Master of Science in Environmental Engineering & Management

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

Browse

Browsing Master of Science in Environmental Engineering & Management by Subject "CIVIL ENGINEERING - Dissertation"

Filter results by typing the first few letters
Now showing 1 - 5 of 5
  • Thumbnail Image
    item: Thesis-Abstract
    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
  • Thumbnail Image
    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.
  • Thumbnail Image
    item: Thesis-Abstract
    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.
  • Thumbnail Image
    item: Thesis-Abstract
    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
  • Thumbnail Image
    item: Thesis-Full-text
    Identification of a methodology for reduction of non revenue water & improvement of pipe borne water service in Colombo city
    Devaraja, SS; Ratnayake , N
    Colombo City being located in the wet zone of Sri Lanka cannot be considered a water-stressed area. However there is an ever-increasing demand for drinking water supply, due to the increase in population and the rapid development of the area. Colombo City receives 66mgd of treated water but the records could account for revenue only 30.48mgd and 8mgd as free, thus showing a gross Unaccounted For Water (1FW) percentage of 42. Colombo City also recorded one of the highest percentages of Non Revenue Water (54%) in the region mainly due to the deteriorated distribution system and associated problems. Most of the pipelines in the distribution system are encrusted and experience frequent leakages which resulted in low pressure zones. This situation created consumer dissatisfaction and development restriction in the city. In this thesis, the author discusses the benefits of NRW reduction the selection of appropriate methodology for water loss management and shows how such benefits can be achieved by applying the developed methodologies to a pilot area of the city. The Author obtained knowledge of various methods by reviewing of case studies and research papers from various countries seminars and donor agencies. An analysis of the Colombo City Water Distribution System showed that 67.6% of pipes comprised with more than 60 years old. encrusted CI pipes and the major factors contributing to NRW are leakages, illegal consumption free water supply and administration losses such as estimated bills water meter errors, human errors etc. Under the pilot scale study, initially the main causes of NRW were identified and more attention was paid to the most significant causes. After studying various strategies "part to whole method was selected as more appropriate to reduce NRW in the pilot area. Accordingly small areas or road stretches were isolated and causes that create NRW were reduced. Implementation of this exercise to cover the entire pilot area helped to reduce NRW by a considerable quantity. In addition to the above pilot scale study further studies were made via IWA water loss management concepts distribution management decentralization and integrated water loss management concepts, economical water loss management with or without smaller diameter deteriorated pipe replacement and improved hydraulics in large pipes preventive maintenance of distribution system and finally target setting for achievement of millennium development goals etc. After implementation of this exercise on water loss management, it shows that fixing of responsibility with proper directions and commitment interest with awareness of all staff members top to bottom is importanl,to ensure positive results and to provide reliable and customer satisfactory service. The aim of the research was to develop appropriate method with strategic framework for water loss management. The method adopted for water loss management is different from country to country city to city and place to place depending on factors such as the condition of infrastructur:maintenance practices resource availability and institutional frame work etc. The shor and long term strategies developed for water loss management for Colombo City could be applied Q similar cities in developing countries.