Master of Engineering in Environmental Engineering & Management

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item: Thesis-Abstract
A critical appraisal of the water supply and sewage disposal arrangements in the univesity of Moratuwa
Sabanesan, SS; Ratnayake, N
A convenient supply of safe water and the sanitary disposal of human wastes are essential ingredients of a healthy, productive life* With this in view a critical appraisal of the water supply and sewage disposal arrangements in the University of Moratuwa was undertaken to explore suitable means of improving the system- Thereby a more satisfactozy and efficient service for the present and the future will be ensured* In this study consideration has been given to the suitability of the present sources in terns of location, quality, adequacy, storage facilities, etc* with regard to existing water supply system* In assessing the sewage disposal arrangements presently prevailing attention has beoi focused on such aspects as location of 3ewers, manholes and treatment units, etc* Further a detailed investigation into the working of the existing treatment units was also undertaken in order to assess the performance of these units in terms of 20 and SS. removal of BOD5 Investigations revealed the inadequacy and inefficiency of the present water supply system* There is evidence of faecal contamination of groundwater* Improper operation and maintenance of the sewage disposal system have resulted in its overall inefficiency* Provision of a central water tower of capacity of 120,000 gallons and centralised pump house is recommended* Further, provision of a simple water treatment unit is suggested* The need for immediate repairs to unit No: 2 and the disinfection of all sewage effluent are highly favoured* 3 The introduction of a new central sewage treatment unit incorporating as far as possible the present sewers and manholes is recommended. To obtain a satisfactory and efficient service a proper management of the water supply and sewage disposal arrangements is essential.
item: Thesis-Abstract
A Pilot plant study of a pebble bed flocculator
Dharmabalan, P; Mampitiyaarachchi., TR
111 smel!, ccuxiiry like t-.Rl LANKA whei-o the Jovernniunt is adopting vario'js ways and means to improve the standard of living of the masses it has become a prime importance to provide safe drinking water. In the past, when the cost of construction and operation and maintenance was cheap when compared to the present day p^ractices, conventional water treatment plants were con.-.tructed just as what was done for thu devoj oped countrier:. This has now been found to be unsatisfactory for use in local conditions in the way of its desxf^ns as well as on tho operation and maintenance aspects. Under these circumstances, it has become an urgent need to carryout research and development on our own to produce safe drinking "ot,i_^ ^. c. ; -.-^ sonable cost. Pebble bed f loccxXIation type of treatment process is one such type of study which have proved to be useful to modify the- existing plants in the island as welJ as for new installations in the future. The scope of this project studies is to understand the operiitlon of '^ebble bed flocculator uncier variable perameters such as the flow rate - turbidity , Pebble size etc. Inorder to assess the performance of the Pebble bed floccu lation pru'-uss c^ilots of log 2/T - t/t^were plotted and changes fc:' varying parameters were observed and studied. From the comparison of the results it could be clearly seen that' it is very promissing and could be losed for medium scaje plarits. The turbidity of raw water that could be treated by thi::. process range from 20 NTU to lOo WT
item: Thesis-Full-text
Poly aluminium chloride as an alternative to alum as a coagulant in water treatment
Dharmasinghe, S; Rathnayake, N
Water generally contains suspended and colloidal solids from land erosion, decaying vegetation, microorganisms, and color producing compounds. In addition, due to urbanization and industrial development, pollution of water bodies has become a serious concern. As surface water is the most common source of water supply, the need for treatment of water increases as the surface water bodies get polluted. Coagulation and flocculation using chemicals, followed by sedimentation or clarification, filtration and disinfection is the conventional method of removal of the above contaminants from raw water. A wide variety of chemicals are used to achieve good coagulation/flocculation in the water industry. Aluminium Sulphate (alum) is one of the most widely used coagulants in Sri Lanka. The main reasons for the usage of alum are its affordability, availability and lack of low cost alternatives. However, there are other costs and problems associated with the use of alum. Due to the high sludge handling cost, pH adjustment and slow formation of flocs, and also recent issues related to availability of alum at a reasonable cost, the need has arisen to select alternative coagulants for the coagulation process. Poly Aluminium Chloride (PACL) is used as a coagulant in a few treatment plants in Sri Lanka and neighboring countries as an alternative to alum. In this study, it was aimed to compare the performance of the two coagulants alum and PACL in turbidity and colour removal and to assess the feasibility of substituting alum with PACL. Jar tests were carried out to obtain the optimum coagulant doses required and floc size using water from the two sources supplying the Colombo North area (Kelani Ganga at Biyagama) and Colombo South area (Kalu Ganga at Kandana) when the seasonal variation in river flows caused variations in turbidity. In addition, a questionnaire survey was carried out to investigate the opinions of engineers, chemists and operators who have used both coagulants in the treatment process. The study revealed that the overall performance of PACL is better than alum with respect to floc size and the optimum dosage required is less for the former. From the opinion survey, it was evident that the majority of those who have used both coagulants recommended the use of PACL, even though some modifications to Plant are needed.
