Browsing by Author "Handapangoda, H.M.A.K."

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Developing a rapid composting machinery system using Berkeley method
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Handapangoda, H.M.A.K.
Municipal solid waste generation and management in most cities especially in developing countries have emerged as one of the stubborn environmental problems at present. This scenario could be attributed to low level of technology as it is not sophisticated and not sufficient to deal with the excessive quantity of waste generation. Recognizing those noteworthy amounts of organic waste fraction of MSW in developing nations like Sri Lanka, there ought to make necessary feasible fitting systems to convert this huge amount into a resource. Composting, one of the environmentally feasible methods that convert organic waste into useful materials brings several drawbacks. This paper suggests a system with computerized automated machineries with the aim of increasing the rate of composting in a comparatively short time period. Berkeley method composting is taken as the principle for this system. The system consists with a shredder, a pill rotator (mixer), an air flow controller, and moisture and temperature controllers. The system is a closed system that implements favorable conditions for the composting process. Air flow, moisture level and temperature can also be controlled in the system. Purpose of shredder is to reduce the size of waste that further facilitate fast composting. Humidity and temperature sensors are used to keep compost pill in optimal level of conditions. Pill rotator (mixer) is rotated periodically in a given time period to facilitate proper mixing to pill. In addition, shredder size, pill rotating time, air supply and moisture and temperature can be changed on waste composition. Advancement of this method is to convert organic materials into usable form in short time period with less space and labor requirement. Energy requirement for the operation process can be generated by solar power is another added advantage of the method. However, further development is needed to overcome bottlenecks and gaps of the system.
E-Waste management in selected institutions in Colombo and Gampaha Districts
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Athukorala, S.M.W.; Handapangoda, H.M.A.K.; Yatawara, M.D.M.D.W.M.M.K.
Electrical and electronic waste (e-waste) is one of the most rapidly growing environmental problems in the world including Sri Lanka. This preliminary study was carried out to identify the attempts of e-waste management in selected institutions in Colombo and Gampaha districts. A questionnaire survey followed by interviews was carried out among randomly selected 20 institutions in Colombo and Gampaha districts. Descriptive statistical methods were used to analyze data. Results revealed that about 55% of respondents reuse their e-waste and 15% of respondents continue recycling the discarded e-waste. Most respondents (95%) has knowledge on e-waste and the effects of unsafe disposal. In addition, 60% of respondents were not aware of any projects or activities on e-waste management by government and local authorities. However, most of the types of electronic devices that are used by these institutions were more or less similar. Further, the survey revealed that the respondents showed willingness to contribute to e-waste management and willingness to pay or willingness to accept for a green product which will not harm the health of human and the environment. The study suggests to conduct proper awareness programmes to the employees in the institutions on handing over, disposal and management of e-waste. In addition, proper monitoring programmes of recycling or disposal is utmost important as e-waste contains a substantial amount of valuable recyclable materials and has potential to become a lucrative business in the country.
Mapping and suitability study of existing locations of waste collection bins at University of Kelaniya
(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Handapangoda, H.M.A.K.; Jayawardana, H.A.D.A.K.; Weerasinghe, V.P.A.
Solid waste management is one of the major environmental and social problems in Sri Lanka. Waste without proper segregation is the one of the main roots of barrier to implement solid waste management systems. University of Kelaniya has established waste collecting bins in different locations in the university premises in order to facilitate waste management within the university premises. The main objective of this study is to map the existing locations of the waste collecting bins in the University using Geographical Information System (GIS). Other objective was to find out the suitability of the existing locations of the waste collecting bins. There are two types of waste collecting bins at University premises. Namely, waste separated bins; biodegradable waste (green), paper waste (blue), polythene and plastic waste (orange), glass (red) and non-separated bins. Locations of the both types of bins were recorded using GPS Garmin eTrex 10 model. GPS data was transferred to ArcGIS10.2 software to map the locations of waste collecting bins. Base map was created by using high resolution satellite image. Building layer, road layer including foot path were digitized using ArcGIS 10.2 software and vector map was developed. Digitized vector layers and transferred GPS points layer were overlayed using overlay function in ArcGIS 10.2 software. Map layout was prepared to show the locations of waste collecting bins. Suitability of the existing locations of the waste collecting bins were studied according to the waste generation amounts in different places. Students canteens, staff canteens, student hostels, student recreational areas were identified as the main waste generation places at Dalugama premises in University of Kelaniya. Amount of waste generated was measured by using a spring weighing scale. Frequency of data collection was once a week. Microsoft Excel was used to analyze the data. The minimum and maximum range of bio degradable waste generation in Dalugama premises was 580-610 kg and non-bio degradable amount was 250-300 kg. Results show that the majority of separated bins are located in high waste generation places. Also it was clear that the generation amount of each type of waste depend on the type of the building, size of the building, amount of staff and students visited or worked and accessibility to bins. Further improvements are recommended in waste collection methods such as not to use separated bins to collect non separated waste and not to use non separated bins to collect separated waste. This will mislead the user when disposing garbage. Existing location of waste bins map can be used as a guide to the administration work as well as visitors and workers in the university.
Moisture reduction in Municipal Solid Waste (MSW) by parabolic solar dish method
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Heshani, A.L.S.; Abeysinghe, A.M.M.S.M.; Handapangoda, H.M.A.K.
The moisture content of MSW in tropical countries is higher when compared with temperate countries due to the climate (hot and humid weather with abundant rainfalls), compositions and types of waste generated. The moisture adversely affects the waste to energy conversion process as the process consumes more energy to evaporate moisture from MSW. Therefore, waste to energy concept receives less attention in MSW treatments, especially in tropical region. However, reduction of moisture of MSW would be beneficial to convert waste into thermal energy effectively and efficiently. Use of solar energy is a widely-practiced strategy to reduce moisture content in many materials. In this concept, the present paper suggests a method to reduce moisture in MSW by utilizing solar energy. Objective of this study is Develop a Model for Moisture Reduction of MSW by using solar energy. The parabolic solar-energy concentration method is applied to convert solar energy into thermal energy. The method is used as a principle of solid waste moisture reduction instrument. Three major components can be identified in the instrument, namely shredder, parabolic dish and compacter. Purpose of shredder is to reduce the size of waste that enables the entry to parabolic center pipes. As well, it increases the surface region of waste to evaporate water vapor without difficulty. The parabolic dish consists with parabolic dish, solar radiation center with hot air fans and waste flow pipes. Concentrated solar energy is centralized by using parabolic dish. Then solar energy is converted into thermal energy when focus onto the counter and exhausted, hot air fan generate Dry Air flow with higher temperature, because of the properties of air flow, it reduces humidity and thereby decrease of moisture content is accelerated. Temperature of dry air flow in center level is higher than boiling point of water (T >100oC), and this high temperature conditions generated from concentrated direct solar energy to center level and heating element converts solar energy into heat through the process of Joule heating, flow passing through this heating element resulting in heating of the air. Contact time of air flow with waste stream depend on moisture reduction of waste. Also, the continuous solid waste stream is transferred through the pipes and speed of flow depends on the decrease rate of moisture content at a center level. Solar electrical energy is used to operate this instrument. This scheme is fully automated and electronic detectors are applied to measure temperature, moisture content. After reducing the moisture content in solid waste, it can be compressed and used to produce pellets. This resultant pellets can be used as fuel. Besides, it can be applied as ecofriendly bricks by mixing with strong solidified materials. In addition, no greenhouse gas emission is expected during the operation. Optimal instrument size depend on the Size of parabolic dish that displays quantity of solar energy concentrated to center point. As most of the industries have to spend a considerable amount of money on reducing the moisture content in the final disposal; especially in the Sri Lankan case, the waste generated is sent to a monopoly holder for further treatment. If industries can use this method as a preprocessing method to reduce moisture content in semi-solid or solid waste, it would reduce a significant cost. The proposed system is controlled according to a computerized system within specified limits. However, further development is needed to overcome bottlenecks and gaps in the system.
Spatial and temporal variations of ground water quality in Kalpitiya peninsula
(Faculty of Science, University of Kelaniya, Sri Lanka, 2020) Dilshara, R.M.P.; Handapangoda, H.M.A.K.; Swarnathilake, D.S.G.G.C.; Amarasinghe, L.D.; Herath, H.M.I.K.; Udayanga, N.W.B.A.L.
Intensive agricultural practices in Kalpitiya have caused excessive usage of fertilizers. The sandy regosol soil and the over irrigation due to the presence of semi-arid climatic conditions in the area have led to nutrient leaching conditions in Kalpitiya. Since 1990s, the groundwater aquifers in Kalpitiya remain contaminated with higher levels of nitrate due to intensive agricultural practices and the current status of groundwater pollution remains poorly studied. Therefore, this study was conducted to evaluate the current status of groundwater pollution in Kalpitiya, with special emphasis on spatial and seasonal variations. Groundwater samples of 50 wells (potable and agricultural) located in five sentinel sites, namely Nawakkadu, Narakkalli, Thalavila, Kandakuli and Kalpitiya town were collected at monthly intervals from November 2018 to March 2020. In addition, the existing land use practices surrounding the respective wells were also recorded. Selected water quality parameters, namely pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), salinity, nitrate and phosphate concentrations were analyzed using standard methods. The General Linear Model (GLM) followed by Tukey’s pairwise comparison was used for statistical analysis. Significant spatial variations (p< 0.05) at 95% level of confidence. EC, nitrate, phosphate and TDS levels in groundwater samples of Nawakkadu, Narakkalli, and Kalpitiya town areas remained above the permissible levels for potable water quality given by the Central Environmental Authority (CEA). Therefore, adequate treatment of groundwater is recommended prior to use for drinking purposes.