filter loading and backwash rates well yields and chlorine dosage in waterworks operation math for...
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Filter Loading and Backwash Rates Well Yields and Chlorine Dosage in
Waterworks Operation
Filter Loading and Backwash Rates Well Yields and Chlorine Dosage in
Waterworks Operation
Math for Water TechnologyMTH 082
Lecture Chapter 4 & 8- Applied Math for Water Plant Operators
Loading Rate Calculations (pg 62-66); Well yield (163-177)Mathematics Chapter 19-20 &23- Basic science Concepts and
Applications (pg 183-190; 197-203)
Math for Water TechnologyMTH 082
Lecture Chapter 4 & 8- Applied Math for Water Plant Operators
Loading Rate Calculations (pg 62-66); Well yield (163-177)Mathematics Chapter 19-20 &23- Basic science Concepts and
Applications (pg 183-190; 197-203)
ObjectivesObjectives
1. Filter overviews
2. Filter loading and backwash rates
3. Well yield
4. Chlorine dosage for a new well
1. Filter overviews
2. Filter loading and backwash rates
3. Well yield
4. Chlorine dosage for a new well
Reading assignment: Chapter 4 & 8- Applied Math for Water Plant Operators Loading Rate Calculations (pg 62-66); Well yield (163-177)Mathematics Chapter 19-20 &23- Basic science Concepts and Applications (pg 183-190; 197-203)
Reading assignment: Chapter 4 & 8- Applied Math for Water Plant Operators Loading Rate Calculations (pg 62-66); Well yield (163-177)Mathematics Chapter 19-20 &23- Basic science Concepts and Applications (pg 183-190; 197-203)
Conventional Treatment Conventional Treatment • Conventional Treatment – common treatment steps used to remove turbidity from the initial source water.
• Conventional Treatment – common treatment steps used to remove turbidity from the initial source water.
2. Flocculation2. Flocculation 3. Sedimentation3. Sedimentation 4. Filtration4. Filtration1. Coagulation1. Coagulation
PretreatmentPretreatment
Raw WaterRaw Water
Rapid or flash Mixing
Alum, polymer
Rapid or flash Mixing
Alum, polymer
SlowSlowFastFast
SludgeSludgeWashwaterWashwater
5. Clear Well Disinfection5. Clear Well Disinfection
Distri
bution
Distri
bution
ClearwellBackwash
pumps
ClearwellBackwash
pumps
ChlorinationOzone
UV
ChlorinationOzone
UV
High Rate FilterHigh Rate FilterDual or Multi Media Filter
-4 times faster then rapid sand -granular activated carbon-anthracite coal-garnet sand and gravel-backwash ready (70 hr longevity)-excellent water quality
Dual or Multi Media Filter-4 times faster then rapid sand -granular activated carbon-anthracite coal-garnet sand and gravel-backwash ready (70 hr longevity)-excellent water quality
High Rate Filters High Rate Filters
Anthracite CoalAnthracite Coal
Fine sandFine sand
Garnet sandGarnet sand
High Rate FilterHigh Rate Filter
Dualmedia FilterDualmedia Filter
Anthracite CoalAnthracite Coal
Fine sandFine sand
Garnet sandGarnet sand
Monomedia Coarse sand
Monomedia Coarse sand
Monomedia FilterMonomedia Filter
Dual-media and multimedia filters
Dual-media and multimedia filters
Req
uire
an e
xt...
Can
oper
ate
at...
Can
not r
educe
...
Do n
ot req
uire...
5% 5%0%
91%1. Require an extremely deep bed
2. Can operate at three or four times the rate of sand filters
3. Cannot reduce turbidity
4. Do not require backwashing
1. Require an extremely deep bed
2. Can operate at three or four times the rate of sand filters
3. Cannot reduce turbidity
4. Do not require backwashing
When mixed media filters composed of garnet, sand, and
crushed anthracite coal are used, which of the following
describes their placement in the filter bed?
When mixed media filters composed of garnet, sand, and
crushed anthracite coal are used, which of the following
describes their placement in the filter bed?
Anth
raci
te c
oa...
Gar
net o
n top,..
.
San
d on
top, a
...
Anth
raci
te c
oa...
8%
92%
0%0%
1. Anthracite coal on top, garnet in the middle, and sand on the bottom
2. Garnet on top, anthracite coal in the middle, and sand on the bottom
3. Sand on top, anthracite coal in the middle, and garnet on the bottom
4. Anthracite coal on top, sand in the middle, and garnet on the bottom
1. Anthracite coal on top, garnet in the middle, and sand on the bottom
2. Garnet on top, anthracite coal in the middle, and sand on the bottom
3. Sand on top, anthracite coal in the middle, and garnet on the bottom
4. Anthracite coal on top, sand in the middle, and garnet on the bottom
In a filter using gravel, anthracite, and sand, the
anthracite should be?
