09/17/02city of aurora treatability index provides operational guidelines by pam benskin & kevin...

09/17/02 City of Aurora

Treatability Index Provides Operational Guidelines

By Pam Benskin & Kevin Linder

City of Aurora, CO


OVERVIEW

• Where we started

•The Challenge

• Our Answer - The Treatability Index

• How it Works

• How it can work for you


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


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.


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.


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.


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.


Our Goal

• Improve and increase usage of valuable, underused data generated in the laboratory to help optimize plant performance.


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.


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.


Our Objective

• Combine the effects of all these variables

•Present the information in a format that is:

•Easy to understand •Timely

•Concise

•Comprehensive


Our Answer

• The tool we developed is called the Treatability Index.


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


Define Parameters Important To Your Treatment Process

• Algae• Chlorophyll-a• Ortho-Phosphate• UV-254• Mn & Fe

•Our important parameters are:


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.


Parameter Qualifier ScoreChlorophyll-a 0 - 2.9 ppm 0

3.0 - 5.9 ppm 16.0 - 8.9 ppm 29.0 and above 3

Historical F.C. problems no problems 0with similar algae present moderate problems 1

many problems 2

Secchi Depth greater than 10 feet 0less than 10 feet 1

Multiple unit or very large no 0F.C. algae present? yes 1

F.C. algal mass less than 500 per ml 0500 - 900 per ml 11000 - 2999 per ml 23000 and above/ml 3Possible Total Rating of 10

Filter Clogging Ratings

Parameters of concern

Ranges and weights

Scoring


Parameter Qualifier ScoreChlorophyll-a 0 - 2.9 ppm 0

3.0 - 5.9 ppm 16.0 - 8.9 ppm 29.0 and above 3

Historical T&O problems no problems 0with similar algae present moderate problems 1

many problems 2

Secchi Depth greater than 10 feet 0less than 10 feet 1

Multiple unit or very large no 0T&O algae present? yes 1

T&O algal mass less than 500per ml 0500 - 900 per ml 11000 - 2999 per ml 23000 and above/ml 3Possible Total Rating of 10

Taste & Odor Ratings


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


Develop Format

• Easy to read

• Pictures and diagrams

• Comments section

• Try to keep it to one page


Aurora Reservoir

Taste & Odor and Filter Clogging Index Ratings:

T&O 1 2 3 4 5 6 7 8 9 10 F.C. 1 2 3 4 5 6 7 8 9 10best w orst best w orst

Diagram:(Approx. gate depths are measured from w ater surface) Water Quality Data:

Tower Parameter Gate 5 Units Change From Last ReportAlgae 209 #/ml decreaseChl-a 1.8 ppb increase

Gate 1 o-Phosphorus 50 ug/l increase12' Iron <0.01 mg/l no change

Manganese 0.05 mg/l increaseGate 2 UV - 254 0.046 abs/cm increase

18' D.O. Comments:

Gate 3 Reservoir is in very early Conditions at Aurora Res continue to look good. 25' stage of stratification

Manganese, Chl-a, and phos levels have increased slightly.Gate 4

35' (Gate 5) Please note: Starting this week, we are reporting Samples were collected from Aurora raw Q.C. Recommended Gate water tap at Wemlinger

Quincy Reservoir

Taste & Odor and Filter Clogging Index Ratings:

T&O 1 2 3 4 5 6 7 8 9 10 F.C. 1 2 3 4 5 6 7 8 9 10best w orst best w orst

Diagram:(Approx. gate depths are measured from w ater surface.) Water Quality Data:

Tower Parameter Value Units Change From Last ReportAlgae 418 #/ml decreaseChl-a 1.51 ppb decrease

Gate 1 o-Phosphorus <10 ug/l decrease15' Iron <0.01 mg/l decrease

Manganese 0.05 mg/l decreaseGate 2 UV - 254 0.040 abs/cm no change

22'Comments:

Gate 3 Q.C. Recommended Gate Algae levels have declined slightly since last week.

29' Manganese levels have returned to normal. Conditions look

good overall.

Reservoir is destratifiedGate 4

38' Bottom Sediment of Reservoir

mg/l decrease8.0

Secchi (photic) zone =16'

Secchi (photic) zone = 16'

How It Looks

Gate data

Parameters of Concern

comments

Index value


Operations staff use this information to:

• Decide which source to use

• Change withdrawal gates

• Prepare treatment for potential T&O problems.


Ideal Scenarios for Treatability Index:

•Wildfire burn area in watershed


Ideal Scenarios for Treatability Index:

Drought


Parameter Qualifier ScoreTurbidity 1-5 ntu 0

5.1-10 ntu 110.1-25.0 225.1 and up 3

UV-254 .01 - .05 0.051- .10 1Greater than 0.10 2

Phosphorous less than 10 ppb 011- 50 ppb 1greater than 50 2

Manganese 0-0.10 00.11- .40 1.41- .70 2greater than 0.70 3Possible Total Rating of 10

TI Ratings

How it Works - Burn in Watershed Scenario


Results • We immediately saw results

• Quantitative data to operators to make solid source decisions• Improved and increased communication between lab and operations

• Learning tool

• Forces timely review of data so important changes do not go undetected


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.


Keys to success

•Synergize

•Identify the parameters that are most problematic • Weigh parameters according to their impact on treatment

• Re-evaluate parameters regularly for relevance

•Measure parameters in a timely manner


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

09/17/02city of aurora treatability index provides operational guidelines by pam benskin & kevin...

Documents

city of aurora utilities

city of aurora overview

connection slide

source water parameters

source water quality

parameters important

important parameters

measured water parameters