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Published byCecilia Smith Modified over 9 years ago
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Using Your Own Resources, or CSI City Sewer Investigation
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Crime / Inflow and Infiltration Scene Crime Scene –Examine the evidence to determine what happened to the victim. –Process Secure the scene Search the scene Collect evidence Interview people Follow the evidence –Determine the Facts. I/I Scene –Examine the evidence to determine what is happening underground. –Process Interview operators Collect data Collect evidence Follow the evidence –Determine the Facts.
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CSI, the Operators Way Use Investigative Skills –Locate the evidence –Determine the message in the evidence –Follow the evidence Common Sense
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What do you already know? Maps Plant Flow Data Pump Station Run Times Overflow records Violations, Backups Employee Knowledge Where does the data lead you? Where is the “Most likely suspect?”
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What’s the Fact in the Figures Long columns of Data can be misleading. –Summarize it –Graph it –Trend it –Analyze it Statistical Analysis helps us find the “facts in the figures.” Date Peak Flow Avg Flow 1/001.50.725 2/001.71.02 3/002.220.89 4/003.11.12 5/001.40.503 6/001.70.396 7/001.110.346 8/001.130.387 9/001.170.36 10/001.20.341 11/001.20.478 12/001.50.554 1/0120.767 2/013.11.29 3/011.50.829 4/011.50.676 5/011.20.429 6/011.20.322 7/012.90.448 8/011.140.586 9/010.980.343 10/011.120.346 11/010.90.336 12/012.70.897
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Wow! Moment
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What do you see? Influent Color –Muddy –Clear Influent Debris –Fish, crawdads –Grass clippings –Leaves –Magnolia Pods What’s the Message?
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What does the Evidence Say?
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Follow the Evidence Use your maps Go look, Ground Inspection! Walk the lines, take your camera, notebook –Dry Weather Missing manhole lids Manhole damage Illegal dumping Missing manholes –Wet Weather
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What does the Evidence Say?
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CSI in the Dark Night time flows, ~ 2:00 am –Small systems should have little flow –Residential mains should have little flow –Test the flow: ORP,TDS Ammonia TSS BOD
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Wet Weather Flooded or overwashed manholes Leaking manholes Check flow –Visual –Depth of flow –Percentage of pipe
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What does the Evidence Say?
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Wet Weather Follow up checks after the rain –As soon as it stops raining –An hour or so later –The next day What did the evidence tell you? What is the next step? Perhaps now you need a TV camera.
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Extended Dry Weather Best time for smoke testing. Find the big leaks –Catch basins –Clean-outs –Gutters –Open taps –Dry traps
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So what do you do?
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Cold Weather Check suspect stream crossings in bitter cold weather. Check the sewage temperature in above and below manholes. If the temperature drops the cold stream water is leaking in!
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Cold Weather & Warm Sewage Warm catch basins Warm manholes
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Assistance of Others Meter readers, public works & safety workers, public. –Missing cleanout plugs –Missing houses with open service laterals –Surface water drains –Gutter connections
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Leak-Leak where is the Leak? Where did the evidence “lead” you? Did you find it? Could you fix it? Do you need help? –Camera crew –Engineer –Contractor –Other
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Using Your Own Resources Use your existing data. Use your operators knowledge. Conduct Ground Inspections –All seasons present inspection opportunities. Find problems: –Fix them (inflow) or –Use the knowledge for a larger project.
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Inflow and Infiltration Benefits of sewer line rehabilitation –Less Risk: –of regulatory action, –of legal action, –of spreading disease. –Lower Costs: –for pumping, treatment, disposal, –from clean-up, –from fines. –Enhanced Reputation: –proper operation and maintenance, –professional management of the system –quality customer service.
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Module #4 Plans for reducing I/I in your community. –What can you do? One Month Three Months Six Months Twelve Months
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Summary Objective One: –Listed your work and the work of others
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Summary Objective Two: –Identify what cities are currently doing in reducing I/I –Metro Nashville’s Program –Small City Example
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Summary Objective Three: Ten Points –Identify Goals –Select Target Area –Quantify Problem –Locate Defects –Select Pipe Segments –Estimate Cost-Benefit –Design & Install –Verify Performance –Follow-up Flow Monitoring – Calculate O & M Savings Using your Resources. –If Ed Norton can…
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Summary Plans for reducing I/I in your Community. –Action Plan Short Term Long Term
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Summary Closing thoughts or comments? Any I/I Epiphanies? Moments of realization? New insights?
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