Transcript Treatability Index

Treatability Index Provides
Operational Guidelines
By Pam Benskin & Kevin Linder
City of Aurora, CO
09/17/02
City of Aurora
OVERVIEW
• Where we started
•The Challenge
• Our Answer - The Treatability Index
• How it Works
• How it can work for you
09/17/02
City of Aurora
Where We Started
•Lab performing lots of analysis on
source water quality
•Data not being translated into an
operational tool
• We needed to make the
connection
09/17/02
City of Aurora
Utilities confront a common
problem:
• Laboratories perform a multitude of
analyses
• Data is complex and awkward
• Data generated rarely reaches the operators
until after the measured water parameters
have changed.
09/17/02
City of Aurora
The Challenge
• Utilities face the challenge of getting
relevant laboratory data on source water
quality to the operators in a timely, concise,
and understandable format.
09/17/02
City of Aurora
Existing Indices weren’t the
ticket
• Existing technical descriptions of source
water quality, do not relate quality level to
treatability.
• Trophic State Index (TSI), is a tool to
indicate the overall condition of lakes or
reservoirs. This index does not take into
account many parameters, (such as
problematic algae species), that may affect
treatment.
09/17/02
City of Aurora
What We Did
• The city of Aurora, CO, water utility staff
investigated the issue of timely transfer of
relevant data from the laboratory to the
operators.
09/17/02
City of Aurora
Our Goal
• Improve and increase usage of valuable,
underused data generated in the
laboratory to help optimize plant
performance.
09/17/02
City of Aurora
We explored several options
• Giving operators copies of algal enumeration
– This data provided limited insight because algal
biomass is not reflected in an algae count, and if
an operator isn’t familiar with algae
identification, the data could be confusing.
• Giving operators chlorophyll-a values
-This data reflects total algal biomass, but does not
address the presence of individual problematic
species of algae.
09/17/02
City of Aurora
Back to the drawing board
• Finding that none of the indices we
investigated served our purpose, operations
and laboratory personnel collaborated to
develop a tool that considered many source
water parameters that affect treatment.
09/17/02
City of Aurora
Our Objective
• Combine the effects of all these variables
•Present the information in a format that is:
•Comprehensive
•Easy to understand
•Timely
•Concise
09/17/02
City of Aurora
Our Answer
• The tool we developed is called the
Treatability Index.
09/17/02
City of Aurora
How It Works
• Define parameters with lab and operational
staff
• Parameters need to be measured in a timely
manner
• Determine relative weight of parameters
• Develop effective format
• Collect data
• Generate report
• Distribute to operators
09/17/02
City of Aurora
Define Parameters Important
To Your Treatment Process
•Our important parameters are:
• Algae
• Chlorophyll-a
• Ortho-Phosphate
• UV-254
• Mn & Fe
09/17/02
City of Aurora
Weigh Parameters
• Weigh the parameters according to
relevance to treatment
• Produce two numbers relating treatability:
– one number addresses taste and odor (T&O),
– the other reflects filter clogging (FC)
tendencies.
09/17/02
City of Aurora
Ranges and
weights
Parameters of
concern
Filter Clogging Ratings
Parameter
Chlorophyll-a
Qualifier
0 - 2.9 ppm
3.0 - 5.9 ppm
6.0 - 8.9 ppm
9.0 and above
Historical F.C. problems no problems
with similar algae present moderate problems
many problems
Secchi Depth
greater than 10 feet
less than 10 feet
Multiple unit or very large no
F.C. algae present?
yes
F.C. algal mass
Score
0
1
2
3
0
1
2
0
1
0
1
less than 500 per ml
0
500 - 900 per ml
1
1000 - 2999 per ml
2
3000 and above/ml
3
Possible Total Rating of 10
Scoring
09/17/02
City of Aurora
Taste & Odor Ratings
Parameter
Chlorophyll-a
Qualifier
0 - 2.9 ppm
3.0 - 5.9 ppm
6.0 - 8.9 ppm
9.0 and above
Historical T&O problems no problems
with similar algae present moderate problems
many problems
Secchi Depth
greater than 10 feet
less than 10 feet
Multiple unit or very large no
T&O algae present?
yes
T&O algal mass
09/17/02
Score
0
1
2
3
0
1
2
0
1
0
1
less than 500per ml
0
500 - 900 per ml
1
1000 - 2999 per ml
2
3000 and above/ml
3
Possible Total Rating of 10
City of Aurora
Ensure Parameters Can Be Measured
in a Timely Manner
•Find methods that allow for quick determination
of parameter levels
•Example- We use HACH methods, (rather than
waiting for atomic absorption results), to determine
the level of Fe and Mn in our source water.
