Transcript PP 6 - Water Treatment(Ch22

Combined Sewer Systems Vs Not
Deep Tunnel
Projects
Chicago - 109 miles - 15.6 bl/gal
Atlanta - 12.5 miles - 177 ml/gal
Milwaukee - 19.4 miles - 521 ml/gal
Atlanta
1995: The Upper Chattahoochee Riverkeeper files a federal lawsuit against Atlanta,
charging that state environmental officials are incapable of making the city stop polluting the
river.
1998: The city signs a consent decree with the federal and state environmental regulators
and the Riverkeeper, agreeing to fix its sewers and stop polluting the Chattahoochee and
South rivers.
2004: Three of four city voters approve a 1 percent sales tax to help pay for the
infrastructure improvements.
***Nov. 10, 2008: Atlanta celebrates compliance with the 1998 consent decree
• $25 million Greenway Acquisition Program, under which nearly 24 miles of
stream buffers in Atlanta and eight metro counties were bought to protect the
waterways from development;
• Separation of 33 miles of combined sewers;
• Construction of CSO Tunnels
Groundwater Pollution
Waste Water Treatment
Primary treatment
1. Physically removing solids, grease, & grit using grates and screens
2. Settling tanks remove suspended and floating solids, but little of the
dissolved materials. Alum added for clumping.
3. 30% of BOD removed
Secondary treatment
1. Aeration Tanks promote growth of bacteria that break down the
dissolved organic wastes.
2. Living filters are also used that contain bacteria growing on sand or
plastic.
3. Settling Tank or Clarification Tank
4. 90% of BOD now removed
Tertiary treatment
1. Chlorine, UV radiation, Ozone, chlorine are used to kill bacteria and
pathogens
2. Chemical processes remove phosphorous, nitrogen, heavy metals,
and chlorine.
3. Water may be rejuvenated with oxygen
Improving Water Quality
Municipal Sewage Treatment
Primary and Secondary
Sewage Treatment
Waste-Water
Treatment
What to do with removed
Waste? - digester
Municipal Sewage Treatment
Effectiveness- shows
concentrations of
pollutant following
treatment
Individual Septic System
Individual Septic Systems
Drain field
Individual Septic Systems
Living Bacterial Culture Inside Tank
Jonesboro
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Amid the 4,000 acres of wetlands in Jonesboro, Ga., are graded pools used
to filter water. The water is pumped in from a treatment plant and flows into
these ponds, which are filled with all kinds of thick vegetation, including
cattails, native grasses and water lilies.
•
There have been complaints from neighbors not about the odor but about
something else entirely: frogs.
•
From the wetlands, the water runs over a gate and into a reservoir, one of
four that were built to store billions of gallons of water. Residents use about
26 million gallons of water a day and through this system, the county
reclaims 10 million gallons of that.
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The price tag is also an advantage — it can be as little as half the cost of
building a regular wastewater treatment plant.
This idea probably won't work for bigger cities like Atlanta because it
requires a lot of land. Still, it's attractive for smaller communities.
Drinking Water