evaluating water quality at combined sewer overflows by a novel approach ting lu ph.d. metropolitan...
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EVALUATING WATER QUALITY AT COMBINED SEWER OVERFLOWS BY A NOVEL APPROACH
Ting Lu Ph.D.
Metropolitan Sewer District of Greater Cincinnati (MSDGC)
OWEA Annual Conference
Sandusky OH
Challenge
WWIP
Asset Management
Water qualityWater quantity
Level of service
Sustainability AFFORDABILITY
Impact of Water Quality
CSO
SSO Private systems
Stormwater runoff
Urban runoff Agriculture
Take home message
Importance of integrating science and technology to solve environmental problems.
A multisource, multiagency and regional strategy is needed in order to lead to full water quality standards compliance.
Outline
Introduction CSO Removal Approach CSO Monitoring Approach Pilot Project Conclusion
210 combined sewer overflow (CSO) that discharge to 19 receiving waters.
MSD collects and treats approximately 192 MGD of wastewater by operating seven major treatment plants.
How Great is MSD’s Environmental Challenge?
MSD’s Wet Weather Strategy
Hydraulic Grade Line inside sewer
Problem Identification: Lick Run Watershed
Typical Year flow
(modeled)
1.7 Billion Gallons
Current number
customers
5,700 accounts
Land Area 2,720 acres
Tunnel Solution
$244 Million
Sustainable Solution
Estimated to reduce 1
billion gallons
Lick Run: Source Control Opportunities
In order to utilize source control,
Monitoring strategy
Source identificat
ion
E. coli
Where is it applied?
Indication of in - stream water qualityCriteria in NPDES permitPrediction of water recreation status Prioritization on capital improvement projects to remove CSOs and SSOsDecision- making to evaluate projects effectiveness to improve water quality
Escherichia coli (E. coli)
Where is it from?• human waste• animal waste
Why is it used?• indication of the disease-causing
bacteria, viruses and protozoans• grown easily• model organism
How is it used?
Culture based method to identify and enumerate microorganisms:
The assumption in the method is that each viable microorganism can produce offspring that form countable colonies in the assay.
Serially dilution
Spread onto Petri
plates
Incubation
Count colony forming
units
Culture based method: as a ‘gold standard’ in microbiological monitoring for more than a century
Water Quality vs. Bacterial activity
Dead Viable but not culturable
(VBNC)
Culturable 0
0.1
0.2
0.3
0.4
0.5
0.6
Perc
en
tag
e
Culture based method
How to quantify
this portion?
Neglecting the VBNC portion could lead to inaccurate information for human health risk
Are E. coli and Fecal coliform the right indicator for water quality and human health risk?
Is there alternative water quality indicators?
Outline
Introduction CSO Removal Approach CSO Monitoring Approach Pilot project Conclusion
Pilot project: develop novel biomarker approach to monitor stream health
Little Miami River (“National and State
Scenic River”)
An Interdisciplinary Approach to Monitor Water Quality
WHERE: Duck Creek stream WHEN: using rain gauge data to identify the time to
monitor the stream by real time monitoring the rain event
HOW: (Standard-NPDES permit analysis coupled with novel molecular approach) o Water Quantity
• System Wide Model o Water Quality
Chemical analysis Biological analysis Molecular Tools: using microbial diversity and
signature bacteria as an indicator
Sampling locations
Membrane filtration
Molecular Approach
How many species are there? ------Bacterial screening: 16S
rRNA based method What are the signature bacteria?
------Bacteroides
Identity: who is present and how many? ------16S rRNA gene
E. coli GCUUGAGUCU CGUAGAGGGG GGUAGAAUUCA. calc GCUAGAGUAU GGGAGAGGAU GGUAGAAUUC
Identification of bacteria because: • Highly conserved primer binding sites• Hypervariable regions
Why Bacteroides are the signature bacteria?
1/3 of fecal flora Anaerobe Host-specific Found to correlate more often than E.coli
to pathogens
Why do we care about this?
1. Measure the project effectiveness
2. Identify Pollution Source: Point Source or Non Point Source Pollution?
Isolate signature bacteria under each monitor site
Bacteria associated with
Cause: Point Source Cause: Non-Point Source
Human feces
Animal feces
Mitigation: e.g. Household Sewage Treatment System (HSTS) elimination, CSO removal
Mitigation: Collaboration with other agenciesto remove the source
Source Identification
3. Water Quality vs. Human Health
Human Health Risk
human feces
animals feces
Active E. coli cells
Live but not
active E. coli cells
Dead E. coli cells
Goal: minimize the human health risks as well as being affordable
Integrated watershed management:
CSO removalvs.
Sustainability
Level of service
vs. Affordability
Water quality
vs. Water
quantity
Acknowledgement
Ms. Beverly Head, MSDGC Mr. Biju Gegore, MSDGC Mr. Donald Linn, MSDGC Dr. David Wendell, University of
Cincinnati Mr. Chris Yoder, Midwest Biodiversity
Institute Dr. Francis de los Reyes III, North
Carolina University Dr. Jorge Santo Domingo, USEPA
Thank you!
Questions or Comments?
For more information contact:
Ting Lu Metropolitan Sewer District of Greater
Cincinnati1600 Gest Street
Cincinnati, OH [email protected]