The Swedish Penal Code of 1965

Colombo City is the commercial capital of Sri Lanka with an estimated resident population of over 750,000 spread over 3741 hectares (ha) and has a population density over 1188 per ha. It is located in the western coast of Sri Lanka and is in wet zone. The topography is of flat terrain with a mix of land and water. Considering the population and the limited undeveloped land available, the disposal of Municipal Solid Waste (MSW) and Sewer is a major environmental problem in Colombo. The major object of this thesis is to identify and evaluate a productive waste management system that is not only environmental friendly but also sustainable and cost effective. In this context, as a sustainable technology, applicability of anaerobic digestion is investigated and methane generation potential of the waste is evaluated. In order to identify a sustainable waste management system, the quantity of waste generated within the city of Colombo is identified. The current practices of disposal of these wastes are then reviewed to identify any issues regarding its sustainability. The majority of the MSW is currently disposed as open landfill that is causing pollution of waterways, with its leachate, as well as the polluting the atmosphere around it with its bad odour. The sewer is discharged to sea or disposed via a self-contained soakage pit. Except for few small-scale anaerobic digestion plants that use solid waste for generation of biogas for localized use, there is no large-scale waste to energy projects in operation in Sri Lanka. The sewer is not used productively at all. Having identified the quantity of waste and the disposal methods practiced, the priority is to identify sustainable and productive methods of disposal of wastes that suits best the local conditions. With this in view research hitherto carried out are studied and available literature is reviewed. The objective is to ascertain the processes that productively harness the energy potential of MSW and Sewer, individually or in combination. There are many physical and chemical methods for treatment of wastes. However bioconversion of waste provides the best options for tapping the energy of the wastes. Of the two main bioconversion methods aanaerobic processes exhibit many advantages over aerobic digestion with its ability of handling high organic loading rates and low sludge production. However, the reason for the increase in applications of anaerobic processes, is, its potential for production of energy using the biogas generated. The methane so produced can replace fossil fuel and therefore has a direct positive effect on greenhouse gas reduction. Therefore, compared with other bioconversion technologies for treatment of MSW and sewer/wastewater, the energy and environment benefits make anaerobic digestion an attractive option. Anaerobic treatment of waste in an engineered landfill bioreactor is found to be the best option for treatment of MSW. Whilst providing a decrease in long term environmental risks and low operational and closure costs it provides with valuable energy source in generation of methane. As for sewer generation of methane in anaerobic processes can be enhanced with co-digestion of different types of waste suitably selected. In this regard co-digestion of sewer and wastewater with food waste is found to be productive and is applied in this study. Literature review is carried out to determine suitable models to predict the methane generation potential. The "First Order Decay Model" is identified as the appropriate model for prediction of methane from MSW in landfills. The "Anaerobic Digestion Model No.1" is applied for prediction of methane from sewer and waste water. Chemical composition of MSW is the primary parameter which affects the methane generation. The chemical composition is computed applying the ultimate analysis and using a stoichiometric based approach. For sewer and waste water the basic parameters of BOD and COD concentrations are available from data gathered. Apart from these two parameters the other parameters relevant to local conditions are not available. Therefore values that closely fit the local conditions are taken from the literature. The study determines the methane generation potential of MSW approximately 2.1 x 106 m3 per annum and anaerobic co-digestion of sewer and food substrates generate 9.1 x 106 m3 per annum. If parameters could be determined for the wastes generated locally the accuracy of the methane generation potential could be further enhanced. In this context, further studies, should be directed from the conventional landfills to "Anaerobic Bioreactor Controlled" landfill, where circulation of liquids including leachate is carried out to increase the biogas yield. For sewer the focus should be on the most economical foot print of parallel banks of number of continuous-flow stirred-tank reactors (CSTR) operating in series to accommodate the total flow rate of sewer

Urea-Hydroxyapatite Nanohybrids for Slow Release of Nitrogen.

