Browsing by Author "Fernando, WAM"

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item: Conference-Full-text
Characterisation of coal fly ash for potential wastewater treatment opportunities
(Department of Earth Resources Engineering, University of Moratuwa, 2021-12) Pannilarathne, IE; Sandaruwan, MGL; Mathissan, P; Jayawardena, CL; Fernando, WAM; Dissanayake, DMDOK; Jayawardena, CL
Lakvijaya coal power plant, which is in Norochcholai, Puttalam District, Sri Lanka, is the largest coal power plant in Sri Lanka. It annually produces about 150,000 tonnes of fly ash (FA) as waste, and the management of it is a pressing concern. Various studies have been conducted to valorise FA in a useful manner without simply dumping it into the nearby lands. To this end, we propose the utilisation of FA in wastewater treatments to adsorb heavy metal ions in wastewater to promote environmental sustainability. The direct application of FA for that purpose may be questionable due to the contaminants present in the FA; however, it is reported commercially. Therefore, we attempt to initiate a preprocessed preparation route to ensure the leachate contains fewer contaminants compared to the use of raw FA. Washing is a commonly used preliminary pre-processing step, though it is not studied extensively in the literature with reference to the FA. Herein, we aimed to study the effects of the number of washing cycles and temperature on the characteristics of the FA. With the results, we could conclude that washing is an effective means of preprocessing to alleviate the contaminants of FA, en route for wastewater treatment.
item: Conference-Abstract
Experimental investigation and performance optimisation of washing cycles for pre-processing of coal fly ash
(Department of Earth Resources Engineering, University of Moratuwa, Sri Lanka, 2022-12-23) Brinthan, K; Shivadhahini, S; Senadheera, UAG; Fernando, WAM; Jayawardena, CL; Jayasundara, DRT; Wickrama, MADMG; Jayawardena, CL
Coal Fly Ash (CFA), a by-product of thermal power plant combustion, has a profound focus among researchers due to its pozzolanic properties, porosity, wide chemical composition, and thermal stability. While being suitable for many applications (e.g., pozzolanic material, soil stabiliser, and structural fill), CFA is also a potential precursor for synthesising zeolites, broadly used in wastewater treatment. However, pre-processing is crucial due to the heterogeneous nature of CFA. This work focused on pre-processing CFA prior to wastewater treatment through continuous washing cycles at various operating temperatures. To this end, we studied the pH and conductivity of the solution after washing over multiple cycles, Sauter mean diameter, and the mineralogy of the settled CFA. The gathered results were analysed and optimised through response surface methodology. This was done to find the best combination of the number of washing cycles and temperature to remove soluble ions and increase the surface area of CFA particles. The analytical outcome revealed that five washing cycles at 70°C were adequate, with minimal soluble ions and maximum surface area. Evidently, these findings demonstrated significant improvements in the physical and chemical properties of CFA as a precursor for zeolite synthesis. Therefore, we recommend further studies on this front to extend the effective usage of CFA for the synthesis of commercial zeolites to be used for wastewater treatment.
item: Conference-Full-text
Leveraging the performance of washing cycles to enhance the preprocessing of coal fly ash
(Department of Earth Resources Engineering, 2023-08-28) Galappaththi, RY; Hissalle, LPAD; Chamith, PLS; Wickrama, MADMG; Fernando, WAM; Jayawardena, CL
Coal is relatively cheap and abundant fossil fuel contributing to 40% of the world's electricity production. However, coal combustion generates a significant number of by-products, majority being the coal fly ash (CFA). The heterogeneous nature of CFA poses significant challenges in its value-added applications hence, requiring appropriate preprocessing treatments which are expensive and technically savvy. Therefore, this research aims to improve CFA's suitability for the application of value-added products through a technique called “washing cycles” which wash the CFA multiple times using distilled water under a controlled environment with continuous and vigilant monitoring to ensure accuracy throughout the entire process. To optimise this washing cycle process, parameters such as the number of washing cycles, stirring time, and temperature were analysed, and the results were optimised through surface response methodology. The analytical findings on the optimization process demonstrated that a suitable pre-treatment involved employing five washing cycles with a stirring time of 7.5 minutes. Furthermore, varying the temperature did not yield a substantial effect on the effectiveness of washing cycles, since the precipitation of Ca2+ ions even complicate the preprocessing. Therefore, we recommend conducting additional investigations into the efficient use of pre-processed CFA to produce value-added applications adhering to circular economy and sustainability.
item: Conference-Full-text
Tsunami modelling and risk assessment of Hambantota, Sri Lanka using integrated remote sensing techniques
(Department of Earth Resources Engineering, 2015-07) Fernando, WAM; Aswer, MLM; Premarathna, MWVS; Suthakar, M; Dassanayake, DMDOK; Senanayake, IP; Samansiri, S; Hemalal, PVA
This study was carried out to develop an inundation and risk assessment model in Hambantota coastal area, based on the 2004 tsunami event. This tsunami event was one of the largest tsunamis to cause devastation to human beings, livelihoods, buildings, roads, rails and other infrastructure facilities in the study area. In addition to this study area, other parts of the coastal belt of Sri Lanka also experienced the chaotic outcomes of this tsunami event. By modelling risk, based on the 2004 tsunami event data, inundation and risk assessment for future tsunami event was modelled with a high safety factor. INSPIRE web portal which has been developed based on the TUN AMI mathematical model, was employed in this study to evaluate both inundation and risks to the local communities and their livelihoods with a higher level of accuracy. The main inputs to INSPIRE are topography data/bathymetry data, vulnerability data and fault parameters of the source earthquake, whereas the output maps provide the inundation area, wave velocity along the terrain and the potential risk to the area under consideration. Results of the study represent the variation of the tsunami inundation and the risk assessment of the Hambantota area based on remotely sensed digital elevation data inputs with different spatial resolutions data such as, ASTER, SRTM, LiDAR and GEBCO. Different inundation output maps were analyzed and the risk prone areas were identified. Furthermore, building structures were assigned risk indices based on the vulnerability to damage and fragility curves were developed in the case of a future tsunami event.