Slow filtration for surface water treatment in the tropics | |
| Author | Uddin, Md. Nizam |
| Call Number | AIT Thesis no. 882 |
| Subject(s) | Water supply Filters and filtration |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering of the Asian Institute of Technology, Bangkok, Thailand. |
| Publisher | Asian Institute of Technology |
| Abstract | In poor and populated tropical Asian Countries, the need of supply of drinking water to an acceptable level of safety needs proper and quick consideration. To do that an economic but a reliable method of water treatment system needs to be investigated. The present study pertains to treatment of available surface sources of water to meet the increasing demand of millions of community dwellers in Asia. Three types of filter combinations were studied as follows: ( 1) Series, coconut-fiber-burnt rick husk filter (2) Series, coconut fiber - sand filter and (3) Dual media filter, using coconut fiber and burnt rick husk as filter media. The combination of filter media were selected from the point of view of economy, local availability and their practical applicability. The study was carried out at three level s of turbidity in raw water. Filtration rates ranging from 0.10 m3/m2-hr to 0.6 m3/m2-hr were tried to find out an optimal filtration rate for each type of filter. The findings of the investigation led to a filtration rate of 0.20 m3/m2-hr as optimal one for burnt rice husk filter of depth 80 cm at all the levels of turbidities. The optimal rate for slow sand filter of depth 80 cm was equal to or less than 0.2 m\'3/m2-hr, to give about one mot h of filter run and that for dual media filter of coconut fiber; depth of 80 cm and burnt rick husk depth of 60 cm was found to be 0.200.25 m\'3/m2-hr to produce water with acceptable level of turbidity value around 5 JTU for water sources of all the levels under investigation. Though removal efficiencies of coliform ranged from 75% in dual media filter to 98.9% in sand filter operating at low rates of 0.20 m3/m2hr, but chlorination is recommended to be practiced before drinking. However, required chlorine doses were found as minimal as 1.0 mg/l to 1.2 mg/l. Finally, the potential use of locally available burnt rice husk which is considered as a solid waste, in place of expensive and scarce fine sand leads to the hope that, the increasing water demand in the tropical countries could be met in a near future; using the country\'s human resources . |
| Year | 1975 |
| Type | Thesis |
| School | Student Research Before 1980 |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Thesis (Year <=1979) |
| Chairperson(s) | Nguyen Cong Thanh |
| Examination Committee(s) | Pescod, M.B. |
| Scholarship Donor(s) | Canadian Government and the World Health Organization |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 1975 |