lesser risk with respect to chemicals and microorganism. All measurements indicated that all sampling locations are badly contaminated with fecal matter and hence it will have the considerable adverse impact on human health.

Browse

Browsing International Research Symposium of UWU-2018 by Subject "Ecology"

Results Per Page

Sort Options