Master of Science in Environmental Engineering & Management

Permanent URI for this collectionhttp://192.248.9.226/handle/123/43

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item: Thesis-Abstract
Batch adsorption study for the removal of textile dyes from aqueous solutions using pandanus amaryllifolius (RAMPE) leaves
(2022) Haththotuwa SLG; Amarasinghe BMWP K
With the development of the manufacturing industry in recent days, there are obvious advantages and some disadvantages to human beings. One of the leading disadvantages is environmental pollution. Water pollution continues due to the continual uncontrolled largescale release of dyes to water bodies mainly from the textile industry effluents. These dyes can threaten directly and indirectly human, plant and animal life. This research is focused on removal of selected textile dyes methylene blue, crystal violet, congo red, reactive red and reactive black B via adsorption. The adsorbent was dried leaf powder of flavouring plant Pandanus amaryllifolius, widely famous as ‘rampe’. Rampe leaves powder was chosen as the adsorbent due to its wide availability, simplicity in preparation and mainly due to its ability to remove poisonous substances. Batch adsorption experiments were carried out at room temperature to investigate the adsorption capacity, kinetics of adsorption and equilibrium data. The analytical instrument UV-Visible Spectrophotometer was used to determine the dye concentrations. Batch test results showed that the adsorbent removes Methylene blue, Crystal violet, Congo red up to 95%, 90%, and 81%. However, reactive red and reactive black B dyes did not show significant removal. Kinetic studies showed that the adsorption followed the pseudo-second order kinetic model. According to the intraparticle diffusion model, adsorption happened with two steps for all three dyes. The equilibrium data comply with Langmuir isotherm with maximum adsorption capacities of 38.46, and 20.33 mg g-1 for methylene blue and crystal violet respectively. Congo red complied with Temkin isotherm. FTIR and SEM analysis of the adsorbent before and after adsorption revealed MB, CV, and CR were adsorbed to PALP with chemisorption by creating hydrogen bonds and significant amount of the mass transfer were happened through papillose cells on the leave surface.
item: Thesis-Abstract
Using GIS-based multi criteria decision analysis for prioratizing drinking water supply needs: an application to southern region in Sri Lanka
(2021) Hewapathirana AS; Manatunge JMA
GIS-based Multi-Criteria Decision Analysis (MCDA) was carried out to prioritize drinking water supply need in the Southern Region, Sri Lanka. The degree of water demand is attributed to population density, water resources availability (Relative Water Balance), water quality (Equivalent Water Quality Index) and new development (Population Pressure) of the region. Spatial distribution of density of Grama Niladhari Division-wise (GND) population was obtained from census data of 2,131 GNDs; assigned to the spatial distribution domestic units available with Survey Department. Water resources availability of each GND was figured out by plotting relative water balance with the aid of average annual rainfall data from the Meteorological Department, Mean evaporation rate and inflow of rivers into the designated research area. Water quality of relevant GNDs was calculated and represented as Water Quality Index (WQI) with the aid of geochemical atlas produced by Dissanayake et al. (1985) and NWSDB treated water quality data. Moreover, the new development of the research area was symbolized with the development corridor stipulated under National Physical Plan for 2050. Four raster files were prepared. To weight criteria, Analytic hierarchy process (AHP) was adopted. To identify the prioritized patches, the weighted linear combination of raster shapefiles was derived as a method of compensatory aggregation. It was understood that a combination of water quality and population density was dominant in the prioritization of water supply needs. The model identified the values as 0.47, 0.39, 0.07 and 0.07 for the main criteria, respectively for relative water balance, equivalent Water Quality Index, population density and population pressure owing to new development. The output of the research was the preparation of an automated GIS tool for prioritization of water supply needs through the GIS model builder facility.
item: Thesis-Abstract
Development of a framework for integrated solid waste management : an application to Kekirawa pradeshiya sabha
(2021) Samanpriya MMM; Jayaweera MW
Municipal solid waste management (MSWM) has evolved into a national concern affecting every individual in Sri Lanka. Poorly managed MSW affects to health and wellbeing of people, pollutes the air, soil, and water, causes flooding, spreads diseases, harms flora and fauna, loss of money, and obstructs resource recovery. Therefore, Sri Lanka has been trying to find a long-lasting solution to MSWM, which should be environmentally, socially, and economically acceptable. Integrated Solid Waste Management (ISWM) provides a contemporary and systematic approach to MSWM. In these efforts, the paradigm shift from landfilling to MSW reduction or prevention is thought vital to be embedded. The government’s new policy on “Vistas of Prosperity and Splendor” and Draft National Environmental Policy (2021) also mandates the use of ISWM for MSWM in Sri Lanka. Embedding circular economy perspectives to ISWM further reduces the amount of MSW produced or retained globally by transforming it into resources. Therefore, the quantity of MSW disposed of at landfills is greatly reduced, and natural resources for manufacturing processes are optimized. This study focused on developing an ISWM framework for MSWM in Sri Lanka based on the circular economy perspectives and under the purview of the present administrative framework. The local needs and conditions were carefully analyzed during the study to determine the most suitable options for all aspects of MSWM, including generation, segregation, collection and transport, sorting, recovery, treatment, and final disposal of MSW. The application of the 3R concept for MSW minimization, promoting source-segregation, increasing the efficiency of collection and transport, producing value-added compost and liquid fertilizer, selling reuse and recyclable materials, pre-processing and reusing of construction and demolition waste, landfilling, and generating electricity through waste incineration were proposed under the ISWM framework developed. The value-addition to the final compost product and liquid fertilizer was considered mandatory, as the government has given priority to organic fertilizer production efforts. The proposed ISWM framework was applied to Kekirawa Pradeshiya Sabha to evaluate the long-term sustenance of the framework developed. The present status of MSWM practices carried out by Kekirawa Pradeshiya Sabha was evaluated through a questionnaire survey, field visits, meetings with officials involved in existing MSWM practices, and a comprehensive literature survey. Based on the deficiencies identified in the current MSWM practices carried out by Kekirawa Pradeshiya Sabha, the proposed ISWM framework developed was tailor-made to overcome the deficiencies identified and improve revenue generation to Kekirawa Pradeshiya Sabha. The current collection of MSW (17%) was increased up to 50% with the provision of two garbage compactors (6-8 m3 each). The open dumping of mixed waste currently being practiced will completely be halted, and an ISWM facility was designed with a compost plant, resource center, construction and demolition waste collection yard, and controlled landfill. The expected output of value-added compost and liquid fertilizers was 3.5 MT/day and 500 L/day, respectively. The electricity generation was 0.2 MW. Only 0.3 MT/day of fly ash will be disposed of in a secure landfill out of 13.8 MT/day of total MSW collected, which accounts iii for 1.3% of the total MSW generation. An economic analysis was carried out to evaluate the economic feasibility of the proposed ISMW framework for Kekirawa Pradeshiya Sabha. The results of economic analysis manifested that the Net Present Value (NPV) was SLR 66.52 million at an interest rate of 10%. The Internal Rate of Return (IRR) was 12%. Further, reduction of greenhouse gas emissions (GHG), land value appreciation, city beautification, improving health and wellbeing of people, promoting tourist attraction, and employment opportunities are other benefits to be gained from the proposed ISWM framework. Therefore, the proposed ISWM framework appears viable from a national economic viewpoint and can be used as a role model for the MSWM by other local authorities, particularly covering agriculture-based cities of Sri Lanka.