item: Thesis-Full-text
Investigation of micro-climatic features (vegetation) affecting the indoor air quality in suburb cities of Colombo
Premachandra, DSPRD; Jayasinghe, C
Considerable number of studies show a favourable impact of vegetation and an adverse impact of synthetic built environment on urban micro-climates. Despite these findings, people eradicate these favourable micro-climatic features for built purposes. In the past few decades suburbs of the Colombo, the capital city of Sri Lanka, was subjected to a rapid development mainly for residential purposes. As a result, paddy fields, marshy lands and large tree canopies have been converted to a built environment with scattered green patches. This study was aimed at determination of the impact of micro-climatic features on air quality and thermal comfort. Air quality investigations were carried out in five residential buildings which were selected based on the surrounding micro-climatic features. Indoor concentrations of CO2, NO2, PM2.5, CO, VOC, temperature, relative humidity and wind speeds were measured during the day time from 9.00 AM to 4.00 PM in each sample building. The results were checked against the air quality standards and an attempt has been made to establish a relationship with micro-climatic features. The results showed that the air quality in suburbs is still in the acceptable range except for peaking of PM2.5 concentration beyond the threshold time to time. Lower levels of temperature and CO2 concentration were observed with good micro-climatic features. Decrease of PM2.5 concentration was also detected with the increase of distance to the main road and vegetation cover. These findings will benefit the township planning in terms of preserving the air quality and thermal comfort levels in suburbs.
item: Thesis-Abstract
Improving the methodologies adopted for assessment of environmental and social impacts of mini hydro power projects
Rohana, RPDI; Manathunge, JMA
This Research is aim to look at the environmental impacts related to Mini hydro projects in Sri Lanka and to determine the available methodologies for identification of Major Environmental Impacts and the options to mitigate the impacts or avoid impacts. It is also tried to look at the monitoring process conducted by project Monitoring Committee during the implementation of mitigations and the public participation in the IEE/EIA process. In this research, twelve mini hydro projects were studies by collecting data from field studies and IEE reports by focusing Environmental Methodologies used and the Monitoring Process of the Projects. The collected data from the twelve Mini Hydro Power Projects are analyzed and discussed comparatively to standards and guidelines in Sri Lanka.. The research observed that the exact gap between predicted impact and the implemented impact is cannot be analysis. In addition, it was observed that the IEE report does not mentioned methods of impact identification. This is a weakness of submission IEE report as well as Term of Reference (TOR). TOR should be laid down the condition that the method of impact identification should be included in the IEE report. All the projects taken to research have neglected the monitoring process and which is an important part of IEE and EIA. The Environmental Monitoring process is not compressive and PP had violated mitigation as well as the conditions stipulated by the PAA. Hence, Monitoring process must be improved to implement of Predicted mitigations satisfactorily. The IEE reports of Sri Lanka are not in unique order, similar to other countries like India. Sri Lanka must have proper stand guideline to be followed by Mini hydro Project As per the studies, the Mini Hydro Projects have to face challenge such as heavy flood, blasting hazards, Landslides and soil erosion. These challenges can be overcome by proper planning and management.
