Emails between Leslie and Fred regarding general questions about the Marcala Plant (specifically Tank A)-
Leslie's Questions
I've attached a drawing that Tiffany made of tank A.
- Are the dimensions correct?
- Is the slope of the floor correct?
- Is there a drain at the end of the tank?
- Is the placement of the ceiling beam correct? And as in the other tanks, no baffles should be placed under this beam, right?
- Where is the first baffle in flocculator B? Is it an up or a down baffle?
- Can you give me more information about your idea for the surge chamber at the beginning of the flocculator?
- The plan is to use flexible (and moveable) baffles in this tank, correct? What will they be made of?
- Is there anything else you think I should know?
Fred's Response
1) Dimensions of Flocc A-- Dimensions are basically correct except that we will have a bit more width as we do not have to creat slots for ferro cement baffles. I think the width will be arounf 98 cm. Also the depth of the water will be 145 at beginning and 155 at end . I had originally assumed 5 cm of freeboard below the beam which has been dropped.
2) The floor slope is correct (10 cm)
3) The drain for tank A is out the side at the beginning of tank B. Thus there is a drain out the side at both the beginning and end of tank B
4) The center beam will not be a problem for tank A as the flexible baffles will be able to be placed under the beam. Actually I figured out a means of placing the ferro cement bafflels under the beams in the other tanks also and they did not end up being the problem I originally thought.Sorry for the extra work resulting from this.
5)The first baffle in B is an underflow baffle and the spacing will be approximately 32 to 35 cm. The spacing is uncertain as I am not sure how heavy a coat of plaster will be placed on end wall. I ask for a thin coat but they really like to use a heavy layer of around 3cm. The width of the opening in the wall between A and B is to be 25cm though this may also decrease to 22 cm if they use a heavy coat of plaster.
6)The idea for the surge chamber at beginning of A is to give a strong wall to take any strong surge from the water entering the tank. My ideaa is to build a 4 inch block wall 9 inches from the beginning wall in A and to install a proper number of two inch openings in the lower portion of this wall to allow for the water tobe slowed down on its entry into the frst baffle chamber. Thus the first flexible baffle would be and overflow baffle. Thsi surge chamber woulf require 13 inches of space in A and you will need to provide me with the proper number of 2 inch openings and the best spacing. This surge wall would also incorporate a 2 by 2 inch hole at bottom to facilitate cleaning. If the surge wall consumers too much space it can be eliminated but I would prefer to have it to protect the flexible baffles from any possibility of damage by operator error in turning the water into the tank at full flow.
7) The flexible baffles will be constructed from polycarbonite roofing panels and fabricated into components of 5 to 7 baffles using pvc connectors to give them strength. While these baffles will be constructed to the width of the tank it is my understanding that there will be sufficient bypassing of water around the bottom and sides to allow for equlization of the filling and empting of tank A and that no provision needs to be made for flow at the bottom of the over baffles as was done with tanks B, C and D and that the baffles can be raised or removed to allow for the cleaning.