•Set a goal to summarize the data within 48
hours of sampling
09/17/02
City of Aurora
Develop Format
• Easy to read
• Pictures and diagrams
• Comments section
• Try to keep it to one page
09/17/02
City of Aurora
Index value
How It Looks
Aurora Reservoir
Taste & Odor and Filter Clogging Index Ratings:
T&O
1
2
3
4
5
6
7
8
best
9 10
Diagram:(Approx. gate depths are measured from w ater surface)
Tower
Gate 2
18'
Gate 3
25'
1
2
3
4
5
6
7
best
8
9 10
w orst
Water Quality Data:
Parameter Gate 5
Units Change From Last Report
Algae
209
#/ml
decrease
Chl-a
1.8
ppb
increase
o-Phosphorus
50
ug/l
increase
Iron
<0.01 mg/l
no change
Manganese
0.05
mg/l
increase
UV - 254
0.046 abs/cm
increase
D.O.
8.0
mg/l
decrease
Comments:
Conditions at Aurora Res continue to look good.
Secchi (photic) zone =16'
Gate 1
12'
F.C.
w orst
Reservoir is in very early
stage of stratification
Manganese, Chl-a, and phos levels have increased slightly.
Gate 4
35'
(Gate 5)
Q.C. Recommended Gate
Please note: Starting
Samplesthis
were
week,
collected
we arefrom
reporting
Aurora raw
water tap at Wemlinger
Quincy Reservoir
Taste & Odor and Filter Clogging Index Ratings:
Gate data
T&O
1
2
3
4
5
6
7
8
best
9 10
F.C.
w orst
1
best
2
3
4
5
6
7
8
9 10
w orst
Diagram:(Approx. gate depths are measured from w ater surface.) Water Quality Data:
Tower
Secchi (photic) zone = 16'
Gate 1
15'
Gate 2
22'
Parameter
Value Units Change From Last Report
Algae
418
#/ml
decrease
Chl-a
1.51
ppb
decrease
o-Phosphorus <10
ug/l
decrease
Iron
<0.01 mg/l
decrease
Manganese
0.05
mg/l
decrease
UV - 254
0.040 abs/cm
no change
Parameters
of Concern
Comments:
Gate 3
29'
Q.C. Recommended Gate
Algae levels have declined slightly since last week.
Manganese levels have returned to normal. Conditions look
good overall.
Reservoir is destratified
Gate 4
38'
09/17/02
Bottom Sediment of Reservoir
City of Aurora
comments
Operations staff use this
information to:
• Decide which source to use
• Change withdrawal gates
• Prepare treatment for potential T&O
problems.
09/17/02
City of Aurora
Ideal Scenarios for Treatability Index:
•Wildfire burn area in watershed
09/17/02
City of Aurora
Ideal Scenarios for Treatability Index:
Drought
09/17/02
City of Aurora
How it Works - Burn in Watershed Scenario
TI Ratings
Parameter
Turbidity
Score
0
1
2
3
UV-254
.01 - .05
.051- .10
Greater than 0.10
0
1
2
Phosphorous
less than 10 ppb
11- 50 ppb
greater than 50
0
1
2
Manganese
09/17/02
Qualifier
1-5 ntu
5.1-10 ntu
10.1-25.0
25.1 and up
0-0.10
0
0.11- .40
1
.41- .70
2
greater than 0.70
3
Possible Total Rating of 10
City of Aurora
Results
• We immediately saw results
• Quantitative data to operators to make solid
source decisions
• Improved and increased communication
between lab and operations
• Forces timely review of data so important
changes do not go undetected
• Learning tool
09/17/02
City of Aurora
TI is flexible
• The real beauty of the TI is the flexibility it
allows any user.
• Individual utilities can change and modify
the weighting and parameters as required
for their system.
09/17/02
City of Aurora
Keys to success
• Synergize
•Identify the parameters that are most
problematic
• Weigh parameters according to their impact on
treatment
•Measure parameters in a timely manner
• Re-evaluate parameters regularly for relevance
09/17/02
City of Aurora
CONCLUSION
• Lots of data not being utilized for optimization
• We faced the challenge of getting this data to
operations in a manner that is beneficial
• Treatability Index - Qualitative as well as
Quantitative
• How to make it work for you
09/17/02
City of Aurora