Master of Engineering in Environmental Engineering & Managementhttp://dl.lib.uom.lk/handle/123/912024-03-29T04:25:16Z2024-03-29T04:25:16ZA critical appraisal of the water supply and sewage disposal arrangements in the univesity of MoratuwaSabanesan, SShttp://dl.lib.uom.lk/handle/123/140152023-10-13T02:34:32ZA critical appraisal of the water supply and sewage disposal arrangements in the univesity of Moratuwa
Sabanesan, SS
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.
A Pilot plant study of a pebble bed flocculatorDharmabalan, Phttp://dl.lib.uom.lk/handle/123/136292023-10-13T02:34:36ZA Pilot plant study of a pebble bed flocculator
Dharmabalan, P
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
Poly aluminium chloride as an alternative to alum as a coagulant in water treatmentDharmasinghe, Shttp://dl.lib.uom.lk/handle/123/133982022-07-11T08:52:53ZPoly aluminium chloride as an alternative to alum as a coagulant in water treatment
Dharmasinghe, S
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.
Investigation of micro-climatic features (vegetation) affecting the indoor air quality in suburb cities of ColomboPremachandra, DSPRDhttp://dl.lib.uom.lk/handle/123/122802022-02-24T08:31:27ZInvestigation of micro-climatic features (vegetation) affecting the indoor air quality in suburb cities of Colombo
Premachandra, DSPRD
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.