2010 OAWWA Annual Conference
Maggie Rodgers, Water Quality Manager
Tyrone Butler, Morgan Plant Manager
Cleveland Water
History of Morgan
Existing Reservoir Issues
Site Constraints
Reservoir Design
Construction Challenges
Tracer Study(ies)
Calculations
1856 - Distribution of water from Lake Erie
1911 - Disinfection
1916 - Garrett Morgan uses “safety hood” to
rescue workers trapped by tunnel collapse
during intake extension
1917 - Filtration
Late 1910’s - 25 MG reservoir
20 MG cell
5 MG cell
Late 1990’s facility plan identified replacement
of the Morgan Reservoir as the #1 priority
Significant cracks
Silt
No piles
Root intrusions
Poor baffling did not allow 20 MG cell to be
removed from service while plant operating
Significant site constraints
Sludge World
Filters
Sed
Basins
El. 581
Flocs
El. 667
MORGAN WATER WORKS PLANT
SITE PLAN
Step 1: Demolish Existing 5
MG Reservoir Cell
Step 2: Construct New
Pump Station
Sludge World
Raw Water
Pump Station
Filters
Sed
Basins
El. 581
Flocs
Step 6: Future West
Reservoir
Chemical
Step 5: Demolish Existing 20
MG Reservoir
Step 4: Construct New
East Reservoir
Step 3: Demolish Existing
Pump Station
El. 667
MORGAN WATER WORKS PLANT
SITE PLAN
Building
Economic downturn – Do we really need two
separate cells?
Maximize size of “East” Reservoir
Needs to be of sufficient volume that the plant
can operate on half while the other half is down
for maintenance/cleaning
15 MG - two 7.5 MG cells
Drilled piers
Resist lateral seismic loading better than driven
Less duration, noise, and vibration
80’ deep to shale bedrock
364 piles R 18 foot spacing
Obstacles
Wooden piles from old pump station and boiler
building foundations
Concrete pads for old pumps
Ohio EPA Policy for Determining Fluoride
Compliance:
“Public water systems that perform tracer studies using
fluoride will not be in violation of ORC 6109.20 as long
as DDAGW has received prior notification of the tracer
study and the fluoride levels in the distribution system
do not exceed the SMCL of 2.0 mg/L.”
327.33'
256'
42'
36.5'
Valve
Closed
180.33'
North Cell (Out -of-service)
To FHS
Pumps
To LS
Pumps
144.67’
108.33’
15.5'
F
144.67'
108.33'
Filter
Effluent
Junction
Chamber 3
F
Clearwell
Effluent
Sampling
Point
South Cell (In Service)
L:W = 45:1
Clearwell
Influent
Sampling
Point
Step dose, reverse tracer
Ohio EPA protocol calls for F addition 10 pipe
diameters before clearwell influent for proper
dispersion
Conduit not accessible at this location
Used regular F feed point in the filter effluent
Stabilize F through the reservoir (1.1 mg/L
target)
Take production to at least 75 MGD
Lower water level in the clearwell to 10 feet
(minimum anticipated operating level)
Source water
30 minutes
Clearwell influent
15 minutes until start
30 minutes during tracer
Clearwell effluent
15 minutes until start
5 minutes during tracer
Figure Tracer
2. Tracer
Study
Results
- Graphical
Method
1st Attempt
Study
Results
– Graphical
Method
T10 9:53
1.4
1.3
Clearwell Effluent
Clearwell Influent
1.2
Avg F Feed
1.1
Raw
Avg F Raw
1
90% Retention
0.9
33.62 lbs
0.7
0.6
F Feed Stop 8:33
0.5
0.4
0.3
0.2
12.76 lbs
0.1
14.39 lbs
Time
13:30
13:15
13:00
12:45
12:30
12:15
12:00
11:45
11:30
11:15
11:00
10:45
10:30
10:15
10:00
9:45
9:30
9:15
9:00
8:45
8:30
8:15
8:00
7:45
7:30
7:15
0
7:00
F (mg/L)
0.8
Why did it take so long for the influent fluoride
to drop?
Much discussion internally and with Ohio EPA
Quantity in feed piping, after pump shut off
responsible for discrepancy
Mathematically subtracted this quantity
Ohio EPA still said no
Figure 2. Tracer Study Results - Graphical Method
1.2
1.1
Clearwell Effluent
Clearwell Influent
1
Avg F Feed
Source
0.9
Avg F Raw
90% Retention
0.8
0.6
0.4
0.3
T10=13:17
F Feed Stop 12:00
0.5
0.2
0.1
Time
15:15
15:00
14:45
14:30
14:15
14:00
13:45
13:30
13:15
13:00
12:45
12:30
12:15
12:00
11:45
11:30
11:15
11:00
10:45
10:30
10:15
0
10:00
F (mg/L)
0.7
2 hrs, 10 minutes for
influent concentration
F to equal effluent
concentration
Sampling continued
until 3 hrs to make
sure steady state was
reached
Effective Volume Factor = T10/T
T = Theoretical Detention Time = 81.3 min
T10 = Time when clearwell effluent F is lower
than the influent F by 10% of the test range
Test range = 1.083 – 0.130 = 0.953 mg/L
T10 F = 0.90 x 0.953 + 0.130 = 0.988 mg/L
Occurred at 77 minutes into the tracer
Influent conduit detention time = 5 minutes
Plug flow assumed since it is a pipe
Clearwell T10 = 72 minutes
Effective Volume Factor = T10/T = 72/81.3 = 0.89
Ohio EPA - Net advection of F must be within 10% of
change in F storage within the clearwell
Net Advection = (F out of clearwell) – (F fed to
clearwell)
Net advection = 45.679 – 10.059 = 35.620 lb
Change in storage = (F in clearwell at t=0) – (F in
clearwell at t=2:10)
Change in storage = 40.363 - 4.524 = 35.839 lb
% F accounted for = (Net Advection)/(Change in
storage) x 100
% F accounted for = 35.620/35.839 = 99.4%
Morgan plant staff
MWH
URS
HMM