item: Thesis-Abstract
Management practices of water treatment sludge in Sri Lanka and re-use potential of sludge material
Anjithan, K; Athapattu, BCL
Sludge remaining at water treatment plants is an inescapable byproduct of the water treatment process. The nature of sludge depends on suspended solids of raw water, coagulant type and chemicals that are used in the treatment process. Direct discharge of sludge into water bodies result in the risk of contamination of surface and ground water that affects water quality and aquatic biota. According to existing legislation, water treatment sludge is classified under industrial waste. Therefore, it is anticipated that the water treatment process would be legislated as a licensable activity in the near future. The National Water Supply and Drainage Board (NWSDB) which is the main potable water supplier in Sri Lanka, has paid attention to identify disposal routes, sustainable practices, and potential applications of water treatment sludge. The objective of this research was to recognize disposal practices and cost effective methods that conform to environmental regulations. To fulfill the objectives, a questionnaire survey was conducted pertaining to chemical usage, sludge production, sludge handling and disposal methods. To introduce sustainable practices, a series of experiments were conducted by adding sludge into production of burnt clay brick, replacing cement by sludge as an adhesive fine material in cement mortar and replacing sand by sludge as fine aggregate in Concrete Paving Blocks (CPB). The questionnaire survey revealed that 50% of selected treatment plants that are operated by NWSDB directly discharge the sludge into inland surface waters with no treatment or dispose to bare lands. Experimental results showed that the required compressive strength of burnt brick could be achieved by adding sludge up to 10% for load bearing walls of single storey buildings. Further, replacement of cement by sludge up to 30% in cement mortar, achieved the required flow of 105% to 115% with the water cement ratio between 0.7 and 1.1. Required compressive strength of cement mortar could be achieved with the addition of 10% sludge with the water cement ratios of 0.7, 0.9 & 1.1, 20% sludge with the water cement ratios of 0.7 & 0.9 and 30% of sludge with the water cement ratio of 0.7. The suitability of a CPB depends on its compliance to the compressive strength requirements. The results showed, the addition of 10% sludge as fine aggregate and 10% bottom ash and sludge as fine aggregate satisfies the requirement specified in the SLS standards for class 1. Hence Concrete Paving Blocks can be successfully produced using 10% of water treatment plant sludge as supplement for sand.Sludge production is an inevitable outcome of potable water treatmentand hence sustainable reuse techniques and disposal methods need to be introduced as a policy for protecting the environment.
item: Thesis-Abstract
Rainfall event analysis for drainage infrastructure design in greater Colombo watershed
(2015-10-19) Keerthirathne, W; Wijesekera, NTS
Since the magnitude and temporal distribution of rain events directly influence the streamflow in watersheds, due focus should be given when selecting the most appropriate storm patterns for the design of hydraulic structures. Design storm can be based on either observed patterns or predetermined distribution such as Alternating Block Method. Lack of recent IDF curves and the concerns that had been raised with ongoing climate variability, engineers worldwide are inclined to use pattern based design events rather than IDF based pattern because they are said to reflect the recent and site specific situations. The present study evaluated fifteen-minute rainfall records of Colombo Meteorological Station for a period of thirty years in order to identify the impact of guideline based and pattern based design storms on runoff responses. Event separation for the study was carried out by using a Minimum Inter event Time (MIT) of 6hrs. Two hundred twenty one events were extracted from continuous data and grouped into five based on event duration. Event analysis was carried out by developing dimensionless mass curves of each event and then analysing the percentile curves representing the dimensionless mass curves. Six design events for event durations 6, 12, 18, 24 and 36hrs were developed from percentile curves. Corresponding Alternating Block Method (ABM) and Uniform Intensity distributions for each duration were developed using IDF curve. Eight design hyetographs corresponding to a ten year Average Recurrence Interval (ARI) for each event duration were developed. A mathematical model for a sub catchment in Colombo watershed was developed using SCS HEC HMS model and the runoff response for each design event was evaluated. A Criticality Indicator was introduced to capture the influence of the design rainfall patterns on both critical parameters of a hydrograph, Namely the flood peak and its time of occurrence. This indicator helped to identify the effects of a flood peak from a particular design rainfall pattern reaching the basin outlet. Envelope design rainfall pattern developed after analysing the historical data produced the most critical rainfall pattern when the event duration is closer to the time of concentration of the watershed. It was observed that there is a high variation in runoff response with the variation of temporal distribution corresponding an event. Runoff response for Alternating Block Method based pattern and the pattern developed with Envelope curves were found as the most consistent when compared with other design events. Therefore, hydraulic structure designs based on limited observed data were found as associated with high uncertainty. This study also concluded that in the absence of sufficiently analysed past rainfall data, Alternating Block Method would stand out as the most suitable design hyetograph. The present work also caution the use of design patterns based on selected events since they would certainly lead to underestimation of flood peaks.
