close

Вход

Забыли?

вход по аккаунту

?

Removing Iron and Manganese from a Front Range Ground Water

код для вставкиСкачать
Removing Iron and Manganese
from a Front Range Ground Water
A Case Study of the
Woodmen Water Treatment Facility (WWTF)
Steve Grooters,
Rick Johnson,
Rick Stevens,
Carl Houck,
Carollo Engineers
Colorado Springs Utilities
Colorado Springs Utilities
Carollo Engineers
Woodmen Water Treatment
Facility
•
•
•
•
Colorado Springs Water Utility
Two separate pressure filter plants
Total of 8 wells
Plant #1 (old plant)
– Two-150 gpm dual media pressure filters
– Wells 1-4
– Rated 300 gpm (0.43 MGD)
WWTF- Plant #1
H2S
150 gpm
150 gpm
Wells 1-4
Cl2
Aeration
Tank
To Storage Tank
Plant #1
Woodmen Water Treatment
Facility
• Plant #2 (new plant)
– Four-250 gpm dual media pressure filters
– Wells 4-8
– Rated 1000 gpm (1.44 MGD)
WWTF- Plant #2
250 gpm
250 gpm
250 gpm
In-line
Aeration
Post Cl2
Wells 4-8
To Finished Water Storage Tank
250 gpm
Plant #2
WWTF Problem Statement
• In 2001 consumers within the WWTF
supply area complained of poor water
quality
– turbidity
– particulates
• Preliminary evaluation showed high levels
of both Fe and Mn in the finished water
Filter #1 Influent
WWTF Problem Statement
• Current EPA regulations do not set MCLs
for Fe and Mn.
• Secondary standards 300 and 50 ug/L for Fe
and Mn, respectively.
–
–
–
–
–
Skin or tooth discoloration
Taste
Odor and color
Staining
Turbidity
WWTF Objective
• Remedy cause of consumer complaints
• Produce the highest water quality possible
Assessment of Current
Conditions
•
•
•
•
•
•
Supply wells
Pre-aeration
Post-aeration
Post-filtration
Backwash
Media
Assessment of Current Conditions
S u p p ly W e lls W a te r Q u a lity D a ta
• Supply
wells
W o o d m e n W a ter T re a tm e n t F a c ility E va lu a tio n
T a b le 5 .1
C o lo ra d o S p rin g s U tilitie s
S a m p le
D e s c rip tio n
W a te r Q u a lity P a ra m e te r (пЃ­ g /L )
F e to t
F e d is
M n to t
M n d is
T u rb id ity
N /A
N /A
N /A
N /A
N /A
W ell # 2 (3/2 0 /0 1)
4230
1980
171
170
6 .2 6
W ell # 3 (5/2 3 /0 1)
3940
<10
9 3 .1
9 0 .3
3 7 .6
W ell # 4 (5/2 3 /0 1)
1280
<10
8 1 .3
6 9 .3
5 .2 8
W ell # 5 (5/2 3 /0 1)
1410
<10
6 6 .5
6 8 .1
1 0 .8
W ell # 6 (5/2 3 /0 1)
470
16
3 6 .0
3 5 .5
1 1 .1
W ell # 7 (3/2 0 /0 1)
3820
1470
79
84
4 .9 3
W ell # 1
Assessment of Current Conditions
T a b le 5 .2
In itial Iro n a n d M a n g a n e s e T e s t R e s u lts
W o o d m e n W a ter T re a tm e n t F a c ility E va lu a tio n
C o lo ra d o S p rin g s U tilitie s
• Pre-aeration, Post-aeration, and Post-filtration
S a m p le
D e s c rip tio n
W a te r Q u a lity P a ra m e te r (пЃ­ g /L )
1
F e to t
F e d is
M n to t
M n d is
T u rb id ity
P re -a e ratio n
2600
250
130
130
6 .3 4
P o st-a era tio n
2000
<10
81
<10
7 .9 0
39
<10
11
<10
0 .2 9
43
<10
225
218
1 .0 4
P re -a e ratio n
540
<10
48
46
3 .3 7
P o st-a era tio n
460
<10
52
50
3 .0 7
29
<10
17
15
0 .2 3