In a filter using gravel, anthracite, and sand, the
anthracite should be?
The
top la
yer .
..
Ben
eath
the
gr...
Bet
wee
n the
sa...
Mix
ed w
ith th
e...
88%
0%
12%
0%
1. The top layer of media
2. Beneath the gravel
3. Between the sand and the gravel
4. Mixed with the sand
1. The top layer of media
2. Beneath the gravel
3. Between the sand and the gravel
4. Mixed with the sand
Pilot Filters Pilot Filters
Anthracite CoalAnthracite Coal
Fine sandFine sand
Garnet sandGarnet sand
The main action of a mixed media filter is:
The main action of a mixed media filter is:
Stra
inin
g
Dis
infe
ctin
g
Coag
ulatin
g
None
of the
ab.
..
87%
9%4%0%
1. Straining
2. Disinfecting
3. Coagulating
4. None of the above
1. Straining
2. Disinfecting
3. Coagulating
4. None of the above
BackwashBackwash• Suspended particles entrapped by filter media. • Accumulation occurs:
– head loss within the filter to reach excessively high levels (6 to 8 feet of hydraulic head).
- Particles pass through the filter, water turbidities reach unacceptable levels
- Rule Backwash at 0.1 NTU- SWTR Allows 0.3 NTU.
• Suspended particles entrapped by filter media. • Accumulation occurs:
– head loss within the filter to reach excessively high levels (6 to 8 feet of hydraulic head).
- Particles pass through the filter, water turbidities reach unacceptable levels
- Rule Backwash at 0.1 NTU- SWTR Allows 0.3 NTU.
Head LossHead Loss• Clean filter =0 psi= one foot of head loss on
a new filter
• As filter clogs more negative pressure
• Pressure builds in a linear fashion
-2.5 to -4.0 psi = 6 to 10 ft of head loss
• More clogged greater the head loss
• Remember 1 ft of water column = 0.433 psi
• 2.31 ft of water for 1 psi change
• Clean filter =0 psi= one foot of head loss on a new filter
• As filter clogs more negative pressure
• Pressure builds in a linear fashion
-2.5 to -4.0 psi = 6 to 10 ft of head loss
• More clogged greater the head loss
• Remember 1 ft of water column = 0.433 psi
• 2.31 ft of water for 1 psi change
Filter BackwashFilter Backwash
• Some plants use head loss, some use time
• Some plants use operator knowledge and turbidity
• Each operator has their own scheme!!
• Parents and diapers--
• Some plants use head loss, some use time
• Some plants use operator knowledge and turbidity
• Each operator has their own scheme!!
• Parents and diapers--
The most critical criterion for determining when a mixed media filter should be backwashed is:
The most critical criterion for determining when a mixed media filter should be backwashed is:
Filt
er e
ffluen
...
Flo
w ra
te
Hea
d loss
Vis
ual in
spec
t...
52%
4%
39%
4%
1. Filter effluent quality
2. Flow rate
3. Head loss
4. Visual inspection of the filter surface
1. Filter effluent quality
2. Flow rate
3. Head loss
4. Visual inspection of the filter surface
Filtration Rate CalculationFiltration Rate CalculationUnit Filter Run= (Total gal filtered gal)
Filter Area (sq ft)
Filtration Rate= (flow gpm)
Area (sq ft)
Units will be gpm
ft2!
Backwash Rate = (flow gpm)
Area (sq ft)
Units will be gpm
ft2!
Downward
Upward
The total water filtered during a filter run (between backwashes) is 2,950,000 gal. If the filter is 15 ft by 20 ft, What is the
unit filter run volume (UFRV)?
The total water filtered during a filter run (between backwashes) is 2,950,000 gal. If the filter is 15 ft by 20 ft, What is the
unit filter run volume (UFRV)?