While slow release of chemicals has been widely applied for drug delivery, little work has been done on using this general nanotechnology-based principle for delivering nutrients to crops. In developing countries, the cost of fertilizers can be significant and is often the limiting factor for food supply. Thus, it is important to develop technologies that minimize the cost of fertilizers through efficient and targeted delivery. Urea is a rich source of nitrogen and therefore a commonly used fertilizer. We focus our work on the synthesis of environmentally benign nanoparticles carrying urea as the crop nutrient that can be released in a programmed manner for use as a nanofertilizer. In this study, the high solubility of urea molecules has been reduced by incorporating it into a matrix of hydroxyapatite nanoparticles. Hydroxyapatite nanoparticles have been selected due to their excellent biocompatibility while acting as a rich phosphorus source. In addition, the high surface area offered by nanoparticles allows binding of a large amount of urea molecules. The method reported here is simple and scalable, allowing the synthesis of a urea-modified hydroxyapatite nanohybrid as fertilizer having a ratio of urea to hydroxyapatite of 6:1 by weight. Specifically, a nanohybrid suspension was synthesized by $\textit{in situ}$ coating of hydroxyapatite with urea at the nanoscale. In addition to the stabilization imparted due to the high surface area to volume ratio of the nanoparticles, supplementary stabilization leading to high loading of urea was provided by flash drying the suspension to obtain a solid nanohybrid. This nanohybrid with a nitrogen weight of 40% provides a platform for its slow release. Its potential application in agriculture to maintain yield and reduce the amount of urea used is demonstrated.Authors thank Hayleys Agro Ltd., Sri Lanka for initiating this research programme at SLINTEC and Nagarjuna Fertilizer and Chemical Ltd (NFCL), India for providing further support. Authors acknowledge Mr Sunanda Gunesekara of SLINTEC for assistance with scaling up the production process to enable the field trials. ARK acknowledges the financial support received from ICTPELETTRA Users Program, Trieste, Italy to conduct photoemission experiments at Materials Science beam line (MSB) and ELETTRA SRS on HA and urea coated HA samples. ARK further acknowledges Dr. R.G. Acres of MSB beam line for his extensive support to conduct photoemission experiments. We acknowledge the Department of Agriculture and Rice Research and Development Institute of Sri Lanka, in particular Dr Priyantha Weerasinghe, Mr D Sirisena and Dr Amitha Benthota for the assistance in carrying out pot and farmers filed trials. NFCL and Central Salt & Marine Chemicals Research Institute, Gujarat, India for TEM and BET analysis

Urea-Hydroxyapatite Nanohybrids for Slow Release of Nitrogen

While slow release of chemicals has been widely applied for drug delivery, little work has been done on using this general nanotechnology-based principle for delivering nutrients to crops. In developing countries, the cost of fertilizers can be significant and is often the limiting factor for food supply. Thus, it is important to develop technologies that minimize the cost of fertilizers through efficient and targeted delivery. Urea is a rich source of nitrogen and therefore a commonly used fertilizer. We focus our work on the synthesis of environmentally benign nanoparticles carrying urea as the crop nutrient that can be released in a programmed manner for use as a nanofertilizer. In this study, the high solubility of urea molecules has been reduced by incorporating it into a matrix of hydroxyapatite nanoparticles. Hydroxyapatite nanoparticles have been selected due to their excellent biocompatibility while acting as a rich phosphorus source. In addition, the high surface area offered by nanoparticles allows binding of a large amount of urea molecules. The method reported here is simple and scalable, allowing the synthesis of a urea-modified hydroxyapatite nanohybrid as fertilizer having a ratio of urea to hydroxyapatite of 6:1 by weight. Specifically, a nanohybrid suspension was synthesized by $\textit{in situ}$ coating of hydroxyapatite with urea at the nanoscale. In addition to the stabilization imparted due to the high surface area to volume ratio of the nanoparticles, supplementary stabilization leading to high loading of urea was provided by flash drying the suspension to obtain a solid nanohybrid. This nanohybrid with a nitrogen weight of 40% provides a platform for its slow release. Its potential application in agriculture to maintain yield and reduce the amount of urea used is demonstrated.Authors thank Hayleys Agro Ltd., Sri Lanka for initiating this research programme at SLINTEC and Nagarjuna Fertilizer and Chemical Ltd (NFCL), India for providing further support. Authors acknowledge Mr Sunanda Gunesekara of SLINTEC for assistance with scaling up the production process to enable the field trials. ARK acknowledges the financial support received from ICTPELETTRA Users Program, Trieste, Italy to conduct photoemission experiments at Materials Science beam line (MSB) and ELETTRA SRS on HA and urea coated HA samples. ARK further acknowledges Dr. R.G. Acres of MSB beam line for his extensive support to conduct photoemission experiments. We acknowledge the Department of Agriculture and Rice Research and Development Institute of Sri Lanka, in particular Dr Priyantha Weerasinghe, Mr D Sirisena and Dr Amitha Benthota for the assistance in carrying out pot and farmers filed trials. NFCL and Central Salt & Marine Chemicals Research Institute, Gujarat, India for TEM and BET analysis