item: Thesis-Full-text
Up-flow anaerobic sludge blanket (UASB) reactor to treat landfill leachate under tropical condition
Iroshani, HPDU; Rathnasiri, PG; Bandara, WMKRTW
With the growth of population and changing the lifestyle, solid waste generation and management has become the major problem all over the world. Open dumping of solid waste has created problems related in health and the living standards of the people. Leachate generated from open dumping has created problems such as, surface and ground water pollution and soil contamination with toxic compounds. This study was conducted to investigate the applicability of Up-flow Anaerobic Sludge Blanket (UASB) reactor to leachate treatment under the ambient temperature condition. Treatment efficiencies were measured in terms of COD reduction percentage of leachate that fed to the UASB reactor. The reactor was operated 94 days at different Hydraulic Retention Times (HRT) with the objective of finding the optimum HRT value. Maximum COD removal efficiency of (64 ± 1) % was achieved when HRT was at 6 hours. Reactor inside pH was controlled within the range of 6.2 – 7.5. Gas production rate, composition and Oxygen Reduction Potential (ORP) were measured for all the HRT values to maintain the reactor in proper anaerobic condition. Methane composition in biogas produced was high for all HRT values and at 6 hours HRT it was (86.11±1.1) %. Maximum TSS removal efficiency of 66% was also achieved at 6 hours of HRT. But maximum VSS removal efficiency of 29% was achieved at 7 hours of HRT. When comparing the heavy metal removal, the highest removal efficiencies were achieved for Pb and Cr which are (55 ± 1)% and (47 ± 1) % respectively.
item: Thesis-Abstract
Development of a drinking water quality index for dry zone of Sri Lanka : application to Kala-Oya basin
Jayaratne, LI; Manathunga, JMA; Athapaththu, BCL
Water Quality Indices have been developed to assess the suitability of water sources for its intended uses which give the status of water quality in water sources. Over past few decades, deterioration of water sources in Sri Lanka is getting critical. Ground water plays a significant role as a drinking water source in rural communities of dry zone while surface water is not that vital. In such circumstances, feasibility of use of water from traditional village irrigation tanks for drinking is utmost importance. To assess the surface water in dry zone, Drinking Water Quality Index was developed following four steps; (1) Selection of parameters considering their importance to the assessment study and availability of data. (2) Development of sub-indices by converting different units and rangers of water quality measurements for selected parameters into common scale, (3) Assigning weighting to the selected parameters considering their contribution to final index, (4) Aggregation of sub- indices and weightings using aggregation equations producing final index. Drinking Water Quality Index was then applied to Kala-oya basin in order to characterize the spatial and temporal variability of surface water quality in the basin. Kala-oya basin, located in the north-western dry zone of Sri Lanka is irrigational watershed which supplies water to agriculture, recreation and domestic purposes including drinking. Drinking Water Quality Index was calculated from ten physicochemical parameters; pH, Conductivity, Total Dissolved Solids, Turbidity, Hardness, Nitrate, Phosphate, Sulfate, Fluoride, Biochemical Oxygen Demand, Chemical Oxygen Demand, Total Coliform and Faecal Coliform periodically measured at 16 sampling sites in three reservoirs in Kala-oya basin; Kalawewa, Dambulu-oya and Bowathenna, from January to December 2014. The results revealed that Drinking Water Quality Index scores varied between 38 to 80 indicating deterioration of water quality. It was observed that surface water samples from 78% of sampling locations were categorized as ‘Marginal’ water quality. Results of remaining locations showed ‘Fair’ and ‘Poor’ water quality. In none of the locations, the score of the DWQI was determined as ‘Good’ or ‘Very Poor’. Water quality analysis done for assessing the level of treatment showed all the locations need advanced water treatment. The Drinking Water Quality Index shows an overall suitability of water bodies for drinking with level of treatments. Proposed Drinking Water Quality Index can be applied for watersheds in other parts of the country.