9.8
33 g
/ft2
101
.7 g
/ft2
983
3 g/ft
2
0.9
833
g/ft2
25%
0%
75%
0%
L= 15 ft, W=20 ft; Rate 2,950,000 galA=L X WUFVR= (Total gallons filtered g) Area (sq ft)
A= 20 ft X 15 ft = 300 ft2
UFVR= (2,950,000 gal) 300 (sq ft) UFVR = 9833 g/ft2
L= 15 ft, W=20 ft; Rate 2,950,000 galA=L X WUFVR= (Total gallons filtered g) Area (sq ft)
A= 20 ft X 15 ft = 300 ft2
UFVR= (2,950,000 gal) 300 (sq ft) UFVR = 9833 g/ft2
Given
Formula
Solve:
Given
Formula
Solve:
1. 9.833 g/ft2
2. 101.7 g/ft2
3. 9833 g/ft2
4. 0.9833 g/ft2
1. 9.833 g/ft2
2. 101.7 g/ft2
3. 9833 g/ft2
4. 0.9833 g/ft2
The total water filtered during a filter run (between backwashes) is 4.8 MG. If the
filter is 20 ft by 30 ft, What is the unit filter run volume (UFRV)?
The total water filtered during a filter run (between backwashes) is 4.8 MG. If the
filter is 20 ft by 30 ft, What is the unit filter run volume (UFRV)?
960
00 g
/ft2
800
0 g
/ft2
800
g/ft
2
0.0
08 g
/ft2
0% 0%0%
100%
L= 20 ft, W=30 ft; Rate 4.8 MGA=L X WUFVR= (Total gallons filtered g) Area (sq ft)
A= 20 ft X 30 ft = 600 ft2
UFVR= (4,800,000 gal) 600 (sq ft) UFVR = 8000 g/ft2
L= 20 ft, W=30 ft; Rate 4.8 MGA=L X WUFVR= (Total gallons filtered g) Area (sq ft)
A= 20 ft X 30 ft = 600 ft2
UFVR= (4,800,000 gal) 600 (sq ft) UFVR = 8000 g/ft2
Given
Formula
Solve:
Given
Formula
Solve:
1. 96000 g/ft2
2. 8000 g/ft2
3. 800 g/ft2
4. 0.008 g/ft2
1. 96000 g/ft2
2. 8000 g/ft2
3. 800 g/ft2
4. 0.008 g/ft2
A filter 20 ft by 25 ft receives a flow of 1940 gpm. What is the filtration rate in
gpm/ft2?
A filter 20 ft by 25 ft receives a flow of 1940 gpm. What is the filtration rate in
gpm/ft2?
3.9
gpd/ft
3
3.9
gpm
/ft2
0.2
5 gpm
/ft2
0.2
5 gpd/ft
3
11%
0%6%
83%
L= 20 ft, W=25 ft; Rate 1940 gpmA=L X WFiltration Rate= (flow gpm) Area (sq ft)
A= 20 ft X 25 ft = 500 ft2
Filtration Rate= (1940 gpm) 500 (sq ft) Filtration Rate = 3.9 gpm/ft2
L= 20 ft, W=25 ft; Rate 1940 gpmA=L X WFiltration Rate= (flow gpm) Area (sq ft)
A= 20 ft X 25 ft = 500 ft2
Filtration Rate= (1940 gpm) 500 (sq ft) Filtration Rate = 3.9 gpm/ft2
1. 3.9 gpd/ft3
2. 3.9 gpm/ft2
3. 0.25 gpm/ft2
4. 0.25 gpd/ft3
1. 3.9 gpd/ft3
2. 3.9 gpm/ft2
3. 0.25 gpm/ft2
4. 0.25 gpd/ft3
Given
Formula
Solve:
Given
Formula
Solve:
A filter 20 ft by 35 ft receives a flow of 1530 gpm. What is the filtration rate in
gpm/ft2?
A filter 20 ft by 35 ft receives a flow of 1530 gpm. What is the filtration rate in
gpm/ft2?
2.2
gpm
/ft2
2.2
gpm
/ft3
0.4
5 gpm
/ft2
0.4
5 gpd/ft
3
89%
0%0%11%
L= 20 ft, W=35 ft; Rate 1530 gpmA=L X WFiltration Rate= (flow gpm) Area (sq ft)
A= 20 ft X 35 ft = 700 ft2
Filtration Rate= (1530 gpm) 700 (sq ft) Filtration Rate = 2.2 gpm/ft2
L= 20 ft, W=35 ft; Rate 1530 gpmA=L X WFiltration Rate= (flow gpm) Area (sq ft)
A= 20 ft X 35 ft = 700 ft2
Filtration Rate= (1530 gpm) 700 (sq ft) Filtration Rate = 2.2 gpm/ft2
1. 2.2 gpm/ft2
2. 2.2 gpm/ft3
3. 0.45 gpm/ft2
4. 0.45 gpd/ft3
1. 2.2 gpm/ft2
2. 2.2 gpm/ft3
3. 0.45 gpm/ft2
4. 0.45 gpd/ft3
Given
Formula
Solve:
Given
Formula
Solve:
A filter 25 ft by 30 ft receives a flow of 3.3 MGD. What is the filtration rate in
gpm/ft2?