Feasibility Study of Biogas Generation from Municipal Solid Waste and Sewerage within the Colombo City Limits

Colombo City is the commercial capital of Sri Lanka with an estimated resident population of over 750,000 spread over 3741 hectares (ha) and has a population density over 1188 per ha. It is located in the western coast of Sri Lanka and is in wet zone. The topography is of flat terrain with a mix of land and water. Considering the population and the limited undeveloped land available, the disposal of Municipal Solid Waste (MSW) and Sewer is a major environmental problem in Colombo. The major object of this thesis is to identify and evaluate a productive waste management system that is not only environmental friendly but also sustainable and cost effective. In this context, as a sustainable technology, applicability of anaerobic digestion is investigated and methane generation potential of the waste is evaluated. In order to identify a sustainable waste management system, the quantity of waste generated within the city of Colombo is identified. The current practices of disposal of these wastes are then reviewed to identify any issues regarding its sustainability. The majority of the MSW is currently disposed as open landfill that is causing pollution of waterways, with its leachate, as well as the polluting the atmosphere around it with its bad odour. The sewer is discharged to sea or disposed via a self-contained soakage pit. Except for few small-scale anaerobic digestion plants that use solid waste for generation of biogas for localized use, there is no large-scale waste to energy projects in operation in Sri Lanka. The sewer is not used productively at all. Having identified the quantity of waste and the disposal methods practiced, the priority is to identify sustainable and productive methods of disposal of wastes that suits best the local conditions. With this in view research hitherto carried out are studied and available literature is reviewed. The objective is to ascertain the processes that productively harness the energy potential of MSW and Sewer, individually or in combination. There are many physical and chemical methods for treatment of wastes. However bioconversion of waste provides the best options for tapping the energy of the wastes. Of the two main bioconversion methods aanaerobic processes exhibit many advantages over aerobic digestion with its ability of handling high organic loading rates and low sludge production. However, the reason for the increase in applications of anaerobic processes, is, its potential for production of energy using the biogas generated. The methane so produced can replace fossil fuel and therefore has a direct positive effect on greenhouse gas reduction. Therefore, compared with other bioconversion technologies for treatment of MSW and sewer/wastewater, the energy and environment benefits make anaerobic digestion an attractive option. Anaerobic treatment of waste in an engineered landfill bioreactor is found to be the best option for treatment of MSW. Whilst providing a decrease in long term environmental risks and low operational and closure costs it provides with valuable energy source in generation of methane. As for sewer generation of methane in anaerobic processes can be enhanced with co-digestion of different types of waste suitably selected. In this regard co-digestion of sewer and wastewater with food waste is found to be productive and is applied in this study. Literature review is carried out to determine suitable models to predict the methane generation potential. The "First Order Decay Model" is identified as the appropriate model for prediction of methane from MSW in landfills. The "Anaerobic Digestion Model No.1" is applied for prediction of methane from sewer and waste water. Chemical composition of MSW is the primary parameter which affects the methane generation. The chemical composition is computed applying the ultimate analysis and using a stoichiometric based approach. For sewer and waste water the basic parameters of BOD and COD concentrations are available from data gathered. Apart from these two parameters the other parameters relevant to local conditions are not available. Therefore values that closely fit the local conditions are taken from the literature. The study determines the methane generation potential of MSW approximately 2.1 x 106 m3 per annum and anaerobic co-digestion of sewer and food substrates generate 9.1 x 106 m3 per annum. If parameters could be determined for the wastes generated locally the accuracy of the methane generation potential could be further enhanced. In this context, further studies, should be directed from the conventional landfills to "Anaerobic Bioreactor Controlled" landfill, where circulation of liquids including leachate is carried out to increase the biogas yield. For sewer the focus should be on the most economical foot print of parallel banks of number of continuous-flow stirred-tank reactors (CSTR) operating in series to accommodate the total flow rate of sewer

The Intersection of Purine and Mitochondrial Metabolism in Cancer

Nucleotides are essential to cell growth and survival, providing cells with building blocks for DNA and RNA, energy carriers, and cofactors. Mitochondria have a critical role in the production of intracellular ATP and participate in the generation of intermediates necessary for biosynthesis of macromolecules such as purines and pyrimidines. In this review, we highlight the role of purine and mitochondrial metabolism in cancer and how their intersection influences cancer progression, especially in ovarian cancer. Additionally, we address the importance of metabolic rewiring in cancer and how the evolving landscape of purine synthesis and mitochondria inhibitors can be potentially exploited for cancer treatment