Pilot Plant

Sedimentation Tank Maintenance

Tank Drainage Manifold

A tank drain system was designed to drain in 30 minutes (Q ~drain~ = 20 L/min. The design is similar to the effluent launder except this manifold is located at the bottom of the tank.

By the same method as was used for the tank effluent manifold the manifold diameter was determined to be 1.905cm (0.75") and the orifice diameter is 0.3572cm (9/64").
* The available head for the sludge ports is the total water depth (84.455cm or 33.25") minus the head loss in the manifold and minus the velocity head at the end of the manifold.
* Kminor was assumed to be 0 in the manifold and 1.0 for the pipe entrances and exits.
* The constant for the determining orifice diameter was found to be 0.63
*Qratio = 0.90
* 15 orifices were assumed to provide a similar layout to the effluent manifold.
The hole size in the drain manifold was increased to 1/4" to allow for faster tank drainage.

Troubleshooting

This section includes some minor issues the team has come across.

Note that there is always at least one operator at the treatment plant during regular hours. The operators are generally willing (and usually able) to help solve problems, so don't hesitate to ask if they're free to help out.

Starting the pilot plant

• Check with the operators to see if it is permissible to run the pilot plant.
• Check that all the cords, including the power strips, are plugged in.
• Check with the plant operators to make sure they haven't turned off parts of the Filtration Plant for maintenance. The operators are also very helpful in figuring out what might be unplugged or turned off.

Starting the alum pump

If the alum pump has been switched on, but no alum is flowing (i.e., the corresponding box in the process controller reads "0" mg/L):

• Go to configuration in the process controller.
• In the top left corner there are methods, files, etc. buttons, and an icon that looks like an open folder. Click on the folder.
• Open the Fall 2008 folder (or a newer folder).
• Open Sept 9 2008 (or any configuration that may have been saved later).

If there is a leak

Determine the source of the leak!

If it is a pipe:

• If the pipe connects the flocculator to the sed tank, plug the inlets with the screw caps already created. The benefit to this over just turning off the plant is that the flocculator can continue to run, since the water can leave through the weir in the flocculator which usually just handles excess flow.
• Dry off the pipe to the best of your ability with a towel.
• When the pipe is completely dry - this is pretty essential, since the caulk will not set properly if it is wet. Wait at least a few hours or a day to ensure that the surface is dry, then caulk the pipe, paying special attention to the bottom of the seal. The cure time is usually 24-48 hours, so leave the pipes plugged for this duration of time.
• If water continues to leak, make sure that the leak is not coming from another location, and repeat the above steps if necessary.

If it is the plant leveling tank:

• Try to determine which component is causing the issue.
• Plug the pipes connecting the flocculator and the sedimentation tanks so that water stops flowing into the plant leveling tank.
• Ask Tom or one of the other nice plant operators if they could show you how to tighten the flanges of the connecting pieces.

If the flocs look funny

If the flocs are white in color and float either:

• The alum dose is too high for the turbidity of the incoming water.
  --> Go into process controller and decrease the alum dose. 20mg/L is a reasonable level; however the turbidity of water changes a lot due to environmental influences.
• The pump that drives the water through the plant is not operating properly either due to objects caught in the screen (leaves?) or electrical issues.
  --> Check to see what the actual flow rate into the plant is, by looking at the digital monitor located next to the wall leading to Cornell University's Flocculator. Manually enter this flow rate into Process Controller, until the pump problem is fixed. Then remember to change it back!

If the effluent water is turbid and does not contain large flocs:

• The alum does is not high enough! Increase the alum dose in Process Controller to account for the increased turbidity. This is likely to occur if there has been a lot of rain.