A filter 25 ft by 30 ft receives a flow of 3.3 MGD. What is the filtration rate in
gpm/ft2?
3.1
gpm
/ft3
0.3
2 gpm
/ft2
3.1
gpm
/ft2
0.3
2 gpd
/ft3
0% 0%
100%
0%
L= 25 ft, W=30 ft;Rate 3.3 MG 1,000,000 gal 1 Day D 1MG 1440 minA=L X WFiltration Rate= (flow gpm) Area (sq ft)
A= 25 ft X 30 ft = 750 ft2
Filtration Rate= (2292 gpm) 750 (sq ft) Filtration Rate = 3.1 gpm/ft2
L= 25 ft, W=30 ft;Rate 3.3 MG 1,000,000 gal 1 Day D 1MG 1440 minA=L X WFiltration Rate= (flow gpm) Area (sq ft)
A= 25 ft X 30 ft = 750 ft2
Filtration Rate= (2292 gpm) 750 (sq ft) Filtration Rate = 3.1 gpm/ft2
1. 3.1 gpm/ft3
2. 0.32 gpm/ft2
3. 3.1 gpm/ft2
4. 0.32 gpd/ft3
1. 3.1 gpm/ft3
2. 0.32 gpm/ft2
3. 3.1 gpm/ft2
4. 0.32 gpd/ft3
Given
Formula
Solve:
Given
Formula
Solve:
Given
Formula
Solve:
Given
Formula
Solve:
A filter 25 ft by 10 ft has a backwash rate of 3400 gpm. What is the filter backwash
rate in gpm/ft2?
A filter 25 ft by 10 ft has a backwash rate of 3400 gpm. What is the filter backwash
rate in gpm/ft2?
13.
1 gpm
/ft3
0.0
74 g
pm/ft
2
13.
6 gpm
/ft2
136
gpd/ft
3
0% 0%
100%
0%
L= 25 ft, W=10 ft; Rate 3400 gpmA=L X WBackwash Rate = (flow gpm) Area (sq ft)
A= 25 ft X 10 ft = 250 ft2
Filter Backwash Rate= (3400 gpm) 250 (sq ft) Filter Backwash Rate = 13.6 gpm/ft2
L= 25 ft, W=10 ft; Rate 3400 gpmA=L X WBackwash Rate = (flow gpm) Area (sq ft)
A= 25 ft X 10 ft = 250 ft2
Filter Backwash Rate= (3400 gpm) 250 (sq ft) Filter Backwash Rate = 13.6 gpm/ft2
1. 13.1 gpm/ft3
2. 0.074 gpm/ft2
3. 13.6 gpm/ft2
4. 136 gpd/ft3
1. 13.1 gpm/ft3
2. 0.074 gpm/ft2
3. 13.6 gpm/ft2
4. 136 gpd/ft3
Given
Formula
Solve:
Given
Formula
Solve:
A filter 20 ft by 15 ft has a backwash rate of 4.5 MGD. What is the filter backwash
rate in gpm/ft2?
A filter 20 ft by 15 ft has a backwash rate of 4.5 MGD. What is the filter backwash
rate in gpm/ft2?
10.
4 gpm
/ft3
0.0
1 gpm
/ft2
10.
4 gpm
/ft2
0.0
1 gpd
/ft3
6%0%
94%
0%
L= 20 ft, W=15 ft; ft;Rate 4.5 MG 1,000,000 gal 1 Day D 1MG 1440min A=L X WBackwash Rate = (flow gpm) Area (sq ft)
A= 20 ft X 15 ft = 300 ft2
Filter Backwash Rate= (3125 gpm) 300 (sq ft) Filter Backwash Rate = 10.4 gpm/ft2
L= 20 ft, W=15 ft; ft;Rate 4.5 MG 1,000,000 gal 1 Day D 1MG 1440min A=L X WBackwash Rate = (flow gpm) Area (sq ft)
A= 20 ft X 15 ft = 300 ft2
Filter Backwash Rate= (3125 gpm) 300 (sq ft) Filter Backwash Rate = 10.4 gpm/ft21. 10.4 gpm/ft3
2. 0.01 gpm/ft2
3. 10.4 gpm/ft2
4. 0.01 gpd/ft3
1. 10.4 gpm/ft3
2. 0.01 gpm/ft2
3. 10.4 gpm/ft2
4. 0.01 gpd/ft3
Well ProblemsWell Problems• Drawdown ft = pumping water level – static water level ft
• Well yield = Flow gallons
duration of Test, min
• Specific yield, gpm/ft = (Well yield gpm) (Drawdown ft)
• Well casing disinfection
lbs= (dose mg/L Cl2)(water in well casing MG)(8.34 lb/gal)
Chlorine lbs = chlorine lbs
% available chlorine
100
• Drawdown ft = pumping water level – static water level ft
• Well yield = Flow gallons
duration of Test, min
• Specific yield, gpm/ft = (Well yield gpm) (Drawdown ft)
• Well casing disinfection
lbs= (dose mg/L Cl2)(water in well casing MG)(8.34 lb/gal)
Chlorine lbs = chlorine lbs
% available chlorine
100
Given
Formula
Solve:
Given
Formula
Solve:
Before the pump is started the water level is measured at 140 ft. The pump is then started. If the pumping water level is determined to be 167 ft, what is the
drawdown in ft?