P la n t # 1 (2/1 3/0 1 )
F in ish e d
P la n t # 2 (1/2 3/0 1 )
F in ish e d
P la n t # 2 (2/1 3/0 1 )
F in ish e d
1
V a lu e s in b o ld in d ic a te fa ilu re to c o m p ly w ith th e U S E P A S e c o n d a ry D rin k in g W a te r R e g u la tio n s .
Assessment of Current Conditions
T a b le 5 .2
In itial Iro n a n d M a n g a n e s e T e s t R e s u lts
W o o d m e n W a ter T re a tm e n t F a c ility E va lu a tio n
C o lo ra d o S p rin g s U tilitie s
• Pre-aeration, Post-aeration, and Post-filtration
S a m p le
D e s c rip tio n
W a te r Q u a lity P a ra m e te r (пЃ­ g /L )
1
F e to t
F e d is
M n to t
M n d is
T u rb id ity
P re -a e ratio n
2600
250
130
130
6 .3 4
P o st-a era tio n
2000
<10
81
<10
7 .9 0
39
<10
11
<10
0 .2 9
43
<10
225
218
1 .0 4
P re -a e ratio n
540
<10
48
46
3 .3 7
P o st-a era tio n
460
<10
52
50
3 .0 7
29
<10
17
15
0 .2 3
P la n t # 1 (2/1 3/0 1 )
F in ish e d
P la n t # 2 (1/2 3/0 1 )
F in ish e d
P la n t # 2 (2/1 3/0 1 )
F in ish e d
1
V a lu e s in b o ld in d ic a te fa ilu re to c o m p ly w ith th e U S E P A S e c o n d a ry D rin k in g W a te r R e g u la tio n s .
Assessment of Current Conditions
Backwash and Filter Media Inspection
• Fe particles and red-coated
media in top 2-3 inches
• Generally good condition
• Poor media expansion
Current Conditions Summary
• Generally good water quality, but
confirmation of high levels of Fe and Mn
• Plant #1-Effective removal of Fe and Mn
– Total manual operation
– Production capacity less than system demand
• Plant #2-Mixed results
– Mn more problematic than Fe
– Further Sampling
Current Conditions Summary
• Filter media condition is OK, but needs
“cleaning”
• Filter Backwash
– Operate within recommended flows to ensure media
expansion
More testing for Plant #2
• Testing to simulate typical daily filter run of
6-hours
–
–
–
–
Backwash
Overnight Shutdown
Next Day Filter Operation
Sample at Various Times
Mn Results
120
110
Manganese Concentration ( пЃ­ g/L)
100
90
80
Total Mn
Dissolved Mn
NOTE: Method detection limit is 10 ug/L.
Secondary Standard for Mn is 50 ug/L
70
60
50
40
30
20
10
0
Pre-Start
0
0.5
Time (minutes)
3
30
45
Iron Results
300
T o ta l F e
D is s o lve d F e
250
Iro n C o n c e n tra tio n (пЃ­ g /L )
N O T E : M e th o d d e te ctio n lim it is 1 0 u g /L
E P A S e co n d a ry S ta n d a rd fo r F e is 3 0 0 u g /L
200
150
100
50
0
P re -S ta rt
0
0 .5
3
T im e (m in u te s )
30
45
Summary of Detailed Testing
• Confirmation of problematic Mn (>100 ug/L)
• D.O. did not fall below 2.0 mg/L during
overnight shut down
– Could not be re-release of Mn
– Must be from source water or particle break
through
• Since Fe removal adequate, we targeted Mn
removal
Treatment Alternatives
• Pre-Cl2
– Addition at the wellhead
– Immediately prior to filters
• Aerated intermediate tank
• Backwash System Enhancement
• Filter Media Replacement
– Dual media
– Greensand
Treatment Alternatives