item: Thesis-Full-text
Analysis of root causes of the excessive chlorine demand in water treatment
Ranasinghe, CJ; Ratnayake, N
To make water suitable for human consumption, water from most sources must first be treated, and the source water that can be used as raw water for public water supplies should conform to quality standards stipulated in the Sri Lanka Standard SLS722. However, sometimes, National Water Supply and Drainage Board (NWSDB) water treatment plants do not receive raw water according to SLS722 due to contamination. In some cases, existing treatment facilities is not enough to face emergency situations, even though the average quality conforms to the SLS 722. In such situations, the operation of treatment plants becomes a challenge, as it is the responsibility of the NWSDB to provide safe drinking water to the consumers, which means that disinfection, has to be carried out even though the chlorine demand may become very high due to excessive amounts of contaminants during such events. The purpose of this research was to analyze the root causes of the excessive chlorine demand in water treatment and recommend an appropriate system capable of removing dissolved iron, ammonia and manganese from the raw water, avoiding the use of chemical treatment if possible, and prepare an emergency plan to face the situation at the Biyagama Water treatment Plant. According to the past water quality data at BWTP colour, turbidity, BOD, faecal coliform, free ammonia content, nitrate, sulfate etc. of raw water were rapidly varying with the occurrence of extreme events such as sudden rainfall followed by prolonged dry season, a few days after flood events etc. In addition, it was found that foul odour is present in the raw water which has been abstracted from the river during the drought season and right after flooding events, etc. In spite of these variations in raw water quality, the treated water quality is achieved through the treatment process without any failure. However, during the drought season and right after flooding event, Chlorine demand at Biyagama Water Treatment Plant was increased and intermediate chlorination was implemented to maintain the optimum Rcl level recently. Hence,aim of this study is to analyze the root causes for the excessive chlorine demand in raw water,investigate adverse effects of treated water due to high chlorine dosages, and prepare an emergency plan to face the situation and suggest the appropriate long term solution to avoid high chlorine demand on treating water without chemicals at the Biyagama Water treatment Plant.Presence of Fe, Mn and TOC in the raw water is known to cause for high chlorine demand at the Biyagama water Treatment Plant. These high chlorine demands have been attributed to the presence and oxidation of Fe, Mn, and TOC by chlorination.In order to find the root causes for the high chlorine demand in the BWTP, it is necessary to first investigate the mechanisms that cause the problem in this particular situation. As such, a comprehensive water quality study was carried out in 19/10/2016 to 21/10/2016, 7/10/2016 to 11/10/2016 and 4/6/2016 to 9/6/2017 by the Biyagama Water Treatment Plant laboratory,Central Laboratory and Bureau Veritase laboratory samples from the intake (raw water),Treated water tank (treated Water), Pattiwila canal and suspected points of connected Marshy area, along the Kelani River up to 5km upstream of Kelani River and along the gahawatta Ela up to BOI waste water treatment plant out let.This study revealed, that the chlorine demand was increased when Fe, Mn or TOC were present alone or together and DO level was less than 5mg/l in raw water at BWTP due to oxidation of Fe, TOC and Mn by chlorination. BWTP is used pre chlorine to alter taste and odor producing compounds, to suppress growth of organisms in the treatment plant, to remove Fe2+,manganese, and to reduce the interference of organic compounds in the coagulation process.However, according to literature, pre chlorination can affect the undesirable THM content of the finished water.According to the WSP at BWTP, there should be an emergency response plan to risk mitigation due to emergency cases. Hence, it is proposed to use the emergency response plan for any similar incident happened in future.However, in the long-term, it is recommended to install tailor made bubble aerator to Biyagama Water treatment Plant to use when the DO content is less than 5.0mg/l in raw water, after pilot scale studies, to include aeration and activated carbon dossing facility to upcoming Kelani Right Bank Project Stage II, to implement the proper catchment management plan to Pattiwila and Mabima Catchment areas to avoid the Mn and Fe contamination, to implement continuous monitoring system to monitor the Fe and Manganese in the raw water at BWTP and to maintain a residual chlorine level of 0.1 to 0.2 mg/l throughout the distribution system in all the time. This may require installing booster chlorination equipment at appropriate locations.
item: Thesis-Abstract
Effectiveness of operational aspects of compost plants in Sri Lanka
Jayathilake, WGAN; Gunawardena, SHP
Solid waste is a major problem in Sri Lanka as it is in many other developing countries. Composting is proven to be a viable solution to address the Solid Waste Management issues the country is facing over many years due to the high content of organic matter composition available in the waste streams. More than 100 compost plants have been established in the country along with the introduction of National Solid Waste Management programme over the past few years. Nevertheless, uncertainty clouds over the long run of these compost plants due to many reasons which would ultimately lead them into failures. The objective of this research is to evaluate the factors contributing to the effectiveness of compost plants and thereby to evaluate the current situation of five selected compost plants with regards to operational aspects. The selected compost plants are currently being operated under Local Authorities in Western province and they were evaluated considering two criteria namely waste supply and compost quality. Under the first criterion effective operating level of the plants was evaluated while second criterion was focused on final compost product quality. According to the results obtained, majority of the plants appear to be ineffective in their operation. Lack of institutional capacity in terms of technical expertise and finance is a major barrier for effective operation of compost plants. Facilitating proper training programmes among plant operators to improve their technical knowhow and introducing appropriate mechanisms for regular monitoring of process parameters are essential to ensure the effectiveness of compost plants. Strategies and practices from the successful cases could be replicated suitably in poor performing plants to address their drawbacks.
item: Thesis-Full-text
Ambient air shed quality management with new coal power plant installation
Kumarasinghe, KAN; De Alwis, A
Average growth rate of electricity demand over last 15 years in Sri Lanka is about 6.5 % per annum. Energy demand in the country was mainly met by hydropower up to the year 1999, and with time thermal generation has become prominent.According to generation expansion planning study – Base case (2013 – 2032), coal is expected to dominate the thermal power sector consumption (75.7 % share) for the next decades in Sri Lanka. During the planning stage of a coal power plant, proper offset provisions should be implemented in order to minimize air shed degradation by achieving relevant emission standards stipulated in regulations. Different factors that influence on ambient air quality degradation should be investigated before the power plant comes fully on stream. Since coal is not considered as a cleaner fuel, health risk is always linked with its hazardous emissions. This assessment was carried out in order to investigate the impacts from three criteria pollutants, (SO2, NOx and PM) emitted from proposed 1200MW coal power plant in Sampoor. Three different scenarios were considered for the development of proposed power plant and four case studies to investigate different conditions under each scenario. Air Dispersion Modeling (AERMOD) was used to predict the ground level concentration within 20 km radius of the emission source. The results from the modeling assessment were used to identify the exposure assessment and then acute health risk impact was identified through dose response measures. The study shows that high efficient coal power plant can be satisfactorily employed in a place where degraded air quality is already prevailed and also when considering ground level ambient air quality concentrations, it is more favorable to install the coal power plants with less number of units having higher capacity. The results show that non carcinogenic human health impact was not identified from the population cluster locations in the vicinity to the power plant. Based on the assessment most preferred option for development of the proposed power plant with required mitigation measures was identified.
item: Thesis-Full-text
Rationalized resource allocation for implementing water safety plans
De Silva, WSA; Ratnayake, N
Water Safety Plan (WSP) is the most credible management tool to achieve water safety worldwide. This study looks into prioritization of risks and optimizing resource allocation for implementing WSPs with multiple stakeholders and multiple domains having no mutual accountability and line of hierarchy. The study methodology was in the form of a descriptive and interpretative case study involving three levels; academic, national and sub national. These levels respectively served the targets of studying similar research, understanding policy and decision making environment and analysing grass root level dynamics in implementing WSPs by focusing on Eheliyagoda water supply scheme under NWS&DB. Both quantitative and qualitative data, belonging to multiple categories, was associated. The analysis showed that the risk-reassessment and improvement plan of WSP need critical revisit beyond semi – quantitative risk matrix method. Only the water supplier (NWS&DB) had incorporated accountability in the WSP while other stakeholders were just collaborating. Standard risk ratings alone were not rational enough to justify strategic decisions on allocating limited resources and instead it might lead to decisions based on induced impressions. It seems to make decision makers defensive even within the domains with accountability while other stakeholders are not convinced on dedicating resources for water safety which may not be under their direct mandate. It was found that graphical interpretation of risks & hazards across all the water supply elements followed with hazard quantification was much convincing in prioritizing risks. Introducing bottleneck analysis to WSP could successfully incorporate the influence of prioritized risks on the coverage of services thus rationally showing where to prioritize resources. Bottlenecks were seen in incorporating consumer element, creating demand for water safety and rationalized budgeting. It was recommended that the guidelines may assign the catchment element to accountable stakeholders other than water suppliers together with demand creation and communication methods.
item: Thesis-Full-text
Use of WSP concepts in risk mitigation of distribution systems at under capacity operation - a case study on Kandy South water distribution system
Abeykoon, AMHK; Ratnayake, N
A Water Safety Plan is one of the most effective ways of ensuring that a water supply is safe and reliable for human consumption and that it meets the health and demand based standards and other regulatory requirements. WSP is based on a comprehensive risk assessment and risk management approach to all the steps in a water supply chain from source to consumer. Recently introduced WSP for distribution systems is a new concept to NWSDB. However, the NWSDB, being the authority directly responsible for treatment and delivery of drinking water to the consumer, has commenced implementation of the WSP approach to the distribution system as a first step. Numerous studies were found in literature for assessing the formation and behavior of disinfection by products, residual chlorine and other hydraulic parameters in water distribution systems. Yet the studies related to WSP for distribution system approach were not frequently found. The risk assessment of an under capacity operating system is carried out throughout this study and the recommendations were made to mitigate those in future. Maligathenna scheme, which is a sub-scheme coming under Kandy South Region was analyzed in detail. The main parameters concerned were Trihalomethane, Residual Chlorine, Pressure, Water Age, Total Organic Carbon, Turbidity and Conductivity. Water quality parameters were tested at site or in the laboratory. A hydraulic model was built using Water GEMs software to determine the hydraulic parameters such as pressure, water age. A special water quality model was developed to assess the performance of the distribution network and predict the parameter values for the future. General conclusions along with the specific recommendations were made based on the results and observations met throughout the study. WSP hazard identification and assessment approach is followed throughout the study. Some alarming findings were listed with respect to TTHM and RCl. However clear and significant relationships among the parameters could not be found. Most of the recommendations which were made at the end of the study are expected to be implemented either in design stage or during operation and maintenance period
item: Thesis-Abstract
Development of environmental management guidelines for Sri Lankan golf courses
(2016-05-26) Abeysuriya, TD; Rathnayake, N; Jayaweera, M
Golf is a precision sport and it is expected that there will be a trend in increasing the number of golfers playing in Sri Lanka, and perhaps new Golf courses to cater to the increasing demand, particularly among tourists, with the major development drive maintained by the government. Even though a golf course can contribute to the sustainability of the ecosystem, it may lead to many environmental risks associated with the activities of the golf courses, unless there are safeguards to protect the environment through proper environmental policies and practices, which can be adopted by all stakeholders, including the staff, clients and visitors of the Golf Course. To achieve the international standards while minimizing the environmental risks associated with them, it is necessary to have an environmental management system for golf courses. Even though the Government of Sri Lanka requires Environmental Imapact Assessments to be carried out for new Golf Courses, there are no monitoring regulations for operation of Golf Courses. Interviews with management staff of the Colombo Golf Club revealed that there is no proper environmental guideline for the golf courses in Sri Lanka at present. It is imperative to develop an environmental guideline and self assessment method suitable for adoption for Golf Courses in Sri Lanka, to ensure proper practices during the operation of the courses before any further damage is done to the environment. This study was carried out to develop an environmental guideline for Sri Lankan golf courses and a self assessment method in order to assist the management of the courses to evaluate their own operations against benchmarks and identify weak areas and take corrective actions where necessary. Review of literature revealed that there are diverse methods adopted by golf courses in USA, UK, Canada and Australia in order to minimize environmental risks caused by Golf Course operations. Having understood the commitment to safeguard the environment in golf courses by the developed countries, it was decided to develop a questionnaire to assess the situation with respect to various aspects of the operation of golf courses relevant to Sri Lanka, and provide guidelines for improvement of the weak areas. General information regarding the operations was collected by using a general questionnaire. After evaluating the methods used in the developed countries, it was decided that the most appropriate method suitable for adoption for the Sri Lankan situation was the Environmental Quotient Questionnaire method for self assessment used by the Unites States Air Force (USAF) and guidelines for preparation of a supporting document such as the Breckland Pines Golf Course Environmental Management Plan. The model questionnaire was prepared with 50 questions in ten subcategories, based on the relevant environmental aspects. The aspects covered were: policy, planning, wildlife & wildlife habitats, clubhouse operations, pest control, pesticide use, fertilizer use, water quality & use, safety and education & awareness. Even though the USAF self assessment method used equal weightages for all environmental aspects, it was decided to factor-in the importance of the aspects of the overall environmental profile of the local situation by giving weights to each category. Since all questions were of the type with three possible answers (yes/no/partial), the weights assigned to each aspect were reflected in the final total marks by varying the number of questions in each category. The number of questions was adjusted several times in order to achieve the intended purpose of capturing the importance as well as the status of environmental management of the golf courses. Thus, after several modifications, the model of the ECQ questionnaire was developed to a satisfactory level to be tested using field data. The final assessment of the Golf Course was obtained as a percentage of the possible 100% if all 50 questions yielded positive answers, as two results - the actual ECQ (only 'yes' answers) and potential ECQ ('yes' and 'partial' answers). This questionnaire was tested with the data of Royal Colombo Golf Course (RCGC) and after minor modifications based on the results of the test, it was used to assess the other golf courses in the country. Benchmark values were also proposed for the status of the Golf Course depending on the ECQ values as per the table below. Total Yes or Partial response Environmental compatibility Level 90% - 100% Advance 70% - 89% Showing Progress 40% - 69% Getting Started 39% or Less Urgent action needed The results of the assessment were compared to the actual status of the Golf courses as perceived by the employees and users of the courses, and were found to be comparable, which showed that the ECQ provided a reliable assessment of the environmental status of the Golf Course, and helped to identify the weak areas that needed urgent attention as well as long term improvements. Ten environmental best practice guidelines were prepared under the topics of policy, planning, wildlife & wildlife habitats, clubhouse operations, pest control, pesticide use, fertilizer use, water quality & use, safety and education & awareness, in order to help the Golf Course management to prepare their own Environmental Management Plans for present and future courses. The final recommendation is to use the ECQ method to assess the current status of existing courses, prepare an environmental management plan for each golf course using the guidelines and to monitor the golf courses annually with the self assessment method, in order to continually improve the ECQ and thus enhance the environmental performance of the Golf Course.
item: Thesis-Abstract
Priority criteria for selecting rural water supply schemes for implementation
(2015-01-06) Mangalika, RADS; Ratnayak, N
Water is a basic need for all living beings, and providing access to safe drinking water to all communities is the responsibility of the government. In the above context particularly due to constraints of funding especially capital cost, adopting priority criteria for implementation of water supply projects after the prefeasibility study is a timely need. It will enable the NWSDB officials to justify their decisions to select the priority order of implementation of water supply projects on a rational basis. Prioritization is being done at present in NWSDB for urban water supply schemes and resettlements. However, there is no such priority criteria developed for selection of RWS schemes for funding at the NWSDB at present. Consequently this study was undertaken to prepare a priority criteria for the selection of RWS schemes which are carried out under RWS Section of NWSDB. The main parameters included in the priority criteria to select whether a proposed project is appropriate for implementation are source adequacy, acceptability of technical option, source extraction and service level to the community, willingness and capacity of the community to perform O&M function, to contribute to capital cost sharing, Tariff / O&M expenses and supply labour and material and justified unit capital cost per house hold. Parameters used for prioritizing the project are water quality and impact of water borne diseases before the project, whether children below 14 years are engaged in water hauling, whether the water hauling distance is above 200 m whether the community pays unjustifiably on drinking water, existing sanitary practices, availability of alternative sources and percentage of vulnerable people in the community. A set of conditions coming under each parameter were determined by formulating ranges to measure the effect of that parameter. Then scores were assigned to parameters and subsequently to conditions. The project that gets the highest score is at the highest priority. Prepared criteria were checked with 10 hypothetical cases. It was found that the resulting priority order is directly relevant to the expected outcome. Then real data related to four projects were applied and tested to ascertain practical problems with the developed Priority Criteria. The Priority Criteria could be applied after making the respective officers preparing pre-feasibility reports aware of how to include the required information. The Officers should be vigilant for special circumstances where some flexibility is needed.
item: Thesis-Abstract
Multiple uses of sub-urban tanks: a case study based on Boralesgamuwa Lake
(2015-01-06) Jayakody, MA; Ratnayake, N; Manatunga, JMA
Among inland water bodies, lakes are relatively stable in contrast to rivers. This has favoured local residents using the lakes in fulfilling their needs for a number of uses and services such as sources of drinking and other domestic purposes, agriculture, energy production, mode of transport, very attractive opportunity for recreation amd leisure space. The lakes provide fishing opportunities and irrigation facilities for the community as a source of living. Boralesgamuwa lake is situated within the Colombo suburbs giving an aesthetic value to the area. This is a valuable water body in several aspects and there are requests and proposals arising from the surrounding community, political authorities and governmental and non-governmental organizations to improve the Boralesgamuwa Lake for several uses such as irrigation, recreational activities, leisure space for community as to develop ecotourism, aquaculture and flood detention. Even though there are such uses, water pollution, solid waste disposal in and around the lake and negative social impacts from visitors could have to be managed in a social and environmental friendly manner, inorder to minimize the negative impacts happening to the lake. In this research, the Boralesgamuwa Lake resources are valued towards determination of its Total Economic Value considering the values of the lake resource such as Direct Use Value, Indirect Use Value, Option Value, Bequest Value and the Existence Value. A questionnaire survey has been conducted, among the users of the lake resources and surrounding community as a methodology for obtaining such values.There, people were asked directly to state their Willingness To Pay towards each value. Then the Total Mean Willingness To Pay was obtained by averaging the Aggregate of individual Willingness To Pay Values. It was estimated at Rs.379.11. Finally, the negative impacts of this valuable water body are discussed in detail proposing a Management Plan for the Boralesgamuwa Lake. Therefore, the study provides an example for the environmentally sound Management Plans of suburban lakes while highlighting their Total Economic Value.
