Browsing by Author "Manipura, A."

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    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.
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    Development of Graphite/Ir Anode for Electro-chemical Denitrification of Landfill Leachate
    (Uva Wellassa University of Sri Lanka, 2016) Sivasubramaniyam, U.; Manipura, A.; Nanayakkara, K.G.N.
    Contamination of water by NO3 can cause health issues such as methernoglobinemia or blue baby syndrome. Previous studies revealed that high concentration of inorganic nitrogen compounds such as NO3 and numerous organic nitrogen compounds present in leachate. Thus, appropriate treatment of landfill leachate is urgently required. Electro¬chemical denitrification is one of the best technologies which can be used in denitrification. In this research, anode was developed by applying iridium (Ir) coating onto the graphite substrate by electro and electro-less plating methods. In electro-less plating, glycerol or formaldehyde was used as reducing agent while 325 ppm It' standard solution was used as the Ir precursor. EDTA was used as complexing agent. In electroplating, Ir was deposited onto well cleaned graphite cathode at 0.3 V and 110 mA from 250 ppm Ir3+ standard solution coating bath. The success of the plating process was initially analyzed using UV-Visible absorbance spectrum studies. UV-Vis spectrums and color changes of plating baths were shown that the Ira" concentrations in the plating bath were reduced with time for all methods. According to UV-Vis spectrums, excess formaldehyde which was used as reducing agent resulted high efficiency of plating. Therefore graphite/Ir anode which used excess formaldehyde in the plating bath was examined for Scanning Electron Micrograph (SEM), Energy Dispersive X-ray spectroscopy (EDX) and denitrification process. Observation of very small sizes of grains and 12.44 % Ir element present in the anode surface were the evidences that Ir deposited onto graphite substrate. Finally, developed anode and commercially available cathode electrodes were used for removing nitrate from nitrate solution. Keywords: Denitrification, Landfill leachate, Iridium, Graphite
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    Relating climatic parameters with leachate chemistry and its association with river water quality
    (Uva Wellassa University of Sri Lanka, 2015) Weerakoon, W.M.D.S.K.; Weragoda, S.K.; Kalpage, C.S.K.; Ziyath, A.M.; Manipura, A.
    Increased solid waste generation due to rapid urbanization and industrialization is a major problem in the world (Golomeova et al. 2013). .Landfilling is the most common disposal method of municipal solid waste (MSW) in developing countries, even though majority of these landfills are not properly managed, and pose a serious threat to the environment due to leachate run-off which contaminates the nearby ground water and surface water bodies (Kjeldsen 1993). The quantity and quality of leachate is influenced by various factors and climatic conditions are one of these governing factors (Chu et al. 1994; Johansen & Carlson 1976). Hence this study was carried out focusing on the impact of climatic parameters on leachate quality and its association with the Mahaweli river water quality which has not yet been further studied. Meantime two main objectives were fulfilled during the process of reaching the main target. They were, investigating seasonal variation of leachate chemistry and Mahaweli river water quality and developing correlation between climatic parameters, leachate chemistry and Mahaweli river water quality. Materials and methods Landfill leachate ,river water samples and ground water samples were collected from the leachate drain of the Gohagoda landfill, four locations along the Mahaweli river- two upstream and two downstream points from where leachate drain to the river and from two wells within the landfill. Weekly sampling was carried out for a period of two months and sample preservation, storage and analysis were performed according to Standard Methods (APHA, 1999). Daily temperature and rainfall data were collected from Horticultural Crop Research and Development Institute (HORDI) Gannoruwa and the statistical computations were performed with MINITAB version 17.0. Results and Discussion All the measured leachate and water quality data are summarized in Table 1.As the first step, primary leachate characteristic values were being compared with the past studies (Wijesekara et al.) and with the recommended standards of tolerance limits for discharge of effluent for inland surface waters by the Central Environmental Authority (CEA). Alkaline pH value represented the methanogenic stage of the landfill(More than 10y of operation) and exceed the CEA value. TDS and EC values of the leachate were very high (1.33× 10 mg/L & 2.05×10 µs/cm) compared to other sites. Dissolved Oxygen showed a very low value (0.09 mg/L) at the leachate drain owing to the anaerobic conditions and oxidisable organic matter related components are measured as BOD and COD. Both of these components were exceeding the CEA values. BOD:COD ratio was stated as 0.911 representing acidogenic condition which contrast with the above results. It is obvious that the uncontrolled dumping of the waste can produce leachate with various ages due to the irregular degradation pattern of the refuse material.(Wijesekara et al).