item: Thesis-Abstract
Feasibility study on waste oil disposal in cement kilns for Sri Lanka
(2014-06-06) Thiruchelvam, AT; De Alwis, AP
1. Main Objective To study the feasibility of disposing the waste oil in the existing Puttalam Cement Kilns for Sri Lanka. To achieve this objective, the current situation in terms of technologies (manufacturing, fuel firing, process control, dust emission equipment and performance, etc.) of Puttalam Cement and the financial viability was evaluated. 2. Introduction Disposing of waste oil in Cement Kilns will give three fold benefits: getting rid of waste oil, almost without any residue, complete energy recovery which contribute to the economy of a country and special disposal facilities are not needed as an existing facility is utilised High flame temperatures and the nature of the product make cement kilns attractive for the destruction of a variety of hazardous organic materials. With proper management, kilns constitute a much less costly alternative to dedicated waste incinerators. Tests by USEPA and others have demonstrated that destruction of organic compounds including, PCBs and organochlorine and organophosphorus pesticides, equals or surpasses that achieved in hazardous waste incinerators tl1at operate at l wer temperatures. Many toxic metallic compounds can also be burned in cement kilns in quantities that are small enough not to adversely affect product quality or safety, since they are bonded to the clinker and become part of the product. 3. Waste Oil It refers to lubricating oils, hydraulic, transmission & heat transfer fluids and insulants that have gone tl1rough their intended use cycle and must be either disposed of or treated and re-used. In this thesis, waste oil from automotive transport sector is only considered. Other transport (aviation and maritime) sector and spent industrial oils are not included here as waste oil since these oils are contaminated with unknown pollutants. 4. Waste Oil Generation and Properties in Sri lanka A pilot survey was carried out to estimate the waste oil generation and centrally collectable amount. According to tl1e survey results, in 1999 around 24,000 - 27,000 ton waste oil was generated by automotive transport sector in Sri Lanka. However, tl1e known collectable amount is 4,500 (about 18% of the generated amount) while the estimated amount is around 17,400 ton per year in 1999 as given in Table 23. With time, awareness, incentives, and enforcement of regulation, the estimated amount can be collected. The laboratory test results show that our waste oil property is within the literature values in terms of physical property and tl1e contaminants such as heavy metals. However, it is interesting to note tl1at tl1e ASTM distillation curve of tl1e waste oil distillate resembles kerosene oil and the quantity distilled also only 63%. This shows that the best option in World of waste oil disposal by rerefining back to lube base may not be possible in Sri Lanka and therefore, tl1e best option for our waste oil is using as alternate fuel which is well supported by tl1e high calorific test results (> 44,000 kJ/kg). However, with the limited number of tests it is difficult to come to a firm conclusion. This is only an indication. 5. Puttalam Cement Cement is manufactured by grinding an artificial rock called "clinker" very finely (to a few microns) mixing with a small amount of gypsum (approximately 4%). Clinker is produced by heating limestone (77%) and some other ingredients (23%) to around 1450°C in a kiln. At Puttalam Cement Factory, there are two identical rotary kilns. The length of a kiln is 54 m. The burner of the kilns were change recently by Rotaflam kiln burner which has an additional jacket tube for a waste oil gun. A complete actual material balance could not be done with the current on line measured and recorded data at Puttalam Cement. Therefore, some assumptions were made using the equipment specifications and international norms 1n domg the material balance. The average amount.......x·ffffff_·raw materials used for one
item: Thesis-Abstract
Recharge of the fresh water aquifer in Mannar Island
(2014-05-05) Wljegoonewardene, SJP
item: Thesis-Abstract
A Steady state water quality model for river systems
(2014-05-05) Karunaratne, G; Senarath, DCH
This work was carried out by me as the final project for the Master's Degree in Environmental Engineering Department of Civil Engineering of the University of Moratuwa. The project concerns mainly in the building up of a Predictive Water Quality Model for a river system for forecasting how a river system would react to a set of given waste effluent dis charges along the stretch of the river under consideration. Throughout my work I was aware of the limitations in the actual application of this model to the local river systems mostly due to the inadequacy in the present sampling programmes in respect of the local rivers for obtaining data. However, by carrylng out this exercise, I felt that an awareness of this problem would be created which would be of some help in improving the situation at least to a certain extent. The work concerns more with the development of the model rather than the application of it to any given river system. I shall gladly welcome any comments on shortcomings of this work so that the model could be improved further.