item: Thesis-Abstract
Development of a model to select the optimum sedimentation process in surface water treatment
(2014-08-08) Liyanage, WW; Ratnayake, N
In the water treatment process, sedimentation is used to remove suspended particles from raw water, and sedimentation tanks have become a common structure at water treatment plants. Generally sedimentation tanks are made of reinforced concrete and may be rectangular, square or circular in plan. With the advancement of technology, there are a number of sedimentation techniques now available. Some sedimentation tanks require coagulation and flocculation separately prior to the water enters the tank, while others provide the flocculation process within the tank by creating a velocity gradient using hydraulic or mechanical forces. The detention time of sedimentation tanks varies from thirty minutes to six hours depending on the sedimentation technique. This makes the sedimentation tank the largest and heaviest structure in the conventional water treatment plant. According to the data available with the drinking water industry, construction cost for sedimentation tank and flocculator is about 25% to 35% of the total construction (civil works) cost of the water treatment plant. Good engineering design should be economical. Unfortunately, based on experience in the potable water industry, the selection of the sedimentation technique mainly depends on the designer’s experience and not based on an analysis of all relevant conditions affecting the economy of the tank throughout the design horizon. Considering the operational cost, most local Engineers select sedimentation tanks operated by natural forces by gravitation and natural aggregation. A literature survey was carried out to find out the design practices on Plain Sedimentation, Clarifiers and Plate/Tube settlers. A field survey was also carried out to collect information on the construction and operation & maintenance costs of the tanks available within NWSDB. Furthermore a number of detailed designs were carried out to prepare cost estimates in order to supplement the collected data. Based on this study, relationships were developed for cost functions and a method has been developed for the selection of an economical sedimentation technique depending on the capacity of the water treatment plant.
item: Thesis-Abstract
Root causes for the failures of existing sewerage system in Colombo Municiple Council area
(2014-08-08) Kumudu Lal, LB; Ratnayake, N
The ageing Colombo Sewerage system has been deteriorating over the years and the system was unable to cater to the increased demand and led to many environmental issues. Therefore, certain improvements were carried out in the last 3 decades to address the prevailed issues. But, sewer pipeline stoppages and collapses were increasing gradually with the dilapidated condition of the system, even with the newly introduced improvements. Collapses, blocks and chokes are experienced regularly in the system. This has led to overflows and short-circuiting which has caused serious pollution in water bodies and the environment as a whole. As most of the major collapses and overflows had not been attended to and not been given necessary priority due to various constraints, the situation became critical day by day, so that life styles of the public have been badly affected. Though a few studies have been conducted to develop the existing sewerage system in Sri Lanka by various non government organizations, the expectations were not achieved successfully and some issues still remain. Only a few recommendations of these researches were implemented. Therefore, it is vital to identify the issues in the existing Sewerage Systems in Colombo Municipal Area, to improve it into a smooth running, environmental friendly sewerage system. Thus, there is a need to conduct a research to explore the root causes for the failures of the existing sewerage system. The case study research approach was used to investigate the research problem, by interviewing key stakeholders, including the Engineers, within a selected administrative district. Further, a questionnaire survey was carried out among the other five administrative districts in the CMC areas to observe whether the identified root causes through the case study are similar and common to the other districts too. This study revealed that there are several types of failures in the existing sewerage system. The related root causes for the failures were further disclosed after evaluating the common reasons for the failures. Furthermore, it was observed that the root causes for the failures are common and acceptable to the entire sewerage system in CMC area through the survey. Further it is recognized that these root causes are generated in all three stages; design, construction and maintenance. Finally, good practices to improve the existing sewerage system are also explored through this study.
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Comparison and performance evaluation of direct aerobic submerged attached growth and anaerobic cum aerobic submerged attached growth systems, for factory sewage
Suraweera, PS; Jayaweera, M; Manatunge, J
Most factories located outside of BOI industrial zones in Sri Lanka do not have proper sewage treatment systems. Due to the high number of employees, these factories are always encountered with the problem of handling large quantities of low strength sewage generated from lavatories, canteens and kitchens. In such factories sewage is usually handled using conventional septic tank - soakage pit systems. Such systems are commonly found infested with insects, and promote further breeding. They cause nuisance due to obnoxious odor, and is a major cause for severe ground and surface water pollution. It has been noted that these factories have critical problems of handling sewage during rainy season, especially when the factory is located in areas with high ground water table such as a marshy land or near a surface water body. The activated sludge suspended growth aerobic systems designed to treat sewage in most of the factories have various operational problems which increase the operator involvement and therefore the plants performance are operator dependent. Activated sludge suspended growth aerobic systems are more susceptible for sludge bulking which leads to poor effluent quality and the unbulking process is very difficult and ~time consuming. In addition to this, the several parameters such as SVI, MLVSS, etc have to be monitored carefully in the conventional activated sludge systems for the proper operation and the maintenance which increase the operational and the maintenance cost. The maintenance departments of factories always request a trouble free sewage treatment plant to minimize their involvement in operation of the plant. Therefore the submerged attached growth aerobic systems are becoming the most appropriate system as an alternative of the activated sludge system for treating low strength effluent, sewage from factories. A leading company in Sri Lanka which provides turnkey solutions for waste water and sewage has introduced submerged attached growth aerobic and anaerobic treatment systems to overcome above issues ..Depending on the affordability of the client and the space availability they have introduce submerged attached growth aerobic systems in two ways. (a) Direct aerobic submerged attached growth systems where sewage is treated only with aerobic treatment (b) Anaerobic cum submerged attached growth aerobic systems where sewage is treated with anaerobic process prior to aerobic treatment. However no proper study has been carried out to find out the most appropriate submerged attached growth system to treat sewage generated from factories. Research suggested that the anaerobic cum submerged attached growth aerobic system is more suitable for treating factory sewage than direct aerobic submerged attached growth system in terms of quantity of sludge wasting and lower operational and maintenance cost which results to a lower unit cost per m3 of treated water.
