Undergraduate Research Symposium Chemical and Process Engineering
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Browsing Undergraduate Research Symposium Chemical and Process Engineering by Author "Ariyadasa, TU"
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- item: Conference-Extended-AbstractEmploying indigenous microalgae for third generation biofuel production(Department of Chemical and Process Engineering, University of Moratuwa, 2019) Maduwanthi, MKC; Nuwanthika, WHC; Withanage, PK; Ariyadasa, TU; Rathnasiri, PGMicroalgae have been identified as a potential source for biofuel production by the researches. Cell disruption and chlorophyll removal of microalgae biomass are the most critical factors, which determine the lipid extraction yield and the biodiesel quality. Thus, the chlorophyll removal and cell disruption before lipid extraction is a mandatory step for the microalgae biodiesel production. This research investigated the growth rate and different pretreatment methods on lipid yield for selected microalgae species. Desmodesmus sp., Scenedesmus sp. & Closteriopsis sp. are the selected indigenous microalgae species, which were isolated from the Beira Lake, Colombo, Sri Lanka. Desmodesmus sp has shown the highest growth rate compared to other two species. Moreover, most suitable cell disruption method, which gave the highest lipid yield for each species were different.
- item: Conference-AbstractEnhancing the sustainability of microalgae biomass generation for production of alpha-linolenic acid via integration of reverse osmosis (ro) reject streams(Department of Chemical & Process Engineering University of Moratuwa., 2023-08-17) Wickramasinghe, S; Ovitigala, M; Ariyadasa, TU; Walpalage, S; Gunawardena, S; Narayana, M; Gunasekera, MIndustrial reverse osmosis (RO) reject streams are a significant source of pollution in surface water bodies and requires effective treatment. Microalgae-based treatment of RO reject streams is an interesting approach as it generates valuable biomass concurrent to bioremediation. This approach also enhances the sustainability of microalgae biomass production by eliminating the requirement of external nutrient supply and reducing the freshwater footprint. However, there is a significant gap in research on utilization of RO reject streams generated by food/pharmaceutical industries for synthesis of microalgaebased high-value bioproducts. The current study was performed to ascertain the potential of using RO reject streams from the local food (RO1) and pharmaceutical (RO2) industries to cultivate Desmodesmus sp. for synthesis of alpha-linolenic acid. Accordingly, a screening experiment was conducted by growth of Desmodesmus sp. in RO1 and RO2 under dilutions of 25%, 50%, 75% and 100% (undiluted sample). Results showed that the highest biomass yields were obtained in 100% RO1 and 100% RO2. Thereafter, Desmodesmus sp. was cultured in 100% RO1 and 100% RO2 using photobioreactors with Modified Bold’s Basal media (3N-BBM) used as the control. Results showed that the use of RO reject streams resulted in a positive effect on the growth and biochemical composition of Desmodesmus sp. The high lipid content in biomass showcased that the use of RO reject streams could enhance the sustainability of microalgae-based alpha-linolenic acid production. However, further research is needed to study the toxicology effects and assess the techno-economic feasibility of using RO reject as the growth media.
- item: Conference-AbstractIntegration of food industry wastewater for cultivation of desmodesmus sp. to synthesize alpha-linolenic acid(Department of Chemical & Process Engineering University of Moratuwa., 2023-08-17) Gamage, GDNC; Hannadige, SKHN; Ariyadasa, TU; Walpalage, S; Gunawardena, S; Narayana, M; Gunasekera, MMicroalgae biomass production for food and fuel applications necessitates the use of resources such as water and nutrients, raising sustainability concerns. This study aimed to integrate food industry wastewaters as a source of nutrients and water for microalgae cultivation while simultaneously performing bioremediation. Nonetheless, wastewaterbased microalgae cultivation requires the identification of suitable wastewater streams, nutrient loads, and appropriate media sterilization methods to prevent culture failure due to contamination. In the current study, the microalga Desmodesmus sp. was cultivated in wastewater-based media for synthesis of the nutritionally-valuable alpha-linolenic acid. This study is the first in literature wherein a comparative assessment was performed between autoclaving and filtration as methods for wastewater sterilization. A screening experiment for Desmodesmus sp. growth was performed using brewery wastewater (BrW), coconut processing industry wastewater (CW) and biscuit wastewater (BiW) obtained from the food industry, under 25%, 50%, 75%, and 100% (undiluted) concentrations. Undiluted BiW was the most suitable media, as it resulted in the highest final biomass yields. Thereafter, undiluted BiW sterilized by autoclaving and filtration was used to culture Desmodesmus sp. in photobioreactors with Modified Bold’s Basal Media used as the control. BiW showed higher biomass yields and specific growth rate compared to the control. A higher lipid productivity of 16.78 mg L d was exhibited in autoclaved medium as compared to 9.92 mg L d in the filtered medium. Thus, BiW sterilized via autoclaving was identified as a promising growth medium for alpha linolenic acid production from a circular economic perspective.
