Jim,
To reiterate our
phone discussion earlier today, based on my knowledge of the screwpress vs
rotary press.
Neither unit does
well with solids concentrations in the 1% range. So thickening would be
required.
Assume 100,000gpd @
1% for both systems
Membrane thickener
to 3%. The filtrate can go to the effluent (67,000gallons). It
is the same as the effluent from the treatment process. All the solids
wasted are still in the sludge holding tank since the capture rate will be
100%.
Drum Thickener to
3%. The filtrate needs to be returned to the MBR since it has about 800+
lbs of waste solids (assume 90% capture rate). Therefore in order to waste
the 8340#’s of solids in the above assumption you will need to waste an
additional 10,000 gallons every day.
Next to
dewatering:
FKC screwpress:
Capture rate will be about 85% so, 33,000gallons with 8260#’s of solids
will equal 7018#’s dewatered to 15% (guess). So, again another 1240#’s of
solids go back to the MBR with the 27,400 gallons of
filtrate.
Fournier:
Capture rate will be about 93% so, 33,000gallons with 8340#’s of solids will
equal 7756#’s dewatered to 15% (guess). So, now the filtrate of
27,390gallons can go to the sludge holding tank since a membrane thickener is in
the loop there.
On to polymer
usage: There is none needed for the membrane thickener. Assume
15#/Dry ton for the drum thickener. @ 4dt/day that will be 60#/day @ $3.00/# or
$180/day (5x50x$180=$45,000/yr)
Secondary benefit
is the sludge storage tank sizing. If the desire is to have a 10 day
storage then with the drum thickener you will need a 1MG
tank.
With the membrane
thickener a .333mg tank will be adequate.
The only downside
to the membrane thickener is the blower usage, but with the storage tank size
decreasing you will only need 1/3rd the air to keep it mixed as you
would with the 1mg tank which should be comparable to the amount of air needed
for the membrane thickener.
Please call me to discuss
this further…it may not be totally clear.
Also, should I send on to
Tom Giese?
Dennis
Gleason
Treatment
Equipment Company
Office:
425-641-4306
Mobile:
425-681-7015