Honduras Interns Progress Report

Date: Wednesday, Sept. 5

Location: Ojojona

Work Completed This Week

Improvements to Plant

• Installed an overflow outlet from the entrance chamber to control the plant flowrate. We used the outlet that goes to the horizontal flocculator for the overflow. We can now limit the level in the entrance chamber to anywhere between 15 and 20 cm. This way, if it rains at night when an operator is not present, the plant flowrate will not increase drastically. We would like to be able to limit the entrance level to below 15 cm, but because of where the pipe leaves the grit chamber this isn't possible. Another problem is that the overflow currently dumps water near the plant. Next week we will try to install an overflow pipe that fits in the cleaning port at the bottom of the tank. We will also work on a plan to carry overflow away from the plant in buried PVC pipe.
• Changed the outlet orifices in the entrance chamber. Before there were four 1 ½ inch orifices in the same vertical 4 in pipe. Now we have two vertical 4 in pipes with two 1 ½ inch orifices each. This way the jets should interfere with each other less. In each tube the orifices are at the same level 90 degrees away from eachother.
• Raised the sulfate barrels 6 inches so that there will be more head driving solution into the float valve bottles when the barrels are almost empty. We don't think it is necessary to raise the chlorine barrels, because it would be simpler just to lower the chlorine float valve.
• Connected the drain spouts from all 6 chemical barrels so that they all drain to the same ½ in PVC pipe that will be routed away from the plant.
  Installed a valve and pipe at the plant outlet that can be used to send water from the plant to a drain pipe instead of the distribution tank. Now when we have problems and are producing dirty water, we don't have to contaminate the storage tank with it. One problem is that the pipe to waste leaves the outlet pipe at a level lower than the normal sed tank water level. When we send water to waste, the sed tank water level drops about 4 inches. This is annoying, but doesn't seem to cause problems so far.
• Antonio hired someone begin making a pit latrine near the plant.

Progress in Problem Solving

• Sulfate sediment and doser clogging problems:
  One day we mixed the sulfate extremely thoroughly to see if this would solve the sediment problem. We added the sulfate slowly while stirring with a pipe. Then we stirred vigorously, switching directions ocasionally, for about 5 min more until all of the granules had dissolved. Next, we mixed the barrel vertically for about 5 minutes with a 5 gallon bucket, pulling solution up from the bottom and dumping it in the top. Even with this much mixing, when we stirred the barrel 20 hours later, a cloud of white particles emerged from the bottom. Is it possible that the solution was still not completely mixed?
• We still need to try making a solution of double concentration to see if that solves the sediment problem.

Flocculator baffles:

• Visited two hardware stores in Tegucigalpa. Could not find corrugated PVC panels. Rooftec Polycarbonate panels made by Amanco are 1049 L ($55.50) for 12' x 42". E-mailed Amanco to see if they can give advice on whether the panels will hold up to water.

Capacitation of plant operators

• We are still waiting to meet with Martin and the JUNTA to discuss assigning one fontanero to the plant and a salary incentive for that person.
• For September, Mario is in charge of operating the plant. He has been more available than Juan was last month and seems to be more committed to learning how to operate the plant. We have been teaching him how to use the dose tables and keep a written record of what he does at the plant. Even though the tables seem pretty streamlined, it will be awhile before he's comfortable filling out the monitoring table and looking up the doses. The more we can do to make things simpler the better.

Plans for the Future

• Will present at Peace Corps convention in Siguatepeque on the afternoon of Sept. 12.
• Sept. 14 Meeting scheduled with Moroceli water board and a few people from Zanmorano University at APP office. Will discuss socialization of the project. We also hope to get more definite population figures.
• Sept. 15 hope to go to Moroceli to look at the site and distribution system again.

Questions for Cornell Team

• Is an automatic alum doser still something we're thinking about? I remember a project to develop one that would raise the dose based on turbidity. This would be really nice to have. The way it is now, an operator will have to go up to the plant in the middle of the night if it rains.
• Monroe's plan for the Moroceli design was to have a floc tank divided into two 21-inch wide sections and have the flow go through them in series. When we run the Mathcad design file for 800 L/min, an estimate of what we need for Moroceli, it calls for baffle spacing of 27 cm in the last section. That's quite a bit wider than here in Ojojona. What kind of problems could this cause?
• This would mean a gap of 1.5 * 27 cm = 41 cm above the bottom baffles and below the top baffles. We're wondering if having that big of a gap could be a problem. It means 41 cm of the baffle will be unsupported. Is that too much?
• Will our current system for connecting the baffles work well when they are that far apart? Will the modules be rigid enough if the baffle spacers are 27 cm long?

Plant Improvement Ideas

• Chemical barrels should be mounted more firmly to the platform. If wind comes and they are empty, they could blow off.
• Any outlet ports installed in the bottom of tanks should have flares so that a standard pipe can be inserted into the port if desired. We're having problems with trying to install and overflow pipe in the grit chamber cleaning port, because there is no flare there.