- item: Conference-Extended-AbstractInvestigation of the effect of solar irradiation and temperature on biomass production of h. pluvialis in photobioreactors under outdoor cultivation in Sri Lanka(Department of Chemical & Process Engineering University of Moratuwa, 2020-03) Perera, ULMSM; Muthunayake, MKC; Madushanka, KWD; Ariyadasa, TU; Rathnasiri, PGComplicated and changeable weather conditions and contamination from fungi, protozoa and bacteria increase difficulties in outdoor microalgae cultivation. In this paper, outdoor microalgae cultivation was investigated in Moratuwa city, Western province Sri Lanka. During December, when both the solar irradiation and temperature is high, the water spray system combined two agro shading nets, each with a shading rate of 40-50% can effectively reduce the temperature to 27±2 0C and control solar irradiation below 13500 lux in the 3 L vertical tubular photobioreactor. Under an initial biomass density of 0.2 g/l and an atmospheric air flowrate of 1 vvm, H. pluvialis had a maximum biomass accumulation of 0.45 g/l and the maximum specific growth rate of 0.020 g/l.day. In addition, reactor system and its design exhibited good performance, implying a potential scale- up opportunity.
- item: Conference-AbstractNutrient recovery from food industry solid waste for cultivation of the microalga Desmodesmus sp. for production of alpha-linolenic acid(Department of Chemical & Process Engineering University of Moratuwa., 2023-08-17) Dayanath, WMS; Edirisinghe, D; Ariyadasa, TU; Walpalage, S; Gunawardena, S; Narayana, M; Gunasekera, MThe generation of food waste by the food processing industry poses significant environmental and economic challenges globally. This study investigated the potential of utilizing industrial food waste as a source of nutrients for cultivation of the microalga Desmodesmus sp. to produce value-added biomass rich in alpha-linolenic acid. The objectives of the study were to identify the type of food waste and dilution factor of food waste hydrolysate to maximize biomass and alpha-linolenic acid yields, and assess the efficacy of nutrient recovery. The current study is the first in reported literature to utilize industrial food waste for synthesis of microalgae-based alpha-linolenic acid. First, a screening experiment was performed for growth of Desmodesmus sp. in hydrolysates of brewery waste (BrW), biscuit waste (BiW), and Thriposha waste (TW) with four dilution factors; 25%, 50%, 75% and 100% (undiluted hydrolysate). Higher biomass yields were achieved in all waste types compared to the control medium (modified Bold’s Basal media; 3N-BBM), with the maximum yield obtained using 100% TW. Thereafter, Desmodesmus sp. was cultured in photobioreactors using 100% TW, with a 3N-BBM control. The biomass growth rate and specific growth rate achieved in 100% TW hydrolysate were 0.503 g L d and 0.214 d respectively, which were significantly higher than the control. Biomass analysis showed that a significantly higher lipid content was present in the 100% TW-cultivated biomass, suggesting a higher alpha-linolenic acid extraction potential. Nevertheless, further research on techno-economic feasibility assessment and toxicology analysis is required prior to large-scale adoption of this process.
- item: Conference-Extended-AbstractTextile dye decolorization & bioelectricity generation in a microbial fuel cell(Department of Chemical and Process Engineering, University of Moratuwa, 2019) Imalsha, DT; Kumari, WMSS; Walawege, OE; Gunawardena, SHP; Ariyadasa, TU; Rathnasiri, PGMicrobial fuel cells (MFC) have been gained a considerable attention during past few decades due to its ability to treat wastewater effluents while generating bioelectricity. In this study anode to cathode area ratio was varied to maximize the output voltage simultaneously achieving the required color reduction. The highest voltage was observed as 515mV from anode to cathode area ratio of 3:1 on the 7th day from the beginning. At the latter stage, all arrangements show more than 85% color reduction at 200h. Therefore, it can be concluded that electrode area ratio has no significant effect for the fractional color reduction.