| Author | Supot Lohwacharin |
| Call Number | AIT Thesis no.1086 |
| Subject(s) | Filters and filtration
|
| Note | A thesis submitted in partial fulfillment of the requirement for the degree of Master of Engineering of the Asian Institute of Technology, Bangkok, Thailand. |
| Publisher | Asian Institute of Technology |
| Abstract | The research was conducted at pilot plant scale to study and compare different configurations of the dual-media filter and the deep sand filter. Different parameters which affected the filter performance were studied. These included filter influent quality, filter depth, effective size of the filter media, and filtration rate. These two types of filters
were backwashed by water alone after each run. The pilot plant consisted of chemical feeders, flocculation tank with mechanical stirrer, sedimentation of tube settler type, and four identical filter columns. The experiments were performed with two filtration rates (7.5 and 10 m3/m2-hr) in each phase of studies. Turbidity, coliform, and alkalinity removal
were determined. Also head loss produced, backwash water used and filter
effluent were measured. The test results were investigated and compared between these two types of filters and between different filter combinations.
It was found that the deep sand filter was more efficient in turbidity removal for particular range of effective size of sand grains since the removal efficiency was a function of media effective size. However~
these two types of filters yielded satisfactory results with removal efficiencies higher than 90 percent. No distinction between these two filters
in terms of coliform removal and alkalinity reduction. The run length of
the dual-media filter was approximately twice the deep sand filter. The
deep sand filter needed higher amount of backwash water and produced head
loss across filter media at a higher rate. Lower filtration rate, length
ened the duration of filtration also lower the head loss-produced rate and
increased removal efficiency. During backwashing there were hydraulic gra
ding of media grain size in both types of filters, finer grains went up to
the upper layers of the filter bed. For the dual-media filter there was
mixing of filter media at the separation zon~, carefully control of the
wash water rate could reduce the mixing. Comparing different configurations of these two types of filters, the dual-media filter was better than
the deep sand filter. |
| Year | 1977 |
| Type | Thesis |
| School | Student Research Before 1979 |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Thesis (Year <=1979) |
| Chairperson(s) | Nguyen, Cong Thanh; |
| Examination Committee(s) | Ouano, E.A.R. ;Samorn Muttamara
; |
| Scholarship Donor(s) | Government of the Federal Republic of Germany ; |
| Degree | Thesis (M.Eng. ) - Asian Institute of Technology, 1977 |