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Study on CBOS capability for sustainable management of rural water supply schemes
Wijesundara, TWMLP; Ratnayake, N
Sixty per cent (60%) of the rural population living in the country does not have access to safe and adequate water supply facilities. The rural population is 75% of the total population as per the 2001 census records. The lack of access to safe drinking water directly relates to health, bygiene and income generation of rural community in Sri Lanka. Target Ten of the Millennium development Goals (MDGs) is to "halve, by 2015, the portion of population without sustainable access to safe drinking water and basic sanitation". If this target to be achieved, development of natural water supply, sanitation and hygiene are required as more than 70% of poor living in rural areas. This has promoted the government and donors to increase user involvement in water supply sector. In the past two decades many rural water supply projects have been implemented with donor assistance. Experience gained from those projects had provided guidance towards implementation policies in rural water supply and sanitation. The challenge facing the water sector today is how to scale up these experiences in order to meet the MDGs. Increased financing is clearly needed, but that alone will not meet the challenge. Client capacity to ensure the sustainability of investments is equally important as evident from the experience of many failures made by rural water supply schemes during the last two decades. Therefore development of policies and strategies is needed with the understanding that water supply is a service and the user community should be considered as the core of sustainability. The rural water supply projects were implemented successfully with community involvement during the construction phase with less emphasis on operation and management. However, during the operation and maintenance period, these projects had faced problems and consequently some of these schemes were abandoned within a period of 5 years or less. The policy for the rural water supply and sanitation sector has recognized the value of water and the need for institutional arrangement for the efficient management of facilities with community participation and the stakeholders. According to the Rural Water Policy, the users should be encouraged to own and manage the facilities and assets. There are seventy-nine community water supply schemes in the Monaragala district including five small towns implemented by the ADB assisted 3rd project completed in the years 2003 to 2005 with community involvement. The community should undertake O&M as per the project policies. Though the ADB assisted 3rd project paid attention to sustainability from the start, there are many examples of CBOs failing in O&M. Further criticism from some local government bodies and the National Water Supply and Drainage Board devalued the capacity of CBOs to undertake O&M of completed WSS. There is strong evidence that supporting agencies are not giving assistance to the CBOs during D&M and the CBOs with committed staff exist many years as if in construction stage. Technical, financial and managerial activities of water supply schemes are directly related to sustainable D&M. Therefore it is needed to assess the CBO's capability in managing water supply schemes with respect to technical, financial, institutional, social and environmental sustainability during he operational stage, in order to ensure sustainability of the project. Even though some indicators for measuring the overall performance of rural water supply schemes have been developed, a structured methodology is needed to assess the capability of the CBO's in the above aspects. to assess capabilities of the CBOs for sustainable rural water management a study was undertaken in the Monaragala and Badulla districts selecting eleven water supply schemes managed by the CBOs. The research focused on the CBOs capability in five main areas for sustainability of water supply schemes; 1) Technical sustainability, 2) Financial sustainability, 3) institutional sustainability, 4) Social sustainability, 5) Environmental sustainability. Data were collected from eleven water supply schemes maintained by CBOs by interviewing consumers \ and officers on a questionnaire and a structured format respectively. These values were compared with the acceptable values of the indicators in order to assess the technical, financial,institutional, social, environmental and overall sustainability of each scheme.sub indicators of each area were analyzed to assess the capability of the CBOs. Qualitative and quantitative analysis of the structured interviews provided insight into the views of the community and officers of the CBOs. The results obtained this way were tested against the situational observations of each scheme in order to check the validity of the specially developed methodology. The more salient findings were; According to the results of the developed methodology only one scheme was found a failure which was Wila Oya Vilage WSS and the sustainability of Athimale WSS cannot be assured and need urgent attention for the improvement of performance indicators related to financial sustainability and all the other schemes are on the sustainable track with respect to the management of the CBOs. It is identified in the assessment using the developed methodology, most of the CBOs are capable of managing WSS assuring technical, financial, institutional, Social and Environmental sustainability; Inappropriate filtration facilities implemented due to financial constraints, water quality variation and reduction in extraction capacity of deep production bore hole wells being impediments for the capability of the CBOs for sustainable rural water management. The methodology developed in this study to assess sustainability of WSS covers almost all the important areas of managing WSS by the CBOs. The indicators to be evaluated in the methodology should be assessed from the views of both officers of the CBO and the sample of consumers. The results of the assessment using this methodology in the study recommend that the CBOs are capable of managing WSSs with an assurance of sustainability. The methodology can be implemented for other WSSs managed by the CBOs to assess the capability of the CBO in managing WSS and also can be adopted for future projects implementation policies. In the study it was identified that it was necessary to establish a support service mechanism for the CBOs during the O&M.