item: Thesis-Abstract
Study of some characteristics of domestic coastwater
(2014-05-02) Sandanam, S; Ratnayake, N
Wastewater renders a potential threat to the environment. The ' types of wastes are many and different like domestic, agricultural, - industrial, hospital, Radioactive wastes etc . Among-these, the problem due to domestic wastewater wil be encountered at al l places where human beings dwell and this causes a great hazard. The domestic, waste which is devoid of celluloid matter that is non-biodegradable, 'is amenable to bio-chemical treatment. This type of treatment activated by' • bacteria is very economical, especially in tropical countries. It depends' highly on the environmental conditions of the locality
item: Thesis-Abstract
Modified Hazen-Williams formula
Mohan, DM
A dimensionally homogeneous and accurate formula has been derived in this research for the estimation of surface resistance in pipes based on explicit friction factor relationship and Darcy-Weisbach equation. The new relationship has been de3ignated as Modified Hazen-Williams formula. The values of coefficient of roughness for commercial pipes have been estimated experimentally and a rational approach put forth to account for reduction in carrying capacity of pipes with age. Chapter 1 delineates the goals of Government of India in water supply and sanitation sectors along with concomitant investments during the International Drinking Water Supply and Sanitation Decade. The need for and scope of present research are also brought out in this chapter. Chapter 2 critically reviews pipe friction formulae in respect of their utility to-Environmental Engineers. Chapter 3 brings forth the limitations of widely used Hazen-Williams and Manning’s formulae and quantifies errors in the estimation of frictional resistance through these formulae. Chapter 4 presents a dimensionally homogeneous and accurate Modified Hazen-Williams formula, similar in form to that of Hazen-Williams, based on explicit friction factor relationship and Darcy-Weisbach equation. A nomograph for the solution of water supply and wastewater systems design and analysis problems is also presented. Chapter 5 demonstrates the applicability of Modified Hazen-Williams formula to the design and analysis of rural and urban water supply systems. Chapter 6 deals with the application of Modified Hazen-Williams formula, through the development of hydraulic elements for partful conditions, to design and analysis of wastewater collection systems. Chapter 7 presents the details of experimental estimation of CR values for commonly used commercial pipes. A comparison of C and CR values on f-R diagram is also provided. Chapter 8 reviews prevalent practices for the reduction in carrying capacity of pipes with age. The data on existing systems in some cities is analysed alongwith experimental information gathered during this research to bring out a rational approach to the reduction in carrying capacity of pipes over design period. Chapter 9 underscores salient conclusions and recommendations drawn from the present research. Appendix I presents a rationale for ascertaining dimensional homogeneity of empirical formulae. Appendix II provides the derivation for explicit equations for pipe diameter and velocity. Appendix III presents a case study on the application of Modified Hazen-Williams formula to the design of a real-life rural water supply system. Appendix IV presents the derivation of hydraulic elements for partful conditions in wastewater lines based on Modified Hazen-Williams formula. Appendix V provides derivation of Modified Shields .equation for the estimation of self cleansing velocity in wastewater lines incorporating Modified Hazen-Williams formula. Appendix VI describes the procedure adopted in this research for calibration of pitotmeters for experimental estimation of values for coefficient of roughness. The thesis concludes., with a list of references on researches and articles relevant to the present research.
item: Thesis-Abstract
Analysis of transmission phase out options in water supply projects
Perera, ULDND
A study on "Analysis of transmission phase out options in water projects" was carried out to analyze possible cost savings to meet any the financial constraints of the project and also to utilize available funds for the benefit maximization through implementation of most customer friendly projects considering the opportunity costs. In order to achieve this target, the TNC water project was selected as a case study and an independent study on duplication of pipe lines were also carried out parallel, to support the analysis. The data required to analyze the transmission system of the TNC project and also to perform the economic analysis on the duplication of pipe lines were collected from the TNC project office, MIS Nihon Sudio consultants I Cey water consultants, NWS&DB and from the University of Moratuwa. The analysis of phase out options of the transmission system of TNC project was carried out by formulating 2 options based on the designs carried out by MIS Nihon Suido consultants. As per the designs carried out by the consultants, the nodal point demands and the bulk demands could be identified separately and the 10th & 20th year demand were rearranged to identify the nodal point demands of each options proposed. Then the "Water CAD" software was used to identify the diameters of transmission lines for the proposed phase out options. The supply and laying costs of DI pipes and specials were calculated and forecasted the future cost figures through reasonable justifications due to abnormal price variations appeared. Then the costs of each transmission line for the proposed options at their implementation stages and the cost of full transmission system were calculated. The present worth of both options was compared with the full transmission cost and the additional funds required for the implementation of both options were then calculated. Based on the above additional fund requirement, the economical interest rates applicable on the decisions of the implementation of each phase out options were calculated. Addition to the above case study analysis, an independent study on pipe line duplication in two different scenarios, theoretical analysis and practical situation based on BS4772 (1988), were also performed and the economically viable diameters of pipe line duplications were identified. Based on the results obtained through both of the studies, the conclusions were made on the economical duplication of pipes in transmission phase out options of water supply projects,
item: Thesis-Abstract
Environmental aspects of drainage systems in road projects
Ravindralingam, K; Ratnayake, N
Drainage systems in Road projects should be given due consideration because it influences the environment. The purpose of this research project is to study road drainage systems, as to how these affect the environment and how environmental factors affect the road, and what type of recommendation could be considered for effective, efficient and best use of the system to use in the anticipated road projects. This study is mainly concerned with the surface drainage system of the road sector. The areas selected for this study are Hakmana Town Intersection in Matara district, 1.3 km Road section from Imbulgoda on Colombo -Kandy road and Kiribathgoda Town intersection on Colombo Kandy road. The data such as Flooding, health problems, Accidents, Condition & maintenance of road drainage systems were collected through questionnaires, levels of the road profile were taken through surveying and the maximum intensities of the rainfall were collected from the department of Meteorology. Design and statistical analyses were carried out using the data. According to analyses, it was found that maintenance work influenced the flood, health problems in these sites were caused only by mosquitoes breeding and mosquitoes breeding were occurred not only by the flooding but also by the disposal of solid waste. According to this research study, it was found that the flood was the main environmental issue of drainage systems in the road projects. This problem could be controlled by proper drainage design and construction and efficient maintenance activities of drainage systems.