• Ion Exchange
• Sequestration
• Filter Media Conditioning with Potassium
Permanganate
Recommended Treatment Alternative
• Evaluation of alternatives based on
– Cost
– Ease of implementation
– Effectiveness for removal of relatively high
levels of both Fe and Mn
– Past proven performance
– Operational equipment already available on site
Recommended Treatment Alternative
• Filter Media “Cleaning”
– Extended backwashing
– Elevated levels of Cl2
• Move Cl2 Point Upstream of Filters
• Chemical Conditioning of Filter Media
Before Cleaning
After Cleaning
Filter Performance Following
Recommended Changes
• Filter Backwash
• Operation for 24 hours
• Sample Collection
T a b le 5 .6
1
2
3
Filter Performance Following
Recommended Changes
IC P E x p e rim e n tal R e s u lts S h o w in g th e E ffe ctive n e s s o f O x id e-C o a te d
M e d ia fo r Iro n a n d M a n g a n e s e R em o va l.
W o o d m e n W a ter T re a tm e n t F a c ility E va lu a tio n
C o lo ra d o S p rin g s U tilitie s
T o ta l Iro n
2
(пЃ­ g /L )
T o ta l M a n g a n e s e
2
(пЃ­ g /L )
2 1 5 0 (1 1 1 3)
7 6 (5)
7
1 0 2 (1 1 8)
BDL
F ilte r # 2 E fflu e n t
7
3 6 (7)
BDL
F ilte r # 3 E fflu e n t
5
4 2 (8)
BDL
F ilte r # 4 E fflu e n t
3
3 6 (4)
BDL
P la n t # 2 L o c a tio n
N u m b e r o f S am p le s
F ilte r Influ e n t
3
F ilte r # 1 E fflu e n t
1
D o e s n o t in c lu d e th e in itia l s a m p le c o lle c te d . T h is s a m p le w a s a n o m a lo u s .
N u m b e rs in p a re n th e s e s in d ic a te s ta n d a rd d e v ia tio n .
B e lo w D e te c tio n L im it (B D L ), w h ic h is 1 0 пЃ­ g /L .
3
Month-long Testing
• Operation similar to 24-hour testing but for
30 straight days.
• Confirmed 24hr testing results.
M a n g a n e s e R e m o va l P e rfo rm a n c e F o llo w in g R e c o m m e n d e d P ro c e s s C h a n g e s
250
M an g an ese (u g /L )
200
150
100
50
0
1 0 /0 6 /0 1
1 0 /1 1 /0 1
1 0 /1 6 /0 1
1 0 /2 1 /0 1
1 0 /2 6 /0 1
D a te
R aw M n
F in is h e d W a te r
1 0 /3 1 /0 1
1 1 /0 5 /0 1
1 1 /1 0 /0 1
Iro n R e m o va l P e rfo rm a n c e F o llo w in g R e c o m m e n d e d P ro c e s s C h a n g e s
5000
4500
4000
3500
Iro n (u g /L )
3000
2500
2000
1500
1000
500
0
1 0 /0 6 /0 1
1 0 /1 1 /0 1
1 0 /1 6 /0 1
1 0 /2 1 /0 1
1 0 /2 6 /0 1
D a te
R aw
F in is h e d W a te r
1 0 /3 1 /0 1
1 1 /0 5 /0 1
1 1 /1 0 /0 1
Conclusions
• WWTF water quality concerns were due to
Fe and Mn release to the distribution system
• Mn was more problematic than Fe
• Pre-chlorination and filter media chemical
conditioning were effective
– Fe from 1088 down to 75 ug/L
– Mn from 76 ug/L down to BDL
Conclusions
• Variation in filter performance suggest that
one or more of the filters may require
underdrain replacement
• Filter-to-waste will be required to provide a
consistent treated water quality
Questions
Документ
Категория
Презентации
Просмотров
3
Размер файла
4 476 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа