Presentation on theme: "EVALUATING WATER QUALITY AT COMBINED SEWER OVERFLOWS BY A NOVEL APPROACH Ting Lu Ph.D. Metropolitan Sewer District of Greater Cincinnati (MSDGC) OWEA Annual."— Presentation transcript:
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
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.
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 Area2,720 acres Tunnel Solution$244 Million Sustainable Solution Estimated to reduce 1 billion gallons
Lick Run: Source Control Opportunities
Monitoring strategy Source identification
Where is it applied? Indication of in - stream water quality Criteria in NPDES permit Prediction of water recreation status Prioritization on capital improvement projects to remove CSOs and SSOs Decision- 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 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?
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
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? S rRNA gene E. coli GCUUGAGUCU CGUAGAGGGG GGUAGAAUUC A. 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 SourceCause: Non-Point Source Human feces Animal feces Mitigation: e.g. Household Sewage Treatment System (HSTS) elimination, CSO removal Mitigation: Collaboration with other agencies to 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 removal vs. 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
Questions or Comments? For more information contact: Ting Lu Metropolitan Sewer District of Greater Cincinnati 1600 Gest Street Cincinnati, OH