| Author | Casiano, Visitacion Legaspi |
| Call Number | AIT Thesis no. EV- 88-28 |
| Subject(s) | Water--Purification--Filtration
|
| Note | A thesis submitted in partial fulfillment of the requirement for the degree of Master of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | Laboratory experiments were carried out with pilot-scale experimental units of coarse-media slow sand filter and rapid sand filter.
Coarse-media slow sand filter was operated with a 0.56 m diameter and 2. 7
m high filter column, filter media size of 1 - 2 mm and media depth of
1.0 mat filtration rates of 0.5 and 0.2 m
3/m2
h . Experiments on rapid sand
filtration were carried out with two different sizes of filter column.
Tests using the 10 cm diameter and 1. 9 m high filter column were conducted
with media size of 1.0 mm and media depth of 1.0 m at filtration rates
of 7 . 5 and 5 .0 m
3/m2h. Another experimental run was carried out with 0.56
m diameter and 2.1 m filter column with filter media size of 1 - 2 mm
and media depth of 1.0 m at filtration rate of 1 . 0 m
3/m2
h. One circular
concrete fish tank with 1.16 m diameter was used for each experimental
unit.
A 1.5m x 1.0m x 1.0m existing biological filter was operated with
0.45 m filter media depth which consists of t he following sizes of crushed
stones: 15 cm depth of 2 cm diameter, 20 cm depth of 0.95 cm diameter and
20 cm depth of 0.51 cm diameter. A filtration rate of 1.92 m
3
;m
2h was
implemented. Eight concrete fish tanks were used with the existing biological filter.
Different parameters were measured in order to monitor the water
quality as well as to be able to compare the performance of the filters.
Experimental results showed that the coarse-media slow sand filter
(CMSSF) has a comparatively higher removal efficiency than the existing
biological filter (EBF). EBF has a mean removal efficiency of 20.6, 2.31,
61.7, 57.66 and 20.37% for turbidity, total phosphorus, ammonia, nitrite
and chemical oxygen demand, respectively with 6.85% nitrate production.
CMSSF at high filtration rate resulted to a removal of 55, 6.23, 81.18,
74.23 and 36.42% for turbidity, total phosphorus, ammonia, nitrite and
chemical oxygen demand, respectively with 17.98% nitrate production. On
the other hand, CMSSF was operated at lower filtration rat e which showed
a mean difference of 52 .13 4.72, 92.54, 87.65 and 31.71%, respectively
with a corresponding nitrate production of 41.68% at lower filtration
rate . It was a lso evident that the coarse-media slow sand filter at 0.20
m
3
/m2
h filtration rate has slightly higher removal efficiency compared
to its performance at 0.50 m
3/m2h filtration rate . Furthermore, dissolved
oxygen has decreased by 34.7 an 48.79% (mean values) after 57 and 33 days
of filtration run for CMSSF at high and low filtration rates , respectively. Dissolved oxygen of the filtered water from EBF has a mean increase of 9. 8% due to the constant flushing of the overflow from the
header tank which was returned back to the c l ear water tank. A similar
arrangement in CMSSF can overcome the problem of DO depletion, which is
not favorable to fish.
Rapid sand filtration carried out with a 10 cm diameter filter
3 2
column at filtration rates of 7 . 5 and 5 . 0 m /m h has only 12 and 9 hours
3 2 filtration run, respectively . Whereas, the filter operated at 1.0 m /m h
has a filtration run of 6 . 75 days. Results showed that removal efficiency
was higher at the lowest filtration rate implemented.
Percentage weight gain of individual fish for all the systems were
found to be increasing but it started to decline after 63 days in the case
of EBF. Likewise, daily weight gain and specific growth rate of individual fish used for all systems was observed to be increasing except for
EBF in which it started to decrease after 21 days of experimentation. |
| Year | 1988 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Environmental Engineering (EV) |
| Chairperson(s) | Vigneswaran, Saravanamuthu |
| Examination Committee(s) | Samorn Muttamara ;Lin, Chang Kwei ;Kriengsak Udomsinrot ;Wee, Kok Leong
|
| Scholarship Donor(s) | German Academic Exchange Scholar (DAAD)
Federal Republic of Germany ; |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 1988 |