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Computer Modeling industrial emissions
Illangasinghe, NK; De Alwis, A; Gunasekera, MY
Air being an important part of the environment is always required to be in a satisfactory condition for the proper functioning of the entire eco system. Air quality is being affected adversely due to several reasons such as increasing number of industries without having proper emission handling systems and increasing number of vehicles. Many industrial stacks observed in Sri Lanka today are not constructed according to the proper stack design requirements. The quality of stack emissions or the dispersion of pollutants from a specific stack is seldom analyzed mainly because of the high costs involved. Even analysis is done on the dispersion from a specific stack it is difficult to get good representative results because the meteorological conditions vary frequently. In this study a stack emission dispersion model named AUSPLUME which is developed by the Victorian Environmental Protection Authority and recommended by several organizations for 'regulatory purpose was studied. This work mainly looks at the following: 1. The applicability of the model in the Environmental Impact Assessment (EIA) 11. Model emissions from the stacks at Holcim Lanka cement plant at Puttlam with the use of AUSPLUME before and after installing a new dust handling system The purpose of the EIA is to predict and identify potentially significant environmental impacts of development projects and to suggest mitigation measures to minimize the negative impacts and maximize the positive impacts. Main stages in the EIA process are, 1. Screening ( find out whether an EIA is required) 11. Scoping ( identification of main issues) lll. Collection and analysis of information IV. Public involvement v. Communicating the findings In the process of analyzing the information AUSPLUME can be used. With available information about the stack, emissions and the meteorological data of the area of concern, the model can predict the concentrations of selected constituents at ground level or elevated levels in the down wind direction. The areas of worst impact, limit of the buffer zone, effects to the high rise buildings or effects to the selected areas of important like high bio diversity, archeology, and residences can be identified using the results obtained with AUSPLUME. For the analysis of the stack emission dispersion from the Holcim Lanka cement plant at Puttlam, the meteorological data obtained at the Palavi weather monitoring station of the Meteorological Department were used. There are two similar stacks at the factory which are placed close by and therefore both of them were considered as a single point source with an equivalent diameter. The area was considered to be a flat terrain since there were no disturbances in the vicinity. The analysis results on the dispersion of particulate matter, NOz and SOz emissions from the stack were compared with ambient air quantity standards for Sri Lanka and European Guideline values which were established by considering human health hazards other than carcinogenity. Certain values were found to be above the limits and the rest below the limit. Anyway in this analysis raw emission data were used and in the real life the raw emissions are mixed with clean air before released to the atmosphere. Therefore due to the dilution the real values can be expected to be much lower. Predicted values were compared with field measurement values available and with predicted values from SCREEN3 model. The results obtained can be used for decision making purposes with a good understanding about their inaccuracy.
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Evaluation of the performance against the design parameters of the unit processes of the Kondawaduwana water treatment plant
Vinothan, K; Manatunge JMA
Eastern Coastal Towns of AmparaDistrict(ECTAD) Water Supply Project has been planned to implement in two phases. The first phase of the project, having capacity of 17,500 t:/day was commissioned in June 2001 The second phase was commissioned in June 2007 and it has a capacity of 72,000m:/day. In phase I the treatment process in the plant consists of Coagulation and Flocculation,Dissolved Air Flotation (DAF), Rapid Sand Filtration, Post Chlorination,ph Correction and Sludge Treatment. The treatment process for the phase II is the same, except for pre- chlorination and addition of powdered activated carbon (PAC)at the flash mixer. The scheme serves the Ampara Township, too. The first recorded water quality issue of coloured water, bad smell and taste were raised by consumers in the year 2004. From 2004, sporadic complaints from consumers were received and steps were taken to flush the pipelines periodically. The regular water quality tests had not revealed the cause for the problem and a series of studies have been carried out and various reports have been submitted. However, the water quality issues still persist. Therefore, four numbers of trials were carried out for collecting the samples to identify the reason for the colour problem with following conditions at the various location of the treatment processes such as the rapid mixing, before DAF,after DAF(floated water), filtered and treated water. > With pre chlori nation and with PAC, > With pre chlori nation and without PAC, > With out pre chllorination and with PAC > With out chlorination without PAC Water samples were collected at various location of the treatment processes like, rapid mixing, before DAF,after DAF(floated water), filtered and treated water. The water samples were tested at NWSDBAmpara,University of Moratuwa and NWSDB central laboratory for parameters such as total iron, dissolved iron, total manganese, dissolved manganese, total organic carbon and chemical oxygen demand. VI
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An Integrated management plan to sustain the restoration of Lunawa lake
Gunawardena, GDSD; Manatunge, JMA
Lunawa Lake, located in the western coastal belt south of Colombo (Sri Lanka) is a small lagoon of 20 ha. with a catchment area of 6.15 km2 Industrial effluent discharged through the storm water drainage system connected to the lake and urbanization had converted the Lunawa Lake into one of the most polluted lakes in Sri Lanka. Encroachment of drainage canals by the inhabitants and sand bar formation at the mouth of the lagoon had caused serious flood problems in the catchment during rainy season. Lunawa Environment Improvement and Community Development Project which is being implemented with JICA fundings helps to convert the polluted Lunawa Lake from an eyesore to an environmentally attractive lake and alleviates flood damage through an improved storm water drainage system. Apart from the engineering works, series of community upgrading activities have also been carried out to uplift the quality of life of the low-income inhabitants of the catchment. The maintenance of the improved lake system is of prime importance for sustainability of the project. The water quality monitoring reveals the signs of gradual transformation of the polluted lake into a more acceptable water body and this is more so evident by the emerging aquatic life and flocking of birds in the lake. This research intends to provide overall insights on Canal and lake water pollution sources in terms of point and non point including identification of stake holders involvement in the Lunawa Lake basin area those who may change the quality of basin environment towards the direction of positive or negative sides as a result of their direct or indirect interventions. The ultimate intention of this research is to fInd out an Action Plan to form a well-defined integrated type stake holders' initiated "Lake Basin Management Plan to Sustain the Restored Lunawa Lake Basin" iii