item: Thesis-Abstract
Preparation of a plan for environmental management of the Heraliyawala Industrial Park in the North Western provincial council area
Fernando, WICDR; Ratnayake, N
This study was done to assess the environmental, hygienic and social condition and suggest methods of improvement of unsatisfactory aspects in the Heraliyawala Industrial Park which is one of the Industrial Estates in Kurunegala district. Assessment of the present status of aspects such as drinking water, wastewater, noise, dust, solid waste etc., was carried out in several industries within the estate. Management of the site and other infrastructure facilities, types of factories and their functions were studied with officials of the Industrial Services Bureau (lSB). Relevant legislation and other requirements concerning environment were obtained from the Provincial Environment Authority, North Western Province, at Kurunegala. A survey was carried out in selected factories after the detailed, study of the industries at the Industrial Park. Collection of test samples of water, wastewater, dust samples and measurement of noise, heat stress, oxygen level, ammonia concentration were done at the site. Some parameters of water & wastewater were tested at the site using direct reading type instrument and for other parameters samples were tested at the National Building Research Organization (NBRO). Weighing of dust samples and necessary calculations were done at the Occupational Hygiene Division of the Department of Labour. The test results and observations were compared with International and Local Standards such as WHO guideline values, standards of the Board of Investment of Sri Lanka (BOI) , Regulations of the Central Environment Authority (CEA) etc., in order to assess the environment within the estate. Social studies were limited to traveling and residential facilities of employees. During the survey, discussions were done with the management as well as employees and relevant information was collected. Drinking water supply and the maintenance of the distribution system, wastewater collection and other maintenance work, water quality in the canal at the boundary of the site into which the factory effluents are discharged were discussed and recommendations were given separately under the Management Plan. Further, remedial measures for control of Noise, Heat, Dust, Ammonia concentration etc., were also proposed under the Management Plan. Solid waste management is one of the issues identified, where waste tyre particles, polythene , garbage collection and disposal, waste burning are the problems encountered. Proposals were also made regarding hygienic matters such as protection of workers against dust, noise and ammonia gas. Personal protective equipment (ppe) were also illustrated. With respect to social aspects, it was found essential to improve the public transport system to the site for the benefit of the employees. Residential facilities should be provided to the employees who are living at a distance of 30 km . .It is very essential to monitor work which are recommended to. Control all the unsatisfactory conditions, by respective authorities.