Before the pump is started the water level is measured at 140 ft. The pump is then started. If the pumping water level is determined to be 167 ft, what is the
drawdown in ft?
307
ft
-27
ft 2
7 ft
0 ft
0% 0%
100%
0%
Static WL= 140 ft, Pumped WL=167 ft
Drawdown ft = pumping water level – static water level ft
Drawdown = 167 ft- 140 ftDrawdown = 27 ft
Static WL= 140 ft, Pumped WL=167 ft
Drawdown ft = pumping water level – static water level ft
Drawdown = 167 ft- 140 ftDrawdown = 27 ft
1. 307 ft
2. -27 ft
3. 27 ft
4. 0 ft
1. 307 ft
2. -27 ft
3. 27 ft
4. 0 ft
Given
Formula
Solve:
Given
Formula
Solve:
During a five minute test for well yield, a total of 740 gallons are removed from the
well. What is the well yield in gpm?
During a five minute test for well yield, a total of 740 gallons are removed from the
well. What is the well yield in gpm?
67
gpm
148
gpm
370
0 gpm
0 g
pm
0% 4%0%
96%
total = 740 gal, time = 5 minutes
Well yield = Flow gallons Duration of Test, min
Well yield = 740 gallons = 148 gpm 5 min
total = 740 gal, time = 5 minutes
Well yield = Flow gallons Duration of Test, min
Well yield = 740 gallons = 148 gpm 5 min 1. 67 gpm
2. 148 gpm
3. 3700 gpm
4. 0 gpm
1. 67 gpm
2. 148 gpm
3. 3700 gpm
4. 0 gpm
Given
Formula
Solve:
Given
Formula
Solve:
How many lbs of calcium hypochlorite (65% available chlorine) is required to disinfect a well if the casing is 18 inches in diameter and 220 ft long, with water level at 100 ft from the top of the well? The desired dose is
50 mg/L?
How many lbs of calcium hypochlorite (65% available chlorine) is required to disinfect a well if the casing is 18 inches in diameter and 220 ft long, with water level at 100 ft from the top of the well? The desired dose is
50 mg/L?
2 lb
s
1 lb
s
.02
lbs
0.6
5 lb
s
24%
6%0%
71%
Cl= 65/100 D=18 in=1.5 ft Well 220-100 =120 ft220 ft - 100 ft = 120 ft water in well(0.785)(D2)(H) = ft3
(0.785)(1.5 ft)(1.5 ft) (120 ft)(7.48 gal/ft3)= 1585 gal(50 mg/L)(.001585 MG)(8.34 lb/gal) = 1.01lbs 65/100
Cl= 65/100 D=18 in=1.5 ft Well 220-100 =120 ft220 ft - 100 ft = 120 ft water in well(0.785)(D2)(H) = ft3
(0.785)(1.5 ft)(1.5 ft) (120 ft)(7.48 gal/ft3)= 1585 gal(50 mg/L)(.001585 MG)(8.34 lb/gal) = 1.01lbs 65/100
1. 2 lbs
2. 1 lbs
3. .02 lbs
4. 0.65 lbs
1. 2 lbs
2. 1 lbs
3. .02 lbs
4. 0.65 lbs
Today’s objective: Filter Loading Rates, Filter Backwash Rates, Well yield and
chlorine dosage of new wells been met?
Today’s objective: Filter Loading Rates, Filter Backwash Rates, Well yield and
chlorine dosage of new wells been met?
Stro
ngly A
gree
Agre
e
Neu
tral
Dis
agre
e
Stro
ngly D
isag
ree
0% 0% 0%0%0%
1. Strongly Agree
2. Agree
3. Neutral
4. Disagree
5. Strongly Disagree
1. Strongly Agree
2. Agree
3. Neutral
4. Disagree
5. Strongly Disagree