 |
|
| |
Four gravity filters
are used as the last treatment stage before the treated water
is post-chlorinated and pumped to the distribution system or
to the reservoirs for storage. The sedimentation, flocculation,
and clarification stages that are completed at the front end
of the treatment plant to settle the suspended solids or turbidity
from the raw water, prepare the water for filtration. The gravity
filters remove small particles from the Clarifier effluent water
that are too light to settle in the Clarifier. Typically the
top of filter turbidity averages 1.0 ntu. The filter effluent
turbidity annual average is 0.09 ntu. The Filter backwash water
waste pipe outfall is located downstream of the raw water intakes. |
| |
 |
 |
|
| |
| Pressure Filters,
with the exception of the Rotary Drum Pressure Filter,
are semi-continuous type machines that enter a wash and
cake discharge mode at the end of the filtration cycle.
The filtration cycle may extend from 5-10 minutes on cake
filtration applications and up to 8 or even more hours
for the polishing of liquids. Since the operation is in
batches, that are usually fed from and discharged to a
continuous process, a surge tank is required upstream
the filter and batch collection of cake downstream the
filter. The collection of filtrate depends on the operating
mode of the filter which can be constant flow rate, constant
pressure or both with pressure rising and flow rate reducing
as for a centrifugal pump.
|
|
| |
 |
|
