Browsing by Author "Wijekoon, P"

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item: Conference-Full-text
Biochar-based Barricade and Wetland as an Integrated Landfill Leachate Treatment System
(IEEE, 2021-06) Dabare, K; Wijekoon, P; Cooray, A; Athapattu, BCL; Vithanage, M; Adhikariwatte, W; Rathnayake, M; Hemachandra, K
Open dumping of municipal solid waste (MSW) imposes severe environmental threats in which landfill leachate generation is considered as the predominant. This study aims on treating landfill leachate using a pilot scale biochar based barricade and wetland system. Biochar was derived from MSW of Karadiyana dumpsite, using the pyrolysis barrel method, providing approximately 500°C of pyrolysis temperature within 2 h of time duration. Characterization of biochar was done using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques. The wetland was constructed using a mixture of biochar and sand in 1:2 volume ratio, whereas the barricade was filled with 7.5 kg biochar and laterite. For additional removal, Canna indica was planted in the wetland. Leachate was diluted in a 1:1 ratio, allowing it to flow through the system at a rate of 10 ml/min. The analysis was continuously carried out for 7 days. The results showed 99.97, 83.95 and 92.73% removal for ammonium-N, phosphate and COD respectively. Thus, suggesting the potential upscaling of the system with further improvements through testing different ratios of biochar and leachate flow rates.
item: Conference-Abstract
Development of an economic driving cycle for motorcycles and estimate emission
(Department of Civil Engineering, University of Moratuwa, 2022-12) Wijekoon, P; Perera, L; Perera, HLK
It is estimated that the transportation sector is responsible for almost a quarter of global energy consumption. When fossil fuels are burned, they release high amounts of greenhouse gases (GHG) which have a severe impact on the environment and humans. Since the number of vehicles is growing rapidly, control of such fuel combustion is essential. Therefore, new policies are to be formulated, especially in developing countries. In developing countries like Sri Lanka, motorcycles (MC) are a popular mode of transportation due to their economic implications. This study looks at how an MC operates under various traffic conditions in Sri Lanka and the content of combustion gases emitted to propose emission policies. For this purpose, the driving cycle for the motorcycle was developed in the first stage. A Driving Cycle (DC) is a speed-time profile, and it represents the driving characteristics of a selected region. DCs is widely used to estimate transport air pollutants and for building emission inventories. Thus, knowledge of the driving cycle is essential for the evaluation of exhaust emissions. Driving Cycles can be used for different purposes, such as setting up emission standards and determining the behaviour of the driver and the traffic condition of the selected route. As driving cycles are dependent on the driver's behaviour, mode of transportation, traffic condition, and road conditions factors, existing driving cycles developed for other vehicle types in Sri Lanka or developed for MCs in other countries cannot be used in Sri Lanka because they are different due to above said reasons. One of the main objectives of this study is the development of a driving cycle for motorcycles. For this study, the most popular types of motorcycles ranging from 100cc to 150cc engine capacities, were used. Motorcycles with these engine capacities were more suitable for this study as they are widely used in major cities as well as sub-major cities of the country. For this study, driving data is collected by motorcycle riders who are frequently riding the motorcycle in urban and suburban areas using a handheld GPS device. During the data collection, special attention is paid to the peak times because the traffic is significantly higher during such times, and thus the amount of combustion gases emitted is also high. This GPS-based data collection is more economical than other methods of collecting data for the driving cycle development. The collected data was filtered and removed the unusual characteristics were by using python code, and after that, data was divided into micro trips, including idle time. Micro trip-based cycle development is suitable for developing a driving cycle to estimate emissions. The micro trips thus created are randomly attached to create several candidates driving cycles. From those driving cycles, the best-representing driving cycle is selected by comparing the Speed Acceleration Frequency Distribution (SAFD) graph. The final DC selected has an average speed of 27.26 km/h, an average running speed of 35.31km/h, an average acceleration of 0.284ms-2, and an average decelerate of 0.2846ms-2. Since there are no facilities in Sri Lanka to run the DC developed on a chassis dynamometer to measure the respective emissions, an approximate method was used in this study by referring to similar studies carried out elsewhere. Based on such comparison, the proposed emission factors for motorcycles are CO 0.5-3.0g/km and HC 0.25-0.4g/km for Sri Lankan conditions. These threshold values are suitable for setting up new emission standards for MCs in Sri Lanka or, in other words setting up local emission goals and adopting a carbon tax for MCs. On the other hand, these policies may encourage users to invest in low-carbon transport modes. It can save fuel by performing periodic emission tests for motorcycles and removing or restoring the engines. It helps to minimize fuel and energy wastage.
item: Conference-Full-text
Trace metals in the atmospheric deposition and gaseous emissions around Karadiyana municipal solid waste dumpsite, Sri Lanka
(IEEE, 2021-07) De Silva, S; Wijekoon, P; Vithanage, M; Adhikariwatte, W; Rathnayake, M; Hemachandra, K
Municipal solid waste accounts for ambient air pollution through heavy metals in atmospheric deposition and greenhouse gases. In the current study, heavy metal pollution was estimated by analyzing dust samples collected from Karadiyana solid waste dumpsite, Sri Lanka. Emission of CO 2 , CH 4 , NH 3 and H 2 S were accounted for four locations within the dumpsite area using an air-trapping box and air quality monitor (Aeroqual HH S500L). Dust was collected from four sampling sites using 1.5 m height dust samplers, for the analysis of Cr, Fe, Ni, Cu, Zn, Cd, and Pb using microwave plasma atomic emission spectrometry (MP-AES) after acid digestion. Average Fe concentration of 1100 µg/L was detected in the samples while Cr concentration was only 13 µg/L. Both Cu and Cd showed an average dissolved element percentage of 54%, while other elements also showed considerable dissolubility percentages. A dissolved element amount of 59% was detected in samples collected from a house adjacent to the dumpsite. Total metal concentrations of 1306 and 2213 µg/L were exhibited at sites A and B, respectively. Both sites A and B showed an average concentration of 590 mg/L of total measured gaseous emissions. CO 2 was detected as the predominant species at all four locations.