item: Thesis-Abstract
Evaluation of public participation and methodologies adopted in environmental impact assessment process in Sri Lanka
Weerakkody, NC; Wijesekera, NTS
"Environment" and "Development" are interdependent and mutually reinforcing each other. The ultimate goal and purpose of both environment and development policies is betterment, improvement and the enhancement of the quality of life. Exploitation of natural and human resources should be planned carefully to ensure a sustainable development. In order to ensure a sustainable development, Western Countries have introduced a planning tool, i.e. Environmental Impact Assessment process to assess the impacts of any development project to its environment. Mitigatory measures also suggested in the EIA report to minimize the negative impacts. Public involvement is one of the significant and important events in the Environmental Impact Assessment Process. This process expects to ensure that the environmental concerns are incorporated into the project. In order to fulfill this requirement, it is necessary to seek public participation throughout the project development process. The ETA process has built-in openings for public participation. Therefore, it needs to investigate whether such participation has been effective or needs improvement to ensure that the development works are not slowed down. The main objective of the study is to identity the present level of public participation in IEE/EIA projects and the methodologies used for development projects. To achieve this objective, thirteen IEEs and fifteen EIAs were selected. The respective IEE/EIA reports and administrative files were analyzed. After analyzing the IEE/EIA reports and files, public participation was looked at in different aspects, i.e. the sectors participated, the stages in the EIA process, the issues raised by the public in their comments and the methodologies adopted in the EIA process. These aspects were studies under different project types, i.e. Mainly IEE/EIA, Effluent generating/Effluent non-generating and localized/spatially distributed projects. Accordingly, general public participation on TEE project is very low compared that with the EIA projects. Study reveals general public participation on IEE projects is 2% and in EIA projects 98%. The overall public response on development projects are fairly low. Data reveals the maximum overall participation on development projects is only 42%. Also, the public is highly concern on social impacts specially in EIA projects, Effluent non-generating projects and spatially distributed projects.
item: Thesis-Abstract
Development of a technical manual for pumping istallations in the water industry with emphasis on water supply systems
De Silva, LSPJ; Ratnayake, N
Pumping stations must be highly reliable. energy saving and economical. while at the same time their capital costs, operational and maintenance costs should be minimized. A technical manual for the multi disciplinary set of expertise who design, construct, operate and maintain pumping installations will help to achieve better performances. The objective of the manual is to impart knowledge on main plant and equipment, infrastructure and associated practical behaviour in pumping installations to those who design, construct, operate and maintain pumping installations. This manual covers planning, design, operation and maintenance aspects, main and ancillary equipment, and also practical behaviours. Chapter 1 has been devoted to discuss the important aspects of pumps needed for designers, operation and maintenance staff. Starting with the classification of pumps, the basics have been covered. Use of system head curves in different situations and affinity laws have been dealt with giving examples. NPSH has been dealt with critically. Pumps in series and parallel, effects of cavitation and recirculation causes of noise and vibration have also been covered. The importance of taking precautions to ensure proper design of sumps have been highlighted in Chapter 2. The adverse effects on pumps and its facilities that can result due to poor shapes and dimensions of sumps have been discussed. Basic dimensions. shapes. undesirable suction layouts and their improvements are provided to avoid mistakes. Chapter 3 summarises the guarantees and the acceptance tests for centrifugal pumps. This chapter will be useful mainly to those who are engaged in pump and other equipment testing and the approval of their performances. Chapter 4 is about pressure surges in pipe lines. The causes for pressure surges and different surge prevention measures have been discussed so that the most appropriate method for a given situation can be selected. A sample calculation has been included. Chapter 5 is on electrical equipment. Power supply and power factor, drivers, different starting methods, motor enclosures. motor protection, ratings and selection of motors, effect of temperature on life of motors, protection of electrical equipment etc. have been dealt with. Chapter 6 on pipe work valves and fittings will assist the Design Engineer to design and size the pipes and valves in pumping stations properly and the erection engineer ..to install them. Recommended flow velocities and a comprehensive list of head losses in valves and fittings have been included. Chapter 7 is about basic planning and design 'aspects of pumping, stations. Importance of minimisation of capital, operation and maintenance costs have been highlighted. Investigation procedures. Selection of pump types, number of pumps, pump speed, layout of equipment, electrical facilities. Positive and negative suction conditions have been discussed. Planning of electrical facilities and energy conservation have also been covered. Chapter 8 is about the civil engineering aspects of pumping stations. Importance of looking into civil as well as mechanical and electrical aspects have been highlighted. Chapter 9 deals on seven practical applications related to pumping stations. Vertical vs Horizontal pumps. performance of submersible pumps and methods of reducing energy costs. decision on whether to repair or replace the pumps. wear caused by sand in-intakes. choice of pump to suit system head. gland packing or mechan-ical seal are the areas covered. Chapter 10 covers the important points and how to size the ancillary equipment such as lime and alum pumps. blowers, chlorinators and overhead cranes. Ditferent types of now meters too have been discussed. Finally Chapter 11 summaries the aspects of operation and maintenance activities in a pumping station.
