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Construction continues to progress well. Nearly all of the bricks are laid for the tank walls and they have begun to build the foundations for the chemical tables. Materials The policarbonate panels for the floc and sed modules arrived Thursday 12.11. Other miscelaneaous materials should arrive next week to be ready for when the Cornell group comes down later this week so that all is ready to begin assembling the modules when the students are here in January.

After discussing with Monroe and the design team, we decided on the size of the floc lamella and arrived at a method for installing the plaques that will form the entrance manifolds in the bottom of the sed tanks.

Tamara

As of Thursday 12.11, pproximately 150 gpm were arriving to the plant from La Chorrera. Earlier in the week the Junta had fixed a broken pipe in the conduction line. With the Manzanal and La Chorrera, so much flowrate is arriving that the new pressure-break box that the Junta built is overflowing because there is not enough capacity in the pipe from the box to the plant to carry all of the water. However, 180 gpm are arriving to the plant, which is nearly full capacity and should be plenty to supply the community. The Junta will need shut off the Manzanal or devise a way to reduce flow from La Chorrera to prevent the pressure-break box from overflowing, since this overflow will cause erosion.

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With the new high flow, the plant was functioning Thrusday, but not optimally. Thursday the incoming turbidity was 10 NTU and the outgoing 5 or 6 NTU. We thought the high effluent turbidity was due to dirty sed tanks and some clogged sed tank entrance tubes. Flocs were forming, but relatively small ones. The plant seems to form better flocs when the flowrate is well below the design flow. However, when the flow is too low (40 gpm) Carlos is not able to form flocs, so there is a lower limit.

Friday 12.12 Antonio went to Tamara to help Carlos and Karin clean the plant. The emptied and cleaned all floc and sed tanks. When reinstalling the floc modules, they glued the spacers together so that they will not fall appart when removed. They also installed a 2" bronze globe valve on the exit tank where the operator fills the bucket for filling the chemical barrels. The handle on the old 2" PVC globe valve had become brittle and broken, likely due to exposure to sun or chlorine. In future plants we need to remember that these large PVC globe valves are not sufficiently durable.

Marcala

Tamar travelled to Marcala Monday 12.08 and Tuesday 12.09 to check up on plant performance there. _________________________________________________. (ball valve, plant cleaing, performance afterward)

Flow Control Modules

As suggested by Scott, Antonio rotated the float 180 degrees in the Ojojona and Tamara flow control modules. We will monitor these modules over the next weeks to see whether they clog less than they did previously.

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