Wastewater Treatment Plant Fieldtrip

1
Wastewater Treatment Plant Fieldtrip

• Mrs. DeWalls 2005 Classes

2
Primary Sewage Treatment

• When sewage reaches the treatment plant it can
  undergo up to 3 levels of purification.
• Mr. Luma first shows us the color and condition
  of the water when it arrives

3
The Bar Screens

• Raw sewage first goes through a mechanical
  process that uses screens to filter out debris
  such as sticks, stones and rags.
• The bar screen is in a large room and continually
  in motion.

4
Grit Chamber and Settling Tanks

• The water is slowed down under these covers.
• The solids will settled out.
• The covers are for odor control, so we could not
  see the process

5
More Odor Control

• The treatment plant has many neighborhoods very
  close.
• These are odor control tubes, that keep the
  neighbors happy.
• They also burn off the byproduct methane along
  with using it as an energy source for the
  digesters.

6
The Sludge Digesters

• The activated sludge process involved pumping the
  sewage into large tanks and mixing it for several
  hours with bacteria-rich sludge and
  microorganisms.

7
Primary Treatment

• Primary treatment removes about 60 of the
  suspended solids and 30 of the oxygen-demanding
  organic wastes from sewage

8
Improved Primary Treatment

• Chemically treated polymers are added to remove
  suspended solids more thoroughly.
• The sight and smell are quite memorable for the
  students.

9
Secondary Treatment (biological )

• No swimming here!
• These aeration tanks have so much air pumped into
  them, to breakdown the remaining solid waste,
  that you would not float if you fell in!

10
A Clean Finish

• The combined primary and secondary treatment
  process removes about
• 97 by weight of the suspended solids
• 95-97 of the oxygen demanding organic waste
• 70 of most toxic metals
• 70 of phosphorus
• 50 of nitrogen

11
Clean Water Act

• With the Clean Water Act most U.S. cities have
  combined primary and secondary sewage treatment
  plants.
• Advanced treatment (the 3 step) is a series of
  specialized chemical and physical processes that
  remove specific pollutants.
• The James River plant targets phosphate removal
  with ferric chloride.

12
This fieldtrip was sponsored by HR WET as a part
of the HR3 Mini-Grant Program.Find out more
about how you can apply for a mini-grant on this
website.