item: Thesis-Abstract
Studies on textile waste water treatment
Premasiri, KW; Rathnayake, N
In Sri Lanka the waste water discharged from most Textile Processing Factories to water bodies are found to be poorly treated or untreated. This may be due to reasons such as involvement of high capital and operation costs for treatment facilities, difficulties encountered in maintenance of mechanical and electrical equipments and the unawareness about the necessity of treatment of waste water. The non availability of literature regarding textile waste treatment may also be a reason for it. As such studies on treatment methods of textile waste water are very important. In this report the author explains available literature on characteristics of textile waste water and its treatment methods and measurements related to waste water. Laboratory studies were carried out for the removal of colour and C.O.D. from textile waste water. Regarding the removal of colour several experimental methods were carried out based on the principle of coagulation and flocculation. For colour adsorption, powdered activated carbon and "commercially available polyelectrolytes were used. The Conventional jar test was employed in these experiments. Conventional activated sludge process was used in' the removal of C.O.D. This was carried out by varying the influent C.O.D; values. A basic Laboratory scale activated sludge plant model complete with aeration tank, settling tank and other essential components was used for this purpose. By adding powdered activated carbon to the waste water and carrying out flocculation and coagulation with alum, 100% removal of colour was achieved at certain dosages. Similarly removal of colour can be achieved by using polyelectrolytes also. Powdered activated carbon requirement varies from 100 mg. to 1000 mg. for 1 liter of waste water.More than 80% of available C.O.D. could be removed by adopting conventional activated sludge treatment method with proper controls.
item: Thesis-Abstract
Optimal regional planning in solid waste management
Katugampola, PI; Bandara, S; Vlach, M
This study investigates the application of linear programming and mixed integer programming techniques for the optimal allocation of waste stream and facility scheduling of a regional solid waste management system, over affixed planning period. Waste disposal options include land filling and waste diversion through recycling and composting. The regional system consist of multiple cities, landfills, material recovery facilities, compost facilities and transfer stations. Mathematical models used for the optimization are formulated to minimize the present worth cost of providing waste management services, subject to mass balance and capacity limitation constraints of the facilities. A hypothetical case study is presented to illustrate the use of the models formulated.
item: Thesis-Abstract
Composting of municipal solid waste
Weerasinghe, TJ; Ratnayake, N
The Colombo Municipal Council dispose of the solid waste by dumping on open marshy land. The land suitable for dumping waste, was fast exhausting and as a mean of lengthening the life time of the available dumping areas, the CMC decided to do a pilot study to determine the feasibility of converting solid waste into compost. Prior to the pi lot study, two other studies, (1) a survey on the production of compost in Sri Lanka, on commercial basis (2) a literature survey, were done.// Three organizations that produce compost on commercial basis were surveyed under the first study. They are, 1. Hiat Aggro Ltd. 2. Department of Agrarian Services 3. Water Resources Board Hiat Agg"ro Ltd. use coir waste, leaves and poul trydroppings to produce compost. Most of the compost produced by this company, are exported and the rest is sold in the local market.// The compost produced by a cultivation officer for the Department of agrarian Services, using garden waste and cow dung, in pits, are sold by the Dept. of Agrarian Services in 1 kg. packets.// The compost produced by the Water Resources Board ,using grass cuttings and cow dung is used in it's plant nursery and the excess is sold in 2 kg. packets, at the sales outlet of the Board.// The second study was on the research work that has been carried out, world over, on composting of municipal waste. The literature survey revealed that there are several fundamental factors that are applicable to a composting operation, such as, carbon to nitrogen ratio, temperature, moisture content ,shredding, aeration, etc.// The last study was the pilot project, where the behavior of six municipal waste piles were studied under different conditions of carbon to nitrogen ratios and aeration. Urea was used to lower the C-N ratio and aeration was provided by using aeration frames.// The non compostable material could be sufficiently removed by hand picking and sieving. The carbon to nitrogen ratio of the waste, in the piles, studied under the pilot project, varied from 23to 88, and within this range, waste decomposed at a fairly satisfactory rate, stabilizing within an almost qual time period. The rate of decomposition retards when the moisture content is over 55% and the optimum range is 40% to 50%, which can be maintained by wetting the piles once in 2-3 days. The solid waste of the Colombo Municipal Council, can be converted into compost in about 40 days, maintaining a temperature above 60 C, within the pile, for over 7 days. • when the particle size is less than 2 inches ( 5 cm ). • when piled on an aeration frame and turned once in 3-4 days. • when moisture content is maintained between 40 and 50%, by wetting once in 2-3 days.// The compost, produced, is more suitable to be used as a soil stabilizer, as it is, and if it is to be used as an organic fertilizer, it should be supplemented with phosphorus. Compost, from municipal waste, can be produced as an odorless, dry powder..

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